Risk Management Series
Design Guide 
for Improving School Safety in Earthquakes, 
Floods, and High Winds

January 2004




FOREWORD AND ACKNOWLEDGMENT



BACKGROUND

Our society places great importance on the education system and its schools, 
and has a tremendous investment in current and future schools. Currently, 
approximately 53 million kindergarten to grade 12 (K-12) students attend over 92,000 
public schools and it is estimated that the public student population will have reached 
54.3 million by 20041; to this figure must be added the substantial population of private 
school students. The sizes of these school facilities range from one-room rural 
schoolhouses to citywide and mega schools that house 5,000 or more students. The 
school is both a place of learning and an important community resource and center.
This publication is concerned with the protection of schools and their occupants 
against natural hazards. These hazards must be recognized as part of the natural 
environment and as extensions of phenomena that designers have always considered. 
Natural hazards can be reduced to extreme phenomena related to the four elements 
(i.e., earth, water, wind, and fire). Earthquakes are highly accelerated and exaggerated 
forms of motion that are always occurring in the earth and floods occur when rivers 
overflow or the wind stirs up the ocean along coastal waters. High winds and tornadoes 
are an extreme form of the beneficial breezes that freshen the air. Fire has been a 
threat to buildings for centuries and was one of the first threats to be the subject of 
regulation. Because of its familiarity and the extensive provisions for fire protection in 
building codes, it is not a subject for detailed consideration in this publication. How-
ever, some considerations relating to the fire protection of schools are presented in 
Chapter 3, Section 3.4. 
Architects and engineers deal with these natural elements all the time; building codes 
always have provisions for protection against fire and wind and the local building code 
(if adopted by the community) will also dictate whether earthquakes or floods must be 
considered as design parameters. However, the major decisions in reducing flood 
damage may be in site selection and layout, not in building design. 
This manual introduces two core concepts: multihazard design and performance-
based design. Neither is revolutionary, but represents an evolution in design thinking 
that is in tune with the increasing complexity of today's buildings and also takes advan-
tage of developments and innovations in building technology:

The concept of multihazard design is that designers need to understand the 
fundamental characteristics of hazards and how they interact, so that design for 
protection becomes integrated with all the other design demands.
_ Performance-based design suggests that, rather than relying on the building code 
for protection against hazards, a more systematic investigation is conducted to 
ensure that the specific concerns of building owners and occupants are addressed. 
Building codes focus on providing life safety and property protection is secondary: 
performance-based design provides additional levels of protection that cover 
property damage and functional interruption within a financially feasible context. 
This publication stresses that identification of hazards and their frequency and careful 
consideration of design against hazards must be integrated with all other design issues, 
and be present from the inception of the site selection and building design process. 
Although the basic issues to be considered in planning a school construction program 
are more or less common to all school districts, the processes used differ greatly, 
because each school district has its own approach. Districts vary in size, from a rural 
district responsible for only a few elementary schools, to a city district or statewide 
system overseeing a complex program of all school types and sizes, including new 
design and construction, renovations, and additions. A district may have had a long-
term program of school construction and be familiar with programming, financing, 
hiring designers, bidding procedures, contract administration, and commissioning a 
new building, but another district may not have constructed a new school for decades, 
and have no staff members familiar with the process.


SCOPE 

This publication is intended to provide design guidance for the protection of school 
buildings and their occupants against natural hazards, and concentrates on grade 
schools (K-12); the focus is on the design of new schools, but the repair, renovation, 
and extension of existing schools is also addressed. It is intended as the first of a series 
of publications in which hospitals, higher education buildings, multifamily dwellings, 
commercial buildings, and light industrial facilities will be addressed. 
The focus of this publication is on the safety of school buildings and their occupants, 
and the economic losses and social disruption caused by building damage and 
destruction. The volume covers three main natural hazards that have the potential to 
result in unacceptable risk and loss: earthquakes, floods, and high winds. A companion 
volume, Primer to Design Safe School Projects in Case of Terrorist Attacks (FEMA 428), covers 
the manmade hazards of physical, chemical, biological, and radiological attacks.
The intended audience for this manual includes design professionals and school 
officials involved in the technical and financial decisions of school construction, 
repair, and renovations. A short brochure based on this manual will also be available 
for school district and school board decision-makers.


ORGANIZATION AND CONTENT OF THE MANUAL

Chapters 1-3 present issues and background information that are common to all 
hazards. Chapters 4-6 cover the development of specific risk management measures 
for each of the three main natural hazards.
Chapter 1 opens with a brief outline of the past, present, and future of school design. 

Past school design is important because many of these older, and even historic, 
schools are still in use and their occupants must be protected. 
Chapter 2 introduces the concepts of performance-based design in order to obtain 
required performance from a new or retrofitted facility. Chapter 3 introduces the 
concept of multihazard design and presents a general description and comparison of 
the hazards, including charts that show where design against each hazard interacts 
with design for other hazards. This latter section includes fire and building security in 
its considerations.

Chapters 4, 5, and 6 outline the steps necessary in the creation of design to address 
risk management concerns for protection against earthquakes, floods, and high winds, 
respectively. Information is presented on the nature of each hazard and its effect on 
vulnerability and consequences of building exposure. Procedures for risk assessment 
are outlined, followed by descriptions of current methods of reducing the effects of 
each hazard. These vary, depending on the hazard under consideration. A guide to 
the determination of acceptable risk and realistic performance objectives is followed 
by a discussion to establish the effectiveness of current codes to achieve acceptable 
performance.

Appendix A contains a list of acronyms that appear in this manual.
The information presented in this publication provides a comprehensive survey of the 
methods and processes necessary to create a safe school, but is necessarily limited. It is 
not expected that the reader will be able to use the information directly to develop 
plans and specifications. The information is intended to help designers and facility 
decision-makers, who may be unfamiliar with the concepts involved, to understand 
fundamental approaches to risk mitigation planning and design. By so doing, they can 
move on to the implementation phase of detailed planning, involving consultants, 
procurement personnel, and project administration, from a firm basis of 
understanding. 



ACKNOWLEDGMENTS

Principal Authors:

Christopher Arnold, Building Systems Development, Inc.
Jack Lyons, School Facilities Consultant
James Munger, James G. Munger and Associates
Rebecca C. Quinn, Consultant
Thomas L. Smith, TLSmith Consulting

Contributors:

Milagros Kennett, FEMA, Project Officer, Risk Management Series Publications
Eric Letvin, Greenhorne & O'Mara, Inc., Consultant Project Manager
John Plisich, FEMA
Mike Robinson, FEMA
Joe Agron, American School and University
Connie Deshpande, Department of Education
Randy Haslam, Jordan, Utah, School District
Danny Kilcollins, Florida Department of Community Affairs
Fred Krimgold, World Institute for Disaster Risk Management
Tom Kube, Council of Educational Facility Planners International
Bill Modzeleski, Department of Education
Jack Paddon, Williams and Paddon Architects and Planners
Bebe Pinter, Harris County Department of Education
John Sullivan, Portland Cement Association
Jon Traw, Traw Associates 
French Wetmore, French and Associates
Deb Daly, Greenhorne & O'Mara, Inc.
Wanda Rizer, Greenhorne & O'Mara, Inc.
Julie Liptak, Greenhorne & O'Mara, Inc.
Bob Pendley, Greenhorne & O'Mara, Inc.

This primer will be revised periodically and EP&R welcomes comments and feedback 
to improve future editions. Please send comments and feedback via e-mail to 
riskmanagementseriespubs@dhs.gov
 



1   U.S. Department of Education, National Center for Education Statistics, Baby Boom Echo Report, 2000




TABLE OF CONTENTS


FOREWORD AND ACKNOWLEDGMENTS i

Background i

Scope iii

Organization and Content of the Manual iii

Acknowledgments iv

CHAPTER 1- AN OVERVIEW OF THE SCHOOL DESIGN AND CONSTRUCTION 
PROCESS
1.1 Introduction 1-1
1.2 School Construction: The National Picture 1-1
1.3 Past School Design 1-2
1.4 Present School Design 1-9
1.5 Future School Design 1-10
1.6 The Design and Construction Process 1-12
1.7 School Design and Construction 1-16
1.7.1 Structure 1-16  
1.7.2 Nonstructural Systems and Components 1-17


CHAPTER 2 - DESIGNING FOR PERFORMANCE 2-1
2.1 Introduction 2-1
2.2 Definitions of Performance-based Design 2 -1
2.3 The Prescriptive Approach to Codes 2-2
2.4 The Performance-based Approach 2-3
2.5 Hazard, Risk, and Probability 2-6
2.6 Acceptable Risk and Performance Levels 2-9
2.7 Correlation Between Performance Groups and Tolerated Levels of Damage 2-10
2.8 Roles of Designers, Code Officials, and  the School District 2-13
2.9  Changes to a Building Designed for  Performance 2-14
2.10 Current Performance-based Codes 2-15
2.11 The O&M Manual and the Occupants'  Handbook 2-17
2.12 Performance-based Design for  Natural Hazards 2-19
2.12.1 Performance-based Seismic Design 2-23
2.12.2 Performance-based Flood Design 2-30
2.12.3 Performance-based High Wind  and Tornado Design 2-32


CHAPTER 3 - MULTIHAZARD DESIGN 3-1
3.1  Introduction 3-1
3.2   The Hazards Compared 3-1
3.2.1  Location: Where are They? 3-2
3.2.2  Warning: How Much Time  is There? 3-6
3.2.3  Frequency: How Likely  are They to Occur? 3-6
3.2.4  Risk: How Dangerous are They? 3-8
3.2.5  Cost: How Much Damage  Will They Cause? 3-10
3.3 Comparative Losses 3-11
3.4   Fire and Life Safety 3-16
3.5 Hazard Protection Methods Comparisons: Reinforcements and Conflicts 3-19


CHAPTER 4 -MAKING SCHOOLS SAFE AGAINST EARTHQUAKES 4-1
4.1 Introduction 4-1
4.2 The Nature and Probability of Earthquakes  4-1
4.2.1 Earthquakes and Other Geologic Hazards 4-1
4.2.2 Earthquakes: A National Problem 4-3
4.2.3 Determination of Local Earthquake  Hazards 4-11
4.3 Vulnerability: What Earthquakes Can Do to Schools 4-15
4.3.1 Vulnerability of Schools  4-15
4.3.2   Earthquake Damage to Schools 4-20
4.3.3 Significant School Damage in Recent  U.S. Earthquakes 4-27
4.3.4 Consequences: Casualties, Financial  Loss, and Operational Disruption 4-32
4.4 Scope, Effectiveness, and Limitations of Codes 4-33
4.4.1 The Background of Seismic Codes 4-34
4.4.2 Seismic Codes and Schools 4-36
4.4.3 The Effectiveness of Seismic Codes 4-37
4.5 Evaluating Existing Schools for Seismic  Risk and Specific Risk Reduction 
Methods 4-38
4.5.1 Rapid Visual Screening 4-38
4.5.2 Systems Checklist for School Seismic  Safety Evaluation 4-41
4.5.3 The NEHRP Handbook for  the Seismic Evaluation of Existing Buildings 
(FEMA 178/310) 4-47
4.6 Earthquake Risk Reduction Methods 4-48
4.6.1 Risk Reduction for New Schools 4-49
4.6.2 Risk Reduction for Existing Schools 4-61
4.7 The School as a Post-earthquake Shelter 4-69
4.8 References and Sources of Additional Information 4-71
4.9 Glossary of Earthquake Terms 4-72


CHAPTER 5 - MAKING SCHOOLS SAFE AGAINST FLOODS 5-1
5.1 Introduction 5-1
5.2 Nature and Probability of Floods 5-1
5.2.1 Characteristics of Flooding 5-3
5.2.2 Probability of Occurrence5 -7
5.2.3 Hazard Identification and Flood Data 5-8
5.2.4 Design Flood Elevation 5-13
5.3 Scope, Effectiveness, and Limitations  of Building Codes and Floodplain  
Management Requirements 5-14
5.3.1 Overview of the NFIP 5-14
5.3.2 Summary of the NFIP Minimum  Requirements 5-16
5.3.3 Model Building Codes and Standards 5-18
5.4 Risk Reduction:  Avoiding Flood Hazards 5-19
5.4.1 Benefits/Costs: Determining  Acceptable Risk 5-20
5.4.2 Identifying Flood Hazards at School Sites 5-22
5.5 Risk Reduction:  Flood-resistant New Schools 5-26
5.5.1 Site Modifications 5-26
5.5.2 Elevation Considerations 5-28
5.5.3 Floodproofing Considerations 5-31
5.5.4 Accessory Structures 5-33
5.5.5 Utility Installations 5-33
5.5.6 Potable Water and Wastewater Systems 5-34
5.5.7 Storage Tank Installations 5-34
5.5.8 Access Roads 5-35
5.6 Vulnerability:  What Floods Can Do to  Existing Schools 5-36
5.6.1 Site Damage 5-36
5.6.2 Structural Damage 5-37
5.6.3 Saturation Damage 5-40
5.6.4 Utility System Damage 5-42
5.6.5 Contents Damage 5-45
5.7 Risk Reduction:  Protecting Existing Schools 5-46
5.7.1 Site Modifications 5-48
5.7.2 Additions 5-51
5.7.3 Repairs, Renovations, and Upgrades 5-52
5.7.4 Retrofit Dry Floodproofing 5-53
5.7.5 Utility Installations 5-53
5.7.6 Potable Water and Wastewater Systems 5-56
5.7.7 Other Damage Reduction Measures 5-57
5.7.8 Emergency Measures 5-57
5.8 The School as an Emergency Shelter 5-59
5.9 References and Sources of  Additional Information 5-60
5.10 Glossary of Flood Protection Terms 5-63



CHAPTER 6 - MAKING SCHOOLS SAFE AGAINST WINDS 6-1
6.1 Introduction 6-1
6.2 The Nature and Probability of High Winds 6-2
6.2.1 Wind/Building Interactions 6-6
6.2.2 Probability of Occurrence 6-15
6.3 Vulnerability: What Wind Can Do to Schools  6-17
6.4 Scope, Effectiveness, and Limitations  of Building Codes 6-23
6.4.1 Scope 6-24
6.4.2 Effectiveness 6-25
6.4.3 Limitations 6-25
6.5 Priorities, Costs, and Benefits: New Schools6-27
6.5.1 Priorities 6-27
6.5.2 Cost, Budgeting, and Benefits 6-28
6.6    Priorities, Costs, and Benefits: Existing  Schools 6-30
6.6.1 Priorities 6-31
6.6.2 Cost, Budgeting, and Benefits 6-32
6.7 Evaluating Schools for Risk from High Winds 6-33
6.7.1 Tornadoes  6-35
6.7.2 Portable Classrooms 6-36
6.8 Risk Reduction Design Methods  6-36
6.8.1 Siting 6-36
6.8.2 School Design 6-37
6.8.3 Peer Review 6-42
6.8.4 Construction Contract Administration 6-42
6.8.5 Post-occupancy Inspections, PeriodicMaintenance, Repair, and 
Replacement 6-43
6.9 Structural Systems 6-44
6.10 Exterior Doors 6-48
6.10.1 Loads and Resistance 6-48
6.10.2 Durability 6-48
6.10.3 Exit Door Hardware 6-49
6.10.4 Water Infiltration 6-49
6.10.5 Weatherstripping 6-50
6.11 Non-load Bearing Walls, Wall Coverings, Soffits,  and Underside of Elevated 
Floors 6-53
6.11.1 Loads and Resistance 6-53
6.11.2 Durability 6-55
6.11.3 Wall Coverings 6-55
6.11.4 Underside of Elevated Floors 6-59
6.12 Roof Systems 6-59
6.13 Windows and Skylights 6-68
6.13.1 Loads and Resistance 6-68
6.13.2 Durability 6-69
6.13.3 Water Infiltration 6-69
6.14 Exterior-mounted Mechanical, Electrical,  and Communications Equipment 6-71
6.14.1 Loads and Attachment 6-72
6.14.2 Equipment Strength 6-74
6.14.3 Durability  6-76
6.15 Schools Located in Hurricane-prone Regions 6-79
6.15.1 Design Loads  6-80
6.15.2 Structural Systems  6-80
6.15.3 Exterior Doors6-80
6.15.4 Non-load Bearing Walls, Wall Coverings,  and Soffits  6-81
6.15.5 Roof Systems 6-81
6.15.6 Windows and Skylights 6-84
6.15.7 Emergency Power 6-86
6.15.8 Construction Contract Administration 6-86
6.15.9 Periodic Inspections, Maintenance,  and Repair 6-86
6.16 Design for Tornado Shelters 6-88
6.17 Remedial Work on Existing Schools 6-91
6.18 References and Sources of Additional  Information 6-94
6.19 Glossary of Wind Terms6-96


APPENDIX A - ACRONYMS















AN OVERVIEW OF THE SCHOOL DESIGN AND CONSTRUCTION PROCESS     1


1.1 INTRODUCTION


This chapter presents an overview of the school building, to provide a context 
for the chapters that follow. Every building is unique and there is great variety in 
school design; however, the purpose of schools, their occupancy, their economic 
basis, and their role in the social scene mean that there are certain common features 
of schools that distinguish them from other building types.
A summary of the national public school inventory is presented (i.e., how many 
students it houses and how many schools it contains) and projections of future needs 
are also outlined. School design of the past is discussed, because many older schools 
are still in use and must be renovated periodically to meet today's needs. The present 
state of school design is also discussed and some trends and ideas that might 
influence future schools are identified. 


1.2   SCHOOL CONSTRUCTION: THE NATIONAL PICTURE 

The estimated value of the national public school inventory is well over $361.6 
billion.1 Of the almost 15,000 local education agencies found throughout the United 
States (U.S.), 41.9 percent are in small towns and rural areas, and enroll 30.4 percent 
of the students; 25.9 percent are in large towns and cities, and enroll 30.7 percent of 
the students; and 32.2 percent of the education agencies are in suburban areas, and 
enroll 39 percent of the students.2

Over half of our school facilities are at least 40 years old3 and, even with minor 
renovations, have passed their prime in terms of adaptability to modern teaching 
methods and tools (e.g., computers, in-class electronic information displays, and 
group learning activities). Almost all states require new construction once 
replacement costs reach a certain level (usually 60 percent4). The most recent studies 
(completed at the close of the last decade) show a range of $100 to over $300 billion 
would be needed to bring our nation's schools into good teaching condition.
In 2001, the decade-long growth in kindergarten to grade 12 (K-12) school 
construction reached a peak. A propensity for deferred maintenance and the poor 
construction quality of many post-World War II schools have resulted in a huge 
renovation demand, and population increases mean that additional space will also be 
necessary.

If new construction, remodeled space, and additions are included, 2001 witnessed 
over $29.5 billion in school construction throughout the United States, with primary 
school projects slightly edging out high school projects in total number, but not in 
construction dollars. The overall school construction intensity dropped slightly to 
$28.2 billion, but is forecast to rise to $29.15 billion by mid-decade. From 2001 
through 2005, it is estimated that almost a billion square feet of either new, renovated, 
or additional square feet will be added to the national school inventory.



1.3   PAST SCHOOL DESIGN

Schools are typically in use for long periods of time; as a result, teaching continues to 
be conducted in facilities that were designed and constructed at the beginning of the 
20th century. Early 20th century school design was based on late 19th century models 
and was relatively static until after World War II. Schools ranged from one-room rural 
school houses to major symbolic civic structures in large cities. Other inner city 
schools were more modest, inserted into small sites on busy streets and constrained 
by budget limits (see Figures 1-1, 1-2, and 1-3).
The typical city school was one to three stories in height and consisted of rows of 
classrooms on either side of a wide, noisy corridor lined with metal lockers; asphalt 
play courts; and, sometimes, rooftop recreational areas. The larger schools sometimes 
had a library, special rooms for art, science, and shop, and an auditorium.
The surge to meet the school construction demands of the post war baby-boom was 
primarily a suburban development. Much larger sites were available, schools were one 
or two stories in height, auditoriums became multiuse buildings, and large parking 
lots appeared. However, many rural schools were located far away from towns and 
their resources, such as fire departments and other services. 
But the fundamental school program of classrooms along double-loaded corridors 
did not change very much. However, in warm climates, the one-story finger plan 
school, constructed of wood and a small quantity of steel, was both economical and 
more human, and the noisy tiled double-loaded corridor became a covered walk, 
open to the air, with the classrooms on one side and a grassed court on the other (see 
Figure 1-4). Compact versions of these plans appeared as schools became larger and 
sites smaller (see Figure 1-5). 
Inner-city high schools were usually large facilities, housing 2,000 to 3,000 students 
(basically small towns with complex social, economic, and class systems; see Figure 1-
6). In the 1960s and 1970s, some design experiments were tried, such as team 
teaching, which spawned large open classrooms with poor acoustics (see Figure 1-7). 

Some of the new large high schools were built as air-conditioned enclosures, with 
many windowless classrooms, in buildings similar to the shopping malls that 
replaced the main street retail centers (see Figure 1-7). At the same time, many 
schools were expanded by adding prefabricated classrooms to accommodate a surge 
in enrollment. Although the prefabricated classrooms were originally intended as 
temporary space, many are now used as permanent classrooms (see Figure 1-8). 
Schools built in the 1980s and 1990s assumed a wide variety of forms, often combining 
classrooms into clusters and focusing on providing an attractive learning 
environment (see Figure 1-9). However, demographic needs, shortage of affordable 
land, and limited funding has also resulted in instances of the adaptation of existing 
non-educational buildings into schools (see Figure 1-10).



1.4 PRESENT SCHOOL DESIGN

As the U.S. begins a new century, there are indications that a new era of social, 
economic, and educational concerns is evolving that will impact school design. New 
statements of design principles are beginning to emerge, although some of the 
following represent perennial concerns:

 The building should provide for health, safety, and security.

 The learning environment should enhance teaching and learning and 
accommodate the needs of all learners.

 The learning environment should serve as the center of the community.

 The learning environment should result from a planning/design process that 
involves all stakeholders.

 The learning environment should allow for flexibility and adaptability to changing 
needs.

 The learning environment should make effective use of all available resources.
These principles lead, in turn, to a number of current design principles, including:

 Design for protection against natural hazards
 Increased design attention to occupant security
 Careful lighting design and increased use of day lighting and comfort control
 Design for durability 
 Long life/loose fit approach: design for internal change and flexibility
 Design for sustainability, including energy efficiency and the use of "green" 
materials 

Some new schools already respond to these needs5 and, indeed, their originators, 
school districts, communities, and designers are among those defining the schools 
of the next decade. Some of the changes are the result of ideology and analysis; others 
are enforced by the effort to provide an improved learning environment and 
enhanced learning resources in an increasingly financially limited school 
construction economy. Some school districts will be hard pressed to provide a 
minimal learning environment with buildings of the utmost simplicity, while 
meeting the requirements for health, safety, and security.



1.5 FUTURE SCHOOL DESIGN

Schools will continue to vary widely in size; however, even in the suburbs, land has 
become scarce and expensive. New schools will be more compact and the sprawling 
one-story campus will become less common (see Figure 1-11). The desire for more 
supportive environments and the rejection of traditional school plans will result in 
more imaginative and often more complex layouts (see Figure 1-12). Moreover, the 
move to repopulate the inner cities will result in the construction of even more dense 
and compact schools. 

However, many educational researchers believe that students improve their learning 
skills in smaller schools. 
Although small schools may be economically unrealistic, methods of organization 
are being explored that provide some of the benefits of small size within a large 
physical complex. Some schools are organized into "learning academies" for each 
grade, with classrooms that can expand and contract, and other activity rooms of 
various sizes. 

Other researchers believe that the conventional library will disappear. The trend in 
many new schools is for the library to take the form of a multi-media center and 
material collections, including laptop computers, that are distributed from mobile 
units to "classroom clusters." 
Schools are increasingly seen as community resources that go beyond the 
educational functions. Adult education and community events now take place on 
evenings, weekends, and throughout the traditional vacation periods; therefore, the 
school day and week have been expanded. These uses are seen as ways of finding 
affordable methods of enhancing community service resources by ensuring that a 
facility's utilization is maximized.
Indications are that the school building will probably increase in importance to the 
community, as its roles expand beyond that of merely providing a K-12 education for 
students during a school year. At the same time, modern technology means that 
today's schools, already far more complex than the relatively simple buildings of a few 
decades ago, will tend to be more fragile and consequently more vulnerable to 
nature's and society's threats unless special attention is paid to their design and 
construction.

The natural hazards will remain: earthquakes and tornadoes will continue to be, for 
some locations, a source of worry and fear. Besides protecting their occupants, 
schools in earthquake-prone regions are often used as post-earthquake shelters. In 
California, this is particularly appropriate because the State's Field Act, enacted in 
1933, following the Long Beach earthquake, requires that public schools be designed 
by a licensed architect or engineer, their plans checked, and the construction on site 
inspected by staff of the Department of State of Architecture. Elsewhere, floods and 
high winds are a familiar threat that also must be addressed by knowledgeable design 
and good construction practice. Schools, or designated areas within them, located in 
hurricane- and tornado-prone areas are increasingly being constructed to provide 
shelter for the occupants.



1.6 THE DESIGN AND CONSTRUCTION PROCESS

Regardless of the size of a school construction program, certain steps are necessary 
and certain procedures must be followed. These will vary greatly in scope between the 
design of a small elementary school and the development of a multi-school program 
of new and remedial construction. Review and regulation procedures by outside 
agencies will also vary. Internal district decisions as to the design and construction 
process (e.g., conventional architect design and competitive construction bid, 
design/build or construction manager) will affect the scope and timing of some of 
the activities.
However, regardless of the size and scope of the project, the following steps should be 
taken; for a small project, they may entail relatively informal meetings among a few 
district staff, the school board, and others; for a large program, formal procedures 
must be established. These steps are summarized in a flow chart (see Figure 1-13) that 
follows this listing.
 Conduct an in-house assessment of the educational needs, with the assistance of a 
public education committee and consultants. Public committees continue 
throughout the programming and design process, acquiring specialist members 
as necessary at different stages for a large program.
 Determine the size and scope of the proposed program. (In a small district, an 
architect may be employed to assist the school district with this task, who may later 
become the design architect).

 Conduct an assessment of the site needs to determine the size and availability of 
sites (and lease/purchase as necessary).
 Develop educational specifications, both in-house and/or consultants.
 Conduct an assessment of financial needs. 
 Identify financial resources, including alternative sources of funding (e.g., state and 
federal programs, local taxes, bond issues).
 Ensure funding (e.g., pass bond issue).
 Appoint a district building program management staff (appointed officials or a 
committee). 
 Determine the design and construction process (i.e., conventional design and bid, 
design/build or construction management).
 Select and hire architects and other special design consultants or design/build 
team members; the timing of hiring will vary, depending on number of projects, 
whether programming is involved, and other variables.
 Develop building programs, including building size, room size, equipment, and 
environmental requirements; this may be done in-house and/or architects or 
independent program consultants may assist. 
 Appoint the district staff and public stakeholders committee for the design phase. 
 Develop designs (architects), together with cost estimates. Hold public meetings 
with architects and encourage public input into the design, together with district 
progress reviews.
 Design completion, district review of contract documents.
 Submit construction documents to the district and any permitting agencies for 
review and approval.
 Submit documents to building department and other required agencies.
 Select the contractor (bidding) or finalize design/build or construction 
management contracts.
 School construction.
 School district administration of construction contract.
 Observation by architect and inspection as required.
 School completed by contractor
 School inspected and accepted by architect.
 School inspected and accepted by school district.
 School commissioned and occupied. 

The sequence of the above steps may vary, depending on the complexity of the 
program; some steps may be implemented simultaneously.
Figure 1-13 shows a flow chart of this typical process. Also shown (in the five boxes to 
the right) are specific activities related to design for multihazards and how these fit 
into the general construction process.



1.7 SCHOOL DESIGN AND CONSTRUCTION 

1.7.1 Structure

The structure provides support for all the elements of a building and ensures that the 
building can sustain all the loads and forces that it will encounter during its life. 
Often concealed behind ceilings, exterior cladding, and decorative facing materials, 
the structure plays a critical role in providing a safe and secure school building. 
Because of the relatively small size of most school buildings and the simplicity of 
design of the traditional school, with numerous internal walls, structural design is 
relatively simple and a well designed and constructed school should not collapse 
unless struck by a severe tornado or terrorist.
Most suburban schools built in the last few decades are typically one or two stories in 
height, with light steel frames or mixed structures of steel and wood frames and also 
with some concrete or concrete masonry walls. Except in the western states, and the 
Atlantic and Gulf coasts, concrete masonry walls may have nominal or no steel 
reinforcing. Reinforced masonry perimeter and/or interior classroom separation 
walls sometimes are used as shear walls to provide lateral support. First floors are 
generally concrete slab-on-grade.

Many schools may have long-span gymnasiums or assembly spaces, using glued-
laminated wood beams, steel trusses, or precast reinforced concrete tees or double 
tees. In these long span structures, large diaphragm and wind uplift forces must be 
transmitted to the perimeter walls or frames and the design and construction of 
wall/roof connections are critical. 
Typical prefabricated teaching spaces consist of classroom-sized wood frame boxes, 
are air-conditioned where necessary, and generally have minimally adequate lighting 
and electrical services. They provide an economical way of solving a problem, but 
rows of prefabricated classroom boxes do not provide an appropriate long-term 
learning and social environment. Also, they are typically less resistant to natural 
hazards.

Inner city schools may be three or four stories in height and are often built on 
congested sites. Structurally, they are usually constructed of reinforced masonry, 
reinforced concrete, and/or steel frames, and sometimes are a mix of these types of 
systems.
Older structures (i.e., pre-World War II) often had unreinforced masonry walls with 
wood floors and roof structures. Another common type was a lightly reinforced 
concrete frame infilled with hollow tile or masonry for walls, together with a wood 
floor and roof structure. Small schools were often of wood frame construction 
throughout, and basements and crawl spaces were common in these structures. Older 
structures are particularly vulnerable to natural hazards. Unreinforced masonry 
structures have performed very poorly in earthquakes and high winds, as have older 
reinforced concrete frames with infill. Older wood frame structures are often 
deficient in their design and construction detailing and are frequently weakened by 
insect attack or dry rot. 


1.7.2 Nonstructural Systems and Components

Nonstructural components and systems comprise architectural components such as 
ceilings and partitions, mechanical, plumbing, and electrical items that provide 
utilities and services to the building and cladding and roofing that provide weather 
protection and insulation.

A wide variety of exterior cladding materials are used for schools. The most common 
materials include brick or concrete masonry, stucco on metal or wood stud frame 
walls, exterior insulation finish systems (EIFS), and various natural and synthetic 
sidings on wood frame structures. Metal or stucco faced insulated panels are also 
used. Metal and glass curtain walls are used infrequently, generally in an urban 
setting. 
Newer schools usually have suspended grid ceilings that support light acoustic panels 
and inset lighting fixtures. Pendant fixtures are also used, in the form of rows of 
linear fluorescent fixtures or single high intensity (HID) fixtures. The latter are often 
large in size when used in assembly spaces or gymnasiums. Incandescent fixtures may 
still be found in older school buildings, but are a source of high energy use and 
should be replaced.
Non-load bearing partitions are often of hollow tile or concrete masonry: however, 
especially in the western states, partitions are of gypsum board over wood or metal 
framing, although concrete masonry or tile may be used in restrooms or other service 
areas. 

School mechanical systems are relatively simple. Older schools and some new ones 
employ perimeter hot water heating together with natural ventilation or forced air. 
Very old schools may still employ steam heating, but most of these systems should 
have been replaced by hydronic systems. Newer schools, particularly when large, 
often employ forced air heating, ventilating, and cooling systems. Concern for energy 
conservation has resulted in the use of innovative systems, including a return to the 
use of natural ventilation and day lighting. 

Plumbing tends to be concentrated in restroom areas, although science, art spaces, 
and school kitchens require more complex plumbing services. Specialized plumbing 
will also be found in mechanical/boiler rooms, the water service and fire protection 
service entrances, and domestic water heaters.
Electrical services have become increasingly complex with the need for ready access 
to power and communications services. The trend in communications devices to 
become wireless may serve to slightly reduce the extent of hard wired commu-
nications. Fire alarm and security services, however, require increasingly extensive 
electrical and electronic services.
Fixed classroom desks and teachers units have been replaced by lighter mobile 
furniture. Libraries still require extensive shelving, although ready access to the 
internet may tend to reduce the use of hard-copy materials. 
Some special spaces, such as science labs, shop, and art rooms, need storage for 
hazardous chemicals and operate heavy equipment, and are vulnerable to earthquake 
damage. Music spaces and gymnasiums all have special equipment and storage needs, 
some of which would be costly to replace in the event of damage.


1 Conservative estimate based upon elementary and secondary school averages developed with the   help of Paul Abramson, President of Stanton 
Leggett & Associates, Education Consultants. 
2  U.S. Department of Education, National Center of Education Statistics; The Digest of Education   Statistics, 2001.
3  U.S. Department of Education, National Center of Education Statistics, The Digest of Education   Statistics, 2001


4 Use of this estimate as a decision tool was developed by Basil Castoldi, Education Facilities, Planning, Modernization and Management, fourth 
edition, Allyn & Bacon publishers, page 385















DESIGNING FOR PERFORMANCE     2


2.1 INTRODUCTION

This chapter introduces a performance-based design process that is 
recommended for adoption by a school district starting a program of school 
construction, addition, or repair. The principles of performance-based design can be 
applied to the design of a single school, of any size, or to a school construction plan 
for a large school district launching a major program. 
Performance-based design seeks to augment current code approaches rather than 
replacing them. However, there is a significant drive to introduce performance-based 
codes and, particularly in the field of fire safety, performance-based codes are now 
used for many applications. In the natural hazards area, although performance-based 
design is well developed for seismic design, prescriptive approaches are still typical 
for floods and high winds. A sound multihazard design approach should provide an 
impetus to adopt a performance-based philosophy for design against risk. 



2.2 DEFINITIONS OF PERFORMANCE-BASED DESIGN

Performance-based design is an evolving concept. The term as currently used has 
multiple definitions and three are presented below:

 A design approach that meets the life safety and building performance intents of 
the traditional code while providing designers and building officials with a more 
systematic way to evaluate alternative design options currently available in codes. 

In this regard, performance-based design facilitates innovation and makes it 
easier for designers to propose new building systems not covered by existing code 
provisions.

 A design approach that identifies and selects a performance level from several 
performance level options. Some provisions in the current version of the 
International Building Code (IBC) are sometimes called performance-based 
because they incorporate distinctions between performance goals for different 
building uses. These performance options are conceived to achieve higher-than-
code-minimum design requirements.

 A design approach that provides designers with tools to achieve specific 
performance objectives such that the performance of a structure can be reliably 
predicted. In the hazards area, this approach has been highly developed for 
seismic design although considerable research is still necessary to ensure the 
requisite reliability and predictability that would allow a performance-based code 
to be possible.



2.3THE PRESCRIPTIVE APPROACH TO CODES 

The traditional approach used in building codes in the United States has been that of 
prescriptive-based codes. Prescriptive-based codes are quantitative and rely on fixed 
values that are prescribed by the codes and intended to achieve a reasonable level of 
fire and life safety as well as reasonable levels of safety from other hazards such as 
earthquakes, floods, and high winds. Prescriptive requirements are based on broad 
classifications of buildings and occupancies, and are typically stated in terms of fixed 
values such as travel distance, fire resistance ratings, allowable area and height, and 
structural design (e.g., dead loads, live loads, snow loads, rain loads, earthquake 
loads, wind loads, etc.). 

Prescriptive codes provide limited rules for addressing various design and 
construction issues (e.g., establishing limits on the allowable area and height of a 
building, based upon construction type and occupancy classification). One of the 
current prescriptive building codes limits the basic area of a non-combustible, 
unprotected school building to 14,500 square feet. Why are this building and its 
occupants considered reasonably safe or acceptable at 14,500 square feet and unsafe 
or unacceptable at 15,000 square feet? This traditional approach is assumed to provide 
an "acceptable level of risk."

This is not to say that buildings designed and built under the prescriptive based 
codes are unsafe, but it is important to understand that the requirements in the 
prescriptive-based codes are judged to be only the minimum necessary to safeguard 
the public health, safety, and general welfare. In some instances, it may be desirable, 
appropriate, or even necessary to raise the level of safety above the prescribed 
minimums.
Under the prescriptive approach, all schools are essentially treated alike. Thus, the 
requirements for an elementary school with 500 students are the same as those for a 
high school with 500 students, although clearly there are differences in these 
buildings due to the age of the occupants and their ability to take proper and 
appropriate action under various emergency conditions. 
Another issue involving school buildings is the use of the facility for purposes other 
than education. In many communities, school buildings are designated as emergency 
shelters to be used in the event of a natural or manmade disaster event. The "normal" 
prescriptive code approach does not address the building features and systems 
necessary for the continuity of service required for an emergency shelter (for security, 
flooding, high wind, or hazardous material release issues).

How can the issues such as these and others be addressed? An innovative procedure 
that is becoming increasingly adopted is the use of a performance-based approach to 
improve or supplement the prescriptive requirements.



2.4THE PERFORMANCE-BASED APPROACH

Although having detailed requirements for "performance" is relatively new to the 
building and fire codes used in the United States, the concept is not. The various 
"prescriptive" building, fire, and life safety codes have all contained provisions for 
what was known as "alternative methods and materials" or "equivalencies." These 
code provisions allow for the use of methods, equipment, or materials not specified 
or prescribed in the code provided the alternative is approved by the code official. It is 
under these provisions of the traditional codes that the performance-based design 
approach can be undertaken.

Under the concept of an alternative method, material, or equivalency, the code 
official must approve the alternative or equivalency if it can be shown to be equivalent 
in quality, strength, effectiveness, fire resistance, durability, and safety. The 
proponent of the alternative method or equivalency is responsible for providing all 
necessary documentation to the code official. Based on the ability of the code official 
to permit alternate methods and materials in the existing prescriptive codes, 
performance-based codes simply offer the code official a system with which to accept 
alternative designs based on performance. In other words, this is nothing new to the 
code official, it is just a more formal way to review designs.
As mentioned previously, taking a "performance" approach is not new to building 
design because decisions based upon performance occur in all most every project. As 
an example, constructing corridor walls out of either gypsum board and steel studs or 
concrete masonry units (CMUs) will meet the prescriptive code requirements for a 
rated corridor in an educational occupancy. However, from a "performance" 
standpoint, the concrete masonry assembly is more desirable due to its ability to 
withstand the normal wear and tear of such occupancy. Another example would be 
the selection of the heating, ventilating, and air conditioning (HVAC) system. 
Although either rooftop units or central boilers/chillers might provide the requisite 
thermal performance, life-cycle cost analysis might support the choice of the central 
boiler/chiller. 

Performance-based design provides a structured way of making decisions that is 
particularly applicable to the issue of life safety and damage reduction from natural 
and manmade hazards. From a designer's standpoint, the performance-based codes 
provide a more formalized system to develop, document, and submit alternative 
materials, methods, and equivalencies.

Unlike relying solely on a prescriptive code, performance-based design addresses an 
individual building's unique aspects or uses, and specific and "stakeholder" needs. 
"Stakeholders" include everyone who has an interest in the successful completion of 
a school project (i.e., the school board members, responsible officials, members of 
the design team, the builders, the community at large, parents, and the code 
enforcement officials). The design team is a sub-group of the "stakeholders," which 
includes individuals such as representatives of the architect, school district, and 
other pertinent consultants.

It is critical to the proper development, approval, and implementation of any 
performance-based design for all of the stakeholders to be actively involved in the 
process. Because the stakeholders establish the acceptable level of risk, it is crucial 
that all stakeholders be involved in the project from the earliest stages. It is also 
important that the stakeholders realize that an incident in a school facility can be 
measured in more ways than just monetary. The loss of a school facility for any reason 
can have organizational, legal, political, social, and psychological impacts. 
The performance-based procedure provides the basis for the development and 
selection of design options, based upon the needs of the specific project, to augment 
the broad occupancy classification requirements. The approach structures a 
comparison of safety levels provided by various alternative designs, and also provides a 
mechanism for determining what level of safety, at what cost, is acceptable to the 
stakeholders. Performance-based design aims at property protection and life safety 
strategies in which the systems are integrated, rather than designed in isolation.



2.5HAZARD, RISK, AND PROBABILITY

But what about "risk"? We often use the terms "hazard" and "risk" interchangeably. 
However, in the performance-based design environment, this substitution is 
incorrect. The definitions of these two words are distinctly different when assessing 
various challenges, and they must be used in the correct context when working with 
stakeholders, especially those not familiar with the terms.
No one should confuse "hazard" or "risk" with "safety." "Safe" is a subjective condition 
that everyone views differently. Society establishes what it considers to be "safe" 
through a process of legal documents: both laws and court interpretations of them. Is 
a building that meets the prescriptive code requirements "safe?" Are you "safe" when 
you occupy a building that is entirely fire-resistant and protected by the latest in 
sprinklers and fire alarm technologies? "Hazard" and "risk" are recognized terms in 
the design, construction, engineering, architectural, and scientific worlds; "safe" is 
not.

The stakeholders must properly and thoroughly evaluate the risk or probability of a 
hazard event occurring in the performance designed facility. The basic questions 
they should ask are:

 What events are anticipated?
 What level of loss/damage/injury/death is acceptable?
 How often might this happen?

As they ask themselves these questions, and develop the variety of scenarios to which 
to apply them, the stakeholders must remember that obtaining consensus on 
acceptable levels of risk is essential to the successful outcome of the project.
Risk analysis incorporates the likelihood of a specific event and the severity of the 
outcome. This process combines both the severity and the probability of all relevant 
hazard loss scenarios. Remember that it is the intent of a performance-based code to 
establish the acceptable or tolerable level of risk. The overall analysis must consider 
not only the frequency of an events' occurrence, but the effectiveness and reliability 
of the entire building as a system. Risk analysis provides a quantitative measure of the 
risk. It also can establish the basis for evaluating acceptable losses and selecting 
appropriate designs.

Risk managers use two different evaluative methods in risk and hazard analysis: 
deterministic and probabilistic.
Deterministic analysis relies on the laws of physics and chemistry, or on correlations 
developed through experience or testing, to predict the outcome of a particular 
hazard scenario. In the deterministic approach, one or more possible designs can be 
developed that represent the worst possible credible events in a specific building. In 
this approach, the frequency of possible occurrences need not be evaluated.
Probabilistic analysis evaluates the statistical likelihood that a specific event will 
occur and what losses and consequences will result. This approach may use both 
statistics and historical information.
History from events involving similar buildings or equipment, building contents, or 
other items can be considered. The frequency of occurrences of a particular type of 
event is evaluated.

Any risk analysis method must anticipate a certain level of "uncertainty." Uncertainty 
describes those factors or circumstances that, if altered, affect the desired outcome.
Risk is the product of potential consequences and the expected frequency of 
occurrence. Consequences may include death, serious injury, or time lost from work, 
the extent of structural damage, monetary loss, interruption of use, or environmental 
impact. The occurrence frequency may be an estimate of how often the project loss 
might occur. 
Risk binning is an alternative to the more classic risk analysis, and is considered to 
be much simpler. Instead of identifying and evaluating every possible hazard, it 
quantifies (measures) the consequences of the most severe events and matches them 
with an approximate event frequency. The concept is based on the idea that, if one 
prepares for the worst-case scenario, lesser damaging events will result in favorable 
outcomes.

For each type of event, the maximum consequence must be established. 
Consequences may include death or serious injury; or massive structural damage, 
absolute loss of production, severe environmental damage, or total business 
interruption. The consequences should represent the largest realistic event of each 
type.

The provisions of the International Code Council (ICC) Performance Code for Buildings 
and Facilities (2003 edition) describe this as the "magnitude of events." These range 
from small, medium, large, and very large. Table 2-1 shows the correlation between 
the "magnitude of events" and acceptable levels of damage
For seismic, flood, and wind events, the ICC Performance Code for Buildings and Facilities 
has established criteria for the various magnitude of events as shown in Table 2-1.



2.6 ACCEPTABLE RISK AND PERFORMANCE  LEVELS 

The performance-based design process begins with establishing the acceptable risk 
and appropriate performance levels for the building and its systems. The basic 
concept of acceptable risk is the maximum level of damage to the building that can 
be tolerated, related to a realistic risk event scenario or probability. For each hazard, 
there are methods of measuring the magnitude of events and their probability, as well 
as terminology to describe levels of damage or performance levels. There are four per-
formance levels, each of which addresses structural damage, nonstructural systems, 
occupant hazards, overall extent of damage, and hazardous materials. The types of 
damage that are defined will vary according to the type of hazard that is being 
addressed. The ICC Performance Code for Buildings and Facilities formalized four design 
performance levels in terms of tolerable limits to the building, its contents, and its 
occupants that apply to all types of hazards. These levels are as follows:
Mild Impact. At the mild impact level, there is no structural damage and the building 
is safe to occupy; injuries are minimal in number and minor in nature; damage to the 
building and contents is minimal in extent and minor in cost; and minimal haz-
ardous materials are released to the environment. 
Moderate Impact. At the moderate level, there is moderate, repairable structural 
damage, and some delay in re-occupancy can be expected; injuries may be locally 
significant, but generally moderate in numbers and in nature; there is a low 
likelihood of a single life loss and very low likelihood of multiple life loss; and some 
hazardous materials are released to the environment, but the risk to the community is 
minimal.

High Impact. At the high impact level, it is expected that there will be significant 
damage to structural elements, but with no falling debris. Significant delays in re-
occupancy can be expected. Nonstructural systems needed for normal building use 
are also significantly damaged and inoperable. Emergency systems may be damaged, 
but remain operational. Injuries to occupants may be locally significant with a high 
risk to life, but are generally moderate in numbers and nature. There is a moderate 
likelihood of a single life loss, with a low probability of multiple life loss. Hazardous 
materials are released to the environment with localized relocation required.
Severe Impact. With severe impact, there will be substantial structural damage, and 
repair may not be technically possible. The building is not safe for re-occupancy, 
because re-occupancy could cause collapse. Nonstructural systems for normal use may 
be completely nonfunctional, and emergency systems may be substantially damaged 
and nonfunctional. Injuries to occupants may be high in number and significant in 
nature. Significant hazards to life may exist. There is a high likelihood of single life 
loss and a moderate likelihood of multiple life loss. Significant hazardous materials 
may be released to the environment, with relocation needed beyond the immediate 
vicinity.


2.7 CORRELATION BETWEEN PERFORMANCE GROUPS AND 
TOLERATED LEVELS OF DAMAGE

The provisions of the ICC Performance Code for Building and Facilities  correlate the 
performance groups and the tolerated levels of damage. Table 2-2 shows this 
relationship. Events are classified as small, medium, large, or very large. Each hazard 
will have its own definitions that modify these generic magnitudes.
Building groups in the ICC Performance Code include: 

 Group I - Buildings that represent a low hazard to human life in the event of failure

 Group II - All buildings except Groups I, III, and IV 

 Group III - Buildings with a substantial hazard to human life, including schools or 
day care centers with a capacity greater than 250 

 Group IV - Buildings designed as essential facilities, including designated 
earthquake, hurricane, or other emergency shelters

Using an elementary school with an occupant load of less than 250 as an example 
(Group II), it can be seen that there is a significant difference in the level of 
performance required when the building is to be used as a designated emergency 
shelter (Group IV). These performance levels clearly are not addressed by the 
prescriptive code requirements.
For hazards such as earthquakes and winds, it may be desirable to set different 
performance objectives for nonstructural versus structural design. Although the 
prescriptive code may provide acceptable structural safety, it may be cost effective to 
spend a small additional amount of resources to enhance the attachment and 
bracing of key nonstructural components and provide for independent inspection of 
their installation. Local information on the characteristics of flood may suggest that 
it is prudent to allow an increased factor of safety above the expected flood elevation 
at the property. Similarly, local experience may suggest that projects should be 
designed for higher wind speeds than the code values.
The flow chart shown in Figure 2-1 summarizes a typical performance-based design 
process for a major design and construction program. It can be used as a checklist for 
a single construction project to structure early discussion between the stakeholders 
and the designers to establish the acceptable risk, performance goals, and objectives 
for the design. 



 2.8 ROLES OF DESIGNERS, CODE OFFICIALS, AND THE SCHOOL 
DISTRICT 

The school district is responsible for retaining the services of the design 
professionals and for the costs of any special services, including contract or third-
party reviews and inspections required by the code official. The district must also 
retain all required documents and reports on the premises and is required to operate 
the building in accordance with the approved design throughout the life-cycle of the 
building.

The design professional is an individual who is registered or licensed to practice his 
or her respective design profession as defined by the statutory requirements of the 
professional registration laws of the state or jurisdiction in which the project is to be 
constructed. The design professional must possess the required knowledge and skills 
to perform design analysis and verification in accordance with the code requirements 
and applicable standards of practice. Design professionals may include architects, 
civil and structural engineers, mechanical engineers, and fire protection engineers, 
to name only a few.

The design professionals and special experts must be able to apply performance 
requirements; provide appropriate analysis, research, computations, and 
documentation; utilize authoritative documents and design guides; and review 
(inspect) the completed construction elements to verify compliance with the 
prescribed design.
All design documentation must be prepared by the design professional. Required 
documentation includes a concept report, a design report, and an operations and 
maintenance (O&M) manual. The design professional must coordinate all plans and 
documents for consistency, compatibility, and completeness, and submit them to the 
code official for review and approval. 

The code official is required to perform a "knowledgeable" review of the proposed 
design and is permitted to use a third-party or peer review. When such third party or 
peer review is used, the cost for such services may be passed on to the submitter. After 
the plans and specifications have been reviewed and approved, a permit is issued for 
the start of construction. During the construction process, inspections and tests must 
be conducted in accordance with the design documents, code official procedures, 
and applicable codes. Upon completion, acceptance testing must be undertaken 
prior to occupancy.
After completion of the project and acceptance testing, the design professional must 
prepare and submit to the code official documentation that verifies that all 
performance and prescriptive code provisions have been met. The code official is 
permitted to require a third-party or peer review of this documentation. After comple-
tion of construction, final inspection, and testing and submission of all required 
documentation, the code official must issue the certificate of occupancy. A temporary 
certificate of occupancy may be issued for a limited timeframe with specified 
conditions, provided that all life safety items are accepted. The code official may also 
require that a temporary certificate be issued for a specific period of time and/or be 
"renewable" on a periodic basis.
The school district is responsible for proper maintenance and operation of the 
building, in accordance with the O&M manual, throughout the life of the building. 
The school district is also responsible for periodically verifying compliance with the 
approved design at a frequency approved by the code official. Documents verifying 
that the building, facilities, premises, processes, and contents are in compliance with 
the approved design documents must be filed with the code official.


 
2.9 CHANGES TO A BUILDING DESIGNED FOR PERFORMANCE

When a building that was designed and constructed using a performance-based 
design is remodeled or altered, or its use changed, a design professional must 
evaluate the existing building and applicable documentation. Any change that results 
in an increase in hazard or risk must undergo a full review and evaluation of the de-
sign. The review and evaluation must be documented in a written report and 
submitted to the code official for review and approval. Such written review must be 
submitted to the code official even when the proposed changes do not exceed the 
original conditions. 
One area of change that can occur is in one or more of the original bounding 
conditions. Bounding conditions by definition are conditions that, if exceeded, 
invalidate performance-based design. These could be maximum allowable conditions 
such as fuel load or type and arrangement of fuel load that must be maintained 
throughout the life of a building to ensure that design parameters are not exceeded.

Some examples of a change in bounding conditions are:

 The original design assumed that the gym would be used only for spectator sporting 
events. Such an arrangement would present a relatively low HVAC load. The desire 
is to now use the same gym for a science fair with the display of many project and 
other related materials. The new use represents a much higher HVAC load than 
originally intended and thus would represent a change in bounding condition. 

 The building was originally designed for use as a high school. Characteristics of 
these occupants to respond to an emergency situation are a bounding condition. 
The desire is now to change the school to one on the elementary level. Because 
the ability of these occupants to respond to an emergency is different, this would 
represent a change in bounding conditions.



2.10 CURRENT PERFORMANCE-BASED CODES

Performance-based codes are not based on broad or generic classifications, but are 
qualitative. They establish, by a consensus process, acceptable or tolerable levels of 
hazard or risk for a variety of health, safety, and public welfare issues. Three model 
codes that are currently available are the ICC Performance Code for Buildings and Facilities, 
the National Fire Protection Association (NFPA) 101 Life Safety Code, and the NFPA 
5000 Building Code. Any one or a combination of these documents would be 
appropriate for use in a performance-based design.
Although the ICC Performance Code for Buildings and Facilities addresses all types of 
building issues, the provisions of the NFPA 101 Life Safety Code, "Performance-based 
Option," address only those issues related to "life safety systems." The provisions of 
the NFPA 5000 Building Code apply not only to life safety issues, but to all traditional 
"building code" issues as well.

This design approach is based on a life safety evaluation, which is a written review 
dealing with the adequacy of life safety features relative to fire, storm, collapse, crowd 
behavior, and other related safety considerations. 
The performance-based design must be prepared by a person with qualifications 
acceptable to the code official. The code official is permitted to require an approved, 
independent third-party review of the proposed design and provide an evaluation of 
the design to the code official. All data sources are required to be identified and 
documented. The code official is empowered to make the final determination as to 
whether the performance objectives are met.
Design specifications and other conditions used in the performance-based design 
must be both clearly stated and shown to be realistic and sustainable. The 
characteristics of the building or its contents, equipment, or operations that are not 
inherent in the design specifications, but that can affect occupant behavior or the 
rate of hazard development, are required to be explicitly identified. The anticipated or 
expected performance of a fire protection system and building features must also be 
documented. 

In addition, the selection of the occupant characteristics must be approved by the 
code official and must reflect the expected population of building users. Response 
characteristics of the occupants should include their sensibility (sensory awareness), 
reactivity, mobility, and susceptibility. Sources of data for these characteristics must 
be documented. It must also be assumed that, in every normally occupied room or 
area, at least one person will be located at the most remote point from the exits. The 
design must also reflect the maximum number of people that every occupied room or 
area is expected to contain.
In those instances where the ability of trained employees (occupants) is part of the 
overall performance design concept, the number of employees, and their training 
and abilities should be identified and documented.



2.11 THE O&M MANUAL AND THE OCCUPANTS' HANDBOOK

The last critical component of the performance-based design process is the O&M 
manual. The design professional is responsible for developing this important 
document, which can be described as an owners manual for the building and all of 
its systems. This document should clearly establish the requirement that the school 
official must ensure that all components of the performance-based design are in 
place, operational, and properly maintained for the entire life-cycle of the building. 
The ICC Performance Code for Buildings and Facilities, the NFPA 101 Life Safety Code, and the 
NFPA 5000 Building Code all provide for the continued use and maintenance of a 
performance-based design facility. Each building or facility designed and constructed 
using a performance-based design relies on certain conditions remaining stable 
throughout the life of the building. 
The O&M manual documents agreements with stakeholders and clearly states that 
the building owner must ensure that the components of the performance-based 
design remain in place and in proper operating condition. The manual provides 
instructions that place restrictions on the building operations, and communicates to 
the building tenants and occupants the limits of building use and their 
responsibilities. It also provides a guide to renovation and documents what actions 
are to be taken if a fire protection system is impaired or removed. The importance of 
the O&M manual cannot be understated. It is the glue that holds the on-going use of 
the building together.

The O&M manual must be submitted with the final design documents, and all of the 
stakeholders must agree on its contents. The manual should contain the 
requirements for the testing, inspection, and maintenance of all systems; outline 
restrictions on building operations; and provide guidelines on how to address any 
changes in occupancy or use. 
This manual also must be made part of the legal documents of the property so that 
they are transferred with any change in ownership. The O&M manual should 
include:

 Descriptions of the commissioning requirements of all fire protection systems
 Identification of all subsystems
 Descriptions of all inspections, testing, and maintenance procedures and schedules
 Information on emergency electrical power systems
 Details on building operations (e.g., critical fuels loads, sprinkler design 
requirements, building use and occupancy, reliability and maintenance of fire 
protection systems)
 Details of the maintenance plans for critical design components
 Qualifications of inspection personnel or inspectors
 Fee schedules for unique or third party inspections required by the code official and 
provisions of changes to the fee schedules 
 Requirements to be followed if any fire protection system is impaired or out of 
service
 Testing criteria for initial acceptance, including pass/fail criteria, 
inspection/testing schedules, periodic testing criteria, and recordkeeping 
requirements
In addition, the manual should spell out any requirements or restrictions, such as 
storage height, commodity type, or fire protection system modifications. 
The O&M manual should also contain the occupants' handbook. In the case of 
school occupancies, this is the portion of the O&M manual that would be provided to 
the faculty and support staff. Less technical than the O&M manual and similar to the 
handbook that comes with a new automobile, this publication informs all occupants 
of the specific building about the design features of the building and its equipment, 
as well as the occupants' responsibilities. It also serves as a guide for renovations and 
changes to workspaces. In addition, the occupants' handbook should provide details 
for the development and submittal of modifications for review and approval by the 
Authority Having Jurisdiction (AHJ), building owner, insurance carrier, or other 
appropriate stakeholders. 



2.12 PERFORMANCE-BASED DESIGN FOR NATURAL HAZARDS

As noted in Section 2.4, a performance-based approach to building design is not new, 
because decisions based on performance occur frequently in almost any project. What 
is new is the attempt to formalize a decision-making process related to expected 
performance and, ultimately to develop performance-based codes to regulate building 
design and construction.
In the natural hazards area, "performance" is used to signify a level of damage or load. 
This, in itself, represents a major change in perception, because the building owner 
or occupant generally believes that adherence to building codes provides a safe 
environment and anticipated degrees of damage are not a normal source of 
conversation between an architect and owner, or even an architect and his engineer. 
Earthquake experience in recent years has forced recognition that damage 
(sometimes severe) will occur in a building designed in accord with the code.
The theory and practice of performance-based design currently is most advanced in 
seismic design and virtually non-existent in design for floods and high winds. 
Advanced seismic engineering practitioners have, for some time, recognized several 
performance objectives in relation to owner's needs, and have used them as a basis 
for establishing design parameters. These objectives, or performance levels, can be 
simply stated as follows:

 Level 1: The building is essentially undamaged and can be immediately operational.

 Level 2: The building is damaged, and needs some repairs, but can remain occupied 
and be functional after minor repairs (of a nonstructural nature) are complete.

 Level 3: The building is both structurally and nonstructurally damaged, but the 
threat to life is minimal and occupant injuries should be minor and few.

 Level 4: The building is severely damaged and will probably have to be demolished; 
it has not collapsed, although there is some likelihood of occupant injury.

In this spectrum, the code conforming building is fairly far down the scale (at Level 
3) and many private and public owners are prepared to pay more to achieve a higher 
level of performance. A hospital should achieve at least Level 2, and preferably Level 
1. A high-tech manufacturing plant might desire to achieve the same level, because of 
the high value of its contents and the business losses if the plant must shut down 
production. The owner of a warehouse that houses a modest and easily replaced 
commercial inventory, with very few occasional occupants, might opt for the 
economies of Level 4.

In the last decade or so, this informal pragmatic approach to performance-based 
seismic design has become formalized; the performance levels have been named and 
carefully defined. Detailed observation of damaged buildings, together with advances 
in materials science, experimental research, and analytical methods, have led to 
much more sophisticated understanding of building response and have enabled 
engineers predict more reliably how a structure will behave under various levels of 
shaking. This prediction is still far from a guarantee, but it has a scientific and 
engineering basis that was non-existent even 2 decades ago. Meanwhile, extensive 
studies of all aspects of performance-based seismic design are underway around the 
country, largely sponsored by FEMA and the National Science Foundation.
The same degree of research and development activity does not, however, apply to 
design for floods and high winds. One reason is that these fields have not had the 
same sophisticated (and fairly expensive) research support that the seismic 
community has enjoyed. Before performance-based design for floods and winds can 
become a reality, a solid research base must be established. The kind of research 
would be different from that of seismic engineering; the engineering problems are 
much simpler, but research into simulating the probabilities and effects of floods 
and winds could yield rich rewards. The objective is to reduce the uncertainties 
associated with these hazards, thus avoiding wasted money and resources. Wind 
design could benefit from materials and component research to improve exterior 
envelope design and construction: at present, many of the available protective 
methods are labor intensive in the most primitive way, often using only hammers, 
nails, and stapling guns.

If design for performance against floods and high winds is to approach the 
sophistication of seismic performance-based design, a new approach to thinking 
about buildings subjected to floods and winds is necessary, paralleling the new 
thinking that has occurred around buildings subjected to earthquakes. When engi-
neers began to think about buildings from the owners' viewpoint, and the different 
ways in which buildings were occupied, it became clear that a seismic code that 
focused only on methods and technical design criteria instead of results was not 
responding to owners' (and society's) needs. Performance-based seismic design is 
still in its infancy, and much research needs to be done, but the essential shift in 
thinking has occurred. 

Performance-based design is not proposed as an immediate substitute for design to 
traditional codes. Rather, it is seen as an opportunity for enhancement and the 
tailoring of the design to match the objectives of the community. Design to the code 
remains as the minimum baseline to ensure safety for school occupants, but the 
special importance to our society of protecting the school population suggests that 
design to a generic code minimum is not sufficient.

To achieve a building code that regulates performance rather than easily inspected 
design construction methods will not be easy, but ultimately one can expect to see a 
rational mix of performance and prescription in the regulatory mix. That shift took 
place in advanced industries (e.g., airplane design) a few decades ago, and airplanes 
are now habitually designed to stringent performance requirements, specified by the 
military or the airline companies.

Designers and owners of buildings in flood or high wind-prone regions need to 
begin to think in terms of a few basic objectives:

 Can the real probabilities and frequencies of events during the useful life of the 
building be defined with a useful degree of accuracy?

 Can the extent and kinds of damage (if any) that can be tolerated be defined?
 Are there ways (if any) in which this acceptable level can be achieved?
 Are there alternative levels of performance that can be achieved and how much do 
they cost over the lifetime/ownership of the building?
 Are these levels below, at, or above design to code enforced criteria?

Serious thought about these basic issues by all the stakeholders is the beginning of 
design for performance.


 
2.12.1 Performance-based Seismic Design

As discussed in Section 2-12, procedures for the application of performance-based 
design seismic design are well advanced. However the procedures are still evolving 
and issues such as terminology, analytical methods, and achieving reliable 
performance prediction are still subject of much research and development. This 
section outlines the general approaches that are current in performance-based 
seismic design; considerable refinement of the approaches and procedures that are 
outlined herein are expected to occur in the next few years.
Determining Acceptable Risk. The performance-based design procedure starts with 
the definition of acceptable risk. Prior to inception of design work for a new or 
retrofitted school building, discussions should be initiated between the design team, 
the school district, and community representatives to explain the level of seismic 
performance that will be achieved by conformance to the code, and other possible 
performance options that may be available. In these discussions, "seismic 
performance" refers to the extent of damage and loss that is likely to occur in 
earthquakes of differing magnitudes. These discussions focus on ensuring that all 
parties understand that "earthquake" or damage-free performance is not possible, 
and compromises must be made between seismic performance, cost, and design for 
learning. "Acceptable risk" refers to the extent and types of damage and loss that the 
school officials and community can tolerate. Clearly, avoidance of casualties is of the 
highest priority, but what are the priorities for issues such as damage to the 
building's structure, nonstructural components, and systems and contents?
The discussion of acceptable risk begins with determining the answer to the 
following question: If the building is designed strictly to the minimum code 
requirements, are the damage and loss that might occur in the design level 
earthquake acceptable? If the answer to this question is positive, an implicit level of 
acceptable risk has been set and design can proceed. If the answer is negative or 
undecided, the following should be addressed:

 What lesser extent and types of damage can be accepted?
 What are the implications for long-term costs and benefits over the life of the 
school building?
 Is the desired performance level affordable within the first-cost resources of the 
district (minimum code requirements must always be provided)?

Issues of uncertainty must also be made clear. It should be noted that the degree of 
uncertainty in predicting performance will be dependent on the existing school 
design in addition to the application of code requirements. The design team for a 
new building has control over this issue; however, for a retrofit, some of the existing 
school characteristics may be less than desirable. 

A new design in which key parameters of good seismic design are provided (i.e., 
continuous load path, structural redundancy, symmetry in plan and section, short 
spans, and well designed nonstructural connections and bracing) will be more 
economical and more predictable in performance than a design in which these 
characteristics are not present. (The simple concept design shown in the How 
Buildings Resist Earthquakes illustration in Section 4.6.1 represents an "optima" 
seismic design that incorporates these features.)
Discussions of these issues should lead to a formal conclusion on performance 
objectives that then serve as a target for the designers, but it is the school district 
representatives who must make the final performance objective decision. The 
implications of this decision must be fully understood and it is the responsibility of 
the design team to provide necessary information, to the extent that it is available.

Traditionally, the architect has been the source of all design information for the 
school authorities but, due to the technical sophistication of performance-based 
design, the structural engineer will probably be consulted. On large projects, the key 
consultants may be involved in early meetings, particularly when the school district is 
represented by a facilities manager or other technical staff. In these instances, the 
district's professional staff may be expected to be able to discuss the project on equal 
terms with the design team. Whether all parties are familiar with the language of 
performance-based seismic design may have significant impact on the extent to 
which seismic performance issues can be a subject for useful discussion and decision-
making. 

If community representatives or committees, whose technical expertise may be more 
limited, are involved, the design team should try to ensure that the issues are 
understood.
For most school districts and communities, the discussion of acceptable risk will be 
an entirely new kind of discussion and the language of seismic performance may be 
unfamiliar. Historically, it has not been common practice to initiate a discussion of 
damage tolerance for a new project. The seismic expectations checklist in Table 2-3 
provides a basis for these discussions. The checklist takes the form of a matrix of 
design expectations that can assist design team members, the school district, and the 
community to agree on seismic performance goals that are reasonably in line with 
the available resources. Agreement on such goals and expectations can help achieve a 
desired level of performance and limit later surprises due to unexpected earthquake 
damage. Such performance objectives statements might properly be part of a project's 
building program and serve as the basis for a performance-based design procedure.
The checklist can be completed or used merely as a basis of discussion. The intent is 
for the school district to arrive at a seismic performance objective that is understood 
and approved, both as to its opportunities and its limitations. 
The above classifications may be modified by poor soil conditions or specific 
seismological forecasts. Note that this table adds a short description to the four 
damage level categories identified in the ICC Performance Code for Buildings and Facilities 
outlined in Section 2.12.

Table 2-4 shows the expected overall and nonstructural damage for the four building 
performance levels defined in FEMA 273, NEHRP Guidelines for the Seismic Rehabilitation of 
Buildings. These performance levels are developed versions of the four general 
performance levels described on page 2-20. The bottom row relates the damage levels 
to those expected for a building designed to a conventional code. FEMA 273 contains 
six such tables that show expected damage to vertical and horizontal structural 
elements; architectural, mechanical, electrical, and plumbing components; and 
building contents. These expectations refer to a building designed using the 
appropriate analytical tools available in FEMA 273, which provides the necessary 
methods of analysis and detailing to achieve these performance levels for high, 
moderate, and low earthquake intensity regions. Some of the terminology in these 
tables may be expected to change as a result of studies now underway.
Reducing Seismic Risk Through Performance-based Design. The general principles of 
performance-based design are discussed in earlier sections of this chapter. For 
seismic risk reduction, performance-based design starts with the recognition that 
some damage will be incurred in a severe earthquake even in a well designed and 
constructed building. Prior to the seismic design, the school districts and the design 
team reach agreement on the desired seismic performance of the building (i.e., the 
extent and type of damage that the school district can tolerate). The extent of this 
damage can be reduced by seismic design measures based on more precise analysis of 
the earthquake forces that the building will encounter, rather than relying on the 
simplified analytical methods of the current seismic code.

These more precisely estimated forces may, in some instances, be less than the forces 
determined by a simple code analysis because less allowance will need to be made for 
uncertainty in the calculations, and the seismic design and construction cost may be 
reduced. Increased protection beyond the minimum code expectations, however, will 
almost inevitably add to the initial cost of the building. The trade-off that the school 
district must consider is that damage reduction will probably result in design and 
construction cost increases. 
The value to the district of increased investment in seismic protective design and 
construction is dependent on the likelihood of damaging earthquakes, and some 
economic analysis can assist in arriving at an affordable solution with satisfactory 
safety and damage control characteristics. This implies that the cost of protection 
must be evaluated over the life of the building, rather than only as an item of the 
initial building cost. As with design to the current code, performance-based design 
starts with the assumption that the basic purpose of seismic design is to protect the 
building occupants from collapse and damage that may be life-threatening.
The performance-based design procedure uses inputs from the information 
evaluations previously described to develop designs that balance the desired 
performance levels with the available resources. 


2.12.2 Performance-based Flood Design

The performance objectives (or performance levels) for flood hazards can be stated as 
follows:

Level 1:  The school building sustains no structural or nonstructural damage, 
emergency operations are fully functional, and the building can be immediately 
operational; the campus is not affected by erosion but may have minor debris and 
sediment deposits. 

Level 2:  The school building is affected by flooding above the lowest floor, but 
damage is minimal due to shallow depths and short duration. Cleanup, drying, and 
minor repairs are required, especially of surface materials and affected equipment, 
but the building can be back in service in a short period of time. Site improvements 
such as bleachers and fences are damaged, and athletic fields are damaged by erosion 
and deposition of sediment and debris.

Level 3:  The school building may sustain structural damage that requires extensive 
repair and partial reconstruction. If the school is used as a shelter, threats to 
occupants are minimal. Nonstructural damage to equipment and finish materials 
requires cleanup, drying, and repairs. Site improvements such as bleachers and 
fences are damaged, and athletic fields are damaged by erosion and deposition of 
sediment and debris.

Level 4:  The school building is severely damaged and likely requires demolition or 
extensive structural repair. Threats to occupants are substantial and warning plans 
should prompt evacuation prior to the onset of this level of flooding. (Note: Level 4 is 
applicable to schools affected by flooding due to failure of dams, levees, or 
floodwalls.)
In addressing the question "what level of loss/damage/injury/death is acceptable?", 
an assessment of the probable magnitude and frequency of flood events during the 
life of a school is relatively straightforward. With the exception of floods caused by or 
exacerbated by failure of dams and levees, an examination of available information 
regarding mapped flood hazard areas, predicted flood elevations, and historic floods 
should identify an adequate estimation of the flooding that may affect a school site. It 
is reasonable to exceed the minimum design flood elevation and loads for essential 
and critical facilities, including schools.

Flooding of buildings rarely results in loss of life and injuries, although that is a 
likely consequence of extreme and unpredictable flooding caused by events such as 
dam or levee failures. Beyond identification of the normal design flood magnitude, 
further examination is required to identify those contributory hazards. State water 
resources agencies can identify the high hazard dams and significant hazard dams 
that are present in the watershed and the failure scenarios that may result in cata-
strophic consequences. Similarly, local agencies or authorities that maintain and 
operate levee and floodwall systems can characterize failure scenarios for protected 
areas. Schools located in areas threatened by these very low probability, high conse-
quence events should have emergency response plans that are closely coordinated 
with the appropriate emergency management authorities.
Chapter 5 identifies a number of recommendations to exceed minimum flood-
resistant requirements to achieve an appropriate level of protection for essential and 
critical facilities, primarily avoidance of flood hazard areas and adding a factor of 
safety to the elevation requirement. Consideration of these recommendations is in 
the spirit of performance-based design. To some degree, the benefits can be 
quantified: the National Flood Insurance Program's (NFIP's) statistics on building 
that exceed the minimum requirements indicate lower damage. It is notable, 
however, that there is insufficient experience with nonresidential buildings that are 
exposed to extreme flooding to quantify the benefits.


2.12.3 Performance-based High Wind and Tornado Design

The performance objectives (or performance levels) for the wind hazard can be stated 
as follows:

Level 1: The school building is essentially undamaged and can be immediately 
operational. 

Level 2:  The school building is damaged, and needs some repairs, but can remain 
occupied and be functional after minor repairs (of a nonstructural nature) are 
complete. 

Level 3:  The school building may be structurally damaged, but the threat to life is 
minimal and occupant injuries should be minor and few. However, nonstructural 
damage (i.e., the building envelope or rooftop equipment) is great, and the cost to 
repair the damage is significant. If rain accompanies the windstorm, or if rain occurs 
prior to execution of emergency repairs, water damage to the interior of the school 
can prohibit occupancy of all or a portion of the school from several weeks to several 
months.

Level 4:  The school building is severely damaged and will probably have to be 
demolished. Significant collapsing may have occurred, and there is great likelihood 
of occupant deaths and many injuries unless the school has a specially designed 
occupant shelter. (Level 4 is applicable to schools struck by strong or violent 
tornadoes. For other types of windstorms, Level 4 should not be reached.)
For the wind hazard, loss of life and injuries due to collapsing building components 
or wind-borne debris is quite rare. Except for strong and severe tornadoes, the major 
threat posed by high winds is damage to the school itself, which can be very costly to 
repair and may prohibit use of the school for a considerable period of time.
In addressing the question "what level of loss/damage/injury/death is acceptable?", 
an assessment of the probable magnitude and frequency of wind events during the 
life of a school is relatively straight forward. With the exception of strong and violent 
tornadoes, complying with the design procedure in ASCE 7 should typically result in 
adequate estimation of the wind loads that a school will experience. (For strong and 
violent tornadoes, wind and wind-borne debris loads derived from FEMA 361 should 
typically provide an adequate estimation.) However, the great challenge with 
performance-based wind design is the assessment of the wind resistance of the 
building envelope and rooftop equipment and the corresponding damage 
susceptibility. 

Assessment of the true performance of the building envelope and rooftop equipment 
is challenging because of several unrelated factors:

 Analytical tools (i.e., calculations) are currently not available for many envelope 
systems and components. Because of the complexity of their wind load response, 
many envelope systems and components require laboratory testing, rather than 
analytical evaluation, in order to determine their load-carrying capacity. 
Unfortunately, current test methods typically have many limitations. For example, 
test assemblies normally test unaged materials. Hence, the test may adequately 
indicate how the system will perform during the first few years of its life, but it may 
not indicate how the system will perform after being exposed to sunlight (which 
may result in heat and/or ultraviolet radiation induced degradation), water 
(which may degrade the system via corrosion or dry rot), or repeated modest wind 
events (which may induce fatigue failure). Also, tests are typically static (i.e., 
uniform pressure distribution), rather than dynamic (i.e., cyclically-induced 
loading). In addition, test assemblies are not typically subjected to wind-driven 
water while simultaneously being subjected to design-level wind pressures.

 It is likely that finite element analysis (FEA) will eventually augment or replace 
laboratory testing, but substantial research is necessary before FEA becomes 
available for the numerous building envelope systems from which architects are 
able to choose.

 Architects have traditionally given little attention to wind resistance of building 
envelopes, and mechanical engineers have given little attention to wind resistance 
of rooftop equipment. For those architects and engineers that try to give attention 
to envelopes and rooftop equipment, their task is hampered by lack of 
comprehensive design guides, lack of analytical tools and lack of realistic long-
term wind resistance data as discussed above.

 Building envelopes are often constructed by several different trades. For example, 
an exterior non-load bearing wall may be framed by one subcontractor, another 
subcontractor may install the insulation and wall covering and another 
subcontractor may install the windows. It is challenging to successfully integrate 
these various subsystems so that wind-driven water infiltration is inhibited and 
load-path continuity is maintained.

 Because the building envelope is exposed to weather, it is natural for various 
envelope components to lose strength over time. If naturally-deteriorated 
components are not replaced before they become overly weak, they can be 
damaged during storms that are well below design wind speed conditions. 

Although appropriate maintenance and repair criteria may be included in the 
O&M manual, it is often difficult to determine if serious corrosion, dry rot, or 
termite attack has occurred in concealed portions of the envelope. 

 Modifications may inadvertently weaken the resistance of the building envelope. 
For example, if a roof system incorporates an air retarder, and a future penetration 
(such as an exhaust fan) through the roof does not maintain the continuity of the 
air retarder at the penetration, the roof system could receive a sufficiently high 
unexpected load to result in roof covering damage. In this example, even though 
maintaining air retarder continuity should be included in the O&M manual, 
compliance with this O&M requirement could easily be overlooked.
Because of the great uncertainty of the true resistances of the building envelope and 
rooftop equipment on a given school, the level of wind and subsequent water 
infiltration damage that could be reasonably expected to result from a design-level 
windstorm at some future time is difficult to quantify at this time. With development 
of comprehensive wind design guidelines for building envelope systems and rooftop 
equipment, development of greatly enhanced test and analytical methods, and 
greater awareness on the part of designers and construction trades on basic design 
and installation techniques to inhibit water infiltration and practices necessary to 
achieve load-path continuity, the magnitude of the uncertainty can be decreased. 
However, significant research funding is needed in order to reduce the uncertainties 
associated with the wind and water resistance of building envelopes and rooftop 
equipment.
Except for strong and violent tornadoes, schools designed and constructed with one 
of the current model building codes (and adequately maintained and repaired), 
typically present a low risk of casualties and injuries. However, some existing schools 
may present higher risk. For example, a glass curtain wall at a cafeteria, or tall 
unreinforced and inadequately braced CMU wall at a gym may be blown in or out 
during a strong thunderstorm. If students or faculty are nearby, they could be injured 
or killed. Or, a roof could blow off and injure students that are on their way to the 
buses. There is also increased risk of casualties and injuries to people seeking refuge 
in a school during a hurricane if the school was not originally designed for this 
purpose.
By considering the recommendations provided in Chapter 6, and implementing 
those that are appropriate for a given school, the spirit of performance-based design 
can be achieved, with respect to both casualties/injuries and building 
damage/interrupted use, for new construction, as well as existing schools. However, 
because of the limitations discussed above, it is not possible at this time to quantify 
the actual performance that the various enhancement recommendations will offer. In 
some cases, the recommendations may be overly conservative and, in others, they may 
be non-conservative. The recommendations will result in enhanced performance, but 
additional research is needed to quantify the magnitude of the enhancement














MULTIHAZARD DESIGN     3


3.1 INTRODUCTION

This chapter compares the effects of three natural hazards that are the 
subject of this publication, in terms of their geographical locations, relative warning 
times, frequency, risk, and potential for damage and loss. Comparative losses are 
discussed and fire and safety considerations are presented. The design methods used 
to protect against the hazards by looking at the ways in which these methods 
reinforce or are in conflict with one another are compared. This is a key aspect of 
multihazard design because the similarities and differences in the ways in which 
hazards affect buildings and how to guard against them demand an integrated 
approach to natural hazards design. This must be pursued as part of a larger 
integrated approach to the whole building design problem. 




3.2 THE HAZARDS COMPARED

Natural hazards are not aberrations; they are part of the natural environment in 
which we live and in which our buildings should be designed to function. Therefore, 
it is necessary for designers to become knowledgeable about all natural hazards in 
order to gain an understanding of how they act and how they can be accommodated 
within the design process, rather than treating them as adversaries that the designer 
must reluctantly accommodate at the expense of more traditional design aspirations. 
This section presents a comparative sketch of the three natural hazards covered in 
this publication together with some issues relating to the common hazard of fire. 
The threat of physical attack is covered in a companion publication, FEMA 428, Primer 
to Design Safe School Projects in Case of Terrorist Attacks. A general understanding of all 
hazards is necessary in order to develop an integrated multihazard approach to 
design. It has been a tenet of multihazard design that design for two or more hazards 
may reinforce one another, thus reducing cost and improving protection, but it has 
also been recognized that at times there may be conflicts between designs for 
different hazards. This section presents, for the first time, a systematic analysis of the 
reinforcements and conflicts between hazard protection methods. This takes the 
form of the matrices shown in Section 3.5. This section is presented to stimulate 
discussion and analysis at the outset of project design and to provide a format for 
further development and discussion of the issues involved. 


3.2.1 Location: Where are They?

The public perception of natural hazards is that earthquakes occur in California, 
floods in many riverine and coastal locations, tornadoes in the Midwest, and 
hurricanes along the Atlantic and Gulf coasts. Although there is some truth to this 
perception as it relates to the highest probabilities for each hazard, hazard maps 
show that the entire United States is vulnerable to one or more of the three main 
natural hazards: earthquakes, floods, or high winds. Earthquakes are predominant in 
the West, but also threaten specific regions in the Midwest, Northeast, and Southeast. 
The great earthquakes centered on the little town of New Madrid, Missouri, in 1811 
and 1812 caused little damage and only a few casualties; a recurrence of these 
earthquakes would impact some of the most populous cities of the Midwest. The worst 
earthquake in the eastern states occurred in Charleston, South Carolina, in 1886; 60 
people were killed and the modest sized city suffered the equivalent of about $25 
million damage in today's dollars. Riverine floods occur along rivers, largely but not 
exclusively in the Midwest, and coastal flooding is associated with storm surges 
caused by high winds. Flash floods caused by sudden, intense rainstorms may occur 
anywhere. Some of the worst floods in U.S. history have been caused by dam failures, 
often when rivers are swollen by flood waters. Extreme winds are regional (e.g., 
hurricanes along the Atlantic and Gulf coasts, the Caribbean, and the South Pacific; 
tornadoes typically in the Midwest; and downslope winds adjoining mountain 
ranges), but high winds can also occur anywhere. 
Floods are fairly specific and predictable in their location, and effective design 
against floods is less a matter of design concept than of siting. A building can be 
located in such a way that floods will never be a problem; however, flood-free loca-
tions are relatively rare and our floodplains are full of existing buildings. Other than 
use of elevation, which can be reasonably effective, design against floods consists of a 
number of detailed measures (e.g., dry and wet floodproofing, which is discussed in 
Chapter 5 of this publication), all of which can be overwhelmed by flooding that 
exceeds the design flood. In some regions of the country, the designer must consider 
two or three natural hazards. In parts of California (in certain coastal and river delta 
regions), buildings are vulnerable to both floods and earthquakes, although the 
probability of simultaneous occurrence is remote. The Hawaiian Islands, Guam, the 
Virgin Islands, Puerto Rico, and parts of the East coast may all be impacted by earth-
quakes, floods, and high winds; although all three are lateral forces, they have many 
different characteristics that must be taken into design consideration.
Figures 3-1, 3-2, 3-3, and 3-4 provide four maps that show an overview of the incidence 
of earthquakes, floods, hurricanes, and tornadoes in the United States. Figure 3-1 
shows the earthquake hazard for the United States; the contour lines on the map 
indicate the 10 percent probability of exceedance of ground motion accelerations 
within each contour area (or the "odds" that there is a 10 percent chance that the 
accelerations will be exceeded in a 50-year period). Maps such as this are used for 
seismic design to estimate the forces for which structures must be designed. Figures 
3-2, 3-3, and 3-4 show the Presidential Disaster Declarations between January 1965 and 
November 2000 for floods, hurricanes, and tornadoes, respectively. These maps show 
only major events, and do not show all the regions where there are hazards. Chapters 
4, 5, and 6 provide information to enable the reader to establish the risk for each of 
these hazards (earthquakes, floods, and high winds) in a local region, respectively.


3.2.2 Warning: How Much Time is There?

The warning times for these hazards vary. Earthquakes are unique among the natural 
hazards because there is no warning at all, although new sensing devices can now 
give a few seconds warning to locations far from the epicenter. Floods (except flash 
floods) can be predicted so as to give hours or days of warning; hurricanes can be 
tracked for days and give several hours of warning before hitting a specific location. 
Tornadoes are more localized and, though visible, may hit a specific location almost 
without notice. 

Although the tornado gives warning and its approach is visible during daylight, its 
winds are often so strong that damage or destruction in its immediate vicinity is 
common. Hurricanes are tracked by the national hurricane tracking system and their 
movement is carefully and thoroughly reported. The hurricane's movement along its 
path is slower and its size is much larger than a tornado, yet even then its precise 
route and timing cannot be predicted until a few hours before making landfall. 
In earthquake-prone areas that experience frequent events, such as California and 
Alaska, there is a continuous generalized prediction, but the earthquake always 
strikes totally without warning. Although much work has been done throughout the 
world to develop a scientific prediction methodology (based on characteristics such 
as changes in the dimensional or physical nature of the ground prior to an 
earthquake; detailed investigation of the geologic strata; or statistical data on the 
incidence of previous earthquakes), earthquakes must still be regarded as random 
events within a general envelope of probability.


3.2.3 Frequency: How Likely are They to Occur?

For all hazards, the regional probabilities are much higher than the local ones, and 
the extreme events are relatively rare for a given site. Inundation of floodplains in 
riverine areas and flooding of poorly protected or sited coastal locations may be 
relatively frequent; the general threat along rivers occurs each winter and spring, and 
a succession of hurricanes roam the Atlantic seaboard every year, bringing the risk of 
extreme winds and storm surge. Traditionally, residents in tornado-prone areas 
retreated to their basements, but engineered safe rooms are now being constructed in 
homes, schools, and other buildings. Earthquakes are perhaps the most difficult to 
deal with, because of their complete lack of warning, their rarity, and their possible 
extreme consequences. Although an earthquake of a given magnitude is still, in 
practical terms, unpredictable, its probability of occurrence can safely be predicted as 
far higher in California or Alaska than in, for example, Massachusetts or Tennessee. 
Even in California, the rarity of a large earthquake is such that many people will not 
experience one in their lifetime. In less seismic parts of the country, one must go 
back several generations, or to folklore, for earthquake stories, but even then there is 
a probability of an event.

Because natural hazards are only broadly predictable, the incidence of future events 
can only be expressed as probabilities. This presents a problem because what may be 
perfectly rational and useful to a mathematician may be confusing or even 
counterproductive to the public and their decision-makers. The probability of 
occurrence of earthquakes, floods, and high winds is commonly expressed by use of 
the term "return period" or "mean recurrence interval." This is defined as the average 
or mean time in years between the expected occurrence of an event of specified intensity.
For example, until recently, earthquake codes used as a basis of severity a level of 
shaking (an acceleration value) that corresponded to a 10 percent probability of 
exceedance in 50 years (or a probability that it would be exceeded one time in 
approximately 500 years, a 500-year return period). More recently, it has become 
apparent that certain areas, such as the Mississippi embayment area, may, in fact, be 
vulnerable to much larger but more infrequent quakes. Therefore, a new set of hazard 
maps has been produced by the United States Geological Survey (USGS) that shows 
acceleration values for a 2 percent probability of exceedance in 50 years 
(approximately 2/3 of design value). Designing to this level would provide real 
protection against a large earthquake. 

Values for high winds are commonly expressed in codes as a 50-year return period, 
much shorter than earthquakes because their incidence is much more frequent. 
Floods are expressed as a 100-year return period (i.e., the "100-year flood"). To the 
public, these return periods seem very long (i.e., why would a business owner 
confronting small crises every day and large ones every month be worried about an 
event that might not occur for 500 years - let alone 2,500 years? ). And if the return 
period for California is 500 years, would it not be another 400 years before something 
of the magnitude of the 1906 San Francisco earthquake occurs?
The problem is that these figures represent mean or average return periods over a 
very long period of time, with the result that the return period is often quite 
inaccurate in relation to the shorter time periods in which most of us are interested 
(i.e., the next year or the next 10 years). Because floods and high winds are relatively 
frequent, the discrepancy between the actual return period and the mean return 
period used in the codes is much more noticeable than the corresponding 
probabilities for earthquakes. 
Currently, these statements of probability are the best we can do. Because they express 
mean values over long periods of time, they tell little about what will really happen 
this year or next year, but they may give a hint as to what will happen in our lifetime. 
Professional disaster planners must assume that disastrous hazards may occur at any 
time. 


3.2.4 Risk: How Dangerous are They?

Deaths and injuries from natural hazards are serious, but are not statistically large on 
an annual basis (e.g., compared to deaths from automobile accidents); nor have we 
recently encountered the number of deaths caused by the Johnstown, Pennsylvania, 
dam failure and flood of 1889 (3,000 killed) or the Galveston, Texas, hurricane of 1900 
(6,000 killed).

Deaths from earthquakes in the United States have been quite small (e.g., less than 
200 people have been killed since 1971, including the San Fernando, California, 
earthquake that killed 65 people in that year and the later Loma Prieta and 
Northridge, California, earthquakes). However, the experience of Kobe, Japan, in 
1995, when over 6,000 people were killed, shows that we cannot be complacent as to 
the ability of a modern city to withstand a direct hit. 
A major concern for those working on reducing earthquake risks is that the United 
States has yet to experience a large earthquake in an urban location (such as the 1906 
San Francisco earthquake or the New Madrid, Missouri, earthquakes of 1811 and 
1812) that seismologists believe to be inevitable. The Northridge earthquake of 1994 
caused approximately 60 deaths, with economic losses estimated to be over $30 
billion. In January 1995, on the anniversary of the Northridge earthquake, an 
earthquake in Kobe, Japan, caused more than 6,000 deaths and economic losses 
estimated to be over $85 billion. 

Since the Loma Prieta, Northridge, and Kobe earthquakes occurred, several analyses 
have been conducted on the potential effects of large earthquakes in California. It is 
estimated that a repeat of the 1906 earthquake on the San Andreas Fault near San 
Francisco would result in 3,000 to 8,000 deaths (depending on the time of day) with 
economic losses from $170 billion to $225 billion in today's dollars. It is also 
estimated that a magnitude 7 earthquake (a moderate to large shock) on the 
Newport-Inglewood Fault in Southern California would kill between 3,000 and 8,000 
people and the economic losses would range from $175 billion to $220 billion.1 
Earthquake-caused fires have historically been a major cause of casualties, most 
notably in the Tokyo earthquake of 1923. Approximately 30,000 people were killed in a 
single fire storm in a park along the Sunida River. Severe damage and casualties were 
caused by fires in the San Francisco earthquake of 1906 and the Kobe, Japan, 
earthquake of 1995.2
In the period between 1987 and 1997, floods caused 407 deaths: 187 were caused by the 
1996 blizzard and flood in the Northeast. Hurricanes caused 599 deaths, 270 of which 
occurred in the 1993 blizzard and storm in the eastern United States. Although these 
numbers for hurricanes are substantial, relative to the size of the impacted area, the 
number of casualties is much less than in tornadoes. Between 1985 and 1997, the 
National Weather Service Storm Prediction Center reported 15 deaths in schools 
alone, of which 9 occurred in 1989.
Statistics for deaths from natural hazards over a recent 20-year period, on a mean 
annual basis, are as follows:3

 Earthquakes 6
 Flash floods 160
 Hurricanes 30
 Tornadoes 100



3.2.5 Cost: How Much Damage Will They Cause?

In the last two decades, losses from natural hazards have escalated. During the period 
from 1987 to 1997, floods caused $30 billion to $37 billion in damage, of which $15 
billion was due to the Midwest floods of 1993. In the same 10-year period, hurricanes 
caused losses of between $60 billion to $66 billion, of which $27 billion was due to 
Hurricane Andrew in Florida and Louisiana. 
The three major California earthquakes that occurred in the period (Whittier 
Narrows, 1987, Loma Prieta, 1989, and Northridge 1994) caused some $36.5 billion in 
damages.

A statistical comparison of percentage of occurrence of property and economic losses 
between January 1986 and December 1992 is as follows:4

 Earthquakes  3
 Hurricanes/Tropical storms 48
 Tornadoes/Other winds 40
 Fire/Explosion 5
 Miscellaneous 4

Although these statistics relate to events prior to the Northridge earthquake of 1994 
and also predate a number of significant floods and hurricanes, the relative 
importance of each hazard has not changed significantly, even though the overall 
dollar values involved have increased sharply.
One cause of this serious increase in the social and economic impacts of natural 
hazards is the rapid pace and intensity of urban and suburban development since 
World War II, particularly in states such as California, the Carolinas, and Florida, all 
of which have their own high hazard probability. Another is the high cost of 
construction, now soaring to levels inconceivable only a few decades ago. A third 
problem is that our political, economic, and social mechanisms for decision-making 
are still ill equipped to deal with the multi-faceted problems of reducing the risks and 
consequences of natural disasters. 


 
3.3 COMPARATIVE LOSSES

The HAZUS-MH (Hazards U.S.-Multihazards) program was developed by the Federal 
Emergency Management Agency (FEMA) to produce loss estimates for use by federal, 
state, regional, and local governments to plan for damage, prepare emergency re-
sponse and recovery programs, and to help examine options to reduce future damage. 
HAZUS-MH is a Geographic Information System (GIS)-based program designed to 
help communities estimate future losses. The methodology covers nearly all aspects 
of the built environment and a wide range of losses. Originally developed to assess 
risks from earthquakes, the methodology has been expanded to address floods 
throughout the U.S. and hurricanes in the Atlantic and Gulf coast regions.
In order to obtain an indication of the magnitude of losses and their relative 
significance for the three hazards considered in this manual, a "Level 1" HAZUS-MH 
analysis was conducted for educational facilities in six areas of the United States. A 
Level 1 analysis uses the building inventory in the HAZUS-MH program and is 
intended to give a broad picture of damage and loss on a regional basis.
The analysis was a regional loss analysis and was based on the building information 
for the EDU 1 occupancy class in the general building stock module from the 
upcoming release of HAZUS-MH. (This occupancy class is the HAZUS-MH 
designation for the school building inventory.) The regions chosen were those prone 
to two or more of the hazards addressed in HAZUS-MH, and deemed to provide a 
useful range geographic range. For each region and applicable hazard, probabilistic 
losses for a 100-and 500-year return period event (earthquake, flood, or high wind) 
were computed. The column "EDU 1 Exposure" in Table 3-1 refers to the total school 
inventory in each region.

The following regions were evaluated:

 Charleston County, South Carolina (Charleston) (earthquake, flood, and hurricane)
 Shelby County, Tennessee (Memphis) (earthquake and flood)
 Bexar County, Texas (San Antonio) (hurricane and flood)
 Salt Lake County, Utah (Salt Lake) (earthquake and flood)
 Suffolk County, Massachusetts (Boston) (earthquake, flood, and hurricane)
 Hillsborough County, Florida (Tampa) (hurricane and flood)

Table 3-1 is a summary of the results for the earthquake, wind, and flood scenarios as 
outlined above. 

Table 3-2 shows another comparison of these losses in the form of the percentage 
loss of school inventory for each event. It is instructive to note, in some cases, the 
wide disparity in losses between the 100-year and 500-year events.



This HAZUS-MH study, though limited in scope and relying on built inventory 
information, reveals some useful information:

  Generally, the 100-year earthquake causes insignificant damage, except in Salt Lake 
City, UT ($3 million).
 The 500-year earthquake causes the most damage in Salt Lake City, UT ($42 
million), followed by Shelby, TX ($15 million) and Charleston, SC ($5 million).
 The 100-year flood causes by far the most damage in Hillsborough, FL ($15 million; 
however, the 500-year flood causes only another $1 million in damage). In Shelby, 
TN, the 100-year flood causes $5 million in damage and the 500-year flood causes 
$9 million. Elsewhere, flood damage is insignificant. 
 The 100-year hurricane causes the most damage in Hillsborough, FL ($20.5 
million), followed by Charleston, SC ($11.5 million) and Suffolk, MA ($10 
million).
 The 500-year flood causes $118 million in damage in Suffolk, MA, $99 million in 
damage in Hillsborough, FL,  and $46 million in damage in Charleston, SC.
Charleston, SC, has the greatest combined threat from earthquakes and hurricanes; 
Hillsborough, FL, has the greatest combined threat from hurricanes and floods. 

The relatively modest damage figures shown in this study could be changed 
dramatically by a single large event, whether an earthquake, flood, or hurricane. It 
should also be noted that none of these locations were on the west coast and, thus, 
the damage figures for earthquakes are low. 



3.3 FIRE AND LIFE SAFETY

Of the many hazards that can endanger a school facility and its service to the 
community, the most prevalent is fire. This is more pervasive than any of the hazards 
noted above. However, design against fire has long been built into our building 
codes, in the form of approved materials, fire-resistant assemblies, exiting 
requirements, the width and design of stairs, the dimensions of corridors, fire 
suppression systems, and many other issues. In fact, fire considerations are now so 
embedded in our design culture and regulation that there is a real danger that some 
designers may not fully realize that fire hazard is a specific design issue that must be 
considered.

According to the Special Report on Educational Property Structure Fires in the United States 
published by the NFPA in 1989, an average of 11,100 structural fires occur annually in 
educational properties. These fires resulted in a direct property loss of nearly $100 
million, with 236 injuries and 3 fatalities. According to both NFPA and the United 
States Fire Administration (USFA), a substantial number of fires in schools are the 
result of arson.

Fires in older school buildings often result in a total loss of the building. This is due 
to a variety of factors, which include: delay of discovery and alarm, remote locations, 
lack of fire walls and/or compartmentation, lack of draft stopping in combustible 
attics, lack of automatic fire sprinkler systems, and inadequate water supplies for 
manual fire suppression activities. Losses in buildings without automatic fire alarm 
and detection systems are twice those in buildings with such systems. Additionally, 
fire losses in buildings without automatic fire sprinkler protection are five times 
higher than those in buildings protected by sprinklers.
Often there appears to be a concern that there is not enough water for automatic fire 
sprinklers. The reality is that the water supply necessary for the proper operation of 
an automatic fire sprinkler system is far less than the amount of water necessary for 
manual fire suppression by the fire department.  As an example, the water supply for a 
fire sprinkler system protecting a typical school building would be in the 350 gallons 
per minute (gpm) range, although 2,500 gpm or more would be required by a typical 
school building without sprinklers.
Since the 1970s, the provisions of the various building codes have continued to 
improve the level of fire and life safety of new school facilities. The level of fire and 
life safety in existing buildings is, however, another matter because the provisions of 
the various building codes are generally not applied to existing facilities except when 
renovations or additions are made and then only to the new work. Given that the 
average age of a school facility in the United States is currently 42 years, it is highly 
likely that older buildings do not provide the same level of protection as newer 
buildings. In order to protect these older facilities, their levels of fire and life safety 
must be evaluated. After an evaluation has been conducted, solutions using 
prescriptive and/or performance approaches can be developed and undertaken.
One system of evaluation is that contained in the existing structures chapter of the 
International Building Code. The "compliance alternatives" section provides a way of 
evaluating the overall level of fire and life safety in an existing building. Although the 
provisions of this section are generally intended to be applied to an existing building 
during changes in occupancy or renovation, it can provide the basis for the 
evaluation of any existing building. 
The evaluation comprises three categories: fire safety, means of egress, and general 
safety. The fire safety evaluation includes structural fire resistance, automatic fire 
detection, and fire alarm and fire suppression systems. Included within the means of 
egress portion are the configuration, characteristics, and support features for the 
means of egress. The general safety section evaluates various fire safety and means of 
egress parameters. The evaluation method generates a numerical score in the various 
areas, which can then be compared to mandatory safety scores. Deficiencies in one 
area may be offset by other safety features.
Another method of evaluating and upgrading an existing facility is the application of 
the provisions of the NFPA 101 Life Safety Code. Unlike the provisions of the various 
building codes, this document is intended to be applied retroactively to existing 
facilities and has a chapter specifically for existing educational occupancies. Even if 
this code is not adopted by the local jurisdiction, it can be used as the basis for an 
evaluation of any existing facility.

There is no question that upgrading an existing school facility can be costly. 
However, the cost of upgrades is far less than the direct and indirect losses of the 
facility to fire. The most effective method of providing fire protection is through 
automatic fire sprinklers, but other lower cost methods can be utilized, including:

 Automatic fire alarm and detection
 Draft stopping in combustible attic spaces
 Smoke and fire compartmentation walls in occupied spaces

Upgrades in fire and life safety can often be coordinated with other building 
renovations or upgrades to help reduce costs. For instance, draft stopping could be 
installed in a wood framed attic during roof deck replacement. Fire sprinklers could 
be installed during asbestos abatement or ceiling replacement/upgrades for seismic 
concerns. 



3.5   HAZARD PROTECTION METHODS COMPARISONS: 
REINFORCEMENTS AND CONFLICTS

An important aspect of designing against all hazards in an integrated approach is 
that the methods used for design may reinforce one another or may conflict with one 
another; in the former case, the costs of multihazard design can be reduced, but, in 
the latter, they may be increased. Table 3-3 summarizes the effects that design for 
more than one hazard may have on the performance and cost of the building, 
addition, or repair. 
The horizontal rows show the five primary hazards. The vertical rows show methods 
of protection for the building systems and components that have significant 
interaction, either reinforcement or conflict. These methods are taken from the 
extended descriptions of risk reduction methods for the three main natural hazards 
discussed herein, together with the methods for security/blast protection presented 
in FEMA 428, Primer to Design Safe School Projects in Case of Terrorist Attacks. In addition, the 
interactions of these four categories of risk protection with fire safety, where they 
occur, are also shown. 

The designations are intended to provoke thought and design integration; they are 
not absolute restrictions or recommendations. In general, reinforcement between 
hazards may be gained and undesirable conditions and conflicts can be resolved by 
coordinated design between the consultants, starting at the inception of design. The 
reader is encouraged to use the list as a basis for discussion relative to specific 
projects and to structure the benefits and conflicts of multihazard design depending 
on local hazards.

Table 3-3 also provides information to help the reader to develop a list of 
reinforcements and conflicts for the particular combination of hazards that may be 
faced. Development of lists such as these can be used to structure initial discussions 
on the impact of multihazard design on the building performance and cost that, in 
turn, guide an integrated design strategy for multihazard protection. The system and 
component heading list is similar to that used for the building security assessment 
checklist in FEMA 426, Reference Manual to Mitigate Potential Terrorist Attacks Against 
Buildings.















MAKING SCHOOLS SAFE AGAINST EARTHQUAKES     4



4.1INTRODUCTION

This chapter outlines the earthquake risk to schools and the processes and 
methods that can be used to reduce it. An explanation of the nature and probability 
of earthquakes is provided, together with procedures for determining the earthquake 
threat to specific locations. An assessment of the scope and effectiveness of seismic 
building codes is followed by an explanation of how to evaluate the vulnerability of a 
school building. Current methods of designing for seismic resistance in new 
buildings and upgrading existing buildings lead to a discussion on determining 
acceptable risk and the use of performance-based design to achieve community 
objectives in providing for seismic safety. 
4.2THE NATURE AND PROBABILITY OF EARTHQUAKES  
Although earthquakes cannot be prevented, modern science and engineering 
provide tools that can be used to reduce their effects. Science can now identify, with 
considerable accuracy, where earthquakes are likely to occur and what forces they will 
generate. This information is readily available and can be obtained for local geo-
graphic regions (see Section 4.2.3). 



4.2.1Earthquakes and Other Geologic Hazards

Earthquakes have long been feared as one of nature's most terrifying phenomena. 
Early in human history, the sudden shaking of the earth and the death and 
destruction that resulted were seen as mysterious and uncontrollable. We now 
understand the origin of earthquakes and know that they must be accepted as a 
natural environmental process. Scientific explanations, however, have not lessened 
the terrifying nature of the earthquake experience. Earthquakes continue to remind 
us that nature can, without warning, in a few seconds create a level of death and 
destruction that can only be equaled by the most extreme weapons of war.
This uncertainty, together with the terrifying sensation of earth movement, creates 
our fundamental fear of earthquakes. Beyond the threat to life is the possibility of the 
destruction of public and private property. Jobs, services, and business revenues can 
disappear instantly and, for many, homelessness can suddenly be very real. The after-
math of a great earthquake can endure for years or even decades. 
Other types of phenomena sometimes accompany earthquake-caused ground 
shaking and are generally identified as geologic hazards:

 Liquefaction occurs when loose granular soils and sand in the presence of water 
change temporarily from a solid to a liquid state when subjected to ground 
shaking. This condition occurs mainly at sites located near rivers, lakes, and bays. 
 Landslides, which involve the slipping of soil and rock on sloping ground, can be 
triggered by earthquake ground motion (see Figure 4-1).
 Tsunamis are earthquake-caused wave movements in the ocean that travel at high 
speed and may result in large coastal waves of 30 feet or more. They are sometimes, 
and incorrectly, called tidal waves.
 Seiches are similar to tsunamis, but take the form of sloshing in closed lakes or 
bays; they have the potential to cause serious damage, although such occurrences 
have been very rare. 
For all of the above geologic hazards, the only truly effective defense is the 
application of good land-use practices that limit development in hazard-prone 
locations. Seismic design and construction is aimed at reducing the consequences of 
earthquake-caused ground shaking, which is by far the main cause of damage and 
casualties. 



4.2.2Earthquakes: A National  Problem

Earthquakes in the United States are a national problem. This was recognized by the 
U.S. Congress in 1977 when it passed legislation authorizing the National 
Earthquake Hazards Reduction Program (NEHRP), which has supported 
considerable research and hazard mitigation implementation since that time. 
Most people now know that earthquakes are not restricted to just a few areas in the 
United States, most notably California and Alaska, and that two of the greatest 
earthquakes known occurred not in California, but near New Madrid, Missouri, in 
1811 and 1812. As shown on a map of earthquake probability in the U.S., more than 40 
of the 50 states are at risk from earthquake-caused damage, life loss, injuries, and 
economic impacts (see Figure 4-2). Certainly the likelihood of a damaging 
earthquake occurring west of the Rocky Mountains, and particularly in California, 
the states of Oregon and Washington, and Salt Lake City, is much greater than it is in 
the East, Midwest, or South. However, the New Madrid, Missouri, and Charleston, 
South Carolina, regions are subject to the possibility of severe earthquakes, although 
with a lesser probability than the western U.S.

There are several common measures of earthquakes. Perhaps the most familiar is the 
Richter Magnitude, devised by Professor Charles Richter of the California Institute of 
Technology in 1935. Richter's scale is based on the maximum amplitude of certain 
seismic waves recorded on a standard seismograph at a distance of 100 kilometers 
(km) from the earthquake epicenter. Because the instruments are unlikely to be 
exactly 100 km from the source, Richter devised a method to allow for the 
diminishing of wave amplitude with increased distance. The Richter scale is 
logarithmic, and each unit of magnitude indicates a ten-fold increase in wave 
amplitude. The energy increase represented by each unit of scale is approximately 31 
times. The scale is open-ended, but a magnitude of about 9.5 represents the largest 
possible earthquake. 

Table 4-1 shows significant earthquakes (Magnitude 6 or over) that occurred in 47 of 
the 50 U.S. states between 1568 and 1989.
Records show that some seismic zones in the United States experience moderate to 
major earthquakes approximately every 50 to 70 years, while other areas have 
"recurrence intervals" for the same size earthquake of about 200 to 400 years. These 
frequencies of occurrence are simply statistical probabilities and one or several 
earthquakes could occur in a much shorter than average period. With current 
knowledge, there is no practical alternative for those responsible for schools located 
in earthquake-prone regions but for them to assume that a large earthquake is likely 
to occur at any time and that appropriate action should be taken. 
Moderate and even very large earthquakes are inevitable, although very infrequent, in 
areas of normally low seismicity. Consequently, in these regions, buildings are very 
seldom designed to deal with an earthquake threat; therefore, they are extremely 
vulnerable. In other places, however, the earthquake threat is quite familiar. Schools 
in many areas of California and Alaska will be shaken by an earthquake perhaps two 
or three times a year and some level of "earthquake-resistant" design has been 
accepted as a way of life since the early 20th century. 
Although, on a national basis, the areas where earthquakes are likely to occur and the 
potential size or "magnitude" of these earthquakes are well identified and scientists 
have a broad statistical knowledge of the likelihood of their occurrence, it is not yet 
possible to predict the near-term occurrence of a damaging earthquake. Therefore, 
lacking useful predictions, it makes sense in any seismic region to take at least the 
minimum affordable prudent actions directed at saving lives. Because most lives are 
lost in earthquakes when buildings collapse, U.S. seismic building code provisions 
focus on requiring that the minimum measures necessary to prevent building 
collapse are taken.
In California, schools are further protected by the Field Act of 1933, which mandated 
additional requirements relating to design qualifications, plan checking, and site 
inspection. (The Field Act is discussed in more detail in Section 4.3.2.)
The following graphics explain some earthquake terminology and characteristics of 
ground motion.

4.2.3 Determination of Local Earthquake Hazards


Until quite recently, the United States was divided into a number of seismic zones, 
which were shown on the maps in the model codes. Zones ranged from Zone 0 
(indicating no seismicity) to Zones 1, 2A, 2B, 3, and 4. Zone 4 indicates the highest 
level of seismicity (see Figure 4-3; only Zones 0, 1, 2A, and 3 are shown). Each zone was 
allocated a factor, or coefficient, from 0.075 to 0.40; this value was a multiplier 
representing the acceleration value for which the building was to be designed. These 
values indicate a four-fold range in acceleration values between Zones 1 and 4.  
Within a zone, all buildings must be designed to the same acceleration value (or 
greater); contour lines show the boundaries between zones.
Current codes, such as the International Building Code, define site seismicity in a 
different way. The United States is still divided into zones by contour lines, but their 
areas are much smaller. Numerical values are also shown on the maps and also 
represent the acceleration value to be used for design, but they are calculated in a 
different way, and many more values are shown that reflect greater precision of 
knowledge. Also, acceleration values for both long and short period buildings are 
shown in a separate series of maps. Figure 4-4 shows a portion of the earthquake 
ground motion map in the International Building Code 2003 corresponding to the 
region shown in Figure 4-3. The simplicity of the old seismic zones is lost, but the 
design information is much more detailed.

If the school district or community desires to obtain more detailed information on 
the seismic hazard than is shown on the code maps, or if the location does not 
enforce a seismic code, but there is concern about seismicity, the U.S. Geological 
Survey (USGS) web page at www.USGS.gov, Earthquake Hazards Program, is an 
excellent resource. The USGS provides more detailed earthquake hazard maps for 
general regions such as the Western, Central, and Eastern U.S. 
Figure 4-5 shows a comparison between the Southeast U.S. and California. The larger 
acceleration values for the latter are symbolized by the darker colors. These maps are 
used as the basis for the maps shown in the IBC. Figure 4-6 shows a comparison, for 
the Southeast U.S., between acceleration values for a 1.0-second period building and a 
0.2- second building. Note the larger acceleration values for the shorter period 
building. 

Figures 4-5 and 4-6 show values for a hypothetical earthquake with a 2-percent 
probability of exceedance in 50 years. This can be visualized as the odds of 
occurrence. The seismic code section of the IBC also shows values for earthquakes 
with a 10-percent probability of occurrence in 50 years (i.e., much shorter odds).
For even more localized information, the USGS provides seismicity information for 
any location in the United States on the basis of latitude and longitude, or Zip Code. 

This information can be obtained by opening the Seismic Hazard listings on the 
USGS web page, and opening Hazards by Latitude and Longitude, or Hazards by Zip 
Code. These listings show information on the expected maximum shaking that is es-
timated for the location. The information and terminology are quite technical and 
may need to be interpreted by qualified staff at the responsible local code office, a 
structural engineer, or perhaps a knowledgeable seismic professional. 



4.3 VULNERABILITY: WHAT EARTHQUAKES CAN DO TO SCHOOLS

This section reviews the experience of schools in earthquakes.  Much of the 
information presented comes from California, because of the prevalence of 
earthquakes in that state. In general, the seismic performance of newer buildings has 
been good, although considerable costly and dangerous nonstructural damage still 
occurs. California public school design and construction has been subject to strict 
regulation since 1933 which undoubtedly contributes to good performance. Many of 
the damage examples shown in this section are of older buildings: this is relevant 
because schools are long-lived buildings and many schools constructed in the early 
decades of the 20th century are still in use.
4.3.1Vulnerability of Schools  
Older unreinforced masonry school buildings present a very high risk, and this type 
of structure has been prohibited by law in California since the mid-1930s, following 
severe damage to schools of this type in the 1933 Long Beach earthquake. 
A structural type that poses perhaps an even greater risk than unreinforced masonry 
is that of the mid-rise nonductile reinforced concrete frame. "Nonductile" refers to 
the frame's lack of ductility (flexibility), or ability to deform considerably before 
breaking (see Figure 4-7). 

Reinforced concrete frames are made ductile by introducing an appropriate, code-
specified amount of specifically designed steel reinforcing; unfortunately, the need 
for this was not recognized in seismic codes until the mid-1970s and so a large 
inventory of these types of structure exists (see Figure 4-8).
Wood frame structures perform effectively, provided that they are well constructed, 
particularly with respect to correct nailing of shear walls as specified in the code and 
properly detailed roof-to-wall connections. Good maintenance, ensuring continued 
protection against moisture and wood attacking insects, is also critical for wood 
frames.
Newer structures, employing frames and fewer walls, also perform effectively if well 
designed and constructed; however, their response differs from that of shear wall 
structures, which are stiff and resistant to lateral forces. Frame structures are more 
flexible, which reduces the forces on the structural members and enables a light and 
safe structure to be designed. 

Modular classrooms are liable to topple off their foundations unless securely attached 
and braced. This damage is not life-threatening, but makes the building unusable; 
fractured power, gas, and waste lines may be a hazard (see Figure 4-9).
If long-span roof and floor members are employed, however, there may be excessive 
drift, or sway, which causes damage to nonstructural components such as hung 
ceilings, light fixtures, light partitions, and contents. Piping, ductwork, electrical 
conduits, and communication pathways (cable trays) may also be damaged. Storage 
units, filing cabinets, and library shelving in any type of structure may be hazardous if 
not properly braced (see Figure 4-10). Broken pipes can create an additional hazard 
in the form of flooding, lack of fire protection water, and, with heating piping or 
domestic hot water piping, this could result in a flood of hot water.
School occupants are particularly vulnerable to nonstructural damage. Although 
students and staff may duck under desks and be safe from falling objects such as 
lighting fixtures and ceiling tiles, ceiling components that fall in hallways and stairs 
can make movement difficult, particularly if combined with power failure and loss of 
lights. Additional falling hazards that are common in schools are large wall-mounted 
televisions (TVs) or ceiling mounted liquid crystal display (LCD) projectors. Heavy 
equipment can be hazardous and falling debris can also cause panic (see Figure 4-11).
Pendant light fixtures have sometimes fallen if they are insecurely attached and not 
designed to swing freely (see Figure 4-12). Sudden breakage of large glass areas is a 
specific hazard because of the dense occupancy in many school rooms; design of 
glazing to resist wind-borne debris and physical attack may also assist in protecting it 
from earthquake motion. This kind of damage has been significant in California 
schools that have suffered recent earthquakes.
Heavy hung lath and plaster ceilings in older auditoriums (and assembly buildings) 
can be dangerous and need careful inspection of their attachment and materials. If 
deficient in safety, replacement is the only acceptable solution (see Figure 4-13).



4.3.2 Earthquake Damage to Schools 

Most information on earthquake damage to schools comes from California. Its high 
incidence of earthquake activity has also resulted in sophisticated seismic building 
codes for all buildings and special plan checking and inspection requirements, 
enforced by the state, for school buildings. 
Considering the number of significant earthquakes in California since the early years 
of the 20th century, there has been remarkably little severe structural damage to 
schools, except in the Long Beach earthquake of 1933, and there have been very few 
casualties. In California, no school child has been killed or seriously injured since 
1933. This good fortune has been primarily because all major California earthquakes 
since 1925 have occurred outside school hours (see Figure 4-14).
In the Long Beach earthquake that occurred at 5:55 p.m. on March 10, 1933, damage 
to unreinforced masonry school buildings was so severe that there would have been 
many casualties had they been occupied. As a result, the state passed the Field Act 
within a month of the earthquake (see Figures 4-15 and 4-16).
The Field Act required that all public school buildings be designed by a California 
licensed architect or structural engineer; all plans were to be checked by the then 
Department of General Services and construction was to be continuously inspected by 
qualified independent inspectors retained by the local school board. The Department 
of General Services set up a special division, staffed by structural engineers, to 
administer the provisions of the Act. The Field Act, which is still enforced today, has 
greatly reduced structural damage to California schools.
The earthquake also resulted in the passage of the Riley Act, which governed all 
buildings, with a few exceptions. The Riley Act required all buildings in the state to 
be designed to a specified lateral force, and effectively outlawed unreinforced 
masonry construction.
In 1952, a series of earthquakes occurred in Kern County, in the Bakersfield region, 
some 70 miles north of Los Angeles. Two groups of earthquakes occurred; the first, in 
the last week of July, included one with a magnitude of 7.6 on the Richter scale. The 
second group occurred in late August, and one earthquake, near the city of 
Bakersfield, had a magnitude of 5.9 on the Richter scale. There were 10 deaths in the 
July earthquake and 2 in the August earthquake.

This earthquake was of particular interest because the incidence of school damage 
might represent that of comparable earthquakes striking in regions today where 
seismic codes have not been adopted and enforced due to the rarity of seismic events 
(see Figures 4-17, 4-18, and 4-19).
There were no casualties in schools in 1952, because these earthquakes also occurred 
outside school hours. At that time, the Field Act had been in force for nearly 20 years, 
and the newer schools had been constructed to conform to its requirements. Of the 
58 masonry schools in the region, 18 had been constructed after the Field Act. Of 
these, one suffered moderate damage; this school was constructed of grouted 
reinforced brick masonry and incurred approximately 1 percent damage. Of the 40 
non-Field Act schools, 1 collapsed, 15 suffered severe damage, and 14 suffered 
moderate damage. In the Bakersfield City School District, 175 classrooms and 6,500 
students were displaced and only about 10 classrooms could quickly be put back in 
service. There was considerable nonstructural damage to ceilings and light fixtures. 
In other states, similar damage to unreinforced masonry (URM) and early reinforced 
concrete structures occurred. Considerable damage to schools occurred in Helena, 
Montana, in 1935 (see Figure 4-20). In 1949, severe damage was inflicted on several 
URM schools, resulting in one fatality, in Seattle (see Figures 4-21 and 4-22). At 
Puyallup High School, three boys on the stage just managed to escape when the roof 
collapsed (see Figure 4-23). Widespread damage to furniture and contents also 
occurred (see Figure 4-24). 


4.3.3 Significant School Damage in Recent U.S. Earthquakes

In the Anchorage, Alaska, earthquake of 1964, which registered 8.4 on the Richter 
scale, a number of public schools were damaged, but there were no collapses. The 
earthquake occurred on Good Friday at 5:36 p.m., when the schools were unoccupied. 
The most seriously damaged school was that shown previously in Figure 4-1; the 
school was subsequently demolished. At the West Anchorage High School (see 
Figures 4-25 and 4-26), a two-story nonductile concrete frame and shear wall 
classroom wing suffered severe structural damage and near total failure in a number 
of columns. Structural distortion also created a number of severe glass breakages.  
The second floor was removed during reconstruction and the first floor was repaired 
and retained.

In the San Fernando, CA, earthquake of 1971, there were no injuries and no schools 
collapsed; however, the earthquake caused $13.2 million in damages (in 1971 dollars), 
and 100 pre-Field Act schools were demolished within 112 years after the earthquake. 
A survey of 1,544 public school buildings showed that only three schools sustained 
severe damage as a result of the Loma Prieta (San Francisco Bay area) earthquake of 
1989. A portable classroom near Santa Cruz was rocked off its unbraced and 
unanchored supports. An elementary school in Los Gatos was subjected to severe 
shaking, but damage was limited to nonstructural and contents shifting, except in 
one classroom wing, where ground heaving raised and cracked the floor slab, jam-
ming a door and window shut. 
A San Francisco High School suffered severe structural cracking. This school was 
constructed in 1920 as an automobile manufacturing building and was structurally 
upgraded in 1947. Restoration costs were estimated at $10 million. Total restorations 
for the San Francisco school district were estimated to be $30 million; for Oakland, 
the district losses were $1.5 million. Though undamaged, an elementary school in 
San Francisco was closed because of the potential collapse of a nearby elevated 
freeway structure, which was considered a hazard to the building and its occupants. 
Hazards from unbraced and unanchored nonstructural items were evident in many 
buildings, including pendant-mounted light fixtures, suspended acoustical ceilings, 
and unanchored furniture and contents such as filing cabinets and shelving.
In the Northridge, California, earthquake of 1994, state inspectors red-tagged 24 
school buildings and yellow-tagged 82 school buildings, although this was later 
considered over-conservative.  No structural elements collapsed. There was, however, 
considerable nonstructural damage that was costly to repair, resulting in the closure 
of a number of schools and, if the schools had been in session, would have caused 
casualties. The Field Act focused on structural design and construction, and only 
recently were nonstructural elements included in the scope of the Act (see Figures 4-
27, 4-28, and 4-29).


4.3.4 Consequences: Casualties, Financial Loss, and Operational Disruption

Casualties in California schools have been few and minor, primarily due to regulation 
by the Field Act and by chance. Significant Alaskan and California earthquakes, from 
Santa Barbara (1925) to Northridge (1984) have all occurred outside of school hours: 
therefore, the effects of a major earthquake when schools are fully occupied have not 
been experienced. In other regions, casualties have been few; in the Seattle 
earthquake of 1949, two school children died in Tacoma when bricks cascaded onto 
exit ways. The closure of Seattle schools for spring vacation had averted fatalities and 
serious injuries in similar building failures at a number of sites in the city.
The impact of school closure as a result of damage is the loss of public service and 
severe disruption for students, faculty, and staff. Ultimately, the taxpayer will pay the 
costs, but this is spread over the whole community, the state, and the Federal 
Government. Typically, schools are self-insured and do not purchase insurance on 
the private market. For a private school, closure means a serious loss of revenue; in 
addition to the costs of repair, the students may not return if the school is closed for a 
long period of time. Therefore, obtaining insurance may be a prudent measure. 
As with any of the natural hazards reviewed in this manual, an earthquake can close a 
school, keeping the school district from doing its main job (i.e., teaching students). 
The length of the closure will depend on the severity and types of damage. It may also 
depend on whether the building was fully insured or whether disaster assistance will 
be available quickly enough to allow speedy repairs and reconstruction. Sometimes 
repairs are put on hold, pending a decision on whether the building should be 
repaired or condemned.
There are also social and psychological factors, such as difficulties imposed on 
students, parents, faculty, staff, and the administration during the time the school is 
not usable. This is illustrated by the following quotation that, although it refers 
directly to hurricanes, also applies to earthquakes and other disasters.  



4.4 SCOPE, EFFECTIVENESS, AND LIMITATIONS OF CODES

Building design in the United States has typically been regulated by the provisions of 
one of three model building codes: the National Building Code (NBC), published by 
Building Officials and Code Administrators International (BOCA); the Standard 
Building Code (SBC), published by Southern Building Code Congress International 
(SBCCI); and the Uniform Building Code (UBC), published by International 
Conference of Building Officials (ICBO). The UBC tended to be most commonly 
adopted in the Western U.S., the NBC was used predominantly in the Northeast and 
Midwest, and the SBC was most commonly used in the South and Southeast. 


4.4.1 The Background of Seismic Codes

Seismic codes currently in use in the United States have been very highly developed 
since the initial regulations for the protection of buildings against earthquakes first 
appeared in the UBC in California in 1927. Beginning in the 1950s, the earthquake-
resistant design provisions of the three model codes used as the basis for building 
regulation in the U.S. were based on recommendations developed by the seismology 
committee of the Structural Engineers Association of California (SEAOC) and 
contained in their publication known as the "Blue Book."   
FEMA, one of the lead agencies in NEHRP, provided support for updating and 
continued development of a seminal document, ATC-3-06, produced by the Applied 
Technology Council (ATC), a non-profit research foundation set up after the San 
Fernando earthquake of 1978 to work on recommended improvements in the seismic 
building code. The ATC-3-06 document, now titled the NEHRP Recommended Provisions 
for Seismic Regulations for New Buildings and Other Structures, has been updated every 3 years 
since 1985. These provisions were adopted by the SBC in 1992 and, in 1997, the seismic 
provisions of the UBC and NEHRP were combined. 
Depending on which code regulated the structural design, seismic design was 
conducted in accordance with one of two significantly different sets of provisions. 
Seismic design of structures under the UBC is governed by provisions developed by 
the SEAOC and structures designed under the NBC and the SBC are governed by 
somewhat different provisions developed by the Building Seismic Safety Council 
(BSSC) of the National Institute of Building Sciences (NIBS). Following a major effort 
by both groups, the 1997 editions of both the UBC and NEHRP Provisions resulted in a 
unification of these design approaches.

Meanwhile, after years of negotiation, all three model code entities have now 
consolidated their services, products, and operations into one member service 
operation, the International Code Council. The ICC first published a unified model 
building code, the International Building Code (IBC) in 2000, with revisions planned 
on a 3-year basis. The seismic provisions of the IBC are based primarily on the unified 
UBC/NEHRP provisions. Subsequently, however, the National Fire Protection 
Association has also developed a model building code, the NFPA 5000, Building 
Construction and Safety Code, first issued in 2002. The American Society of Civil 
Engineers (ASCE) published ASCE 7 Minimum Design Loads for Buildings and Other 
Structures, which gives requirements for dead, live, soil, flood, wind, snow, rain, ice, 
and earthquake loads. ASCE 7 is referenced in the UBC, IBC, and NFPA model codes.
Thus the seismic codes are in a state of transition, and the intent of developing a 
single, nationally applicable model code has not yet been realized. Currently, 
jurisdictions are faced with continuing with one of the three original model codes, 
which will become increasingly out of date because they will no longer be revised and 
published, or adopting the IBC or NFPA 5000 model codes. Some large municipal 
jurisdictions will continue to produce their own codes, which will be derived from 
some combination of the model codes.  
As noted above, seismic codes have the primary purpose of establishing the minimum 
lateral forces for which buildings must be designed. To do this, the code provides an 
equation, in which the vibrating seismic forces are represented by a single static 
force, called the "base shear," applied at the base of a building. Variables in the 
equation enable the designer to adjust the design force for varying site seismicity, 
alternative soil conditions, different structural and nonstructural systems and 
materials, different building heights, and occupancies of varying importance. 
In addition, the codes have a number of provisions that deal with the detailed design 
of some building components, such as reinforcing steel in concrete structures and 
welding in steel structures. Because the actual forces on the building are estimated in 
a very simplified manner, a large safety factor is introduced, so that the design forces 
tend to be over-estimated.


4.4.2 Seismic Codes and Schools

Seismic codes are concerned primarily with types of structures and there are a few 
provisions that relate to specific occupancies. The IBC categorizes school buildings 
as Type II:  "...buildings and other structures that represent a substantial hazard to 
human life in the event of failure..."  Type II buildings are assigned an Importance 
Factor of 1.25. This means that the seismic force calculated by use of the Equivalent 
Lateral Force procedure would be multiplied by 1.25 so that schools are designed to a 
higher standard than ordinary buildings. 
As previously mentioned, in California, K-12 schools are regulated by the Field Act, 
which is the only significant legislation that singles out the design and construction 
of schools to resist earthquakes and is an important model. However, the Field Act is 
not a code; it requires that schools be designed by a licensed architect or structural 
engineer, that plans and specifications be checked by a special office of the 
Department of the State Architect, and that independent testing and inspection be 
conducted during construction. The Greene/Garrison Act of 1976 made the Field Act 
provisions retroactive and required that all nonconforming schools be brought up to 
the current code level. 

Implementing the nonstructural provisions of the seismic code will significantly 
reduce damage to the nonstructural components and reduce the possibility of 
closing the school because of ceiling and lighting damage, partition failures, and 
loss of essential utilities. In this instance, the code goes somewhat beyond the 
structural objective of only reducing the risk of casualties. However, this is an 
important issue for schools, for recent experience in earthquakes has shown that 
nonstructural damage to schools is dangerous to the occupants, costly to repair, and 
operationally disruptive.


4.4.3 The Effectiveness of Seismic Codes 

Building codes originated in the effort to reduce risk to health and safety, rather than 
reducing property loss, but, as they evolved, they indirectly and directly assisted in 
reducing building damage. They establish the minimum standards for safety 
commensurate with affordability and other impacts such as measures that might 
create extreme inconvenience to occupants or seriously reduce the building's 
functional efficiency.
Among engineers, there is general agreement that, based on California's earthquake 
experience, regulation through a properly enforced seismic code has largely fulfilled 
the intent of ensuring an acceptable level of safety against death and injury. The 
performance of school buildings in recent California earthquakes substantiates this; 
structural damage has been minimal in the more recently designed schools. 
Application of the Field Act ensures that schools are designed and constructed to 
more rigorous standards than most other buildings. 
Some qualifications, however, follow:

 Even in California, the standards of code enforcement vary considerably, and 
smaller jurisdictions may not have trained engineering staff to conduct effective 
plan checks and inspections. 
 The nonstructural provisions of the seismic codes are often not adopted at the local 
level. Even in California, nonstructural components have not been regulated to 
the same level of care as structural components, and have been the cause of 
considerable economic loss and disruption of operation. 
 In regions of moderate earthquake risk that have recently introduced seismic 
design regulation, the code may be misinterpreted and design errors made due to 
inexperience of both designers and building officials.



4.5 EVALUATING EXISTING SCHOOLS FOR SEISMIC RISK AND 
SPECIFIC RISK REDUCTION METHODS

A set of well developed procedures exists for the seismic evaluation of buildings, and a 
number of FEMA-sponsored publications are available to assist in the evaluation 
process. These guides have been developed since the 1980s and have been used 
extensively. However, this section also provides a simple seismic evaluation checklist 
that focuses specifically on schools.

The procedures are listed below in the order in which they would be used, starting 
with a simple screening process. 


4.5.1 Rapid Visual Screening

The Rapid Screening Procedure (RSP) was published in FEMA 154, Rapid Visual 
Screening of Buildings for Potential Seismic Hazards: a Handbook. The procedure is intended 
as an initial step in identifying hazardous buildings and their deficiencies. Buildings 
identified by this procedure to be potentially hazardous must be examined in more 
detail by a professional engineer experienced in seismic design. Because this 
screening is aimed at providing a low cost method of identifying large inventories of 
potentially hazardous buildings for public and private owners, and thus reducing the 
number of buildings that should be subject to a more detailed evaluation, it is 
designed to be performed from the street without benefit of entry into a building. 
The screening process can be completed in 20-30 minutes for each building. In some 
cases, hazardous details may not be visible, and seismically hazardous structures will 
not be identified as such. Nonstructural interior components are not evaluated. 
Conversely, buildings identified as potentially hazardous may prove to be adequate.
Typically, a school district will not be faced with the problem of lack of building 
access and the RSP procedure is most useful for large school districts, municipalities, 
or even states that wish to get an economical preliminary evaluation of the seismic 
risks faced by their school inventory. The procedure is not intended to provide a 
definitive evaluation of the individual buildings. 

The methodology is based on a visual survey of the building and a data collection 
form used to provide critical information. The collection form includes space for 
sketches and a photo of the building as well as pertinent earthquake-safety related 
data. The FEMA handbook for the procedure provides the inspector with background 
information and data required to complete the form (see Figure 4-30). The procedure 
is designed to be usable by people with some knowledge of buildings who are not 
necessarily professional architects or engineers or familiar with seismic design. It has 
been successfully applied by architectural and engineering students. The 
methodology enables the inspector to identify significant seismic-related defects and 
to arrive at a numerical score, with a hazard ranking of 1-6 (see Figure 4-30).
The ranking of surveyed buildings can be divided into two categories: those 
acceptable as to risk to life safety or those that may be seismically hazardous and 
should be studied further. A score of 2 is suggested as a "cut-off" based on current 
seismic knowledge (i.e., if a building has a structural "score" of 2 or less, it should be 
investigated by a structural engineer experienced in seismic design).


4.5.2 Systems Checklist for School Seismic  Safety Evaluation

Table 4-2 represents a simplified version of the FEMA 178/310 Evaluation Procedure; 
also see Section 4.5.3. This version focuses on structural and nonstructural systems 
and components that will be found in schools. The data are organized on a systems 
basis and are designed to establish whether the building is a potential seismic hazard 
and, if so, what its specific vulnerabilities are. Use of the checklist requires some 
seismic engineering knowledge, but the information can be obtained by inspection 
and no engineering calculations are necessary. The checklist can be used in 
conjunction with the RSP procedure, and will augment the RSP analysis because it 
assumes that the building will be accessible and design drawings are available. Both 
of these conditions are likely to be met in evaluating a public school building.
The checklist can also be useful in interdisciplinary discussions between consultants 
and school district personnel, and can assist in fee negotiation with the client. 


4.5.3 The NEHRP Handbook for the Seismic Evaluation of Existing Buildings (FEMA 
178/310) 

For those buildings that, as the result of a preliminary screening, are candidates for a 
more detailed investigation, the BSSC developed a procedure for the systematic 
evaluation of any type of building (FEMA 178 and 310, The NEHRP Handbook for the 
Seismic Evaluation of Existing Buildings). This procedure can be used to evaluate the 
structural and nonstructural systems and components for any type or size of 
individual school building. However, the procedure focuses on evaluating whether 
the building is a potential earthquake-related risk to human life posed by the 
building or a building component. The procedure does not address code 
compliance, damage control, or other aspects of seismic performance not related to 
life safety.

The handbook methodology involves the use of two sets of questions: one set 
addresses the characteristics of 15 common structural types and the other, instead of 
addressing complete structural systems, deals with structural elements, foundations, 
geologic site hazards, and nonstructural components and systems. These questions 
are designed to uncover the flaws and weaknesses of a building, and are in the form 
of positive evaluation statements describing building characteristics that are essential 
if the failures observed in past earthquakes are to be avoided. The evaluating architect 
or engineer should address each statement and determine whether it is true or false. 
True statements identify conditions that are acceptable and false statements identify 
conditions in need of further investigation. The handbook also specifies a process 
for dealing with statements that are found to be false. 
The evaluation requires some basic structural calculations and a site visit and follow-
up field work will be necessary. The primary product of the evaluation is the 
identification of weak links in the building that could precipitate structural or 
component failure. Although the procedure will provide guidance on structural 
deficiencies, it is not intended to identify appropriate seismic retrofit options. The 
design engineer needs to understand the overall deficiencies of the building before 
attempting to identify retrofit design approaches. The overall deficiencies may be due 
to a combination of component deficiencies, inherent adverse design, construction 
failures, deterioration, or a serious weak link.


 
4.6 EARTHQUAKE RISK REDUCTION METHODS

Although the general principles of design are similar for new or existing schools, 
there are differences in code requirements and overall project delivery processes that 
reflect the design freedoms of new buildings and the constraints of existing ones. 
Engineering of structural and nonstructural risk reduction methods is similar for 
new and existing schools. New school design offers the possibility of construction on 
a site subject to less ground motion because of better soil conditions or further 
proximity to a fault. It can be designed with the most appropriate structural system, 
using known and tested materials and a good building configuration. These 
possibilities are not available when retrofitting an existing school; the building may 
have been designed to an obsolete seismic code or no code at all, its materials may be 
questionable, and the building configuration and structural system may be 
inappropriate. Therefore, the protection of an existing school must start with a 
careful evaluation of its vulnerability. Seismic retrofitting is expensive and time-
consuming; however, the adoption of an incremental retrofit procedure, as described 
in Section 4.6.2, can help to keep time and cost within reasonable limits. 


4.6.1 Risk Reduction for New Schools

Methods of design for earthquake protection involve three main aspects of the 
school: its site, its structure, and its nonstructural components. 

In terms of risk reduction, the first priority is the implementation of measures that 
will reduce the risk of casualties to students, staff, and visitors.  The second priority is 
the reduction of damage that leads to downtime and disruption. The third priority is 
the reduction of damage and repair costs.
Alternative measures to achieve these objectives are as follows, in ascending order of 
cost:

 New Schools Regulated by Seismic Codes
 Provide personal protection training.
 Evaluate code provisions against risk priorities. Evaluate whether design to 
current code will meet acceptable risk objectives for damage costs and 
reduction of downtime.
 Consider adopting California's Field Act model for quality control of design 
and construction; can be administered by a single district with specification 
provisions for inspection in contract documents. 
 Use performance-based design procedures if code-based design does not meet 
acceptable risk objectives.
 New Schools Not Regulated by Seismic Codes
 Provide personal protection training.
 Design to appropriate code standards on a voluntary basis.
 Use performance-based design procedures to meet acceptable risk objectives.
 Consider adoption of seismic code; requires community-wide cooperation.
Damage reduction is common to all the objectives. The following sections give an 
overview of the design strategies that are used to achieve acceptable levels of 
protection in new schools.

School Sites. Protection of schools and their occupants from earthquakes depends on 
correct seismic design and construction to resist the estimated earthquake forces that 
the building could encounter at its site. Because ground motion from a single earth-
quake may vary considerably, depending on the nature of the soil and the distance of 
the building from known earthquake faults, careful site selection is a critical first step 
in reducing the forces on the building, although a single school site or a small 
district will rarely have this option. School sites are generally selected based on 
factors such as availability, served student population, cost, convenience of access for 
the school students and staff, and general demographic concerns rather than 
seismicity. However, a large district that is developing a multi-school plan of new 
facilities should include recognition of any natural hazard vulnerabilities as a factor 
in the evaluation of alternative sites. A school district can reduce its seismic 
vulnerability by reducing the intensity of earthquake shaking to be expected at a site 
over the life of the building. There are several ways in which this can be 
accomplished:

 Locate the building in an area of lower seismicity, where earthquakes occur less 
frequently or with typically smaller intensities. Although it would be very rare for a 
school district to make a site selection decision based solely on seismic risk, 
moving a school even a few miles in some cases can make a big difference to its 
seismic hazard, such as locating a school within 1 mile of a major fault versus 
being 5 to 10 miles away from it
 Locate the building on a soil type that reduces the hazard. Local soil profiles can be 
highly variable, especially near water, on sloped surfaces, or close to faults. In an 
extreme case, siting on poor soils can lead to liquefaction, land sliding, or lateral 
spreading of the soil. Frequently, similar buildings located less than 1 mile apart 
have performed in dramatically different ways because of differing soil conditions 
in earthquakes. Even when soil-related geologic hazards are not present, 
earthquake motions that have to travel through softer soils will be amplified more 
than those traveling through firm soils or rock. If general knowledge of site 
conditions is a concern, the effects of soil hazard on risk should be determined by 
the use of geotechnical and structural engineers to assess the potential 
vulnerabilities associated with differing site conditions. Variables in 
vulnerabilities should be weighed against the costs, both direct and indirect, of 
locating the facility on soils that will result in better performance.

 Engineer the building site to increase building performance and reduce 
vulnerability. If building relocation to an area of lower seismicity or to an area 
with a better natural soil profile is not a cost-effective option, the soil at the 
designated site can sometimes be treated to reduce the hazard. For example, on a 
liquefiable site, the soil can be grouted or otherwise treated to reduce the 
likelihood of liquefaction occurring. Soft soils can be excavated and replaced, or 
combined with foreign materials to make them stiffer. Alternatively, the building 
foundation itself can be modified to account for the potential effects of the soil, 
reducing the building's susceptibility to damage even if liquefaction or limited 
land sliding does occur. The school board should weigh the additional costs of 
modifying the soil characteristics or the building foundation with the expected 
reduction in damage and loss. However, because most schools are one or two 
stories in height, site area usage is considerable, and site treatment is likely to be 
costly.

In most cases, it is probable that a designated school site will be accepted. Proposed 
construction directly over a fault is probably the only location characteristic that 
would lead to rejection of an otherwise suitable site. The forces for which the school 
must be designed are also increased if it is in close proximity of a fault, which will 
increase the structural cost.  Sites are assigned to one of six categories, from A, which 
represents hard rock, to F, which represents soils vulnerable to potential failure or 
collapse such as liquefiable soils, sensitive clays, and weak soils and clays. Variations 
in soil type are covered by increasing or decreasing the design forces by application 
of a coefficient within the calculation of the Equivalent Lateral Force (ELF) 
equation, which is used to establish the design lateral forces on the building. 
The ELF procedure assumes a soil type B. For categories A through E, design forces 
must be modified by application of a coefficient, or multiplier. For Category A soils, 
the multiplier is 0.8  (i.e., the values are reduced). For Category E soils, the multiplier 
can be as high as 2.5 for short-period buildings such as schools. For buildings located 
on type F soils, a site-specific geotechnical investigation must be performed to 
establish design values.
Reducing Damage to School Structures. Minimum standards and criteria for 
structural design are defined in the seismic codes. The codes provide maps that show 
whether the location is subject to earthquakes and, if so, the probability of 
occurrence, expressed by varying levels of seismic forces for which a building must be 
designed. Seismic codes are adopted by state or local authorities, so it is possible for a 
seismically-prone region to be exempt from seismic code regulations if the local 
community feels that the adoption of a seismic building code is not desired. Based on 
historic and scientific data, although the seismic hazard exists, some communities 
may choose to ignore the risk, because no one has experienced an earthquake in 
their lifetime. Such a policy should be of serious concern to school district officials, 
the local school board, and parents.  
This is a difficult issue because, although the risk may appear to be minimal, the 
effects could be catastrophic if a significant event were to occur. The very fact that 
such an event is rare means that the community may have no history of design for 
earthquakes and the building stock will be especially vulnerable. School buildings 
are an important community resource (along with other essential buildings such as 
hospitals, and fire and police stations) that should not gamble on the avoidance of a 
rare event. 
Because of systematic observation of earthquake damage to buildings and extensive 
analytical and experimental research, seismic design in the 20th century has become 
a highly developed technology. 

Reducing structural damage in earthquakes depends on:

 The correct application of code criteria and analytical methods. Seismic codes have 
become increasingly complex and a high standard of care and engineering 
judgment is necessary to ensure correct application. 
 The correct selection and application of structural systems and materials. Different 
structural systems have varied characteristics that must be matched to the nature 
and purpose of the school. Flexible planning, for example, implies the use of a 
frame structure rather than relying on shear walls that may impact planning 
freedom. 
 The following two graphics show the basic types of structural lateral force resisting 
systems.
 The correct design of critical elements such as frames, shear walls, and diaphragms 
and their connections to one another: earthquake forces search out the weak 
links between structural members.  Serious damage and collapse is often initiated 
by connection failure. These are the critical elements that provide seismic 
resistance; they must be correctly sized, located, and detailed.  
 Careful attention to key structural design principles such as provision of a direct 
load path and structural redundancy. 
 The correct design of the connections between structural elements and 
nonstructural components. 
 Configuration of the building (its size and shape) to be as simple and regular as 
planning and aesthetic requirements permit. Experience has shown that certain 
building shapes and architectural design elements contribute to bad seismic 
performance and need expensive structural design methods to make them 
achievable. 
 A high level of quality control to ensure that the building is properly constructed. 
Careful seismic design is valueless if not properly executed.
 A high level of maintenance to ensure that the building retains its integrity over 
time. Corrosion of steel and termite infestation or dry rot in wood can seriously 
affect structural integrity.

The following graphics show some problems caused by irregular building 
configurations.

Reducing Damage to Nonstructural Components and Systems. Nonstructural 
components and systems are defined as those elements that do not contribute to the 
seismic resistance of the building (see Figure 4-31). They typically comprise from 75 
to 80 percent of the total school building by value, and they transform the structure 
into a working environment that provides weather protection, heating, cooling, 
lighting, and acoustic control. Damage to these components can be costly and 
render the building functionally useless even if the building structure performs in 
accordance with the intent of the seismic code. Nonstructural components are 
generally broadly classified as:

 Architectural
 Exterior envelope - opaque or glazed, roof and wall coverings
 Veneers
 Interior partitions
 Ceilings
 Parapets and appendages (e.g., signs and decorative elements) 
 Canopies and marquees
 Chimneys and stacks
 Mechanical 
 Boilers and furnaces 
 HVAC source equipment and distribution components
 Electrical and Electronic
 Source power equipment and distribution components
 Source communications equipment and distribution components
 Light fixtures 
 Plumbing
 Storage vessels and tanks
 Piping systems 
 Hazardous materials distribution
 Furnishings and Interior Equipment 
 Bookcases, filing cabinets, and other storage 
 Shop and art equipment 
 Hazardous materials (HazMat) storage

Reduction of damage to nonstructural components depends on using methods of 
supporting and bracing the components to prevent failure (see examples in Figures 
4-32, 4-33, 4-34, and 4-35). Seismic codes provide the design force for which the above 
components must be designed, together with a number of specific design 
requirements that must be followed. 

4.6.2 Risk Reduction for Existing Schools

Procedures and Design Strategies. Additions to an existing school must meet all of the 
code requirements for a new building. There is currently no seismic code that applies 
to the retrofit of existing schools. Typically, the standards to be applied are derived 
from the code for new buildings and negotiated with the applicable building 
department. It is generally recognized that it is difficult or almost impossible to bring 
an existing structure up to full compliance with a current code and so some 
compromises have to be made; there is, however, no general agreement as to how the 
code for new buildings is applied to the retrofit design of existing ones. 
Reducing the seismic risk for an existing building requires the same general design 
principles as those necessary for a new building, but the architect and engineer are 
faced with existing structural and nonstructural systems and materials that may be far 
from ideal and, as previously stated, to bring them up to the standard of a new 
building could be difficult or almost impossible. 

The process should begin with an evaluation procedure similar to those outlined in 
Section 4.5. If the result of these evaluations is the need to retrofit an existing school 
or schools, the NEHRP Guidelines for the Seismic Rehabilitation of Buildings (FEMA 273) is 
the authoritative source document and can be used to help a school district select 
seismic protection criteria. The architect and engineer can also use the document for 
the design and analysis of seismic retrofit projects. 

FEMA 273 adopted the approach of providing methods and design criteria to achieve 
several different levels and ranges of seismic performance (unlike a conventional 
code that implies, but does not define, a single performance level). In doing this, the 
document shows that there is always the possibility of damage in a seismic event and 
the term "seismic performance" refers to the nature and extent of damage that the 
building exhibits. FEMA 273 provides a thorough and systematic procedure for 
performance-based seismic design, intended to result in the development of a design 
that targets achieving the owner's level of acceptable risk within the owner's available 
resources. 

The performance-based design approach outlined in FEMA 273 provides uniform 
criteria by which existing buildings may be retrofitted to attain a wide range of 
performance levels, when subjected to earthquakes of varying severities and 
probabilities of occurrence. The process starts by requiring that the user select 
specific performance goals as a basis for design. In this way, users can directly 
determine the effect of different performance goals on the design requirements, 
including their complexity and cost. 

Typical design strategies for improving the protection of an existing school include 
(see Figure 4-36):

 Modifying and improving local components or materials, such as beam/column 
connections. This involves retrofitting connections and strengthening structural 
members by such methods as adding reinforcing or replacing them with new 
components.
 Removing or reducing configuration irregularities. This involves providing seismic 
separations in irregular configurations or adding shear walls or bracing to reduce 
torsional effects, thereby strengthening and/or stiffening the entire structural 
system. This is a major retrofit that involves adding bracing or shear walls, 
replacing many structural members. 
 Reducing the mass of the building (to reduce forces). This involves changing the 
location of heavy items (e.g., bookcases) within the building, but would not apply 
to a one-story building, except where a tile or slate roof covering might be 
replaced with a lightweight material. 

Retrofit Methods. Seismic (base) isolation (to reduce force on the building 
superstructure) is a new technique that has been successfully used in the retrofit of 
large buildings, but it is not appropriate to the scale and nature of school buildings 
unless the school building is considered a historical building. A newer technique is 
passive energy dissipation, the insertion of supplemental energy devices (to reduce 
movement), which might be applicable to certain types of school structures (e.g., 
large gymnasiums, multiuse buildings, or auditoriums). 
Seismic retrofit at any large scale is expensive, both in design and construction, 
because of the more complex analyses that must be conducted and the construction 
constraints that must be overcome. In addition, closure of a school for an extended 
period (beyond that of the normal summer break) is usually unacceptable. Major 
seismic retrofit is rare, although some successful projects have been done, primarily 
with the goal of saving a building that is not only a place of learning, but a historic 
community resource as well. The retrofitting of the B.F. Day School in Seattle was one 
such project (see Figures 4-37 and 4-38).       

Incremental Seismic Rehabilitation. An approach that greatly improves the feasibility 
of retrofitting a school is that of "Incremental Seismic Rehabilitation." A full 
description of this procedure is presented in Incremental Seismic Rehabilitation of School 
Buildings (K-12) (FEMA 395). The principles of this process follow.
Whereas extensive single-stage seismic retrofitting of an existing school represents a 
significant cost, retrofit actions can be divided into increments and integrated into 
normal repairs and capital improvement projects. Implementation of incremental 
seismic retrofit requires assessing the buildings, establishing retrofit priorities, and 
planning integration with other projects. Integration will reduce the cost of the 
seismic work by sharing engineering design costs and some aspects of construction 
costs. An "integration opportunity" occurs when a seismic retrofit measure can be 
paired with other repair or replacement tasks or categories. Integration opportunities 
are a key consideration in determining the sequence of operations that will be 
conducted.
School districts often categorize maintenance and capital improvement projects in 
the following eight categories;

 Re-roofing
 Exterior wall and window replacement
 Fire and life safety improvements
 Modernization/remodeling/new technology accommodation
 Under floor and basement maintenance and repair
 Energy conservation/weatherizing/air conditioning
 Hazardous materials abatement
 Accessibility improvements 


FEMA 395 provides five matrices that show possible combinations of seismic 
improvement measures with typical work categories. A typical matrix from FEMA 395, 
showing possible seismic improvements relating to roof maintenance and repair is 
shown in Table 4-3.
Incremental seismic retrofit is an effective, affordable, and non-disruptive strategy to 
achieve responsible seismic risk mitigation.
At the lower levels of protection, some effective construction measures (e.g., bracing 
nonstructural bookcases and filing cabinets, and anchoring key desktop equipment 
such as computers) can be implemented by school district maintenance personnel. 
As a last resort in cases of extreme risk and badly antiquated school buildings, 
demolition is the only solution. 



4.7 THE SCHOOL AS A POST-EARTHQUAKE SHELTER

In the aftermath of any damaging earthquake, there is an immediate need of shelter 
for people who have been displaced from their homes. There are three kinds of 
shelters:

 First is the immediate need for shelter on the day or night of the earthquake. The 
American Red Cross has a congressional mandate to provide this after any 
disaster, with the intent that this will be available only for a few weeks.
 Following the immediate need, there is a need for longer-term housing, while 
homes and apartments are being repaired. This is generally accomplished by 
governmental subsidies that enable people to move into vacant hotel rooms or 
apartments. This kind of shelter depends, to some extent, on the availability of 
these forms of housing on the market in the local area. This is sometimes 
augmented by temporary housing; where the season and climate allow, this can be 
provided by tents and FEMA has, in the past, maintained a stock of modular 
housing that can be moved to a local site within a month or two, depending on 
the availability of land. This housing may be occupied for a year or so, depending 
on the scale of the disaster. 
 Finally, there is permanent replacement housing that is typically provided by the 
home building industry and non-profit housing organizations, with possible 
financial aid programs from the Federal Government. 

It is common in earthquake-prone regions for school sites to provide the first kind of 
immediate shelter. There are several good reasons for this. First, schools are 
conveniently located in every community, with easy and known access to the local 
population that they serve. Second, schools have suitable space (e.g., gymnasiums or 
multiuse rooms) where large numbers of people can be accommodated for a few days. 
Food services are often available and there is ample space for assembly, processing, 
and delivery of goods and equipment. Third, because schools are public property, the 
financial costs of making use of the facilities for a few weeks are minimal, and 
arrangements can be worked out in advance. Finally, particularly in California, where 
schools are subject to the Field Act, schools are well constructed and probably among 
the most likely of all the community's buildings to survive intact and in a usable 
condition.
The only problem that has been encountered is that of ensuring that the time of use 
is limited; no school district wishes for its schools to be used as shelters for weeks, 
unless it is during the summer break. However, improvisation can generally ensure 
that some semblance of a normal school teaching program can be reinstated within 
a day or so of a moderate event. 
No specific design decisions are necessary for this use, nor is it necessary to stockpile 
emergency supplies, because they could use up valuable storage space for years and 
then be useless if needed. The exact circumstances of the event and the number and 
types of people to be accommodated will determine the supplies that are necessary. 
Experience has shown that local and even regional manufacturers and suppliers are 
very effective in providing services after an event. Following the Coalinga 1983 
earthquake, temporary shelter was provided in the high school gymnasium. A 
regional beer canning plant substituted drinking water for beer for a few shifts and 
rapidly delivered the chilled cans to the site.
However, pre-event planning should be undertaken between the school district and 
the local emergency services agency to anticipate key issues that will need quick 
solutions if an event occurs. This includes determining what spaces will be available 
and how many people can be accommodated, signing a pre-contract with a local 
engineer or architect for immediate post-earthquake inspection to determine safety, 
looking at strategies for continued operation in the event some spaces are occupied 
by refugees, and the possible provision of food and sanitary supplies by the district. 
Possible use of school buildings as a safe haven for the community in the event of 
chemical, biological, radiological, or explosive attack involves complex design and 
construction issues. This use of school property is discussed in FEMA 428, Chapter 6, 
and FEMA 453. 



4.8 REFERENCES AND SOURCES OF ADDITIONAL INFORMATION

ASCE, 2000, Prestandard and Commentary for the Seismic Rehabilitation of Buildings, American 

Society of Civil Engineers, FEMA Publication 356, Washington, DC (FEMA 273 
published as a standard). 

Building Construction and Safety Code NFPA 5000, National Fire Protection Association, 

Quincy, MA, 2002 .
Incremental Seismic Rehabilitation of School Buildings (K-12) (FEMA 395), Virginia 
Polytechnic Institute/Building Technology Incorporated, Silver Spring, MD/Melvyn 
Green & Associates, Inc., Torrance, CA, Federal Emergency Management Agency, 
Washington, DC, 2002.

International Building Code 2003, International Code Council, Birmingham, AL, 2003.

Minimum Design Loads for Buildings and Other Structures, ASCE 7-02,  American Society of 
Civil Engineers, Reston, VA, 2002.

NEHRP Commentary on the Guidelines for the Seismic Rehabilitation of Buildings (FEMA 274), 
Building Seismic Safety Council, Washington, DC, 1997.

NEHRP Guidelines for the Seismic Rehabilitation of Buildings (FEMA 273), Building Seismic 
Safety Council, Washington, DC, 1997. 

NEHRP Handbook for the Seismic Evaluation of Existing Buildings (FEMA 178), Building 
Seismic Safety Council, Washington, DC, 1992.

The NEHRP Recommended Provisions for Seismic Regulation for New Buildings, 2000 Edition, 2 
volumes and maps (FEMA 368) and Commentary (FEMA 369).

Primer to Design Safe School Projects in Case of Terrorist Attacks (FEMA 428), Federal 
Emergency Management Agency, U.S Department of Homeland Security, 
Washington, DC, 2003.

Rapid Visual Screening of Buildings for Potential Seismic Hazards (FEMA 154), Applied 
Technology Council, FEMA, Washington, DC, 1988.

Reducing the Risks of Nonstructural Earthquake Damage: a Practical Guide (FEMA 74), Wiss, 
Janney, Elstner Associates, Inc., Washington, DC, 1994.

Seismic Design Criteria of Nonstructural Systems for New School Facilities, EQE 
International/Salt Lake City School District, Salt Lake City, UT, 2001.




4.9 GLOSSARY OF EARTHQUAKE TERMS

Acceleration. Rate of change of velocity with time.

Amplification. A relative increase in ground motion between one type of soil and 
another or an increase in building response as a result of resonance. 

Amplitude. Maximum deviation from mean of the center line of a wave.

Architectural Components. Components such as exterior cladding, ceilings, 
partitions, and finishes.

Building. Any structure whose use could include shelter of human occupants.
Component (also Element). Part of an architectural, structural, electrical, or 
mechanical system.

Configuration. The size, shape, and geometrical proportions of a building.

Connection. A method by which different materials or components are joined to each 
other.

Damage. Any physical destruction caused by earthquakes.

Deflection. The state of being turned aside from a straight line, generally used in the 
horizontal sense; see also "Drift."

Design Earthquake. In the IBC, the earthquake that produces ground motions at the 
site under consideratio
n that are two/thirds those of the "Maximum Considered 
Earthquake."

Design Ground Motion. See "Design Earthquake."

Diaphragm. A horizontal or nearly horizontal structural element designed to transmit 
lateral forces to the vertical elements of the seismic force resisting system.
Drift. Vertical deflection of a building or structure caused by lateral forces; see also 
"Story Drift."

Ductility. Property of some materials, such as steel, to distort when subjected to forces 
while still retaining considerable strength.

Earthquake. A sudden motion or vibration in the earth caused by the abrupt release of 
energy in the earth's lithosphere.  

Effective Peak Acceleration and Effective Peak Velocity-Related Acceleration. 
Coefficients shown on maps in the IBC for determining prescribed seismic forces.
Elastic. Capable of recovering size and shape after deformation.
Epicenter. A point on the earth's surface that is directly above the focus of an 
earthquake.

Exceedance Probability. The probability that a specified level of ground motion or 
specified social or economic consequences of earthquakes will be exceeded at a site 
or in a region during a specified exposure time.

Exposure. The potential economic loss to all or certain subsets of the built 
environment as a result of one or more earthquakes in an area; this term usually 
refers to the insured value of structures carried by one or more insurers.

Fault. A fracture in the earth's crust accompanied by displacement of one side of the 
fracture with respect to the other in a direction parallel to the fracture.
Focus. The location of a fault break where an earthquake originates; also termed 
"Hypocenter." 

Force. Agency or influence that tries to deform an object or overcome its resistance to 
motion.

Frame, Braced. Diagonal members connecting together components of a structural 
frame in such a way as to resist lateral forces.

Frame, Space. A structural system composed of interconnected members, other than 
bearing walls, that is capable of supporting vertical loads and that also may provide 
resistance to seismic forces.


Frame System, Building. A structural system with an essentially complete space frame 
providing support for vertical loads; seismic forces are resisted by shear walls or 
braced frames. 

Frame System, Moment. A space frame in which members and joints are capable of 
resisting lateral forces by bending as well as along the axis of the members; varying 
levels of resistance are provided by ordinary, intermediate, and special moment 
frames as defined in the IBC with special frames providing the most resistance.
"g". The acceleration due to gravity or 32 feet per second.

Ground Failure. Physical changes to the ground surface produced by an earthquake 
such as lateral spreading, landslides, or liquefaction. 

Hypocenter. See "Focus."

Intensity. The apparent effect that an earthquake produces at a given location; in the 
United States, intensity generally is measured by the modified Mercalli intensity 
(MMI) scale.

Irregular. Deviation of a building configuration from a simple symmetrical shape.
Joint. Location of connections between structural or nonstructural members and 
components.

Liquefaction. The conversion of a solid into a liquid by heat, pressure, or violent 
motion; sometimes occurs to the ground in earthquakes.
Load, Dead. The gravity load created by the weight of all permanent structural and 
nonstructural building components such as walls, floors, roofs, and fixed service 
equipment.

Load, Live. Moving or movable external loading on a structure; it includes the weight 
of people, furnishings, equipment, and other items not permanently attached to the 
structure.

Loss. Any adverse economic or social consequences caused by earthquakes.

Mass. A constant quantity or aggregate of matter; the inertia or sluggishness that an 
object, when frictionlessly mounted, exhibits in response to any effort made to start it 
or stop it or to change in any way its state of motion.

Maximum Considered Earthquake Ground Motion. The most severe earthquakes 
effects considered in the IBC.  These are represented by the mapped spectral response 
accelerations at short and long periods, obtained from maps reproduced in the IBC, 
adjusted for Site Class effects using site coefficients.

Mercalli Scale (or Index). A measure of earthquake intensity named after Giuseppe 
Mercalli, an Italian priest and geologist.

Nonbuilding Structure. A structure, other than a building, constructed of a type 
included in Chapter 14 of the IBC.

Occupancy Importance Factor. A factor, between 1.0 - 1.5, assigned to each structure 
according to its Seismic Use Group (SUG).

Partition. See "Wall, Nonbearing."

Period. The elapsed time (generally in seconds) of a single cycle of a vibratory motion 
or oscillation; the inverse of frequency.

P-Wave. The primary or fastest waves traveling away from a fault rupture through the 
earth's crust and consisting of a series of compressions and dilations of the ground 
material.

Quality Assurance Plan. A detailed written procedure that establishes the systems and 
components subject to special inspection and testing.

Recurrence Interval. See "Return Period."

Resonance. The amplification of a vibratory motion occurring when the period of an 
impulse or periodic stimulus coincides with the period of the oscillating body.
Return Period. The time period in years in which the probability is 63 percent that an 
earthquake of a certain magnitude will recur.

Richter Magnitude (or Scale). A logarithmic scale expressing the magnitude of a 
seismic (earthquake) disturbance in terms of the maximum amplitude of the seismic 
waves at a standard distance from their focus named after its creator, the American 
seismologist Charles R. Richter.

Rigidity. Relative stiffness of a structure or element; in numerical terms, equal to the 
reciprocal of displacement caused by unit force.

Seismic. Of, subject to, or caused by an earthquake or an earth vibration.

Seismic Event. The abrupt release of energy in the earth's lithosphere causing an 
earth vibration; an earthquake.

Seismic Force Resisting System. The part of the structural system that is designed to 
provide required resistance to prescribed seismic forces. 

Seismic Forces. The actual forces created by earthquake motion; assumed forces 
prescribed in the IBC that are used in the seismic design of a building and its 
components. 

Seismic Hazard. Any physical phenomenon such as ground shaking or ground failure 
associated with an earthquake that may produce adverse effects on the built 
environment and human activities; also the probability of earthquakes of defined 
magnitude or intensity affecting a given location.

Seismic Risk. The probability that the social or economic consequences of an 
earthquake will equal or exceed specified values at a site during a specified exposure 
time; in general, seismic risk is vulnerability multiplied by the seismic hazard.
Seismic Use Group. A classification assigned in the Provisions to a structure based on 
its occupancy and use as defined in the IBC.

Seismic Waves. See "Waves, Seismic."

Seismic Zone. Generally, areas defined on a map within which seismic design 
requirements are constant; in the IBC, seismic zones are defined both by contour 
lines and county boundaries.

Shear. A force that acts by attempting to cause the fibers or planes of an object to slide 
over one another.

Shear Panel. See "Wall, Shear."

Shear Wall. See "Wall, Shear."

Speed. Rate of change of distance traveled with time irrespective of direction.
Stiffness. Resistance to deflection or drift of a structural component or system.
Story Drift. Vertical deflection of a single story of a building caused by lateral forces.

Strain. Deformation of a material per unit of the original dimension.

Strength. The capability of a material or structural member to resist or withstand 
applied forces.

Stress. Applied load per unit area or internal resistance within a material that 
opposes a force's attempts to deform it.

S-Wave. Shear or secondary wave produced essentially by the shearing or tearing 
motions of earthquakes at right angles to the direction of wave propagation.
System. An assembly of components or elements designed to perform a specific 
function such as a structural system.

Torque. The action of force that tends to produce torsion; the product of a force and 
lever arm as in the action of using a wrench to tighten a nut.

Torsion. The twisting of a structural member about its longitudinal axis. 

Velocity. Rate of change of distance traveled with time in a given direction; in 
earthquakes, it usually refers to seismic waves and is expressed in inches or 
centimeters per second.

Vulnerability. The degree of loss to a given element at risk, or set of such elements, 
resulting from an earthquake of a given intensity or magnitude; expressed in a scale 
ranging from no damage to total loss; a measure of the probability of damage to a 
structure or a number of structures.

Wall, Bearing. An interior or exterior wall providing support for vertical loads.

Wall, Cripple. A framed stud wall, less than 8 feet in height, extending from the top of 
the foundation to the underside of the lowest floor framing.

Wall, Nonbearing. An interior or exterior wall that does not provide support for 
vertical loads other than its own weight as permitted by the building code; see also 
"Partition."

Wall, Shear. A wall, bearing or nonbearing, designed to resist lateral forces parallel to 
the plane of the wall.  

Wall System, Bearing. A structural system with bearing walls providing support for all 
or major portions of the vertical loads; seismic resistance may be provided by shear 
walls or braced frames.

Waves, Seismic. Vibrations in the form of waves created in the earth by an earthquake.

Weight. Name given to the mutual gravitational force between the earth and an object 
under consideration; varies depending on location of the object at the surface of the 
earth










MAKING SCHOOLS SAFE AGAINST FLOODS     5



5.1 INTRODUCTION

This chapter introduces the nature and probability of floods and the types of 
flood damage that result when school facilities are located in flood hazard areas. 
Avoidance of such areas is the most effective way to minimize risks to occupants, 
including health hazards and damage to property. When a school must be built in a 
flood hazard area, site layout and facility design measures can minimize damage and 
risks. The chapter also provides an overview of measures that designers should 
consider in order to reduce risks at existing schools that are already located in areas 
prone to flooding. 



5.2 NATURE AND PROBABILITY OF FLOODS

Flooding is the most common natural hazard in the United States, affecting over 
20,000 local jurisdictions and representing more than 70 percent of Presidential 
Disaster Declarations. Several evaluations have estimated that 10 percent of the 
Nation's land area is subject to flooding. Some communities have very little land that 
is identified as exposed to flooding, although others lie entirely within the 
floodplain.
Flooding is a natural process that may manifest in a variety of forms: long-duration 
flooding along rivers that drain large watersheds; flash floods that send a devastating 
wall of water down a mountain canyon; and coastal flooding that accompanies high 
tides and on-shore winds, hurricanes, and Nor'easters. When the natural process is 
unaltered by human activity, flooding is not a problem. In fact, species of plants and 
animals that live adjacent to bodies of water are adapted to a regimen of periodic 
flooding. 

Flooding is only considered a problem when human development is located in flood-
prone areas. Problems can result, not only exposing people to dangerous situations 
and property to damage, but also disrupting the natural functions of floodplains and 
redirecting surface flows onto lands that are not normally subject to flooding. 
Flooding along waterways normally occurs as a result of excessive rainfall or 
snowmelt that creates flood flows that exceed the capacity of channels. Flooding 
along shorelines is usually due to coastal storms that generate storm surges or waves 
above normal tidal fluctuations. Factors that can affect the frequency and severity of 
flooding and the resultant types of damage include:

 Channel obstructions due to fallen trees, accumulated debris, 
and ice jams
 Channel obstructions due to road and railroad crossings where the bridge or 
culvert openings are insufficient to convey floodwaters
 Erosion of shorelines and stream banks, often with episodic collapse of large areas 
of land
 Deposition of sediment that settles out of floodwaters or is carried inland by wave 
action
 Failure of dams (whether due to seismic activity, lack of maintenance, flows that 
exceed the design, or destructive acts) may suddenly and unexpectedly release 
large volumes of water
 Failure of levees (whether associated with flows that exceed the design, weakening 
by seismic activity, lack of maintenance, or destructive acts) may result in sudden 
flooding of areas thought to be protected


5.2.1 Characteristics of Flooding 

Each type of flooding has characteristics that are important aspects of the hazard and 
that must be considered in the selection of school sites, the design of new schools, 
and the expansion or retrofit of existing flood-prone schools in ways that minimize 
damage.
Riverine flooding is due to the accumulation of runoff from rainfall or snowmelt 
such that the volume of flow exceeds the capacity of waterway channels and spreads 
out over the adjacent land. Riverine flooding flows downstream under the force of 
gravity. Its depth, duration, and velocity are functions of many factors, including 
watershed size and slope, degree of upstream development, soil types and nature of 
vegetation, steepness of the topography, and characteristics of storms (or depth of 
snowpack and rapidity of melting). Figure 5-1 illustrates a cross-section of a riverine 
floodplain.

Coastal flooding is experienced along the Atlantic, Gulf, and Pacific coasts, and many 
larger lakes, including the Great Lakes. Coastal flooding is influenced by storm 
surges associated with tropical cyclonic weather systems (hurricanes, tropical storms, 
tropical depressions, typhoons), extratropical systems (Nor'easters), and tsunamis 
(surge induced by seismic activity). Coastal flooding is also generally characterized by 
wind-driven waves. Wind-driven waves affect reaches along the Great Lakes 
shorelines, where winds blowing across the broad expanses of water generate wind-
driven waves that can rival those experienced along other coastal shorelines. Some 
Great Lakes shorelines experience coastal erosion, in part associated with 
fluctuations in water levels. Figure 5-2 is a schematic of the coastal floodplain.
Riverine and coastal flooding can be characterized by a number of factors that 
become important in the selection of school sites, site design, and design of school 
buildings:

 Depth. The most obvious characteristic of any flood is the depth of water. 
Depending on many factors, such as the shape of a river valley or the presence of 
obstructing bridges, riverine flooding may rise just a few feet or tens of feet above 
normal. The depth of coastal flooding is influenced by such factors as the tidal 
cycle, the duration of the storm, the elevation of the land, and the presence of 
waves. Depth is a critical factor in building design because the hydrostatic forces 
that are exerted on a vertical surface (such as a foundation wall) are directly 
related to depth and because costs associated with protecting buildings from 
flooding significantly increase with depth.
 Duration. Duration is the measure of how long the water remains above normal 
levels. The duration of riverine flooding is primarily a function of watershed size 
and the longitudinal slope (which influences how fast water drains away). Small 
watersheds are more likely to be "flashy," which refers to the rapidity with which 
floodwaters rise and fall. Areas adjacent to large rivers may be flooded for weeks or 
months. Most coastal flooding is influenced by the normal tidal cycle, as well as 
how fast coastal storms move out of the area. Areas subject to coastal flooding can 
experience long duration flooding where drainage is slow, or may be impacted on 
the order of 12-24 hours if storms move rapidly. Flooding of large lakes, including 
those behind dams, can be of very long duration because of the sheer volume of 
water that must flow past a control point. For building design, duration is 
important because it affects access, building usability, saturation and stability of 
soils, and building materials. Information about flood duration is sometimes 
available as part of a flood study or could be developed by a qualified engineer.
 Velocity. The rates at which floodwaters move range from extremely rapid 
(associated with flash floods) to nearly stagnant (in backwater areas and expansive 
floodplains). Velocity is important in site planning because of the potential for 
erosion. In structural design, velocity is a factor in hydrodynamic loads, including 
impact loads and drag forces. With respect to public safety, even shallow high 
velocity water poses threats to pedestrians and vehicles. Accurate estimates of 
velocities are difficult to make, although limited information may be found in 
floodplain studies.
 Wave action. Waves contribute to erosion and scour, and also contribute 
significantly to loads on buildings. The magnitude of wave forces can be 10 or 
more times higher than wind and other design loads. Waves must be accounted 
for along coastal shorelines, in flood hazard areas that are inland of open coasts, 
and other areas subject to waves, including areas with sufficient fetch that winds 
generate waves (such as lakes and expansive riverine floodplains).
 Impacts from debris and ice. Floating debris and ice contribute to loads that must 
be accounted for in design. The methods and models used to predict and 
delineate flood hazard areas do not specifically incorporate debris, thus there are 
few sources to characterize potential impacts other than past observations. 
 Erosion and scour. Erosion refers to a lowering of the ground surface in response to 
a flood event or the gradual recession of a shoreline due to long-term coastal 
processes. Scour refers to a localized lowering of the ground surface during a flood 
due to the interaction of currents and/or waves with structural elements, such as 
pilings. Erosion and scour may affect the stability of foundations and filled areas, 
and can cause extensive site damage. Soil characteristics influence susceptibility to 
scour. 


5.2.2 Probability of Occurrence

In order to guide and regulate development, and to develop specific designs to resist 
flood forces, it is necessary to identify the "design flood." For decades, the design 
flood has been referred to as the "base flood." More precisely, it is the "1%-annual 
chance flood," but is commonly called the "100-year flood." The latter term is often 
mis-understood because it conveys the impression that a flood of that magnitude will 
occur only every 100 years. Statistically, the 1%-annual chance flood has one chance 
in 100 of occurring in any given year. The fact that a 1%-annual chance flood is 
experienced at a specific location does not alter the probability that a comparable 
flood will occur at the same location in the next year, or even twice in one year. 
Regardless of the flood selected for design purposes, the designer must determine 
specific characteristics associated with that flood. A flood of a specific return 
frequency is determined in a multi-step process that typically involves using computer 
models that are in the public domain. If a sufficiently long record of floods exists, the 
design flood may be determined by applying statistical tools to the record. 
Alternatively, sometimes water resource engineers apply computer models to simulate 
different rainfall events over watersheds and to predict how much water will run off 
and accumulate in channels. Other computer models are used to characterize the 
flow of water down the watershed and predict how high it will rise. For coastal areas, 
both historical storms and simulated storm models can be used to predict the 
probability that floodwaters will rise to a certain level.
The National Flood Insurance Program (NFIP), described in Sections 5.3.1 and 5.3.2, 
uses the 1%-annual chance flood as the basis for flood hazard maps, for setting 
insurance rates, and for application of regulations in order to minimize future flood 
damage. The 1%-annual chance flood is also used to examine older buildings to 
determine measures that are applied in order to reduce future damage.
Communities are encouraged to treat schools as essential critical facilities because of 
the significant and long-term impacts on students and the community if a damaged 
school is closed for an extended period of time. Essential and critical facilities usually 
are intended to remain operational in the event of extreme environmental loading 
from floods, hurricanes, snow, or seismic events. A higher level of protection has 
been determined to be appropriate for facilities that are important to protect in order 
to enhance rapid recovery, including hospitals, emergency operations centers, 
emergency shelters, water treatment plants, and other buildings that support vital 
services. 


5.2.3 Hazard Identification and Flood Data

Flood hazard maps are prepared to identify areas of the landscape that are subject to 
flooding, usually flooding by the 1%-annual chance flood. Maps prepared by the NFIP 
are the minimum basis of state and local floodplain regulatory programs. Some states 
and communities have prepared maps that reflect a floodplain determined using a 
"higher standard," such as assuming the upper watershed area is built-out completely 
according to existing zoning. Some communities use a flood of record or a 
historically significant flood as the basis for regulation.
The flood hazard maps used by the appropriate regulatory authority should be 
consulted during site selection, site design, and building design (whether for new 
buildings or existing buildings). Since the NFIP began producing Flood Insurance 
Rate Maps (FIRMs), these maps have been prepared for over 19,200 communities. 
FIRMS are prepared for each local jurisdiction that has been determined to have 
some degree of flood risk and, typically, the maps may be viewed by visiting 
community planning or permit offices1. Many FIRMs do not show detailed 
information about predicted flood elevations along all bodies of water and the 0.2%-
annual chance flood hazard areas often are not shown. In these cases, additional 
engineering analyses are necessary in order to determine the flood-prone areas and 
the appropriate characteristics of flooding required for site layout and building 
design. 

If a proposed school site or an existing school is affected by flooding, a site-specific 
topographic survey is critical for delineating the land that is below the design flood 
elevation (DFE). If detailed flood elevation information is not available, a floodplain 
study may be required to identify the important flood characteristics and data 
required for sound design. Having flood hazard areas delineated on a map conveys a 
degree of precision that may be misleading. Flood maps have a number of limitations 
that should be examined, especially during site selection and design of essential and 
critical facilities such as schools:

 Flood hazard areas are approximations: the flood elevations shown and the areas 
delineated should not be taken as absolutes, in part because they are based on 
numerical approximations of the real world. 
 NFIP FIRMs and Flood Insurance Studies (FISs) were prepared to meet the 
requirements of the NFIP. For the most part, floodplains along smaller streams 
and drainage areas (less than 1 square mile) are not shown.
 Especially for older maps, the topography used to delineate the flood boundary may 
have had contour intervals of 5, 10, or even 20 feet, which significantly affects the 
precision with which the boundary is determined. The actual elevation of the 
ground relative to the flood elevation is critical, as opposed to whether an area is 
shown as being in or out of the mapped flood hazard area. 
 Older maps may not reasonably account for upland development that increases 
rainfall-runoff and tends to increase flooding.
 The scale of the maps may not itself to precise determinations.
 Flooding may have been altered by development, whether upland development that 
increases runoff or local modifications that alter the shape of the land surface of 
the floodplain (such as fills or levees).
 Local conditions are not reflected, especially conditions that change regularly, 
such as streambank erosion and shoreline erosion.
The flood hazard maps prepared by the NFIP show different zones that identify some 
differences in flooding characteristics:
 A Zones. Flood hazard areas where engineering analyses have not been performed 
to develop detailed flood elevations and boundaries, also called "unnumbered A 
Zones" or "approximate A Zones," for the base flood (1%-annual chance flood). 
Additional engineering analysis and site-specific assessments usually are required 
to determine the design flood elevation.
 AE Zones or A1-A30 Zones. These designations are used for flood hazard areas where 
engineering analyses have produced detailed flood elevations and boundaries for 
the base flood (1%-annual chance flood). For riverine waterways with these zones, 
FISs include longitudinal profiles showing water surface elevations for different 
frequency flood events.
 Floodways. The floodway includes the waterway channel and adjacent land areas 
that must be reserved in order to convey the discharge of the base flood without 
cumulatively increasing the water surface elevation more than a designated 
height. Floodways are designated for most waterways that have AE Zones. FISs 
include data on floodway widths and mean floodway velocities. 
 AO and AH Zones. Areas of shallow flooding are generally shown where the flood 
depth averages from 1 to 3 feet, where a clearly defined channel does not exist, 
where the path of flooding is unpredictable, and where velocity flow may be evi-
dent.  These zones are characterized by ponding or sheetflow. 
 Shaded X (or B) Zones. This zone shows areas of the 500-year flood (0.2%-annual 
chance flood), or areas protected by flood control levees. This zone is not shown 
on many NFIP maps and its absence does not imply that flooding of this frequency 
will not occur. 
 Unshaded X (or C) Zones. These zones are all land areas not mapped as flood 
hazard areas (either 1%- or 0.2%-annual chance flood hazard areas) that are 
outside of the floodplain that is designated for the purposes of regulating 
development pursuant to the NFIP. These zones may still be subject to small 
stream flooding and local drainage problems.
 V Zones (V, VE, and V1-V30). Also known as "coastal high hazard areas," V Zones are 
relatively narrow areas along open coastlines and some large lake shores that are 
subject to high-velocity wave action from storms or seismic sources. V Zones 
extend from off-shore to the inland limit of a primary frontal dune or to an inland 
limit where breaking waves are predicted to be at least 3 feet in height.2
 Coastal A Zone. The principal sources of flooding in Coastal A Zones are 
astronomical tides, storm surges, seiches, or tsunamis. These zones extend inland 
to include areas where the potential for breaking wave heights exists during 
conditions of the base flood. Coastal A Zones are not delineated on NFIP maps; 
this zone is identified in ASCE 7 and ASCE 24 because waves sufficient to 
contribute to damage are present. 

Flood hazards and characteristics of flooding must be identified in order to 
appropriately evaluate the impact of site development, to calculate flood loads, to 
design floodproofing measures, or to identify and prioritize retrofit measures for 
existing schools. Many characteristics are not shown on the flood hazard maps but 
may be found in the FIS or the study or report prepared by the entity that produced 
the flood hazard map. Otherwise, additional research is required. Table 5-1, on page 
5-22, outlines a series of questions to facilitate this objective.


5.2.4 Design Flood Elevation  
 
The design flood elevation establishes the minimum level of flood protection that 
must be provided. DFE as used in the model building codes is defined as either the 
base flood elevation (BFE) determined by the NFIP or the elevation of a design flood 
designated by the community, whichever is higher. The DFE will always be at least as 
high as the BFE. Communities may use a design flood that is higher than the base 
flood for a number of reasons, (e.g., to account for future upland development, 
recognize a historic flood, or incorporate a factor of safety, known as freeboard). 

Figure 5-4 shows the relationship between the BFE and the DFE. School planners and 
designers should check with the appropriate regulatory authority to determine the 
minimum flood elevation to be used in site planning and design. For essential and 
critical facilities such as schools, it is common that state and local regulations cite 
the 0.2% chance flood (500-year flood) as the design minimum or the regulations 
may call for added freeboard of 1, 2, or 3 feet above the minimum flood elevation. 



5.3 SCOPE, EFFECTIVENESS, AND LIMITATIONS OF BUILDING CODES 
AND FLOODPLAIN MANAGEMENT REQUIREMENTS 

With respect to design and construction to resist flood damage, the existing 
minimum requirements in model building codes and regulations are based on the 
National Flood Insurance Program. The original authorizing legislation for the NFIP 
was passed in 1968. Congress expressly found that "a program of flood insurance can 
promote the public interest by encouraging sound land use by minimizing exposure 
of property to flood losses . . . "
The most convincing evidence of the effectiveness of the NFIP minimum 
requirements is found in flood insurance claim payment statistics. Buildings that pre-
date the NFIP requirements are, by and large, not constructed to resist flood damage. 
Buildings that post-date the NFIP (i.e., those that were constructed after a community 
joined and began applying the minimum requirements) are designed to resist flood 
damage. The NFIP reports that aggregate loss data indicate that buildings that meet 
the minimum requirements experience 70 percent less damage than do buildings 
that pre-date the NFIP. There is ample evidence that buildings that exceed the 
minimum requirements are even less likely to sustain damage. 
5.3.1Overview of the NFIP
The NFIP is intended to encourage states and local governments to recognize and 
incorporate flood hazards in land use and development decisions. In some states and 
communities, this is achieved by guiding development to areas with lower risk. When 
decisions result in development within flood hazard areas, application of the criteria 
set forth in Federal Regulation at 44 CFR 60.3 minimize exposure and flood-related 
damage. State and local governments are responsible for the application of the 
provisions of the NFIP through regulatory permitting processes. At the federal level, 
the NFIP is managed by FEMA and has three main elements:

 Hazard identification and mapping, under which engineering studies are 
conducted and flood maps are prepared in partnership with states and 
communities to delineate areas that are predicted to be subject to flooding under 
certain conditions. 
 Floodplain management criteria for development, which establish the minimum 
requirements to be applied to development within mapped flood hazard areas with 
the intent of recognizing hazards in the entire land development process. 
 Flood insurance, which provides financial protection for property owners to cover 
flood-related damage to buildings and contents.

Federal flood insurance is designed to provide property owners, including school 
districts, an alternative to disaster assistance and disaster loans. Disaster assistance 
has limited coverage for full costs to repair and clean up and is available only after 
the President of the United States signs a disaster declaration for the area. 
Importantly, school districts should be aware that they may be subject to a mandated 
reduction in disaster assistance payments if a public school building is not covered by 
flood insurance. NFIP flood insurance claims are paid any time damage from a 
qualifying flood event occurs, regardless of whether a major disaster is declared.
Another important objective of the NFIP is to break the cycle of flood damage. Many 
buildings have been flooded, repaired or rebuilt, and flooded again. Before the NFIP, 
in some parts of the country, this cycle occurred every couple of years, with 
reconstruction taking place in the same flood-prone areas using the same 
construction techniques that did not adequately resist flood damage. By guiding 
development to lower risk areas and by requiring compliance with performance 
measures to minimize exposure of new buildings and buildings that undergo major 
renovation or expansion, the long-term objective of disaster resistant communities 
can be achieved. 


5.3.2 Summary of the NFIP Minimum Requirements 

The performance requirements of the NFIP are set forth in federal regulation at 44 
CFR Part 60. The requirements apply to all development, which the NFIP broadly 
defines include buildings and structures, site work, roads and bridges, fills and other 
activities. Buildings must be designed and constructed to resist flood damage, which 
is primarily achieved through elevation (or floodproofing). Additional specific 
requirements apply to existing development, especially existing buildings. Existing 
buildings that are proposed for substantial improvement, including repair of 
substantial damage, are subject to the regulations. 
Although the NFIP regulations primarily focus on how to build, one of the long-term 
objectives of the program is to guide development to less hazardous locations. 
Preparing flood hazard maps and making the information available to the public is 
fundamental in satisfying that objective. With that information, people can make 
informed decisions about where to build, how to use site design to minimize 
exposure to flooding, and to how to design buildings that will resist flood damage.

The NFIP's broad performance requirements for site work are as follows:

 Building sites shall be reasonably safe from flooding.
 Adequate site drainage shall be provided to reduce exposure to flooding. 

 New and replacement sanitary sewage systems shall be designed to minimize or 
eliminate infiltration of floodwaters into the systems and discharges from the 
systems into floodwaters.
 Development in floodways shall be prohibited unless engineering analyses show 
that there will be no increases in flood levels. 

The NFIP's broad performance requirements for new buildings proposed for flood 
hazard areas (and substantial improvement of existing flood-prone buildings) are as 
follows:

 Buildings shall be designed and adequately anchored to prevent flotation, collapse, 
or lateral movement resulting from hydrodynamic and hydrostatic loads, 
including the effects of buoyancy.
 Buildings shall be constructed by methods and practices that minimize flood 
damage (primarily by elevating to or above the base flood level or by specially 
designed and certified floodproofing measures).
 Buildings shall be constructed with electrical, heating, ventilation, plumbing, and 
air conditioning equipment and other service facilities that are designed and/or 
located so as to prevent water from entering or accumulating within the 
components.

Designers should determine if there are any applicable state-specific requirements 
pertinent to floodplain development. Some states require that local jurisdictions 
apply standards that exceed the minimum requirements of the NFIP. Some states have 
direct permitting authority programs that impose higher standards, while some states 
have direct permitting authority over certain types of construction or certain types of 
applicants. 
As participants in the NFIP, states are required to ensure that development that is not 
subject to local regulations, such as state construction, satisfies the same 
performance requirements. If schools are exempt from local permits, this may be 
accomplished through a state permit, a governor's executive order, or other 
mechanism that applies to entities not subject to local authorities.


5.3.3 Model Building Codes and Standards 

The 2000 and 2003 editions of the International Building Code (IBC) and the 2003 
edition of the National Fire Protection Association's Building Construction and 
Safety Code (NFPA 5000) are the first model codes to include comprehensive 
provisions to address flood hazards. Both codes are consistent with the minimum 
provisions of the NFIP that pertain to design and construction of buildings. The 
NFIP requirements that pertain to site development and floodways generally are 
found in other local ordinances. The codes require designers to identify anticipated 
environmental loads and load combinations, including wind loads, seismic loads, 
snow loads, soil conditions and flood loads. 
The IBC and NFPA 5000 reference standards that are developed through a rigorous 
consensus process. The best known is Minimum Design Loads for Buildings and Other 
Structures (ASCE 7), produced by the American Society of Civil Engineers (ASCE). The 
model building codes require that applicable loads be accounted for in the design. 
The designer must identify the pertinent, site-specific characteristics and then use 
ASCE 7 to determine the specific loads and combined loads. In effect, it is similar to a 
local floodplain ordinance that requires determination of the environmental 
condition (in/out of the mapped flood hazard area, DFE/depth of water) and then 
specifies certain conditions that must be met during design and construction. The 
1998 edition of ASCE 7 was the first version of the standard to explicitly include flood 
loads, including hydrostatic loads, hydrodynamic loads (velocity and waves), and 
debris impact loads. 
The IBC and NFPA 5000 also refer to a standard first published by ASCE in 1998, Flood 
Resistant Design and Construction (ASCE 24). Developed through a consensus process, 
ASCE 24 addresses specific topics pertinent to designing buildings in flood hazard 
areas, including floodways, coastal high hazard areas, and other high-risk flood 
hazard areas such as alluvial fans, flash flood areas, mudslide areas, erosion-prone 
areas, and high velocity areas. 



5.4 RISK REDUCTION: AVOIDING FLOOD HAZARDS 

Flood hazards are unlike earthquake hazards and wind hazards. Those hazards often 
are assigned at the county level because the hazards themselves do not significantly 
vary from one geographic location within a county to another. Of course, there may 
be site-specific variations in those hazards, such as soils susceptible to liquifaction 
during seismic activity, or local topographic differences that influence wind speeds. 
However, for the most part, the earthquake and wind hazards cannot be avoided by 
choosing alternative locations. 
Flood hazards are site-specific. When a flood hazard map is prepared, lines drawn on 
the map appear to precisely define the hazard area. Land that is on one side of the 
line is "in" the mapped flood hazard area, while the other side of the line is "out." 

Although the delineation may be an approximation, having hazard areas shown on a 
map facilitates avoiding such areas to the maximum extent practical. Where it is 
unavoidable, school districts should carefully evaluate all of the benefits and all of the 
costs in order to determine long-term acceptable risks and to develop appropriate 
plans for design and construction of new schools.

Section 5.6 describes the damage that is sustained by existing buildings that are 
exposed to flood hazards, including: site damage; structural and nonstructural 
building damage; destruction or impairment of service equipment; loss of contents; 
and health and safety threats due to contaminated floodwaters. These types of 
damage, along with loss of function and community service, are avoided if schools 
are located away from flood hazard areas. Damage is minimized when schools that 
must be located in flood hazard areas are built in compliance with minimum 
requirements.


5.4.1 Benefits/Costs: Determining Acceptable Risk

Many decisions that are made with respect to schools are, in part, based on a 
determination of acceptable risk. Risk includes the potential losses associated with a 
hazard. Ideally, risk is defined in terms of expected probability and frequency of the 
hazard occurring, people and property exposed, and potential consequences. 
Choosing a site or accepting donated land that is affected by flooding is a decision to 
accept some degree of risk. Although the flood-prone land may have a lower initial 
cost, the incremental costs of construction plus the likely increased costs of mainte-
nance, repair, and replacement may be significant. Another cost of locating a school 
in a flood-prone area is access. Although the building may be elevated and protected, 
if access is restricted periodically, the use of the school also is affected. 
The school district's planning team and the design team can influence the degree of 
risk (e.g., the frequency with which flooding may affect the site). They control it 
through selection of site design and building design measures. Fundamentally, this 
process is a balancing of the benefits of an acceptable level of disaster resistance with 
the costs of achieving that degree of protection. With respect to mitigation of future 
hazard events:

 Benefits are characterized and measured as damage avoided if the mitigation 
measures (including avoiding flood hazard areas) are implemented.
 Costs are the costs associated with implementing measures to eliminate or reduce 
exposure to hazards. 

Section 5.6 describes damage and losses that are incurred by buildings exposed to 
flooding. Direct damage includes damage to physical property, including the site, the 
building, building materials, utilities, and building contents. Indirect damage that is 
not listed includes health hazards, functionality impacts, emergency response, 
evacuation, and expenses associated with occupying another building during repairs.
For the most part, benefits are difficult to measure because they are associated with 
damage that does not occur, cleanup that is not required, and service that is 
uninterrupted because flooding does not shut down a school. In addition, benefits 
accrue over long periods of time, thus making it more difficult to make a direct 
comparison of benefits with costs of mitigation. Mitigation costs can more readily be 
expressed in terms of the higher costs of a flood-free site or the initial capital costs of 
work designed to resist flood damage. Thus, without a full accounting of both 
benefits and costs, decision makers may not be able to make fully informed decisions. 
Some questions that should be answered include:

 If the site is flood-prone and the building is out of the flood hazard area or elevated 
on fill, what are the average annual cleanup costs associated with removal of sand, 
mud, and debris deposited by floods of varying frequencies?
 If the school building is elevated by means other than fill, will periodic inundation 
of the exposed foundation elements cause higher average annual maintenance 
costs?
 If the school building meets only the minimum elevation requirements, what are 
the average annual damage and cleanup costs over the anticipated useful life of 
the building, including the occurrence of floods that exceed the design flood 
elevation?
 How do long-term costs associated with periodic inundation compare to up-front 
costs of selecting a different site or building to a higher level of protection?
 If access to the school is periodically restricted due to flooding, especially long-
duration flooding, what cost impacts will result? How often would the school 
district have to provide an alternate location to continue classes? 


5.4.2 Identifying Flood Hazards at School Sites

To the extent practical, schools and attendant athletic fields and facilities should be 
located outside of known flood hazard areas. The best available information 
regarding flooding should be examined, including flood hazard maps, records of 
historical flooding, and advice from local experts, and others who can evaluate flood 
risks.   

As part of site selection and to guide locating the school building and other 
improvements on a site, designers should investigate site-specific flood hazard 
characteristics. Table 5-1 outlines questions that will produce information that must 
be determined prior to initiating site layout and design work.




5.5 RISK REDUCTION: FLOOD-RESISTANT NEW SCHOOLS

When a decision is made to build a new school on a site that is affected by flooding, 
the characteristics of the site and the nature of flooding must be examined prior to 
making several design decisions. The most important consideration is location of 
the buildings.
Risks and certain costs associated with flood-resistant construction are minimized by 
putting principal buildings on the highest available ground. Positioning the 
buildings, parking lots, and athletic fields is influenced by identification of all site 
constraints, which include such factors as presence of flood hazard areas (see Table 5-
1), wetlands, poor soils, steep slopes, sensitive habitats, mature tree stands, and other 
environmental factors required by the authority that approves development plans and 
all applicable regulatory authorities.
Several aspects of design of flood-resistant buildings and sites are important and are 
described in this section, including site modifications, foundation type and elevation 
considerations, floodproofing options, flood-resistant accessory structures, building 
service equipment and utility installations, and access roads.


5.5.1 Site Modifications

When sites that are affected by flood hazard areas must be used, and when flood 
hazard areas cannot be avoided, it may be appropriate to evaluate certain site 
modifications that may be feasible to provide a level of protection to buildings. The 
evaluations involve engineering analyses in order to determine if the desired level of 
protection can be provided cost-effectively, while ensuring that site modifications do 
not alter the floodplain in ways that increase flooding. Typical site modifications 
(with cautions that must be examined to determine effectiveness) include:

 Earthen fill. Fill can be placed in the flood hazard area with the effect of moving the 
floodplain boundary. If the fill is placed and compacted to be stable during the 
rise and fall of floodwaters and is protected from erosion, modifying a site with fill 
in order to elevate a school is preferred over other methods of elevation. Not only 
will the building be less exposed to flood forces, but, under some circumstances 
(long duration floods), the school may be able to continue to function. Whether 
nonstructural fill is placed solely to modify the site, or structural fill is placed for 
the purpose of elevating buildings, placement of fill can change flooding 
characteristics. Engineering analyses can be conducted to determine if 
eliminating floodplain storage by fill will result in changing the flow of water, 
creating higher flow velocities, or increasing the water surface elevation. 
 Excavation. Excavation alone rarely results in significantly altering the floodplain 
on a given parcel of land. It is more commonly used in conjunction with fill in 
order to off-set or compensate for the adverse impacts of fill.
 Earthen levee or dike. A levee is a specially designed barrier that modifies the 
floodplain by keeping the water away. Levees are significant structures that require 
detailed, site-specific geotechnical investigations; engineering analyses to identify 
whether flooding will be made worse on other properties; structural and site 
design to suit existing constraints; design of interior drainage (on the land side); 
and long-term commitment for maintenance, inspection, and repairs. It is 
important to remember that areas protected by levees are protected only up to a 
certain design flood level; once overtopped, most levees fail and catastrophic 
flooding of previously protected areas results. Levees that protect essential and 
critical facilities usually are designed for the 0.2%-annual chance flood (500-year) 
and have added height (called "freeboard") to increase the factor of safety (see 
Figure 5-4).
 Floodwall. Floodwalls are similar to levees in that they provide protection only up to 
a certain design flood level, and overtopping can result in catastrophic flooding. A 
floodwall typically is a significant structure that is designed specifically to hold 
back water of a certain depth based on the design flood for the site. Generally, due 
to design factors, floodwalls are most effective in areas with relatively shallow 
flooding. As with levees, designs must accommodate interior drainage on the land 
side, and maintenance and operations are critical for adequate performance. 
Floodwalls that protect essential and critical facilities usually are designed for the 
0.2%-annual chance flood (500-year) and have added height (freeboard) to 
increase the factor of safety. 



5.5.2Elevation Considerations

The selection of the appropriate method of elevating school buildings above the 
design flood elevation depends on many factors, including cost, level of safety and 
property protection desired, nature of the flood hazard area, etc. The minimum 
requirement is that the lowest floor (including basement) be at or above the DFE 
(plus freeboard, if required); given the importance of school buildings, additional 
height above that elevation is appropriate. Elevation can be accomplished by 
different foundation methods: 

 Slab-on-grade on structural fill. This is considered to be the safest method to elevate 
a building. Structural fill can be placed and shaped so that, when water rises up to 
the DFE, it will not touch the building (Figure 5-5) and building access is 
maintained. The fill must be designed to minimize adverse impacts such as 
increasing flood elevations on adjacent properties, increasing erosive velocities, 
and causing local drainage problems. To ensure stability, especially as floodwaters 
recede and the soils drain, fill must be designed for the anticipated water depths 
and duration. A geotechnical engineer or soil scientist may need to examine 
underlying soils to determine if consolidation over time may occur. In addition, 
the effects of long-term compaction of the fill should be considered, and may 
prompt additional elevation as a factor of safety. The horizontal extent of fill from 
the foundation should be designed to facilitate access by emergency and fire 
vehicles, with a minimum 25-foot width recommended. Designers are cautioned to 
avoid excavating a basement into fill without added structural protection due to 
the potential for significant hydrostatic loads and uplift on basement floors.
 Stem walls (earth-filled perimeter walls). Stem wall foundations are designed to come 
in contact with floodwaters on the exterior. They are more stable than perimeter 
walls (crawlspaces), but could experience structural damage if undermined by 
local scour and erosion. Designs must account for anticipated debris and ice 
impacts and incorporate methods and materials to minimize impact damage.
 Columns or shear walls. Open foundations minimize changes to the floodplain and 
local drainage patterns, and the area under the building can be used for student 
activities or parking (see Figure 5-6). Columns and shear walls must also account 
for hydrodynamic loads and debris and ice impact loads. Flood loads on shear 
walls are reduced if they are oriented parallel to the anticipated direction of flow. 
Erodible soils may be present and local scour may occur; both must be accounted 
for in designs by extending the foundation wall below the expected scour depth.
 Extended solid perimeter walls (crawlspace). Unlike stem wall foundations, solid 
perimeter walls enclose an open area and must be designed with openings 
specifically intended to equalize interior and exterior water levels to prevent 
differential hydrostatic pressures that could lead to structural damage. Wall design 
must also account for hydrodynamic loads, and debris and ice impact loads. The 
enclosed area (the crawlspace) must not contain equipment (including ductwork) 
below the DFE (plus freeboard, if required). Designers must provide adequate 
underfloor ventilation and subsurface drainage to minimize moisture problems 
after flooding.
 Pier supports for portable classroom units. Manufactured buildings must be elevated 
above the DFE (plus freeboard, if required). Pier supports must also account for 
hydrodynamic loads, and debris and ice impact loads, and units must be anchored 
to resist wind loads. Although written specifically for manufactured housing units, 
FEMA 85, Manufactured Home Installation in Flood Hazard Areas, has useful 
information that is applicable to portable classrooms. 


5.5.3 Floodproofing Considerations 

According to the model building codes and the NFIP regulations, schools are treated 
as nonresidential buildings and may be dry floodproofed using measures to prevent 
water from penetrating the building envelope and utilities. However, careful 
consideration of the implications of potential physical damage and safety should be 
undertaken before a decision is made to construct new schools using floodproofing 
methods. 
All flood protection measures are designed for certain flood conditions. Therefore, 
there is always a chance that the design will be exceeded (i.e., water will rise higher 
than accounted for in the design). When this happens to a dry floodproofed 
building, the consequences can be catastrophic. As a general rule, floodproofing is a 
poor choice for new essential and critical facilities (including schools) when 
avoidance of the floodplain or elevation methods to raise the building above the 
flood level can be applied. Floodproofing may be acceptable for retrofitting existing 
schools under certain circumstances (see Section 5.7.4).
Dry floodproofing involves a combination of design and special features that are 
intended to prevent the entry of water into a building while also resisting flood 
forces. It involves structural reinforcement so that exterior walls are sufficiently 
robust to withstand the loads described in Section 5.2.1 (hydrostatic pressure, 
hydrodynamic loads, wave loads, and debris impact loads). For NFIP flood insurance, 
floodproofing must extend at least 1 foot above the BFE or premiums will be very 
costly. Therefore, a higher level of protection is recommended. Exterior walls must 
also be designed to prevent infiltration and seepage of water, whether through the 
wall itself or through any openings, including where utility lines penetrate the 
envelope. Floodproofing techniques are considered to be permanent measures if they 
are always in place and do not require any specific action to be effective. 
If located below the DFE, typical doors and windows present significant failure 
points. Special doors and window shields are available commercially and can be 
designed to provide protection against fairly deep floodwaters. The building must be 
specifically designed for these protective measures or loads may cause frames to 
separate from the building.
Use of contingent floodproofing measures that require installation or activation, 
such as window shields or inflatable barriers, significantly reduces the certainty that 
floodproofing will be effective. Rigorous adherence to a periodic maintenance plan is 
critical to ensure proper functioning. Not only must the school have a formal, written 
plan, but the people responsible for implementing the measures must be informed 
and trained. Also critical to success is that school personnel must receive a credible 
warning with sufficient time to allow getting to the site and putting the measures in 
place. In addition, floodproofing devices often rely on flexible seals that require 
periodic maintenance and that, over time, may deteriorate and become ineffective. 
Therefore, a maintenance plan must be developed and an annual inspection and 
training must be conducted. 
Safety of occupants remains a concern with floodproofed buildings. Regardless of the 
degree of protection provided, floodproofed buildings should not be occupied during 
flood events because failure or overtopping of the floodproofing measures is likely to 
cause catastrophic structural damage. When human intervention is required, the 
people responsible for implementing those measures remain at risk while at the 
school, even if a credible warning system is in place because of the many 
uncertainties associated with predicting the onset of flood conditions. 


5.5.4 Accessory Structures 

Depending on the nature of structures that are accessory to a school, full compliance 
with floodplain management regulations is required and is appropriate to minimize 
future damage. Buildings that serve educational purposes (e.g., offices, classrooms), 
even if detached from the primary school building, are not accessory in nature. 
Portable classrooms are not accessory structures; accessory structures commonly 
associated with schools include storage sheds, bleachers, garages, restrooms, and 
refreshment stands.
Accessory structures may be "wet floodproofed" using techniques that allow them to 
flood while minimizing damage. They must be anchored to resist flotation, collapse, 
and lateral movement. Flood-resistant materials must be used and utilities elevated 
above the DFE (plus freeboard, if required). Openings must be provided to allow the 
free inflow and outflow of floodwaters to minimize hydrostatic loads that cause 
structural damage. Other flood damage and flood loads must be accounted for by 
other means. Because wet floodproofed accessory buildings are designed to flood, 
school staff must be aware that contents will be damaged. 


5.5.5 Utility Installations 

Utilities associated with new schools in flood hazard areas must be protected either 
by elevation or special design measures. Utilities subject to this provision include all 
systems, equipment, and fixtures, including mechanical, electrical, plumbing, and 
heating, ventilating, and air conditioning systems and equipment. Potable water 
systems (wellheads and distribution lines) and wastewater collection lines are 
addressed in Section 5.7.6. 
Utility systems and equipment are best protected when elevated above the DFE (plus 
freeboard, if required). Equipment inside elevated buildings is also elevated and 
equipment inside accessory structures must be elevated if the accessory building is 
wet floodproofed. Exterior equipment must be elevated on fill or on platforms, or 
other support structures. Designers should pay particular attention to underfloor 
utilities and ductwork to ensure that they are properly elevated.
Although it is difficult to achieve, the model building codes and NFIP regulations 
provide an alternative that allows utility systems and equipment to be located below 
the DFE. The alternative requires that such systems and equipment be designed, 
constructed, and installed to prevent floodwaters from entering or accumulating 
within the components during flood events.


5.5.6 Potable Water and Wastewater Systems

New installations of potable water systems and wastewater collection systems are 
required to resist flood damage, including damage associated with infiltration of 
floodwaters and discharge of effluent. Health concerns arise when water supply 
systems are exposed to floodwaters and contamination from flooded sewage systems 
pose health and environmental risks. On-site water supply wellheads should be 
protected with watertight casings to minimize infiltration of surface waters. 
Sewer collection lines should be located and designed to avoid infiltration and 
backup due to rising floodwaters. Devices designed to prevent backup are available 
and are recommended to provide an added measure of protection. 
On-site sewage disposal systems are unlikely for most new school construction. 
However, in the event such systems are considered, designers are advised that local or 
state health departments may impose constraints that limit or prevent locating septic 
fields in floodplain soils or within a mapped flood hazard area. If allowed, septic 
fields should be located on the highest available ground to minimize inundation and 
impairment by floodwaters.  


5.5.7 Storage Tank Installations 

Whether above ground or under ground, storage tanks located in flood hazard areas 
must be designed to resist flotation, collapse, and lateral movement. Aboveground 
tanks must be elevated or adequately anchored to account for maximum buoyancy 
under design flood conditions, assuming the tanks are empty. Similarly, 
underground tanks must be anchored for maximum buoyancy under design flood 
conditions, assuming the tanks are empty. In all cases, designers are cautioned to 
address hydrodynamic loads and debris impact loads that may affect tanks that are 
exposed to floodwaters. Vents and fill openings or cleanout accesses should be 
elevated above the DFE or designed to prevent the inflow of floodwaters or outflow of 
the contents of tanks. 

 
5.5.8 Access Roads
 
Access roads to schools should be designed to minimize impacts on flood hazard 
areas, minimize damage to the road itself, and to minimize exposing vehicles to 
dangerous situations, although balancing those elements can be difficult, depending 
on the site and specific flood characteristics. Designers should take the following 
into consideration:

 Safety factors. Although a school's access road is not required to carry regular 
traffic like other surface streets, a flood-prone road always presents a degree of risk 
to public safety. To minimize those risks, some regulatory authorities require that 
access roads be designed to be no more than 1 foot or 2 feet below the DFE. To 
maximize evacuation safety, two separate accesses to different feeder roads are 
recommended. In some circumstances, especially long-duration flooding where a 
school is built on fill, dry access may allow continued operations. 
 Floodplain impacts. Engineering analyses may be required to document effects on 
flood elevations and flow patterns if large volumes of fill are required to elevate a 
road to minimize dangerous flooding above the driving surface.
 Drainage structure and road surface design. The placement of multiple drainage 
culverts, even if not needed for local drainage, can facilitate the passage of 
floodwaters and minimize the potential for a road embankment to act as a dam. 
Embankments should be designed to remain stable during high water and as 
waters recede, and should be sloped and protected to resist erosion and scour. For 
roads that are designed to flood, the surface and shoulders should be designed to 
resist erosion.




5.6 VULNERABILITY: WHAT FLOODS CAN DO TO EXISTING SCHOOLS

Existing flood-prone schools are exposed to damage, and the nature and severity of 
damage is a function of site-specific flood characteristics. As described below, damage 
may include: site damage; structural and nonstructural building damage; destruction 
or impairment of service equipment; loss of contents; and health and safety threats 
due to contaminated floodwater. 
Regardless of the nature and severity of damage, flooded schools are closed while 
cleanup and repairs are undertaken. The length of the closure, and thus the impact 
on the ability of the school district to return to teaching, depends on the severity of 
the damage and lingering health hazards. It may also depend on whether the 
building was fully insured or whether disaster assistance is made available quickly to 
allow speedy repairs and reconstruction. Sometimes repairs are put on hold pending 
a decision on whether a school should even be rebuilt at the flood-prone site. When 
damage is substantial, reconstruction is allowed only if compliance with flood-
resistant design provisions is achieved (see Section 5.7.3).


5.6.1 Site Damage

The degree of site damage associated with flooding is a function of several variables 
related to the characteristics of the flood, as well the site itself:

 Erosion and scour. All parts of a school site that are subject to flooding by fast 
moving flows could experience erosion, and local scour could occur around any 
permanent obstructions to flow. Graded areas, filled areas, and cut or fill slopes 
are especially susceptible. Stream and channel bank erosion is a natural 
phenomenon that may, over time, threaten site improvements and buildings. 
 Debris and sediment removal. Even when buildings are not subject to flood damage, 
floods can produce large quantities of debris and sediment that can damage a site 
and that are expensive to remove, especially from athletic fields. 
 Fences. Some fences trap floating debris and can significantly restrict the free flow 
of floodwaters. Fences can be damaged by flowing water and can be flattened if the 
buildup of debris results in significant loads. 
 Playing field surfaces. In addition to damage by erosion and scour, graded grass 
fields and applied track surfaces can be damaged by standing water and deposited 
sediments. 
 Accessory structures. Accessory structures such as storage sheds, bleachers, 
restrooms, and refreshment stands can sustain both structural and nonstructural 
damage. Such structures may be designed and built using techniques that 
minimize damage potential. 
 Access roads. Access roads that extend across flood-prone areas may be damaged by 
erosion, washout of drainage culverts, failure of fill materials, and loss of surface. 
 Other. Objects outside of buildings, including cars and school buses, can be 
damaged or washed away.


5.6.2 Structural Damage

Structural damage includes all damage to the load-bearing portions of a building. 
Damage to other components of buildings is described below: finish materials 
(Section 5.6.3), utility service equipment (Section 5.6.4), and contents (Section 5.6.5). 
Structural damage can be caused by each of the characteristics of flooding described 
in Section 5.2.1:

 Depth. The hydrostatic load or pressure against a wall or foundation is directly 
related to the depth of water (see Figure 5-7). Standard stud and siding, or brick 
faced walls, may collapse under hydrostatic loads associated with relatively shallow 
depths of water. Reinforced masonry walls perform better than unreinforced 
masonry walls, although an engineering analysis is required to determine 
performance. Walls and floors of below-grade areas (basements) are particularly 
susceptible to damage by hydrostatic pressure. When soils are saturated, pressures 
against below-grade walls are a function of the total depth of water, including the 
depth below-grade and the weight of the saturated soils.
 Buoyancy and uplift. If below-grade areas are essentially watertight, buoyancy or 
uplift forces can rupture concrete floors or float a building out of the ground (see 
Figure 5-8). Flood-prone buildings that are not adequately anchored can be floated 
or pushed off foundations. Although rare for large and heavy school buildings, 
this is a concern for outbuildings and portable (temporary) classrooms.
 Duration. Long duration saturation can cause dimensional changes and contribute 
to deterioration of wood members, although saturation is unlikely to result in 
significant structural damage to masonry construction. Saturation of soils, a 
consequence of long duration flooding, increases pressure on below-grade 
foundation walls. 
 Velocity, wave action, and debris impacts. Each of these components of dynamic 
loads can result in structural damage if buildings are not designed to resist 
overturning, repetitive pounding by waves, or short-duration impulsive loads 
generated by floating debris or ice.

 Erosion and scour. Structural damage is associated with foundation failure when 
erosion or scour results in partial or complete removal of supporting soil. Erosion 
of slopes, especially unprotected slopes, can lead to slope failures and loss of 
foundation supporting soil. 


5.6.3 Saturation Damage

Many flood-prone buildings are exposed to flooding that is not fast moving or that 
may be relatively shallow and not result in structural damage. Simple saturation of the 
building and its furnishings can result in significant and costly damage, including 
long-term health complications associated with mold. Floodwaters often are 
contaminated with chemicals or petroleum products. Under such circumstances, 
recovery generally involves removal of nonstructural materials and finishes because 
cleanup and decontamination is expensive and time-consuming. Damage to contents 
is discussed in Section 5.6.5. 
Saturation damage varies somewhat as a function of duration. Use of water-resistant 
materials will help to minimize saturation damage and reduce the costs of cleanup 
and restoration to service (see Flood-Resistant Materials Requirements, FIA-TB-2): 
 Wall finishes. Painted concrete and concrete masonry walls usually resist water 
damage, provided the type of paint used can be readily cleaned. Tiled walls may be 
acceptable, depending on the type of adhesive and foundation (gypsum board 
substrate and wood-framed walls with tile typically do not remain stable). 

 Flooring. Most schools have durable floors that resist water damage. Ground floors 
typically are slab-on-grade and finished with tile or sheet goods. Flooring 
adhesives since the early 1990s likely are latex-based and tend to break down when 
saturated. Most carpeting, even indoor-outdoor materials, are difficult to clean. 
Wood floors are particularly susceptible to saturation damage. Short duration 
inundation may not cause permanent deformation of some wood floors, such as 
may be present in older buildings. However, because of low tolerance for surface 
variations, gymnasium floors are particularly sensitive and tend to warp after 
flooding of any duration. 
 Wall and wood components. When soaked for long periods of time, some building 
components change composition or shape. Wet wood will swell and, if dried too 
quickly, will crack, split or warp. Plywood can delaminate and wood door and 
window frames may swell and become unstable. Gypsum wallboard, wood 
composition panels, other wall materials, and wood cabinetry not intended for wet 
locations can fall apart (see Figure 5-9). The longer these materials are wet, the 
more moisture, sediment, and pollutants they will absorb. Some wall materials 
such as the paper facing on gypsum wallboard, "wick" standing water, resulting in 
damage above the actual high-water line (see Figure 5-10).
 Metal components. Metal structural components are unlikely to be permanently 
damaged by inundation. Metal partitions are particularly susceptible when 
saturated because they cannot be thoroughly dried and cleaned. Depending on 
the degree of corrosion protection on the metal, repetitive flooding by saline 
coastal waters may contribute to long-term corrosion.
 Metal connectors and fasteners. Depending on the composition of the metal, 
repetitive flooding, especially by saline coastal waters, may contribute to long-term 
corrosion. Connectors and fasteners are integral to the structural stability of 
buildings, therefore, failure due to accelerated corrosion would jeopardize the 
building.



5.6.4 Utility System Damage

Utility system service equipment that is exposed to flooding is vulnerable to damage. 
Damage may result in total loss or may require substantial cleaning and restoration 
efforts. The degree of damage varies somewhat as a function of flooding 
characteristics. Certain types of equipment and installation measures will help to 
minimize damage and to reduce the costs of cleanup and restoration to service: 

 Displacement of equipment and appliances. Installation below the flood level 
exposes equipment and appliances to various flood forces, including drag due to 
flowing water and buoyancy. Gas-fired appliances are particularly dangerous:  
flotation can separate the appliance from the gas source, resulting in building 
fires, and explosive situations. Displaced equipment may dislodge lines from fuel 
oil tanks, not only contributing to the threat of fires, but also causing water 
pollution and environmental damage. Firefighting efforts are compounded if 
access to the school is limited due to flooded roads.
 Corrosion. Corrosion related to inundation of equipment and appliances may not 
be apparent immediately, but can increase maintenance demand and shorten the 
useful life of some equipment and appliances. 
 Electrical systems and components. Electrical systems and components, and 
electrical controls of HVAC systems, are subject to damage simply by getting wet 
even for short durations. Unless specifically designed for wet locations, switches 
and other electrical components can short out due to deposits of sediment or 
otherwise not function even when allowed to dry before operation. Wiring and 
components that have been submerged may be functional, although generally it is 
more cost-effective to discard flooded outlets, switches, and other less expensive 
components than to attempt thorough cleaning.
 Ductwork damage. Ductwork is subject to two flood-related problems. Flood forces 
can displace ductwork and saturated insulation can overload support straps, 
causing failure.
 Mold and dust. Furnaces, air handlers, and ductwork that have been submerged 
must be thoroughly cleaned and sanitized. Otherwise, damp conditions contribute 
to the growth of mold and the sediment can be circulated throughout the school, 
causing respiratory problems.
 Gas-fired systems. Water-borne sediment can impair safe functioning of jets and 
controls in gas-fired furnaces and water heaters, necessitating that they be 
professionally cleaned and inspected prior to restoration of service.
 Tanks (underground). Underground storage tanks are subjected to significant 
buoyant forces and can be displaced, especially when long-duration flooding 
occurs. Computations of stability should be based on the assumption that the tank 
is empty in order to maximize safety. Tank inlets, fill openings, and vents should 
be above the DFE or designed to prevent the inflow of floodwaters or outflow of 
tank contents during flood conditions.
 Tanks (aboveground). Aboveground storage tanks are subject to buoyant forces and 
displacement due to moving water. Standard strapping of propane tanks may be 
inadequate for the anticipated loads. Tank inlets, fill openings, and vents should 
be above the design flood elevation or designed to prevent the inflow of 
floodwaters or outflow of tank contents during flood conditions.
Damage to public utility service (potable water supply and wastewater collection) can 
have consequential damage to schools:

 Water supply. Potable water supply systems may become contaminated if public 
water distribution lines or treatment facilities are damaged, or if wellheads are 
submerged.
 Sewer backup. Sewers back up during heavy rains due to infiltration and inflow of 
stormwater into the sewer lines and manholes, cross connections between storm 
and sanitary sewers, and/or flooded wastewater treatment plants. Sewer backup 
into a school poses a major health hazard. Even when the water has receded, 
exposed building components, finish materials, and contents are severely 
contaminated and usually must be removed because adequate cleaning is difficult, 
if not impossible. 


5.6.5 Contents Damage

Schools may contain high value contents that can be damaged and unrecoverable 
when subjected to flooding. For the purpose of this discussion about the nature of 
flood-related contents damage, the term "contents" includes furniture, computers, 
laboratory equipment and materials, records, and library materials. The following 
types of contents often are considered total losses: 

 Furniture. Depending on the nature of wood furniture, it may withstand short-
duration inundation, requiring only cleanup. In long-duration flooding, porous 
woods become saturated and swollen, and joints may separate. Furniture with 
coverings or pads generally cannot be restored. Metal furniture is difficult to 
thoroughly dry and clean, is subject to corrosion, and typically is discarded.
 Computers. Flood damaged computers and peripheral equipment cannot be 
restored after inundation, although special recovery procedures may be able to 
recover information on hard drives.
 School records. When offices are located in flood-prone space, valuable school 
records may be lost. Although expensive, some recovery of computerized and paper 
records may be possible with special procedures.
 Library books and collections. It is generally not economical to recover library 
materials and special collections that are saturated by floodwaters. 
 Laboratory materials and equipment. Depending on the nature of laboratory 
materials, cleanup may require special procedures. Generally, equipment is 
difficult to restore to safe functioning.
 Kitchen goods and equipment. Stainless steel equipment and surfaces generally have 
cleanable surfaces that can be disinfected and restored to service. Because of 
contamination, kitchen contents and perishables cannot be recovered. 



5.7 RISK REDUCTION: PROTECTING EXISTING SCHOOLS
Schools that already are located in flood hazard areas may be made more resistant to 
flood damage. School districts may take such action when flood hazards are iden-
tified and there is a desire to proactively undertake risk reduction measures. Interest 
may be prompted by a flood or by the requirement to address flood resistance as part 
of proposed substantial improvements or additions. Table 5-2 offers some questions 
to help identify building characteristics that are important when considering risk 
reduction measures.
Work on existing school buildings and sites is subject to codes and regulations and 
the appropriate regulatory authority with jurisdiction should be consulted. With 
respect to reducing flood risks, work generally falls into the following categories 
described in Sections 5.7.1 though 5.7.8.


5.7.1 Site Modifications 

Modifying an existing school property that is subject to flooding requires careful 
examination by an experienced professional engineer. Determining the suitability of 
a specific measure requires a complex evaluation of many factors, including the na-
ture of flooding and the nature of the site. Table 5-1 identifies questions to be 
examined relative to flood hazards that influence the measures that may be applicable 
to modifying existing school sites. Some characteristics may make it infeasible to 
apply flood-resistant measures to existing schools (e.g., depths greater than 3 to 4 feet, 
very high velocities, flash flooding or rapid rate of rise [insufficient warning], and 
very long duration). Each of these measures has limitations, including the fact that 
the level of protection will be exceeded by floods that are larger than the design 
flood.
Site modifications may be designed to keep water away from a building. In each case, 
careful attention must be given to internal drainage. The rain that falls on the school 
and the portion of the site inside these flood protection measures will collect and 
must be accounted for or it may contribute to damage. Two general approaches are 
taken:  provide sufficient ponding storage capacity or install pumps to transfer 
accumulated runoff outside the protection measure. Site modifications include:
 Regrading the site (berm). Where a school is exposed to relatively 
shallow flooding and sufficient land area is available, 
regrading the site or construction of a non-engineered 
earthen berm may provide adequate protection.

 Earthen levee or dike. Earthen levees are engineered structures that are designed to 
keep water away from land area and buildings (Figure 5-11). Hydraulic evaluations 
and geotechnical investigations are required to determine their feasibility and 
effectiveness. For existing school sites, constraints include the availability of land 
(levees have a large "footprint" and require large land areas), cost (including 
availability of suitable fill material and long-term maintenance), and difficulties 
with site access. Levees rarely are used to protect a single site, although they may 
offer a reasonable solution for a group of buildings. Locating levees and 
floodwalls within a designated floodway generally is not allowed. Rapid onset 
flooding makes it impractical to design a flood levee with access points that 
require installation of a closure system. Earthen levees may also be subject to high 
velocity flows that cause erosion and affect the stability of earthen levees. 

 Permanent floodwall. Floodwalls are freestanding, permanent engineered structures 
that are designed to prevent encroachment of floodwaters. Typically, floodwalls 
are located at some distance from buildings so that structural modification of the 
existing building is not required. Floodwalls may protect only the low side of a site 
(in which case they must "tie" into high ground) or completely surround a site 
(which may affect access because special closure structures are required and must 
be installed before the on-set of flooding, Figure 5-12).

 Mobilized floodwall. This category of flood protection measures includes fully 
engineered flood protection structures that have permanent features (foundation 
and vertical supports) and features that require human intervention to mobilize 
when a flood is predicted (horizontal components called planks or stop-logs). 
Mobilized floodwalls have been used to protect entire sites or to tie into 
permanent floodwalls or high ground. Due to the manpower and time required 
for proper placement, these measures are better suited to locations with sufficient 
warning times.

A common problem associated with the site modifications listed above is access. 
Depending on the topography of the site, construction of barriers to floodwaters may 
require special access points. Access points may be protected with manually installed 
stop-logs or designed gates that drop-in, slide, or float into place. Whether activated 
by automatic systems or manually, access protection requires sufficient warning time.
Other significant constraining factors include poor soils and insufficient land area. 
These also make site modifications either infeasible or very costly. A school may be 
among several buildings and properties that can be protected, increasing the 
benefits. For any type of barrier, rainfall that collects on the land side must be 
accounted for in the design.


5.7.2 Additions 

The model building codes treat additions as new construction. Therefore, additions 
to existing schools that are located in flood hazard areas are required to comply with 
the code. Elevation of an addition on fill may not be feasible unless structural fill can 
be placed adjacent to an existing building. Section 5.5.2 outlines other elevation 
options that are applicable to additions. Utility service equipment for the addition 
must also meet the requirements for new construction and new installations (see 
Section 5.5.5).
With respect to code compliance and designing additions to resist flood damage, one 
of the more significant issues that may come up is ease of access. If the lowest floor of 
the existing school building is below the DFE, steps, ramps, or elevators will be 
required for the transition to the new addition. Under the regulations of the NFIP 
and guidance that FEMA offers to jurisdictions that may wish to consider variances, it 
is not considered appropriate to grant a variance to the elevation requirement for an 
addition because alternative means of access are available. 


5.7.3 Repairs, Renovations, and Upgrades

Every school that is considered for upgrades and renovations, or that is being 
repaired after substantial damage from any cause, must be examined for structural 
integrity and stability to determine compatibility with structural modifications that 
may be required to achieve acceptable performance. When an existing school is 
located in a flood hazard area, that examination should include consideration of 
measures to resist flood damage and reduce risks. 
The model building codes and the regulations of the NFIP and the model building 
codes require that work that constitutes 'substantial improvement' of an existing 
building be in compliance with the flood-resistant provisions of the code. Non-
substantial improvements should take into account measures to reduce future flood 
damage, such as many described in Section 5.7.7 and wet floodproofing measures that 
allow water to enter the building to avoid structural damage, and emergency 
measures (see Section 5.7.8).

Compliance with flood-resistant provisions means the building must be elevated or 
dry floodproofed. Both options can be difficult for schools, given the typical size and 
complexity of school buildings. Dry floodproofing is described in Section 5.7.4 and is 
generally limited to water depths on the order of 3 to 5 feet. 

Elevating an existing building presents an entirely different set of challenges and 
also requires detailed structural engineering analyses. It involves the same equipment 
and methods used to move other types of buildings, and expert building movers have 
successfully moved large, heavy, and complex buildings, sometimes by segmenting 
them. A school building that is elevated-in-place must meet the same performance 
standards set for new construction (see Section 5.5).


5.7.4 Retrofit Dry Floodproofing

Modifications of an existing building may be required, including construction of a 
reinforced supplementary wall, measures to counter buoyancy (especially if there is 
below-grade space), installation of special watertight doors or barriers, and providing 
watertight seals around points of entry of utility lines. The details of structural 
investigations and structural design of such protection measures are beyond the 
scope of this manual. 
Detailed structural engineering evaluations are required to determine whether an 
existing building can be dry floodproofed due to the tremendous loads that may be 
exerted on a building not originally designed for such conditions. The following 
elements must be examined:  

 Structural strength of walls.
 The effects of buoyancy on below-grade areas.
 Protection where utilities enter the building; and the seepage of water through 
walls. Secondary walls can be constructed immediately adjacent to existing walls, 
with a waterproof membrane, to provide adequate strength. 

Application of waterproofing products or membranes may minimize infiltration of 
water through exterior walls, although there are limitations and concerns with 
durability. Measures that require human intervention are considered emergency 
measures and are discussed in Section 5.7.8. 


5.7.5 Utility Installations 

Some aspects of an existing school's utility systems may be modified to reduce 
damage. The effectiveness of such measures depends not only on the nature of 
flooding, but the type of utility and the degree of exposure. Table 5-2 listed some 
questions that will help facility planners and designers to examine risk reduction 
measures.
Even if a school building is unlikely to sustain extensive structural damage due to 
flooding, high costs and delayed reoccupancy may result from flood-damaged utility 
systems. Risk reduction design measures can be applied whether undertaken as part 
of large-scale retrofits of existing schools or as separate projects:

 Relocate from below-grade areas. The most vulnerable utility installations are those 
located in below-grade areas, and the most effective protection measure is to 
relocate them to properly elevated sites or platforms that are at least 2 feet above 
the DFE. The complexity of re-routing pipes, conduits, ductwork, electrical service, 
lines, and connections will depend on site-specific factors.
 Elevate components. Whether located inside or outside of the building, some 
components of utility systems can be elevated-in-place on platforms, including 
electric transformers, water heaters, air conditioning compressors, furnaces, 
boilers, and heat pumps (see Figures 5-13 and 5-14).  
 Anchor tanks and raise openings. Existing tanks can be elevated or anchored (both 
underground and aboveground tanks), as described in Section 5.5.7. If anchored 
below the DFE, tank inlets, vents, fill pipes, and openings should be elevated above 
the DFE or fitted with covers designed to prevent the inflow of floodwaters or 
outflow of the contents of the tanks.
 Protect components. If utility components cannot be elevated, it may be feasible to 
construct watertight enclosures or enclosures with watertight seals that require 
human intervention to install when flooding is predicted.
 Elevate control equipment. Control panels, gas meters, and electrical panels can be 
elevated, even if the equipment cannot be protected.
 Separate electrical controls. Where areas within an existing school are flood-prone, 
separation of control panels and electrical feeders will facilitate shutdown before 
floodwaters arrive and help protect the safety of workers during cleanup.


5.7.6 Potable Water and Wastewater Systems

All plumbing fixtures that are connected to the potable water system may become 
weak points in the system if they allow floodwaters to contaminate the system. 
Relocating such uses to at least 2 feet above the DFE provides protection. Wellheads 
can be sealed with watertight casings or protected with a sealed enclosure.
Wastewater system components become sources of contamination during floods. 
Rising floodwaters may force untreated sewage to backup through toilets. Specially 
designed back-flow devices can be installed or restrooms below the DFE can be pro-
vided with overhead piping that may require specially designed pumps in order to 
operate properly. Septic tanks can be sealed and anchored. 


5.7.7 Other Damage Reduction Measures 

A number of steps can be taken to make existing schools in flood hazard areas more 
resistant to flood damage, which also facilitates rapid recovery, cleanup, and 
reoccupancy. Whether these measures are applicable to a specific school depends, in 
part, on the characteristics of the flood hazard and the characteristics of the building 
itself. School facility planners and designers should consider the following:

 Retrofit the building envelope with openings specifically designed to allow 
floodwaters to flow in and out to minimize hydrostatic pressure on walls. Although 
allowing water to enter the building, this measure minimizes the likelihood of 
major structural damage. Walls that enclose interior spaces would also be 
retrofitted with openings.
 Replace interior walls that have cavities with flood-resistant construction or 
removable panels to facilitate cleanup and drying.
 Abandon use of below-grade areas (basements) by filling to prevent structural 
damage.

 Permanently relocate high-value uses that often are found on the ground floor of 
schools (e.g., offices, school records, libraries, and computer laboratories) to 
higher floors or elevated additions.
 Install backflow devices in sewer lines.
 Pre-plan actions to move damageable furniture and high-value contents from lower 
floor to higher floors, when a flood warning is issued.
 Replace wall, flooring, and finish materials with flood-resistant materials. 
 Use epoxy or other impervious paints on concrete and other pervious surfaces to 
minimize contamination. 
 Install separate electric circuits and ground fault interrupter circuit breakers in 
areas that will flood. Emergency measures should be provided so that electrical 
service can be shut down to avoid electrocution hazards.
 Relocate chemicals to areas not subject to flooding.


5.7.8 Emergency Measures

Emergency response to flooding is outside the scope of this manual. However, 
because some existing schools may not be retrofitted to provide protection against 
the design flood, it may be appropriate to examine feasible emergency measures that 
may provide some protection. The following discussion pertains only to emergency 
measures that have been used to reduce flood damage to older buildings that are 
already located in flood hazard areas. These measures do not achieve compliance 
with building and life safety codes, do not provide protection to occupants, and 
experience a very high frequency of failure. 
Emergency barriers are measures of "last resort," and should be used only when a 
credible flood warning with adequate lead-time is available and dependable. These 
measures have varying degrees of success, depending on the available manpower, 
skill required, long-term maintenance of materials and equipment, suitability for site-
specific flood conditions, and sufficiency of warning. Complete evacuation of 
protected buildings is required as these measures should not be considered adequate 
protection for occupants. Further, emergency barriers are not acceptable in lieu of 
designed flood resistant protection for new buildings. Typical examples include:
 Sandbag walls. Unless planned well in advance or emergency workers are under the 
direction of trained personnel, most sandbag barriers are not constructed in 
accordance with proper practices, leading to leakage and failures. Because of the 
intensive work effort and length of time required for protection from even 
relatively shallow water, sandbag walls are not a reliable protection measure. To be 
effective, sandbags and sand should be stockpiled and checked regularly to ensure 
the sandbags have not deteriorated. Sandbags have some drawbacks, including 
high disposal costs and their tendency to absorb pollutants from contaminated 
floodwaters.
 Water-filled barriers. A number of vendors make barriers that can be assembled with 
relative ease, depending on the source water for filling. The barriers must be 
specifically sized for the site. Training is important so that personnel know how to 
place and deploy the barriers. Proper storage, including cleaning after 
deployment, is necessary to protect the materials over long periods of time.
 Panels for doors. For shallow and short-duration flooding, plywood panels or panels 
of other sturdy material can be made for doorways to minimize the entry of 
floodwaters. Effectiveness is increased significantly if a flexible gasket or sealant is 
provided and the mounting hardware is designed to apply even pressure. 
Personnel must know where the materials are stored and be trained in 
deployment.



5.8 THE SCHOOL AS AN EMERGENCY SHELTER

Emergency managers regularly identify schools to serve as short-term and/or long-
term shelters. They are attractive sites for shelters because they have kitchen facilities 
that are designed to serve many people, restroom facilities that are likely to be 
adequate for many people, and space for cots in gymnasiums, cafeterias, and wide 
corridors.
New schools that are to be used for emergency sheltering are appropriately designed 
as essential or critical facilities that warrant a higher degree of protection than other 
schools. If located in or adjacent to flood hazard areas, it is appropriate to provide 
protection for the building and utility systems to at least the 0.2%-annual chance 
(500-year) flood level or, at a minimum, 2 to 3 feet above the DFE. Additional 
guidance on hazard-resistant shelters is found in FEMA 361, Design and Construction 
Guidance for Community Shelters. 
Additional measures that may be appropriate for consideration by the school district 
and designer include:

 Wastewater service must be functional during conditions of flooding.
 Emergency power service must be provided.
 Dry-ground access is important in the event flooding exceeds design levels.




5.9 REFERENCES AND SOURCES OF ADDITIONAL INFORMATION

Obtaining Selected Publications: 

 FEMA publications may be obtained at no cost by calling (800)480-2520, faxing a 
request to (301)497-6378, or downloaded from the library/publications section 
online at http://www.fema.gov. 

 U.S. Army Corps of Engineers publications can be found online at: 
http://www.usace.army.mil/inet/functions/cw/cecwp/NFPC/nfpc.htm.

American Society of Civil Engineers, Inc. Flood Resistant Design and Construction, 
ASCE/SEI 24-98, Reston, VA, 2000.

American Society of Civil Engineers, Inc. Minimum Design Loads for Buildings and Other 
Structures, ASCE-7-02, Reston, VA, 2002.

Federal Emergency Management Agency, Answers to Questions about Substantially Damaged 
Buildings, FEMA 213, Washington, DC, May 1991.

Federal Emergency Management Agency, Answers to Questions about the National Flood 
Insurance Program, FEMA 387, August 2001
. 
Federal Emergency Management Agency, Coastal Construction Manual, FEMA 55 (3rd 
Edition), 2000.

Federal Emergency Management Agency, Design and Construction Guidance for 
Community Shelters, FEMA 361, Washington, DC, July 2000
.
Federal Emergency Management Agency, Engineering Principles and Practices for 
Retrofitting Flood-prone Residential Buildings, FEMA 259, Washington, DC, January 1995.

Federal Emergency Management Agency, Floodproofing Non-Residential Structures, FEMA 
102, Washington, DC, May 1986.

Federal Emergency Management Agency, Protecting Building Utilities From Flood Damage: 
Principles and Practices for the Design and Construction of Flood Resistant Building Utility Systems, 
FEMA 348, Washington, DC, November 1999. 

Federal Emergency Management Agency and American Red Cross, Repairing Your 
Flooded Home, FEMA 234/ARC 4477. Washington, DC. (available at 
http://www.redcross.org, local Red Cross chapters, and FEMA).

Federal Emergency Management Agency, NFIP Technical Bulletins:

 User's Guide to Technical Bulletins, FIA-TB-0, April 1993. 
 Openings in Foundation Walls, FIA-TB-1, April 1993.
 Flood-Resistant Materials Requirements, FIA-TB-2, April 1993.
 Non-Residential Floodproofing-Requirements and Certification, FIA-TB-3, April 1993. 
 Elevator Installation, FIA-TB-4, April 1993. 
 Free-of-Obstruction Requirements, FIA-TB-5, April 1993. 
 Below-Grade Parking Requirements, FIA-TB-6, April 1993.
 Wet Floodproofing Requirements, FIA-TB-7, December 1993.
 Corrosion Protection for Metal Connections in Coastal Areas, FIA-TB-8, 1996.
 Design and Construction Guidance for Breakaway Walls Below Elevated Coastal Buildings, FIA-
TB-9, 1999.
  Ensuring That Structures Built on Fill In or Near Special Flood Hazard Areas Are Reasonably 
Safe From Flooding, FIA-TB-10, 2001. 
 Crawlspace Construction for Buildings Located in Special Flood Hazard Areas, FIA-TB-11, 2001.
International Code Council, Inc. ICC Performance Code for Buildings and Facilities(tm),  
Country Club Hills, IL, 2003.

International Code Council, Inc. International Building Code(r), Country Club Hills, IL, 

2003.
National Fire Protection Association. Building Construction and Safety Code (NFPA 5000), 
Quincy, MA, 2003.
 
U.S. Army Corps of Engineers, Flood-Proofing Systems & Techniques, 1984.

U.S. Army Corps of Engineers, Flood-Proofing Regulations, EP 1165-2-314, 1992.

U.S. Army Corps of Engineers, National Flood-Proofing Committee, Flood-Proofing - How To 
Evaluate Your Options, Washington, DC, July 1993.

U.S. Army Corps of Engineers, Flood-Proofing Programs, Techniques and References, 
Washington, DC, 1996.

U.S. Army Corps of Engineers, Flood-Proofing Performance - Successes & Failures, 
Washington, DC, 1998.


Organizations and Agencies

Federal Emergency Management Agency:  10 regional offices (www.fema.gov) can be 
contacted for advice and guidance on NFIP mapping and regulations. 

NFIP State Coordinating offices help local governments to meet their floodplain 
management obligations and may provide technical advice to others; the offices are 
listed by the Association of State Floodplain Managers, Inc., 
(www.floods.org/stcoor.htm). 

State departments of education or agencies that coordinate state funding and 
guidelines for schools may have state-specific requirements.
U.S. Army Corps of Engineers:  District offices offer Flood Plain Management Services 
(www.usace.army.mil/inet/functions/cw/). 



5.10 GLOSSARY OF FLOOD PROTECTION TERMS

Base flood. The flood having a 1 percent chance of being equaled or exceeded in any 
given year; sometimes referred to as the 100-year flood.

Base flood elevation (BFE). The height of the base (1 percent or 100-year) flood in 
relation to a specified datum, usually the National Geodetic Vertical Datum of 1929 or 
the North American Vertical Datum of 1988. 

Design flood. The greater of the following two flood events:  (1) the base flood, 
affecting those areas identified as special flood hazard areas on a community's Flood 
Insurance Rate Map (FIRM); or (2) the flood corresponding to the area designated as 
a flood hazard area on a community's flood hazard map or otherwise legally 
designated.

Design flood elevation (DFE). The elevation of the design flood, including wave 
height, relative to the datum specified on a community's flood hazard map.
Dry floodproofing. An adjustment, modification, or addition of a feature or 
combinations of these that eliminate or reduce the potential for flood damage by 
sealing walls and closing openings to keep water from entering a building. 
FEMA. Federal Emergency Management Agency, the federal agency that administers 
the National Flood Insurance Program (NFIP).

Flood Insurance Rate Map (FIRM). Insurance and floodplain management map 
issued by FEMA that identifies areas of base flood hazard in a community. Some 
areas' maps also include base flood elevations, 500-year floodplain boundaries, and 
regulatory floodway boundaries.

Flood Insurance Study (FIS). Engineering study performed by FEMA to identify flood 
hazard areas, flood insurance risk zones, and other flood data in a community; used 
in the development of the FIRM.

Floodplain. The area including a watercourse and the land adjacent to it that is 
flooded during a flood of a given recurrence interval (e.g., 10-year flood, 50-year flood, 
100-year flood, etc.).

Floodplain management regulations. Zoning ordinances, subdivision regulations, 
building codes, health regulations, or special-purpose ordinances, that set flood 
protection standards for new construction and land use.

Floodway. The stream channel and that portion of the adjacent floodplain that must 
remain open to permit passage of the base flood. 

Freeboard. The additional height to which a building is protected from flooding 
above the base flood elevation to provide additional factor of safety and to account for 
uncertainties, usually 1 to 3 feet for critical/essential facilities. 

Human intervention. Actions that must be taken by one or more persons in order for a 
building to be floodproofed before floodwaters arrive. 
Hydrodynamic force. The force of moving water, including the impact of debris and 
high velocities. 

Hydrostatic pressure. The pressure put on a structure by the weight of standing water. 
The deeper the water, the more it weighs and the greater the hydrostatic pressure. 
Lowest floor. The lowest floor of the lowest enclosed area (including a basement) of a 
building. 

National Flood Insurance Program (NFIP). Federal program to identify flood-prone 
areas nationwide and make flood insurance available for properties in communities 
that participate in the program. 

Substantial damage. Damage to a building from any cause such that the cost to repair 
it to its pre-damaged condition is equal to 50 percent or more of its pre-damaged 
value. 

Substantial improvement. A modification or remodeling of a building such that the 
value of the addition or remodeling is equal to 50 percent or more of the building's 
original appraised value. 

Wet floodproofing. Permanent or contingent measures applied to a building and/or 
its contents that prevent or provide resistance to damage from flooding by modifying 
interior finishes, removing damageable items from lower areas, and allowing water 
into the building.




Four Examples of Schools Vulnerable to Flood Hazards

Two schools in Gurnee, Illinois, were damaged by floods in 1986. The school district's actual costs 
were over $1.6 million to repair and replace the facilities, supplies, and materials. Not included in 
these figures are the costs for transportation and rental, and disruption of the school year for children 
who, for several months, attended school in a vacant department store 4 miles away. For an 
additional 2 years of renovation and reconstruction, the children attended school in another 
community, 8 miles away. One school was later rebuilt as a flood protected facility for a cost of $17 
million, all of which was paid by local taxpayers. 
In April 2003, a dry floodproofed private school in Jackson, Mississippi, experienced a soaking when 
a sudden downpour dumped 9 inches of rain on the area. Because the event occurred in the pre-dawn 
hours when no one was on site to install the floodproofing measures (e.g., water-tight doors and 
special seals), water entered the building, causing damage to carpets, walls, furniture, and 
equipment.
In 1989, Hurricane Hugo vividly revealed the importance of knowing whether schools are prone to 
flooding. The local emergency manager's records identified the McClellanville, South Carolina, 
school as an approved hurricane shelter. Unfortunately, that designation was based on erroneous 
information because the school turned out to be four feet lower than indicated in those records. When 
storm surge flooding inundated the school, people had to break through the ceiling and lift everyone 
up to the attic. 
Flooding in the spring of 2001 tested flood protection for the Oak Grove Lutheran High School in 
Fargo, North Dakota. Prompted by the failure of temporary earth and sandbag dikes during the 1997 
Red River flood of record, which resulted in over $3.5 million in damage to the school, the city 
designed and constructed a brick-faced permanent floodwall. Five access points, wide enough for 
vehicles, were protected with an "invisible" closure that is an integral part of the floodwall. A crew 
of six was able to install the closures in less than 2 hours.


Local drainage problems create ponding and local flooding that often is not directly associated with a 
body of water such as a creek or river. Although these problem areas generally are relatively shallow 
and often are not characterized by high velocity, considerable damage may result, especially when 
poor drainage causes repetitive damage. Some local drainage problems are exacerbated by old or 
undersized drainage system infrastructure. Because drainage problems typically occur as sheetflow or 
along waterways with very small drainage areas, this type of flooding often is not mapped or 
regulated.


1 Flood maps may also be viewed online at FEMA's Map Store at http://www.fema.gov. For a fee, copies may be ordered online or by calling (800) 
358-9616. The Flood Insurance Study (FIS) and engineering analyses used to determine the flood hazard area also may be ordered through the 
FEMA webpage


2  Because V Zones are generally limited in extent, such areas are unlikely sites for schools. The specific design and construction provisions for V 
Zones are not addressed in this manual. More information can be found in FEMA 55, Coastal Construction Manual.




The DFE is the highest elevation of either the flood hazard area shown on a community's Flood 
Insurance Rate Map, or another flood as legally designated by a community (e.g., accounting for 
future development)




Construction of public schools may be regulated by a state board or agency and thus may not be 
subject to local permit requirements, including local floodplain management regulations. In these 
cases, the NFIP minimum requirements must still be satisfied, whether through regulation, executive 
order, or a state building code.


"Substantial improvement" is any repair, reconstruction, rehabilitation, addition or improvement of a 
building, the cost of which equals or exceeds 50 percent of the market value of the building before the 
improvement or repair is started (certain historic structures may be excluded)


"Lowest floor" means the lowest floor of the lowest enclosed area (including basement). An 
unfinished or flood-resistant enclosure, usable solely for parking of vehicles, building access, or 
storage in an area other than a basement, is not the lowest floor provided the enclosure is built in 
compliance with applicable requirements



Floodproofed schools must never be considered safe for occupancy during periods of high water; 
floodproofing measures are intended only to reduce physical damage



School districts should be aware of the importance of flood insurance for flood-prone existing schools. 
If not insured for flood peril, the amount of flood insurance coverage that should have been in place 
will be deducted from any federal disaster assistance payment that would otherwise have been made 
available. A district may have to absorb up to $1 million in unreimbursed flood damage per building 
because the NFIP offers $500,000 in building coverage and $500,000 in contents coverage


Selected References:  Flood Proofing:  How to Evaluate Your Options (USACE, 1993); 
Floodproofing Non-Residential Structures (FEMA 102); Non-Residential 
Floodproofing-Requirements and Certification (FIA-TB-3); and Engineering Principles and 
Practices for Retrofitting Flood-prone Residential Buildings (FEMA 259). Although written primarily 
for homes, this last reference contains very detailed checklists and worksheets that can be modified 
for school buildings. They also provide some guidance for evaluating the costs and benefits of various 
measures.


Dry floodproofing refers to measures and methods to render a building envelope and utility systems 
substantially impermeable to floodwaters
















MAKING SCHOOLS SAFE AGAINST WINDS     6


6.1 INTRODUCTION

A well-designed, constructed, and maintained school may be damaged by a 
wind event that is much stronger than what the building was designed for; however, 
except for tornado damage, this scenario is a very rare occurrence. Rather, most 
damage occurs because various building elements have limited wind resistance due to 
inadequate design, application, or material deterioration. Wind with sufficient speed 
to cause damage to weak schools can occur anywhere in the United States and its 
possessions.1 Although the magnitude and frequency of strong windstorms varies by 
locale, all schools should and can be designed, constructed, and maintained to avoid 
wind damage (other than that associated with tornadoes). In tornado-prone regions, 
consideration should be given to designing and constructing portions of schools to 
provide occupant protection.2
This chapter discusses structural and nonstructural building components and 
illustrates a variety of wind-induced damages. Because of the frequency and 
significant consequences of nonstructural component failure, emphasis is given to 
these elements. 
Numerous examples of best practices pertaining to new and existing schools are 
presented for consideration. Incorporation of those practices that are applicable to a 
specific project will result in greater wind-resistance reliability and will, therefore, 
provide enhanced protection for occupants and decreased expenditures for repair of 
wind-damaged facilities. 



6.2 THE NATURE AND PROBABILITY OF HIGH WINDS

A variety of windstorm types occur in different areas of the U.S. The characteristics of 
the type of storms that can impact the site should be considered by the design team. 
The primary storm types are:

 Straight-line wind. This type of wind event is the most common. The wind is 
considered, in general, to blow in a straight line. Straight-line wind speeds range 
from very low to very high. High winds associated with intense low pressure can 
last for upward of a day at a given location. Straight-line winds occur throughout 
the U.S. and its possessions (see Figure 6-1).

 Down-slope wind. Wind flowing down the slope of mountains is referred to as down-
slope wind. Down-slope winds with very high wind speeds frequently occur in 
Alaska and Colorado. In the continental U.S., mountainous areas are referred to as 
"special wind regions" (see Figure 6-1). Neither ASCE 7 or model building codes 
provide guidance on wind speeds in special wind regions. If the local building 
department has not established the basic speed, use of regional climatic data and 
consultation with a wind engineer or meteorologist is advised. 
 Thunderstorm. This type of storm can rapidly form and produce high wind speeds. 
Approximately 10,000 severe thunderstorms occur in the U.S. each year, typically in 
the spring and summer. They are most common in the Southeast and Midwest. 
Besides producing high winds, they often create heavy rain. Hail and tornadoes 
are also sometimes produced. Thunderstorms commonly move through an area 
quite rapidly, often causing high winds for only a few minutes at a given location. 
However, thunderstorms can also stall and become virtually stationary.

 Downburst. Also known as microburst, it is a powerful downdraft associated with a 
thunderstorm. When the downdraft reaches the ground, it spreads out 
horizontally and may form one or more horizontal vortex rings around the 
downdraft. The outflow is typically 6,000 to 12,000 feet across and the vortex ring 
may rise 2,000 feet above the ground. The life-cycle of a downburst is usually 
between 15 to 20 minutes. Observations suggest that approximately 5 percent of all 
thunderstorms produce a downburst, which can result in significant damage in a 
localized area.

 Northeaster (nor'easter). This type of storm is cold and violent and occurs along the 
northeastern coast of the U.S. These storms blow in from the Northeast and may 
last for several days.

 Hurricane. This is a system of spiraling winds converging with increasing speed 
toward the storm's center (the eye of the hurricane). Hurricanes form over warm 
oceans. The diameter of the storm varies between 50 and 600 miles. A hurricane's 
forward movement (translational speed) can vary between approximately 10 to 25 
miles per hour (mph). Besides being capable of delivering extremely strong winds 
for several hours, many hurricanes also bring very heavy rainfall. Hurricanes also 
occasionally spawn tornadoes. The Saffir-Simpson Hurricane Scale rates the 
intensity of hurricanes. The five-step scale ranges from Category I (the weakest) to 
Category V (the strongest). Hurricane-prone regions are defined in Section 
6.2.1.Of all the storm types, hurricanes have the greatest potential for devastating a 
very large geographical area and, hence, affect great numbers of people. The terms 
"hurricanes, tropical cyclones, and typhoons" are synonymous for the same type of 
storm. See Figure 6-1 for hurricane-prone regions.

 Tornado. This is a violently rotating column of air extending from the base of a 
thunderstorm to the ground. The Fujita scale categorizes tornado severity based 
on observed damage. The six-step scale ranges from F0 (light damage) to F5 
(incredible damage). Weak tornadoes (F0 and F1) are most common, but strong 
tornadoes (F2 and F3) frequently occur. Violent tornadoes (F4 and F5) are rare. 
Tornado path widths are typically less than 1,000 feet; however, widths of 
approximately 1 mile have been reported. Wind speed rapidly decreases with 
increased distance from the center of a tornado. A school on the periphery of a 
strong or violent tornado could be subjected to moderate to high wind speeds, 
depending upon the distance from the core of the tornado. However, even though 
the wind speed might not be great, a school on the periphery could still be 
impacted by many large pieces of wind-borne debris. Tornadoes are responsible 
for the greatest number of wind-related deaths each year in the U.S. Figure 6-2 
shows frequency of occurrence for 1950 to 1998 and Figure 6-3 shows the design 
wind speeds used for the design of community tornado shelters.


6.2.1 Wind/Building Interactions 

When wind interacts with a building, both positive and negative (i.e., suction) 
pressures occur simultaneously (see Figure 6-4). (Note: negative pressures are less 
than ambient pressure, and positive pressures are greater than ambient pressure.) 
The school must have sufficient strength to resist the applied loads in order to 
prevent wind-induced building failure. The magnitude of the pressures is a function 
of the following primary factors:

 Exposure. The characteristics of the ground roughness and surface irregularities in 
the vicinity of a building influence the wind loading. ASCE 7 defines three 
exposure categories, Exposures B, C, and D.3 Exposure B is the roughest terrain 
and Exposure D is the smoothest. Exposure B includes urban, suburban, and 
wooded areas. Exposure C includes flat open terrain with scattered obstructions 
and areas adjacent to water surfaces in hurricane-prone regions (which are 
defined below under "basic wind speed"). Exposure D includes areas adjacent to 
water surfaces outside hurricane-prone regions, mud flats, salt flats, and unbroken 
ice. Because of the wave conditions generated by hurricanes, areas adjacent to 
water surfaces in hurricane-prone regions are considered to be Exposure C rather 
than the smoother Exposure D.The smoother the terrain, the greater the wind 
load; therefore, schools (with the same basic wind speed) located in Exposure D 
would receive higher wind loads than those located in Exposure C. 

 Basic wind speed. ASCE 7 defines the basic wind speed as the wind speed with a 50-
year mean recurrence interval (2 percent annual probability), measured at 33 feet 
above grade in Exposure C (flat open terrain). If the building is located in 
Exposure B or D, rather than C, an adjustment for the actual exposure is made in 
the ASCE 7 calculation procedure.Since the 1995 edition of ASCE 7, the basic wind 
speed has been a peak gust speed. Prior to that time, the basic wind speed was a 
fastest-mile speed (i.e., the speed averaged over the time required for a mile-long 
column of air to pass a fixed point). Because the measuring time for peak gust 
versus fastest-mile is different, peak gust speeds are typically about 20 miles per 
hour (mph) faster than fastest-mile speeds (e.g., a 90-mph peak basic wind speed is 
equivalent to a 70-mph fastest-mile wind speed). Most of the U.S. has a basic wind 
speed (peak gust) of 90 mph, but much higher speeds occur in Alaska and in 
hurricane-prone regions. The highest speed, 170 mph, occurs in Guam. 
Hurricane-prone regions are along the Atlantic and Gulf of Mexico coasts (where 
the basic wind speed is greater than 90 mph), Hawaii, and the U.S. possessions in 
the Caribbean and South Pacific (see Figure 6-1).In determining wind pressures, 
the basic wind speed is squared; therefore, as the velocity is increased, the 
pressures are exponentially increased. For example, the uplift load on a 30-foot 
high roof covering at a corner area of a school in Exposure B is 37.72 pounds per 
square foot (psf) with a basic wind speed of 85 mph (per ASCE 7-02). If the speed is 
doubled to 170 mph, the roof corner load increases by a factor of four to 151 psf.

 Topography. Abrupt changes in topography, such as isolated hills, ridges, and 
escarpments, cause wind speed-up; therefore, a school located near a ridge would 
receive higher wind loads than a school located on relatively flat land. ASCE 7 
provides a procedure to account for topographic influences.

 Building height. Wind speed increases with height above the ground. Therefore, the 
taller the school, the greater the speed and, hence, the greater the wind loads. 
ASCE 7 provides a procedure to account for building height.

 Internal pressure (i.e., building pressurization/depressurization). Wind striking a 
building can cause either an increase in the pressure within the building (i.e., 
positive pressure), or it can cause a decrease in the pressure (i.e., negative 
pressure). Internal pressure changes occur because of the porosity of the building 
envelope. Porosity is caused by openings around doors and window frames, and by 
air infiltration through walls that are not absolutely airtight. A door or window left 
in the open position also contributes to porosity. 

Wind striking an exterior wall exerts a positive pressure on the wall, which forces 
air through openings and into the interior of the building (this is analogous to 
blowing up a balloon). At the same time the windward wall is receiving positive 
pressure, the side and rear walls are receiving negative (suction) pressure; 
therefore, air within the building is being pulled out at openings in these other 
walls. As a result, if the porosity of the windward wall is greater than the combined 
porosity of the side and rear walls, the interior of the building is pressurized. But if 
the porosity of the windward wall is less than the combined porosity of the side 
and rear walls, the interior of the building is depressurized (this is analogous to 
letting air out of a balloon).


When a building is pressurized, the internal pressure pushes up on the roof. This 
push from below the roof is combined with the suction above the roof, resulting 
in an increased wind load on the roof. The internal pressure also pushes on the 
side and rear walls. This outward push is combined with the suction on the 
exterior side of these walls. Therefore, a pressurized building increases the wind 
load on the side and rear walls (see Figure 6-5) as well as on the roof.
 When a building is depressurized, the internal pressure pulls the roof down, which 
reduces the amount of uplift exerted on the roof. The decreased internal pressure 
also pulls inward on the windward wall, which increases the wind load on that wall 
(see Figure 6-6).

 When a school becomes fully pressurized (e.g., due to window breakage), the loads 
applied to the exterior walls and roof are significantly increased. The build-up of 
high internal pressure can also blow down interior partitions and blow ceiling 
boards out of their support grid. The breaching of a small window is typically 
sufficient to cause full pressurization of the school's interior.
 ASCE 7 provides a design procedure to assess the influence of internal pressure on 
the wall and roof loads, and it provides positive and negative internal pressure 
coefficients for use in load calculations. Buildings that can be fully pressurized are 
referred to as partially enclosed buildings. Buildings that have limited internal 
pressurization capability are referred to as enclosed buildings. 

 Aerodynamic pressure. Because of building aerodynamics (i.e., the interaction 
between the wind and the building), the highest uplift loads occur at roof corners.  
The roof perimeter has a somewhat lower load, followed by the field of the roof. 
Exterior walls typically have lower loads than the field of the roof. The ends of 
walls have higher suction loads than the portion of wall between the ends. 
However, when the wall is loaded with positive pressure, the entire wall is 
uniformly loaded. Figure 6-7 illustrates these aerodynamic influences. The 
negative values shown in Figure 6-7 indicate suction pressure acting upward from 
the roof surface and outward from the wall surface. Positive values indicate positive 
pressure acting inward on the wall surface.

 Aerodynamic influences are accounted for by use of external pressure coefficients, 
which are used in load calculations. The magnitude of the coefficient is a 
function of the location on the building (e.g., roof corner or field of roof) and 
building shape as discussed below. Positive coefficients represent a positive 
pressure, and negative coefficients represent negative (suction) pressure. External 
pressure coefficients are found in ASCE 7.

 Building shape affects the magnitude of pressure coefficients and, therefore, the 
loads applied to the various building surfaces. For example, the uplift loads on a 
low-slope roof are larger than the loads on a gable or hip roof. The steeper the 
slope, the lower the uplift load. Pressure coefficients for monoslope (shed) roofs, 
sawtooth roofs, and domes are all different from those for low-slope and gable/hip 
roofs.
 Building irregularities such as bay window projections, a stair tower projecting out 
from the main wall, dormers, chimneys, etc., can cause localized turbulence. 
Turbulence causes wind speed-up, which increases the wind loads in the vicinity of 
the building irregularity as shown in Figures 6-8 and 6-9.

As shown in Figure 6-9, the built-up roof's base flashing was pulled out from 
underneath the coping and caused a large area of the membrane to lift and peel. 
Some of the wall covering on the stair tower was also blown away. Had the stair tower 
not existed, the built-up roof would not have been damaged.
Loads exerted on the building envelope are transferred to the structural system, 
where they are transferred through the foundation and into the ground.
Information pertaining to load calculations is presented in Section 6.8.2.
For further general information on the nature of wind and wind-building 
interactions, see Buildings at Risk: Wind Design Basics for Practicing Architects, American 
Institute of Architects, 1997.

To avoid damage in the vicinity of building irregularities, attention needs to be given 
to attachment of building elements located in turbulent flow areas.



6.2.2 Probability of Occurrence

Most buildings are designed for a 50-year mean recurrence interval wind event (2 
percent annual probability). A 50-year storm would be expected to happen about once 
every 50 years; however, a 50-year storm can occur more or less frequently. A 50-year 
storm may not occur within any 50-year interval, but two 50-year storms could occur 
within 1 year.
ASCE 7 requires schools with a capacity greater than 250 occupants and schools used 
for hurricane or other emergency shelters to be designed for a 100-year mean 
recurrence interval wind event (1 percent annual probability); therefore, these 
schools are designed to resist stronger, rarer storms than most buildings. The 
importance factor is used to adjust the mean recurrence interval. For a 50-year 
interval, the importance factor is 1.00. For a 100-year interval, the importance factor is 
1.15. 

When designing a school, architects and engineers should consider the following:

 Routine winds. In many locations, winds with low to moderate speeds occur daily. 
Damage is not expected to occur during these events.
 Stronger winds. At a given site, stronger winds (e.g., winds with a basic wind speed in 
the range of 70 to 80 mph peak gust) may occur from several times a year to only 
once a year or less frequently. 70 to 80 mph is the threshold at which damage 
normally begins to occur to building elements that have limited wind resistance 
due to problems associated with
 inadequate design, strength, application, or material deterioration.
  Design level winds. Schools that experience design level events and 
events that are somewhat in excess of design level should 
experience little, if any damage; however, design level storms 
frequently cause extensive building envelope damage. Structural 
damage also occurs, but less often. Damage experienced with 
design level events is typically associated with inadequate design, 
application, or material deterioration. The exceptions are wind-
driven water infiltration and wind-borne debris (missiles) 
damage. Water infiltration is discussed in Sections 6.10.4, 6.11.3, 
and 6.13.3. 
 Tornadoes. Although more than 1,200 tornadoes typically occur each year in the 
U.S., the probability of a tornado occurring at any given location is quite small. 
The probability of occurrence is a function of location. As shown in Figure 6-2, 
only a few areas of the U.S. frequently experience tornadoes, and tornadoes are 
very rare in the west. The Oklahoma City area is the most active location in the 
U.S., with 106 recorded tornadoes between the years 1890 and 2000. 

 Except for window breakage, well designed, constructed, and maintained schools 
should experience little if any damage from weak tornadoes. However, because 
many schools have wind-resistance deficiencies, weak tornadoes often cause 
building envelope damage. Most schools experience significant damage if they are 
in the path of a strong or violent tornado (see Figure 6-10). In the classroom wing, 
shown in Figure 6-10, all of the exterior windows were broken, and virtually all of 
the cementitious wood-fiber deck panels were blown away. Much of the metal 
decking over the band and chorus area also blew off. The gymnasium collapsed, as 
did a portion of the multi-purpose room. The school was not in session at the time 
the tornado struck.



6.3 VULNERABILITY: WHAT WIND CAN DO TO SCHOOLS
  
When damaged by wind, schools typically experience the following types of building 
component damage in descending order of frequency of occurrence (see Figures 6-11 
through 6-16):
Ramifications of the above types of damages include: 

 Property damage. Including repair/replacement of the damaged components (or 
replacement of the entire facility), plus repair/replacement of interior building 
components, mold remediation, furniture, equipment, and books caused by water 
and/or wind entering the school. Even when damage to the building envelope is 
limited, such as blow-off of a portion of the roof covering or broken glazing, 
substantial water damage frequently occurs because heavy rains often accompany 
strong winds (particularly in the case of thunderstorms, hurricanes, and 
tornadoes; see Figure 6-17).  

 Debris such as roof aggregate, gutters, HVAC equipment, and siding blown from 
schools can damage automobiles, residences, and other buildings in the vicinity 
of the school.
 Debris can travel well in excess of 300 feet in wind events. If non-school property is 
damaged by school building debris, the school district will likely be responsible 
for the damage.
 Portable classrooms are often particularly vulnerable to significant damage because 
they are seldom designed to the same wind loads as permanent school buildings. 
Portable
classrooms are frequently blown over during high-wind events 
because the inexpensive techniques that are typically used are 
inadequate to anchor the units to the ground. Wind-borne debris 
from portables or an entire portable classroom may impact the 
permanent school building and cause serious damage.

  Injury or death. Although infrequent, school occupants or people 
outside schools have been injured and killed when struck by 
collapsed building components (such as exterior masonry walls 
or the roof structure) or wind-borne building debris. The greatest 
risk of injury or death is during strong hurricanes and 
strong/violent tornadoes. 

  Interrupted use. Depending upon the magnitude of wind and 
water damage, it can take days, months, or more than a year to 
repair the damage or replace a facility (see Figure 6-18). In 
addition to the costs associated with repairing/replacing the 
damage, other financial ramifications related to interrupted use 
of the school can include the cost of bussing students to an 
alternative school and/or rental of temporary facilities. These 
additional costs can be quite substantial. 
There are also social and psychological factors, such as difficulties imposed on 
students, parents, faculty and the administration during the time the school is not 
usable.




6.4 SCOPE, EFFECTIVENESS, AND LIMITATIONS OF BUILDING CODES

In the following section, the IBC is discussed. In some jurisdictions, NFPA 5000 or 
one of the earlier model building codes or a specially written state or local building 
code may be used. The specific scope and/or effectiveness and limitations of these 
other building codes will be somewhat different than that of the IBC. It is incumbent 
upon the architect/engineer to be aware of the specific code (including the edition 
of the code and local amendments) that has been adopted by the authority having 
jurisdiction.  

6.4.1 Scope

With respect to wind performance, the scopes of the model building codes have 
greatly expanded since the mid-1980s. Significant improvements include:
 Recognition of increased uplift loads at the roof perimeter and corners. Prior to the 
1982 edition of the Standard Building Code and Uniform Building Code and the 
1987 edition of the National Building Code, these model codes did not account for 
the increased uplift at the roof perimeter and corners. Therefore, schools 
designed in accordance with earlier editions of these codes are very susceptible to 
blow-off of the roof deck and/or roof covering.

 Adoption of ASCE 7 for wind design loads. Although the three model codes 
permitted use of ASCE 7, the 2000 edition of the IBC was the first model code to 
require ASCE 7 for determining wind design loads. ASCE 7 has been more 
reflective of the current state of the knowledge than the model codes, and use of 
this procedure has typically resulted in higher design loads. 
 Roof coverings. Several performance and prescriptive requirements pertaining to 
wind resistance of roof coverings have been incorporated. The majority of these 
additional provisions were added after Hurricanes Hugo (1989) and Andrew 
(1992). Poor performance of roof coverings was widespread in both of those 
storms. Prior to the 1991 edition of the SBC and UBC and the 1990 edition of the 
NBC, these model codes were essentially silent on roof covering wind loads and 
test methods for determining uplift resistance. Code improvements continued to 
be made through the 2003 edition of the IBC.
 Glazing protection. The 2000 edition of the IBC was the first model code to address 
wind-borne debris requirements for buildings located in the wind-borne debris 
regions of hurricane-prone regions (via reference to the 1998 edition of ASCE 7). 
(The 1995 edition of ASCE 7 was the first edition to address wind-borne debris 
requirements).
 Parapets and rooftop equipment. The 2003 edition of the IBC was the first model 
code to address wind loads on parapets and rooftop equipment (via reference to 
the 2002 edition of ASCE 7, which was the first edition of ASCE 7 to address these 
elements).


6.4.2 Effectiveness

Except for hurricanes and tornadoes, the 2003 edition of the IBC is believed to be a 
relatively effective code, provided that it is properly followed and enforced. This code 
is also believed to be an effective code for hurricanes, except that it does not account 
for water infiltration due to puncture of the roof membrane by missiles, nor does it 
adequately address the vulnerabilities of brittle roof coverings (such as tile) to 
missile-induced damage and subsequent progressive cascading failure.
The 2003 IBC relies on several referenced standards and test methods developed or 
updated in the 1990s. Most of these standards and test methods have not been 
validated by actual building performance during design level wind events. 

Therefore, 
the actual performance of buildings designed and constructed to the minimum 
provisions of the 2003 IBC remains to be determined. Future post-storm building 
performance evaluations may or may not show the need for further enhancements.
The 2003 IBC does not account for tornadoes; therefore, except for weak tornadoes, it 
is ineffective for this type of storm.


6.4.3 Limitations

Limitations to building codes include the following:

 Because codes are adopted on the local or state level, the adopting authority has the 
power to not adopt all wind-related provisions of a model code, or to write their 
own code rather than follow a model code. In either case, important provisions of 
the current model code may be stricken, thereby resulting in schools that are 
more susceptible to wind damage when they are designed and constructed in 
accordance with the minimum requirements of the locally adopted code. Also, 
often there is a significant time lag between the time a model code is updated and 
the time it is implemented by the adopting authority. When lag occurs, schools 
designed to the minimum requirements of the outdated code are not taking 
advantage of the current state of the knowledge. Therefore, these schools are 
prone to poorer wind performance compared to schools designed according to 
the current model code.

 Adoption of the current model code does not ensure good wind performance.  
Rather, the code is a minimum tool that should be used by knowledgeable design 
professionals in conjunction with their training, skills, and professional 
judgment. To achieve good wind performance, in addition to good design, the 
construction work must be effectively executed and the school must be adequately 
maintained and repaired.

 Specific limitations of the 2003 IBC include lack of provisions pertaining to blow-off 
of aggregate from built-up and sprayed polyurethane foam roofs, and limitations 
of some of the test methods used to assess wind and wind-driven rain resistance of 
building envelope components (improved test methods need to be developed 
before this code limitation can be overcome). In addition, the code does not 
address protection of occupants in schools (and other buildings) located in 
tornado-prone regions.

 The 2003 IBC does not address the need for continuity, redundancy, or energy-
dissipating capability (ductility) to limit the effects of local collapse and to prevent 
or minimize progressive collapse in the event of the loss of one or two primary 
structural members such as a column. However, even though this issue is not 
addressed in the IBC, Chapter 1 of ASCE 7 does address general structural 
integrity, and the ASCE 7 Chapter 1 Commentary provides some guidance on this 
issue. 



6.5 PRIORITIES, COSTS, AND BENEFITS: NEW SCHOOLS

Prior to evaluating schools for risk from high winds and beginning the risk 
reduction design process, it is first necessary to consider the priorities, costs, and 
benefits of potential risk reduction measures. These factors, as discussed below, 
should be considered within the context of performance-based wind design as 
discussed in Section 2.12.3.


6.5.1 Priorities

As previously discussed in this manual, the first priority is the implementation of 
measures that will reduce risk of casualties to students, faculty, staff, and visitors. The 
second priority is the reduction of damage that leads to downtime and disruption. 
The third priority is the reduction of damage and repair costs. To realize these priori-
ties, as a minimum the school should be designed and constructed in accordance 
with the latest edition of a current model building code such as the IBC (unless the 
local building code has more conservative wind-related provisions, in which case the 
local building code should be used as the basis for design). In addition, the school 
should be adequately maintained and repaired. 

For schools that will be used for emergency response after a storm and/or those 
schools that will be used for hurricane shelters, measures beyond those required by 
the IBC should be given high priority (see Section 6.15).
For schools in coastal Alaska and other areas that experience frequent high-wind 
events (such as parts of Colorado), measures beyond those required by the IBC should 
be given high priority. Several of the recommendations for schools in hurricane-
prone regions (Section 6.15) are also applicable to these schools, with the exception 
of the wind-borne debris recommendations. (Limited amounts of wind-borne debris 
are generated in storms other than hurricanes and tornadoes.)
For schools located in tornado-prone regions, priority should be given to the 
incorporation of specially designed occupant shelters within the school (see Section 
6.16). The decision to incorporate occupant shelters should be based on the 
assessment of risk (see Section 6.7.1). 
 
For schools located in areas where the basic wind speed is greater than 90 mph, 
priority should be given to incorporation of design, construction, and maintenance 
enhancements. The degree of priority given to these enhancements increases as the 
basic wind speed increases (see Sections 6.8.3 to 6.8.5 and 6.9 to 6.14 for enhancement 
examples).


6.5.2 Cost, Budgeting, and Benefits

The cost for complying with the IBC should be considered as the minimum baseline 
cost.  
For schools that will be used for emergency response after a storm and/or those 
schools that will be used for hurricane shelters, the additional cost for implementing 
measures beyond those required by the 2003 edition of the IBC will typically add only 
a small percentage to the total cost of construction. Sections 6.8 and 6.15 discuss ad-
ditional measures that should be considered. 

For all other schools other than those discussed above, the additional cost for 
implementing enhancements will typically add only a very small percentage to the 
total cost of construction. Sections 6.8 to 6.14 discuss additional measures that should 
be considered.

The yearly cost of periodic maintenance and repair will be greater than the 
alternative of not expending any funds for periodic maintenance (i.e., deferred 
maintenance and repair). If, however, the deferred maintenance option is selected, 
eventually maintenance and repairs will be required, and the extent and cost of the 
work will typically be much greater than the costs associated with the periodic option. 
Also, if a windstorm causes damage that would have otherwise been avoided had 
maintenance or repairs been performed, the resulting costs can be significantly 
higher. (Note:  Maintenance and repair costs are reduced when more durable 
materials and systems are used; see Section 6.8.2, under "Step 4: Durability.")
Budgeting. It is important for the school district to give consideration to wind 
enhancement costs early in the development of a new school project. If 
enhancements, particularly those associated with schools used as hurricane shelters, 
emergency response after a storm, and tornado shelters, are not included in the 
initial project budget, often it is very difficult to find funds later during the design of 
the project. If the additional funds are not found, the enhancements may be 
eliminated because of lack of forethought and adequate budgeting. 
Benefits. If strong storms do not occur during the life of a school, there is little 
benefit to spending the money and effort related to wind resistance. However, 
considering the long life of most schools (hence, the greater probability of them 
experiencing a design level event) and considering the importance placed on 
students and the value of the school to the community, clearly it is prudent to invest 
in adequate wind resistance. By doing so, the potential for loss of life and injuries can 
be significantly reduced or virtually eliminated. Investing in wind resistance also 
minimizes future expenditures for repair or replacement of wind-damaged schools 
and avoids costly interrupted building use.
Fortunately, most of the enhancements pertaining to increased wind resistance are 
relatively inexpensive compared to the benefit that they provide. In evaluating what 
enhancements are prudent for a specific school, an enhancement that provides 
greater performance reliability at little cost is an enhancement worthy of 
consideration (see Figure 6-19).
Wind resistance enhancements may also result in decreased insurance premiums. 
The school district's insurer should be consulted to see if premium reductions are 
available, and to see if special enhancements are required in order to avoid paying a 
premium for insurance. For those school districts that self-insure, enhanced wind 
resistance should result in a reduction of future payouts.



6.6 PRIORITIES, COSTS, AND BENEFITS:  EXISTING SCHOOLS

Prior to evaluating existing schools for risk from high winds and beginning the risk 
reduction design process, it is first necessary to consider the priorities, costs, and 
benefits of potential risk reduction measures. These factors, as discussed below, 
should be considered within the context of performance-based wind design as 
discussed in Section 2.12.3. 

 
6.6.1 Priorities

In prioritizing work at existing schools, an assessment should be made on all schools 
within the district to ascertain which schools are vulnerable to damage and therefore 
most in need of remedial work. As part of the assessment, the nature of the 
vulnerability and the needed remedial work should be identified at the various 
schools. In making the district-wide assessment, all applicable hazards should be 
assessed and the needs prioritized. For some districts or some schools within a given 
district, the high priority work may be related to wind, or it may be related to one of 
the other hazards. In some instances, the same remedial work item can mitigate wind 
and other hazards. For example, strengthening the roof deck attachment can 
improve both wind and seismic resistance. 

School districts located in following areas are in greatest need of assessing their 
schools (listed in descending order of priority): hurricane-prone regions and school 
districts outside of hurricane-prone regions that have schools that will be used for 
emergency response after a storm; tornado-prone regions; areas where the basic wind 
speed is in excess of 90 mph (the priority increases as the basic wind speed increases); 
and areas where the basic wind speed is 90 mph or less.
For school districts in hurricane-prone regions, the first priority needs to be given to 
those schools that will be used as hurricane shelters. Other priorities are as discussed 
at the beginning of Section 6.5.1.

For school districts in tornado-prone regions, the first priority needs to be given to 
occupant protection (see Section 6.16). Other priorities are the same as discussed at 
the beginning of Section 6.5.1.
For all other school districts, the priorities are the same as discussed at the 
beginning of Section 6.5.1.

In some instances, perhaps all the funds available for the year for remedial work will 
be spent at one school. In other instances, perhaps the available funds will be used 
for remedial work at several different schools.
See Section 6.17 for specific remedial work guidance.


6.6.2 Cost, Budgeting, and Benefits

Wind-resistance improvements would ideally address all elements in the load path 
from the building envelope to the structural system and into the ground. (Load path 
is discussed in Section 6.8.2 under "Step 3:  Detailed Design"); however, this approach 
can be very expensive if there are many inadequacies throughout the load path. The 
maximum return on dollars invested for wind-resistance improvements is typically 
achieved by performing work related to the building envelope. Obviously if there are 
serious structural deficiencies that could lead to collapse during strong storms, these 
types of deficiencies should receive top priority; however, this scenario is infrequent. 
Because elements of the building envelope are the building components that are 
most likely to fail in the more commonly occurring moderate wind speed events, 
strengthening these elements will avoid damage during those storms. Of course, if a 
storm approaching a design level event occurs, in this scenario, the building 
envelope will remain attached to the structure, but a structural element may fail. For 
example, if the connections between the roof joists and bearing walls are the weak 
link, the roof covering will remain attached to the roof deck and the deck will remain 
attached to the joists, but the entire roof structure will blow off because the joists will 
detach from the wall. Although loss of the entire roof structure is more catastrophic 
than the loss of just the roof covering, much stronger events are typically required to 
cause structural damage. Hence, on a school district-wide level, strengthening 
building envelopes can result in maximum return on funds spent on wind-resistance 
improvements. Of course, for a specific school, the actual scope of wind-resistance 
work should be tailored for that school, commensurate with the findings from the 
evaluation (as discussed in Section 6.6.1) and the benefit/cost analysis (as discussed 
in below under "Benefits").

Costs can be minimized if wind-resistance improvements are executed as part of 
planned repairs or replacement. For example, if the roof deck is inadequately 
attached in the perimeter and corners, and the roof covering has another 10 years of 
remaining service life, it would typically be prudent to hold off performing deck 
attachment upgrade until it is necessary to replace the roof covering. Then, as part of 
the reroofing work, the existing roof system could be torn off, the deck reattached, 
and the new membrane installed.5 With this approach, the full service life of the roof 
membrane (and, hence, its full economic value) is achieved.

Budgeting. As it is with new construction, it is important for the school district to give 
consideration to wind enhancement costs early in the development of a major 
repair/renovation project (see discussion in Section 6.5.2).
Benefits. The benefits for spending money and effort related to wind resistance of 
existing schools are the same as described for new schools in Section 6.5.2.




6.7 EVALUATING SCHOOLS FOR RISK FROM HIGH WINDS

To evaluate risk for wind storms other than tornadoes, the following steps are 
recommended:

 Step 1: Determine the basic wind speed from ASCE 7. As the basic wind speed 
increases beyond 90 mph, the risk of damage increases and it continues to 
increase as the speed increases. To compensate for the increased risk of damage, 
design, construction and maintenance enhancements are recommended (see 
Section 6.8). 

 Step 2: For schools not located in hurricane-prone regions, 
determine if the school will be used for emergency response after 
a storm (e.g., temporary housing, food or clothing distribution, 
or a place where people can fill out forms for assistance). If so, 
refer to the design, construction, and maintenance 
enhancements recommended for schools in hurricane-prone 
regions (see Section 6.15).

 Step 3: For schools in hurricane-prone regions, determine if the 
school will be used for a hurricane shelter and/or for emergency 
response after a storm. If so, refer to the design, construction, and 
maintenance enhancements recommended in Section 6.15. 

 Step 4: For existing schools, evaluate the wind resistance of the building. The 
resistance will be a function of its original design and construction, various 
additions or modifications, and condition of building components (which may 
have weakened due to deterioration or fatigue).

 As a first step, calculate the wind loads on the school using ASCE 7 and compare 
these loads with the loads that the school was originally designed for. (The 
original design loads may be noted on the contract drawings. If not, determine 
what building code or standard was used to develop the original design loads and 
calculate the loads using that code or standard.) If the original design loads are 
significantly lower than current loads, upgrading the load resistance of the 
building envelope and/or structure should be considered (see Section 6.6.2). 
(Note:  An alternative to comparing current loads with original design loads is to 
evaluate the resistance of the existing school as a function of the current loads to 
determine what elements are highly overstressed.)

 As a second step, perform a field investigation to evaluate the primary building 
envelope elements and structural system elements to determine if the school was 
generally constructed as indicated on the original contract drawings. As part of 
the investigation, the primary elements should be checked for deterioration. Load 
path continuity should also be checked.
 The above evaluations will allow development of a vulnerability assessment that can 
be used along with the site's wind regime to assess the risk. See Section 6.17 for 
remedial work recommendations.


6.7.1 Tornadoes  

Neither the IBC or ASCE 7 require buildings (including schools) to be designed for 
tornadoes, nor are occupant shelters required in buildings (including schools) 
located in tornado-prone regions. Because of the extremely high pressures and 
missile loads that tornadoes can induce, constructing tornado-resistant schools is 
extremely expensive. Therefore, when consideration is voluntarily given to tornado 
design, the emphasis typically is on occupant protection, which is achieved by 
"hardening" portions of a school for use as safe havens.

In this manual, the term "tornado-prone regions" refers to those areas of the U.S. 
where the number of recorded F3, F4, and F5 tornadoes per 3,700 square miles is six 
or greater (see Figure 6-2). However, a school district may decide to use other 
frequency values (e.g., 1 or greater, 16 or greater, or greater than 25) in defining 
whether or not the district is in a tornado-prone area. In this manual, tornado 
shelters are recommended for schools in tornado-prone regions. 
FEMA 361, Design and Construction Guidance for Community Shelters, includes a 
comprehensive risk assessment procedure that designers can use to assist school 
districts in determining whether a tornado shelter should be included as part of a 
new school. See Section 6.16 for design of tornado shelters.
Where the number of recorded F3, F4, and F5 tornadoes per 3,700 square miles is one 
or greater, if the school does not have a tornado shelter, the best available refuge 
areas should be identified as discussed in Section 6.16.


6.7.2 Portable Classrooms 
 
Unless portables are designed and constructed (including anchorage to the ground) 
to meet the same wind loads as the main school building, students and faculty should 
be considered at risk during high winds. Therefore, portables should not be occupied 
when high winds are forecast (even though the forecast speeds are well below design 
wind conditions for the main building). Also, during winds that are well below 
design wind conditions, it should be recognized that wind-borne debris from 
disintegrating portables could impact and damage the main school building and/or 
nearby residences.




6.8 RISK REDUCTION DESIGN METHODS
  
The keys to enhanced wind performance are devoting sufficient attention to design, 
construction contract administration, construction, maintenance, and repair. Of 
course, it is first necessary for the school district to budget sufficient funds for this 
effort (see Sections 6.5.2 and 6.6.2). This section provides an overview of these 
elements:

6.8.1 Siting

Where possible, a school should not be located in Exposure D. Locating the facility 
on a site in Exposure C or preferably in Exposure B would decrease the wind loads. 
Also, where possible, avoid locating a school on an escarpment or upper half of a hill. 
Otherwise, if the school is located on an escarpment or upper half of a hill, the 
abrupt change in the topography would result in increased wind loads. When siting 
on an escarpment or upper half of a hill is necessary, the ASCE 7 design procedure 
accounts for wind speed-up associated with this abrupt change in topography.
Trees in excess of 6 inches in diameter, poles (e.g., light fixture poles, flag poles, 
power poles), or towers (e.g., electrical transmission and communication towers) 
should not be placed near the school. Blow-down of large trees, poles, and towers can 
severely damage a school and injure occupants.
Providing at least two means of site egress is prudent for all schools, but is 
particularly important for schools used for hurricane shelters and emergency 
response after a storm. Two means of egress facilitate emergency vehicles that need to 
reach or leave the site. With multiple site egress roads, if one route becomes blocked 
by trees or other debris or by floodwaters, another access route should be available.
To the extent possible, site portable classrooms so that, if they disintegrate during a 
storm that approaches from the prevailing wind direction, debris will avoid 
impacting the main school building and residences. Debris can travel in excess of 
300 feet. Destructive winds from hurricanes and tornadoes can approach from any di-
rection. These storms can also throw debris much farther.


6.8.2 School Design 

Good wind performance depends on good design (including detailing and 
specifying), materials, application, maintenance, and repair. A significant 
shortcoming of any of these five elements could jeopardize the performance of a 
school against wind. Design, however, is the key element to achieving good 
performance of a school against wind.  Design inadequacies frequently cannot be 
compensated for by the other four elements. Good design, however, can compensate 
for other inadequacies to some extent.

Step 1: Calculate Loads

Calculate loads on the main wind-force resisting system (MWFRS; i.e., the primary 
structural elements such as beams, columns, shear walls, and diaphragms that 
provide support and stability for the overall building), the building envelope, and 
rooftop equipment in accordance with ASCE 7 or the local building code, whichever 
procedure results in the highest loads.6 The importance factor for most schools will 
be required to be 1.15. For schools with an occupant load of 250 or less and not 
intended for use as shelters, a 1.00 importance factor is permitted; however, a value of 
1.15 is recommended for all schools. 

Uplift loads on roof assemblies can also be determined from Factory Mutual Global 
(FMG) Data Sheets. In some instances, the loads derived from ASCE 7 or the local 
code may exceed those derived from FMG, but, in other cases, the FMG loads may be 
higher. If the school is FMG-insured, and the FMG-derived loads are higher than 
those derived from ASCE 7 or the building code, the FMG loads should govern; 
however, if the ASCE 7 or code-derived loads are higher than those from FMG, the 
ASCE 7 or code-derived loads should govern (whichever procedure results in the 
highest loads). 

Step 2: Determine Load Resistance 

After loads have been determined, it is necessary to determine a reasonable safety 
factor (when using allowable stress design) or reasonable load factor (when using 
strength design). For building envelope systems, a minimum safety factor of two is 
recommended; for anchorage of exterior-mounted mechanical, electrical and 
communications equipment (such as satellite dishes), a minimum safety factor of 
three is recommended. 

For structural members and many cladding elements, load resistance can be 
determined by calculations, based on test data. For other elements (such as most 
types of roof coverings), load resistance is primarily obtained from system testing.
Load resistance criteria need to be given in contract documents. For structural 
elements, the designer of record typically accounts for load resistance by indicating 
the material, size, spacing, and connection of elements. For nonstructural elements, 
such as roof coverings or windows, the load and safety factor can be specified. In this 
case, the specifications should require the contractor's submittals to show that the 
system will meet the load resistance criteria. This performance specification 
approach is necessary if, at the time of design, it is unknown who will manufacture 
the system.

Regardless of which approach is used, it is important that the designer of record 
ensure that it can be demonstrated that the structure, nonstructural building 
envelope, and exterior-mounted mechanical, electrical, and communications 
equipment have sufficient strength to resist design wind loads.

Step 3: Detailed Design

Design, detail, and specify the structural system, building envelope, and exterior-
mounted mechanical, electrical, and communications equipment to meet the 
factored design loads (based on appropriate analytical or test methods) and as 
appropriate to respond to the risk assessment discussed in Section 6.7.
As part of the detailed design effort, load path continuity should be clearly indicated 
in the contract documents. Load paths need to accommodate design uplift, racking, 
and overturning loads. Load path continuity obviously applies to MWFRS elements, 
but it also applies to building envelope elements. Figure 6-19 shows a load path 
discontinuity between a piece of HVAC equipment and its equipment curb. Figure 6-
20 illustrates the load path concept. 

Step 4: Durability

Because some locales have very aggressive atmospheric corrosion (such as schools 
located near oceans), special attention needs to be given to specification of adequate 
protection for ferrous metals, or specify alternative metals such as stainless steel. 
Corrosion Protection for Metal Connectors in Coastal Areas, FEMA Technical Bulletin 8-96, 
August 1996, contains information on corrosion protection. Attention also needs to 
be given to dry rot avoidance, for example, by specifying preservative-treated wood.  
Appendix J of the Coastal Construction Manual, FEMA 55, Third Edition, 2000, presents 
information on wood durability.

Durable materials are particularly important for components that are concealed, 
which thereby prohibit knowing that the component is in imminent danger of 
failing.  
Special attention also needs to be given to details. For example, details that do not 
allow water to stand at connections or sills are preferred. Without special attention to 
material selection and details, the demands on maintenance and repair will be 
increased, along with the likelihood of failure of components during high winds.

Step 5: Rain Penetration

Although prevention of building collapse and major building damage is the primary 
goal of wind-resistant design, consideration should also be given to minimizing 
water damage and subsequent development of mold from penetration of wind-driven 
rain. To the extent possible, non-load bearing walls and door and window frames 
should be designed in accordance with rain-screen principles. With this approach, it 
is assumed that some water infiltration will occur. The water is intercepted in an air-
pressure equalized cavity that provides drainage from the cavity to the outer surface of 
the building. See Sections 6.11.3 and 6.13.3, and Figure 6-47 for further discussion and 
an example. Further information on the rain-screen principle can be found in Facts 
and Fictions of Rain-Screen Walls, M.Z. Rousseau, Construction Canada, 1990.  
In conjunction with the rain-screen principle, it is desirable to avoid using sealant as 
the first line of defense against water infiltration. When joints are exposed, obtaining 
long-lasting watertight performance is difficult because of the complexities of sealant 
joint design and application.


6.8.3 Peer Review

If the design team's wind design expertise and experience is limited, wind design 
input and/or peer review should be sought from a qualified individual(s). The design 
input or peer review could be for the entire school or for specific components such as 
the roof or glazing systems that are critical and/or beyond the design team's 
expertise.  
Regardless of the design team's expertise and experience, peer review should be 
considered when the school:

 is located in an area where the basic wind speed is greater than 90 mph (peak gust)
 will be used for emergency response after a storm
 will be used for a hurricane shelter
 will incorporate a tornado shelter


6.8.4 Construction Contract Administration

After a suitable design is complete, the design team should ensure the design intent 
is achieved during construction. The key elements of construction contract 
administration are submittal reviews and field observations, as discussed below.
Submittals. The specifications need to stipulate the submittal requirements. This 
includes specifying what systems require submittals (e.g., windows) and test data 
(where appropriate). Each submittal should demonstrate development of a load path 
through the system and into its supporting element. For example, a window submittal 
should show that the glazing has sufficient strength, its attachment to the frame is 
adequate, and the attachment of the frame to the wall is adequate.
During submittal review, it is important for the designer of record to be diligent in 
ensuring that all required submittals are submitted and that they include the 
necessary information. The submittal information needs to be thoroughly checked to 
ensure its validity. For example, if a test method used to demonstrate compliance with 
the design load appears erroneous, the test data should be rejected unless the 
contractor can demonstrate the test method was suitable.
Field Observations. It is recommended that the design team analyze the design to 
determine which elements are critical to ensuring high-wind performance. The 
analysis should include the structural system and exterior-mounted electrical 
equipment, but it should focus on the building envelope and exterior-mounted 
mechanical and communications equipment. After determining the list of critical 
elements to be observed, observation frequency needs to be determined. Observation 
frequency will depend on the magnitude of the results of the risk assessment 
described in Section 6.7, complexity of the facility, and the competency of the general 
contractor, subcontractors, and suppliers.

See Section 6.15.8 for schools located in hurricane-prone regions.

6.8.5 Post-occupancy Inspections, Periodic Maintenance, Repair, and Replacement

The design team should advise the school administration of the importance of 
periodic inspections, maintenance, and timely repair. It is important for the 
administration to understand that, over time, a facility's wind-resistance will degrade 
due to exposure to weather unless it is periodically maintained and repaired.  
The building envelope and exterior-mounted equipment should be inspected once a 
year by persons knowledgeable of the systems/materials they are inspecting. Items 
that require maintenance, repair, or replacement should be documented and 
scheduled for work. [Note:  The deterioration of glazing is often overlooked. After 
several years of exposure, scratches and chips can become extensive enough to 
weaken the glazing.]

The goal is to repair or replace items before they fail in a storm. This approach is less 
expensive than waiting for failure and then repairing the failed components and 
consequential damages.

If unusually high winds occur, a special inspection is recommended. The purpose of 
the inspection is to assess if the strong storm caused damage that needs to be 
repaired to maintain building strength and integrity. In addition to inspecting for 
obvious signs of damage, the inspector should determine if cracks or other openings 
have developed that allow water infiltration, which could lead to corrosion or dry rot 
of concealed components.

See Section 6.15.9 for schools located in hurricane-prone regions.




6.9 STRUCTURAL SYSTEMS

Based on post-storm damage evaluations, with the exception of tornado events, the 
structural systems (i.e., MWFRS and structural components such as roof decking) of 
school buildings have typically performed quite well during design wind events. 
There have, however, been notable exceptions; in these cases, the most common 
problem has been blow-off of the roof deck, but instances of collapse have also been 
documented (Figure 6-15). The structural problems have primarily been due to lack of 
an adequate load path, with connection failure being a common occurrence. 
Problems have also been caused by reduced structural capacity due to termites, 
workmanship errors (commonly associated with steel decks attached by puddle 
welds), and limited uplift resistance of deck connections in roof perimeters and 
corners (due to lack of code-required enhancement in older editions of the model 
codes).
With the exception of tornado events, structural systems designed and constructed in 
accordance with the IBC should typically offer adequate wind resistance, provided 
attention is given to load path continuity and to material durability (with respect to 
corrosion and termites). However, the greatest reliability is offered by cast-in-place 
concrete. There are no reports of any cast-in-place concrete buildings experiencing a 
significant structural problem during wind events, including the strongest 
hurricanes (Category V) and tornadoes (F5).  
The following design parameters are recommended (see Section 6.15.2 for schools 
located in hurricane-prone regions):

 If a pre-engineered structure is being contemplated, special steps should be taken to 
ensure the structure has more redundancy than is typically the case with pre-
engineered buildings.7 Steps should be taken to ensure the structure is not 
vulnerable to progressive collapse in the event a primary bent is compromised or 
bracing components fail.

 Exterior load bearing walls of masonry or precast concrete should be designed to 
have sufficient strength to resist external and internal loading of components and 
cladding. CMU walls should have vertical and horizontal reinforcing and grout to 
resist wind loads. The connections of precast concrete wall panels should be 
designed to have sufficient strength to resist wind loads.

 For roof decks, specify concrete, steel, or wood sheathing (plywood or oriented 
strand board [OSB]). See Section 6.15.2 for schools located in hurricane-prone 
regions.

 For steel roof decks, specify screw attachment rather than puddle welds (screws are 
more reliable and much less susceptible to workmanship problems). See Figures 6-
21 and 6-22. The decking shown in Figure 6-21 was attached with puddle welds. 
However, at most of the welds, there was only superficial bonding of the metal 
deck to the joist, as illustrated at this weld. Only a small portion of the deck near 
the center of the weld area (as delineated by the circle) was well fused to the joist.  

At the weld, shown in Figure 6-22, the deck was well bonded to the joist. When the 
decking blew off due to failure of nearby weak welds, at this location the metal 
decking tore and a portion of it remained attached to the joist. Tearing of the 
decking, rather than debonding, is the desired failure mode, but deck tearing is 
rare due to welding reliability problems. Screw attachment is a more reliable 
attachment method.

 For attachment of wood sheathed roof decks, specify screws, or ring-shank or screw-
shank nails in the corner regions of the roof. Where the basic wind speed is 
greater than 90 mph, also specify these types of fasteners for the perimeter regions 
of the roof.

 For precast concrete decks, design the deck connections to resist the design uplift 
loads (the dead load of the deck itself is often inadequate to resist the uplift load; 
see Figure 6-23).

 For precast Tee decks, design the reinforcing to accommodate the uplift loads in 
addition to the gravity loads. Otherwise, large uplift forces can cause Tee failure 
due to the Tee's own prestress forces after the uplift load exceeds the dead load of 
the Tee (see Figure 6-24).

 For schools that have mechanically attached single-ply or modified bitumen 
membranes, refer to the decking recommendations presented in the National 
Research Council of Canada, Institute for Research in Construction, Wind Design 
Guide for Mechanically Attached Flexible Membrane Roofs, B1049, 2004.
 If an FMG-rated roof assembly is specified, the roof deck also needs to comply with 
the FMG criteria.



 
6.10 EXTERIOR DOORS

This section addresses primary and secondary egress doors, sectional (garage) doors, 
and rolling doors. See Section 6.15.3 for schools located in hurricane-prone regions.

6.10.1 Loads and Resistance

The IBC requires that the door assembly (i.e., door, hardware, frame, and frame 
attachment to the wall) be of sufficient strength to resist the positive and negative 
design wind pressure. Architects should specify that doors comply with wind load 
testing in accordance with ASTM E 1233. Architects should also specifically design 
the attachment of the door frame to the wall (e.g., specify the type, size, and spacing 
of frame fasteners).

See Section 6.15.3 for schools located in hurricane-prone regions.


6.10.2 Durability 

Where corrosion is problematic, anodized aluminum or galvanized doors and frames, 
and stainless steel frame anchors and hardware are recommended. 
6.10.3Exit Door Hardware
For primary swinging entry/exit doors, exit door hardware is recommended to 
minimize the possibility of the doors being pulled open by wind suction. Exit 
hardware with top and bottom rods offers greater securement than exit hardware that 
latches at the jamb.


6.10.4 Water Infiltration

When heavy rain accompanies high winds (e.g., thunderstorms, tropical storms, and 
hurricanes), it can cause wind-driven water infiltration problems (the magnitude of 
the problem increases with the wind speed). Leakage can occur between the door and 
frame, and frame and wall, and water can be driven between the threshold and door. 
When the basic wind speed is greater than 120 mph, because of the very high design 
wind pressures and numerous opportunities for leakage path development, some 
leakage should be anticipated when design wind speed conditions are approached. 
To minimize infiltration, the following are recommended:

 Vestibule. Designing a vestibule is a method to account for the infiltration problem. 
With this approach, both the inner and outer doors can be equipped with 
weatherstripping, and the vestibule itself can be designed to tolerate water. For 
example, water-resistant finishes (e.g., concrete or tile) can be specified and the 
floor can be equipped with a drain.

 Door swing. With respect to weatherstripping, out-swinging doors offer an 
advantage compared to in-swinging doors. With out-swinging doors, the 
weatherstripping is located on the interior side of the door, where it is less 
susceptible to degradation. Also, some interlocking weatherstripping assemblies 
are available for out-swinging doors. 
Another challenge with doors is successful integration between the door frame and 
wall. See Section 6.13.3 for discussion of this juncture.  
ASTM E 2112 (Standard Practice for Installation of Exterior Windows, Doors and Skylights) 
provides information pertaining to installation of doors, including the use of sill pan 
flashings with end dams and rear legs (see Figure 6-25). It is recommended that de-
signers use E 2112 as a design resource.


6.10.5 Weatherstripping

A variety of pre-manufactured weatherstripping components are available, including 
drips, door shoes and bottoms, thresholds, and jamb/head weatherstripping. A few 
examples of weatherstripping options are:
 Drip. These are intended to shed water away from the opening between the frame 
and door head, and the opening between the door bottom and the threshold (see 
Figures 6-26 and 6-27). Alternatively, a door sweep can be specified (see Figure 6-
28); however, for high-traffic doors, periodic replacement of the neoprene will be 
necessary.

 Door shoes and bottoms. These are intended to minimize the gap between the door 
and threshold. Figure 6-27 illustrates a door shoe that incorporates a drip. Figure 
6-29 illustrates an automatic door bottom. Door bottoms can be surface-mounted 
or mortised. For high-traffic doors, periodic replacement of the neoprene will be 
necessary.
 Thresholds. These are available to suit a variety of conditions. Thresholds with 
vertical offsets offer enhanced resistance to wind-driven water infiltration. 
However, where Americans with Disabilities Act (ADA)-compliant thresholds are 
required, or at high-traffic doors, the offset is limited. However, at other doors, 
high offsets are preferred.

 Thresholds can be interlocked with the door (see Figure 6-30) or thresholds can have 
a stop and seal (see Figure 6-31). In some instances, the threshold is set directly on 
the floor. Where this is appropriate, specify setting the threshold in butyl sealant 
to avoid water infiltration between the threshold and floor. In other instances, the 
threshold is set on a pan flashing as discussed in Section 6.10.4. If the threshold 
has weep holes, specify that the weep holes should not be obstructed (see Figure 6-
30).

 Adjustable jamb/head weatherstripping. This type of jamb/head weatherstripping is 
recommended because these units have wide sponge neoprene that offers good 
contact with the door (see Figure 6-32). The adjustment feature also helps ensure 
good contact, provided the proper adjustment is maintained.
 Meeting stile. At the meeting stile of pairs of doors, an overlapping astragal 
weatherstripping offers greater protection than weatherstripping that does not 
overlap.





6.11 NON-LOAD BEARING WALLS, WALL COVERINGS, SOFFITS, AND 
UNDERSIDE OF ELEVATED FLOORS

This section addresses exterior non-load bearing walls and provides guidance for 
interior non-load bearing masonry walls. Exterior wall coverings and soffits, as well as 
the underside of elevated floors, are also discussed.

See Section 6.15.4 for schools located in hurricane-prone regions.



6.11.1 Loads and Resistance

The IBC requires that exterior non-load bearing walls, wall coverings, and soffits (see 
Figure 6-33) have sufficient strength to resist the positive and negative design wind 
pressure. Architects should specify that wall coverings and soffits comply with wind 
load testing in accordance with ASTM E 1233.  

Depending upon wind direction, soffits can experience either positive or negative 
pressure. Besides the cost of repairing damaged soffits, wind-borne soffit debris can 
cause property damage and injuries.

Particular care should be given to the design and construction of exterior non-load 
bearing walls constructed of masonry. Although these walls are not intended to carry 
gravity loads, they must be designed to resist the positive and negative wind loads in 
order to avoid collapse. Because of their great weight, when these types of walls 
collapse, they represent a severe risk to life as shown in Figure 6-14. 
Special consideration should also be given to interior non-load bearing masonry 
walls. Although these walls are not required by building codes to be designed to resist 
wind loads, if glazing is broken, the interior walls could be subjected to significant 
load as the school rapidly becomes fully pressurized. To avoid occupant injury (see 
Figure 6-34), it is recommended that interior non-load bearing masonry walls that are 
adjacent to student areas be designed to accommodate loads exerted by a design wind 
event, using the partially enclosed pressure coefficient. By doing so, wall collapse may 
be prevented if the building envelope is breached. This recommendation is 
applicable to schools in tornado-prone areas that do not have shelter space designed 
in accordance with FEMA 361, to schools located in areas with a basic wind speed 
greater than 120 mph, and to schools that will be used for hurricane shelters.


6.11.2 Durability

Where corrosion is problematic, stainless steel fasteners are recommended for wall 
and soffit systems. For other components (e.g., furring, blocking, struts, and 
hangars), the following are recommended: nonferrous components (such as wood), 
stainless steel, or steel with a minimum of G-90 hot-dipped galvanized coating. In 
addition, if air can freely circulate in a cavity (e.g., above a soffit), access panels are 
recommended so components within the cavity can be periodically observed for 
corrosion.


6.11.3 Wall Coverings

There are a variety of exterior wall covering options. Brick veneer, exterior insulation 
finish systems (EIFS), metal wall panels, and aluminum and vinyl siding have often 
exhibited poor wind performance. Veneers (such as ceramic tile and stucco) over 
concrete and cement-fiber panels and siding have also blown off. Blow-off of wood 
siding and panels is rare.
Figure 6-35 shows brick veneer that was blown off. The bricks were attached to the 
back-up wall with corrugated metal ties. All of the following failure modes are 
commonly found in the vicinity of this type of common failure: 1)The nails pull out 
of the studs (smooth shank nails are typically used, hence they have limited 
withdrawal resistance; 2)The ties do not extend far enough into the mortar joint (i.e., 
the tie is not long enough); 3)Although the ties make contact with the mortar, they 
are not well-bonded to it; 4)The ties are spaced too far apart; and 5)The ties provide 
essentially no resistance to compression. Hence, when a great amount of positive 
pressure is applied to the bricks, the brick joints flex. This flexing weakens the 
mortar joint. Walls that have not had bricks blown away have been found to be 
capable of being deflected with hand pressure. Although they look sound, in this 
condition they are very vulnerable to failure. Good reliable wind performance of brick 
veneer is very demanding on the designer and applicator.
Figure 6-36 shows EIFS blow-off. In this case, the expanded polystyrene (EPS) was 
attached to gypsum board, which was attached to metal studs. The gypsum board 
detached from the studs, which is a common EIFS failure mode. When the gypsum 
board on the exterior side of the studs is blown away, it is common for gypsum board 
on the interior side to also be blown off. This then allows the school to become fully 
pressurized and allows entrance of wind-driven rain. Other common failure modes 
include separation of the EPS from its substrate and separation of the synthetic 
stucco from the EPS. Good reliable wind performance of EIFS is very demanding on 
the designer and applicator. Maintenance of EIFS and associated sealant joints is also 
demanding in order to minimize reduction of EIFS' wind resistance due to water 
infiltration.
Another issue associated with EIFS is the potential for misdiagnosis of the wall 
system. EIFS is sometimes mistaken to be a concrete wall. If school personnel 
believed that an EIFS wall covering was a concrete wall and sought shelter from a 
tornado, instead of being protected by several inches of concrete, only two layers of 
gypsum board (i.e., one layer on each side of the studs) and a layer of EPS would be 
between the occupants and wind-borne debris. The debris could easily penetrate such 
a wall. 

EIFS can also be applied over concrete or CMU. In this scenario, the concrete or 
CMU could provide adequate missile protection provided it was thick enough and 
adequately reinforced. However, with this wall construction, there is still risk of blow-
off of the EIFS. As discussed in Section 6.15.4, if the concrete or CMU is left exposed, 
there is no covering to be blown off.

Wind performance of metal wall panels is highly variable. Performance depends 
upon strength of the specified panel (which is a function of material, panel profile, 
panel width and whether or not the panel is a composite) and the adequacy of the at-
tachment (which can either be by concealed clips or exposed fasteners). A common 
problem is excessive spacing between clips/fasteners. Clip/fastener spacing should 
be specified, along with the specific type and size of fastener to be used. 

Figures 6-13 
and 6-43 illustrate metal wall panel problems.

To minimize water infiltration at metal wall panel joints, it is recommended that 
sealant tape be specified at sidelaps when the basic wind speed is in excess of 90 mph. 
However, end laps should be left unsealed so that moisture behind the panels can 
wick out. End laps should be a minimum of 3 inches (4 inches where the basic wind 
speed is greater than 120 mph) to avoid wind-driven rain infiltration. At the base of 
the wall, a 3-inch (4-inch) flashing should also be detailed, or the panels should be 
detailed to over-lap with the slab or other components by a minimum of 3 inches (4 
inches).
Vinyl siding blow-off is typically caused by nails spaced too far apart and/or the use of 
vinyl siding that has inadequate wind-resistance. Vinyl siding is available with 
enhanced wind resistance features, such as an enhanced nailing hem, greater 
interlocking area, and greater thickness. 
Secondary Protection. Almost all wall coverings permit the passage of some water past 
the exterior surface of the covering, particularly when rain is wind-driven. Hence, 
most wall coverings should be considered as water-shedding, rather than as water-
proofing coverings. To avoid moisture related problems, it is recommended that a 
secondary line of protection with a moisture barrier (such as housewrap or asphalt-
saturated felt) and flashings around door and window openings be provided. 
Designers should specify that horizontal laps of the moisture barrier be installed so 
that water is allowed to drain from the wall (i.e., the top sheet should lap over the 
bottom sheet so that water running down the sheets remains on their outer surface). 
The bottom of the moisture barrier needs to be detailed to allow drainage.
In areas that frequently experience strong winds, enhanced flashing details are 
recommended. Enhancements include use of flashings that have extra-long flanges, 
and use of sealant and tapes. Flashing design should recognize that wind-driven 
water can be pushed vertically. The height to which water can be pushed increases 
with wind speed. Water can also migrate vertically and horizontally by capillary action 
between layers of materials (e.g., between a flashing flange and housewrap). It is 
recommended that designers attempt to determine what type of flashing details have 
successfully been used in the area where the school will be constructed.
If EIFS is specified, it is strongly recommended that it be designed with a drainage 
system that allows for dissipation of water leaks.


6.11.4 Underside of Elevated Floors

If sheathing is applied to the underside of joists or trusses elevated on piles (e.g., to 
protect insulation installed between the joists/trusses), its attachment should be 
specified in order to avoid blow-off. Stainless steel or hot-dip galvanized nails or 
screws are recommended. ASCE 7 does not provide guidance for load determination.




 
6.12 ROOF SYSTEMS

Because roof covering damage has historically been the most frequent and costly type 
of wind damage, special attention needs to be given to roof system design.
Code Requirements. The IBC requires load resistance of the roof assembly to be 
evaluated by one of the test methods listed in IBC's Chapter 15. Architects are 
cautioned that designs that deviate from the tested assembly (either with material 
substitutions or change in thickness or arrangement) may adversely affect the wind 
performance of the assembly. The IBC does not specify a minimum safety factor. 
However, for the roof system, a safety factor of two is recommended. (To apply the 
safety factor, divide the test load by two to determine the allowable design load. 
Conversely, multiply the design load by two to determine the minimum required test 
resistance.)

For metal panel systems, the IBC requires test methods UL 580 or ASTM E 1592. It is 
recommended that architects specify use of E 1592 because it is more likely to give a 
better representation of the system's uplift performance capability. 
Load Resistance. Specifying load resistance is commonly done by specifying a Factory 
Mutual Research (FMR) rating, such as Factory Mutual (FM) 1-75. The first number 
("1") indicates that the roof assembly passed the FMR tests for a Class 1 fire rating. 
The second number ("75") indicates the uplift resistance in psf that the assembly 
achieved during testing. Applying a safety factor of two to this example, this assembly 
would be suitable where the design uplift load is 37.5 psf. 
As previously discussed, because of building aerodynamics, the highest uplift load 
occurs at roof corners. The perimeter has a somewhat lower load; the field of the roof 
has the lowest load. FMG Data Sheets are formatted so that a roof assembly can be 
selected for the field of the roof. That assembly is then adjusted to meet the higher 
loads in the perimeter and corners by increasing the number of fasteners or 
decreasing the spacing of adhesive ribbons by a required amount; however, this 
assumes that the failure is the result of the pulling-out of the fastener from the deck, 
or that failure is in the vicinity of the fastener plate, which may not be the case. Also, 
the increased number of fasteners required by FM may not be sufficient to comply 
with the perimeter and corner loads derived from the building code. Therefore, if FM 
resistance data are specified, it is prudent for the architect to separately specify the 
resistance for the field of the roof (1-75 in the example above), the perimeter (1-130), 
and the corner (1-190).  

Edge Flashings and Copings. Roof membrane blow-off is almost always a result of 
lifting and peeling of the metal edge flashing or coping, which serves to clamp down 
the membrane at the roof edge (see Figure 6-37). Therefore, it is important for the 
architect to carefully consider the design of metal edge flashings, copings, and the 
nailers to which they are attached. ANSI/SPRI ES-1, Wind Design Standard for Edge Systems 
Used in Low Slope Roofing Systems provides general design guidance, including a 
methodology for determining the outward-acting load on the vertical flange of the 
flashing/coping (ASCE 7 does not provide this guidance). A minimum safety factor 
of three for edge flashings, copings, and nailers is recommended for schools. 
ANSI/SPRI ES-1 also includes test methods for assessing flashing/coping resistance. 
For FMG-insured schools, FMR approved flashing should be used and Data Sheet 1-49 
should also be consulted. 
The traditional edge flashing/coping attachment method relies on concealed cleats 
that can deform under wind load and lead to disengagement of the flashing/coping 
(see Figure 6-38) and subsequent lifting and peeling of the roof membrane (as shown 
in Figure 6-11). When a vertical flange disengages and lifts up (as shown in Figure 6-
38), the edge flashing and membrane are very susceptible to failure. Normally, when a 
flange lifts such as shown in Figure 6-38, the failure continues to propagate and the 
metal edge flashing and roof membrane blow off. 

Storm-damage research has revealed that, in lieu of cleat attachment, use of exposed 
fasteners to attach the vertical flanges of copings and edge flashings has been found 
to be a very effective and reliable attachment method (see Figure 6-39). 
If cleats are used for attachment, it is recommended that a bar be placed over the roof 
membrane near the edge flashing/coping as illustrated in Figure 6-40. The purpose 
of the bar is to provide secondary protection against membrane lifting and peeling in 
the event that the edge flashing/coping fails. A robust bar specifically made for bar-
over mechanically attached single-ply systems is recommended. The bar needs to be 
very well anchored to the parapet or deck. Depending upon design wind loads, a 
spacing between 4 and 12 inches on center is recommended. A gap of a few inches 
should be left between each bar to allow for water flow across the membrane. After 
the bar is attached, it is stripped over with a stripping ply.
Gutters. Special design attention needs to be given to uplift attachment of gutters, 
particularly those in excess of 6 inches wide.  Recommendations are provided in 
"Honing in on hangars," Professional Roofing, Thomas L. Smith, October 2002, pp. 32 
(available on-line at www.nrca.net).

Roof System Performance. Storm-damage research has shown that sprayed 
polyurethane foam and liquid-applied roof systems are very reliable high-wind 
performers. If the substrate to which the foam or liquid-applied membrane was 
applied does not lift, it is highly unlikely that the sprayed polyurethane foam (SPF) or 
the liquid-applied membrane will blow-off. Both systems are also more tolerant of 
missiles than other systems. Built-up roofs (BURs) and modified bitumen systems 
have also demonstrated good wind performance provided the edge flashing/coping 
does not fail (edge flashing/coping failure is common). The exception is aggregate 
surfacing, which is prone to blow-off (see Figure 6-11). Modified bitumen adhered to 
a concrete deck has demonstrated excellent resistance to progressive peeling after 
blow-off of the metal edge flashing. Metal panel performance is highly variable. Some 
systems are very wind-resistant, while others are quite vulnerable. 
Of the single-ply attachment methods, the paver-ballasted and fully adhered methods 
are the least problematic. Systems with aggregate ballast are prone to blow-off, unless 
care is taken in the design of the size of aggregate and the parapet height (see Figure 
6-8). Performance of protected membrane roofs (PMRs) with factory-applied 
cementitious coating over insulation boards is highly variable. When these boards 
are installed over a loose-laid membrane, it is critical that an air retarder be 
incorporated to prevent the membrane from ballooning and disengaging the boards. 
ANSI/SPRI RP-4 (which is referenced in the IBC) provides wind guidance for 
ballasted systems using aggregate, pavers, and cementitious-coated boards. 
The National Research Council of Canada, Institute for Research in Construction's 
Wind Design Guide for Mechanically Attached Flexible Membrane Roofs, B1049 (2004) provides 
recommendations related to mechanically attached single-ply and modified 
bituminous systems. B1049 is a very comprehensive wind design guide and includes 
discussion of air retarders, which can be effective in reducing membrane flutter, in 
addition to their beneficial use in ballasted single-ply systems. When a mechanically 
attached system is specified, careful coordination with the structural engineer with 
respect to selection of deck type and thickness is important. If a steel deck is 
specified, it is critical to specify that the membrane fastener rows run perpendicular 
to the steel flanges in order to avoid overstressing attachment of the deck to the deck 
support structure (see Figures 6-41 and 6-42). In Figure 6-42, the flange with 
membrane fasteners carries essentially all of the uplift load because of the deck's 
inability to transfer any significant load to adjacent flanges. Hence, at the joists, the 
deck fasteners on either side of the flange with the membrane fasteners are the only 
connections to the joists that are carrying uplift load. Had the membrane fasteners 
shown in Figure 6-42 been run perpendicular to the deck flanges, each of the 
fasteners connecting the deck to the joists would have been carrying uplift load. 
Recommendations related to metal panels is provided in "Insights on Metal Roof 
Performance in High-wind Regions," Professional Roofing, Thomas L. Smith, February 
1995, pp. 12 (available on-line at  www.nrca.net).

Parapet Base Flashings. Loads on parapet base flashings were first introduced in the 
2002 edition of ASCE 7. The loads on base flashings are greater than the loads on the 
roof covering if the parapet's exterior side is air-permeable. When base flashing is 
fully adhered, it has sufficient wind resistance in most cases. However, when base 
flashing is mechanically fastened, typical fastening patterns may be inadequate, 
depending upon design wind conditions (see Figure 6-43). Therefore, it is imperative 
that base flashing loads be calculated and attachments be designed to accommodate 
the loads. It is also important for designers to recognize and specify different 
attachment spacings in parapet corner regions versus regions between corners. 
Further discussion is provided in "Detailing ASCE 7's changes," Professional Roofing, 
Thomas L.  Smith, July 2003, pp. 26 (available on-line at www.nrca.net).

Lightning Protection Systems. When not adequately integrated into a roof system, a 
lightning protection system can become detached from the roof during high winds. 
The detached system can damage the roof covering (see Figure 6-44). In addition, a 
detached system is no longer capable of providing lightning protection. Most 
manufacturers of lightning protection systems and most roofing manufacturers 
provide vague or inadequate details for securing a lightning protection system to a 
roof.  

During prolonged high winds, repeated slashing of the membrane by loose 
conductors ("cables") and puncturing by air terminals can result in lifting and 
peeling of the membrane. It is, therefore, important to adequately design the 
attachment of the lightning protection system. Recommendations pertaining to 
wind-resistant design, and specification and installation of lightning protection 
systems are provided in  "Integrating a Lightning Protection System in a Roof 
System," Thomas L. Smith, 12th International Roofing and Waterproofing 
Conference Proceedings (CD), National Roofing Contractors Association, 2002.
Hurricane-prone Regions. See Section 6.15.5 for schools in hurricane-prone regions.

Tornado-prone Regions. In order to reduce the number of wind-borne missiles, it is 
recommended that aggregate surfacings, pavers, tile, and slate not be specified on 
schools in tornado-prone regions (as defined in Section 6.7.1; see Figure 6-8).





6.13 WINDOWS AND SKYLIGHTS

This section addresses exterior windows and skylights. See Section 6.15.6 for schools 
located in hurricane-prone regions

6.13.1 Loads and Resistance

The IBC requires the window, curtain wall, or skylight assembly (i.e., the glazing, 
frame, and frame attachment to the wall or roof) to have sufficient strength to resist 
the positive and negative design wind pressure (see Figure 6-45). Architects should 
specify that these assemblies comply with wind load testing in accordance with ASTM 
E 1233. It is important to specify an adequate load path and to check its continuity 
during submittal review.

In tornado-prone regions, some school districts may desire to have laminated glazing 
installed at exterior openings in order to provide wind-borne debris protection 
during weak tornadoes. Laminated glazing may also offer protection during strong 
tornadoes, but should not be relied upon for violent tornadoes. Further discussion is 
provided in Section 6.15.6.

6.13.2 Durability

Where corrosion is problematic, anodized aluminum or stainless steel frames and 
stainless steel frame anchors are recommended.
6.13.3Water Infiltration
When heavy rain accompanies high winds (e.g., thunderstorms, tropical storms, and 
hurricanes), it can cause wind-driven water infiltration problems; the magnitude of 
the problem increases with the wind speed. Leakage can occur at the glazing/frame 
interface, at the frame itself, or between the frame and wall. When the basic wind 
speed is greater than 120 mph, because of the very high design wind pressures and 
numerous opportunities for leakage path development, some leakage should be 
anticipated when design wind speed conditions are approached.  
The challenge with windows and curtain walls is successful integration between these 
elements and the walls. To the extent possible, detailing of the interface between the 
wall and the window or curtain wall units should rely on sealants as the secondary 
line of defense against water infiltration, rather than making the sealant the primary 
protection.  

When designing joints between walls and windows and curtain wall units, consider 
the shape of the sealant joint (i.e., a square joint is typically preferred) and the type of 
sealant to be specified. The sealant joint should be detailed so the sealant is able to 
bond on only two opposing surfaces (i.e., a backer rod or bond-breaker tape should 
be specified). For concealed sealants, butyl is recommended. For exposed sealants, 
polyurethane is recommended. During installation, cleanliness of the sealant 
substrate is important (particularly if polyurethane or silicone sealants are specified), 
as well as tooling of the sealant. ASTM E 2112 provides guidance on design of sealant 
joints, as well other information pertaining to installation of windows, including the 
use of sill pan flashings with end dams and rear legs (see Figure 6-46). It is 
recommended that designers use ASTM E 2112 as a design resource.
Sealant joints can be protected with a removable stop as illustrated in Figure 6-47. The 
stop protects the sealant from direct exposure to the weather and reduces the wind-
driven rain demand on the sealant.

Where water infiltration protection is particularly demanding and important, it is 
recommended that on-site water infiltration testing in accordance with ASTM E 1105 
be specified.


6.14 EXTERIOR-MOUNTED MECHANICAL, ELECTRICAL, AND 
COMMUNICATIONS EQUIPMENT

Exterior-mounted mechanical (e.g., exhaust fans, HVAC units, relief air hoods, boiler 
stacks), electrical, and communications equipment (e.g., light fixtures, antennae, 
satellite dishes) are often damaged during high winds. Damaged equipment can im-
pair the use of the school, the equipment can become missiles, and water can enter 
the facility where equipment was displaced (see Figures 6-19 and 6-48).
Problems typically relate to inadequate equipment anchorage, inadequate strength of 
the equipment itself, and corrosion.


6.14.1 Loads and Attachment

Rooftop Equipment. Criteria for determining loads on rooftop equipment were added 
to the 2002 edition of ASCE 7. A minimum safety factor of three is recommended for 
the design of equipment anchorage.

To anchor membrane fans, small HVAC units, and relief air hoods, the following 
minimum prescriptive attachment schedule is recommended:

 For curb-mounted units, specify #14 screws with gasketed washers.
 For curbs with sides less than 12 inches, specify one screw at each side of the curb.
 For curbs between 12 inches and 24 inches, specify two screws per side. 
 For curbs between 24 inches and 36 inches, specify three screws per side. 
 For units that have flanges attached directly to the roof, attachment with #14 pan-
head screws is recommended. A minimum of two screws per side, with a maximum 
spacing of 12 inches on center is recommended.
Figure 6-49 illustrates the use of supplemental securement straps to anchor 
equipment. The supplemental attachment was marginal; the straps were too light and 
the fasteners used to secure them were corroded. This illustrates the validity of the 
supplemental securement, and it also illustrates the need to execute the securement 
with attention to detail. In lieu of one screw at each end of the strap, two side-by-side 
screws offer a stronger and more reliable connection (this of course requires a 
slightly wider strap).

Electrical and Communications Equipment.  Damage to exterior-mounted electrical 
equipment is infrequent, in large part, because of the small size of most equipment 
(e.g., disconnect switches). Exceptions are communication masts (see Figure 6-50), 
surveillance cameras, service masts, and satellite dishes. These failures are typically 
caused by failure to perform wind load calculations and anchorage design. Service 
mast failure is typically caused by collapse of overhead power lines; this can be 
avoided by underground service. Where overhead service is provided, it is 
recommended that the service mast not penetrate the roof. Otherwise, a downed 
service line could pull the mast and rupture the roof membrane.

ASCE 7 provides load calculation criteria for trussed towers. The ASCE 7 criteria are 
consistent with ANSI/EIA/TIA-222-E. The ASCE 7 approach is a simplified procedure. 
The IBC allows use of either approach. ASCE 7 does not provide guidance for on-site 
power distribution poles nor for light fixture poles. However, the National Electrical 
Safety Code, ANSI/C2 provides guidance for determining wind loads on power poles. 
The AASHTO Standard Specification for Structural Support for Highway Signs, Luminaries and 
Traffic Signals provides guidance for determining wind loads on light fixture poles.
See Section 6.8.1 regarding siting of light fixture poles, power poles, and electrical 
and communications towers.



6.14.2 Equipment Strength
It is common for equipment components such as fan cowlings and access panels to 
be blown off during storms. Design of these elements is the responsibility of the 
equipment manufacturer. Although poor equipment performance has been 
documented, manufacturers have not offered enhanced equipment for high-wind 
regions. Therefore, it is incumbent upon the architect/engineer to give special 
design attention to equipment strength.

Damage investigations have revealed that cable tie-downs have been effective in 
securing fan cowlings when a sufficiently strong cable and anchor details were used 
(see Figure 6-51). For fan cowlings less than 4 feet in diameter, 1/8-inch diameter 
stainless steel cables are recommended. For larger cowlings, use 3/16-inch diameter 
cables.  When the basic wind speed is 120 mph or less, specify two cables. Where the 
basic wind speed is greater than 120 mph, specify four cables. (As an alternative to 
cables, heavy stainless steel straps could be screwed to the cowling and curb.) To 
minimize leakage potential at the anchor point, it is recommended that the cables be 
anchored to the equipment curb (rather than anchored to the roof deck). The 
attachment of the curb itself also needs to be designed and specified.  
To minimize blow-off of equipment access panels, job-site modification will typically 
be necessary (such as the attachment of hasps and locking devices such as a 
carabineer). The modification details will need to be tailored for the equipment, 
which may necessitate detail design after the equipment has been delivered to the job 
site.  Alternatively, factored loads on the equipment could be specified, along with the 
requirement for the manufacturer to demonstrate compliance with the load 
requirement.


6.14.3 Durability  

To avoid corrosion-induced blow-off, it is recommended that exterior-mounted 
mechanical, electrical, and communications equipment be nonferrous, stainless 
steel, or steel with minimum G-90 hot-dip galvanized coating for the equipment itself, 
equipment stands, anchors, and fasteners. When equipment with enhanced 
corrosion protection is not available, the designer should advise the school district 
that periodic equipment maintenance and inspection is particularly important to 
avoid advanced corrosion and subsequent equipment damage during a windstorm.
The recommendations given in Sections 6.8 through 6.14 are summarized in Table 6-
1.




6.15 SCHOOLS LOCATED IN HURRICANE-PRONE REGIONS 


The IBC, through ASCE 7, prescribes that exterior glazing in schools in wind-borne 
debris regions be provided with wind-borne debris protection (either by use of 
laminated glass or shutters, as discussed in Section 6.15.6). Schools in hurricane-
prone regions also have to be designed for a 100-year mean recurrence interval wind 
event if they are to be used as shelters. These are the only hurricane-related 
requirements currently in the IBC. These requirements do not provide adequate 
protection to occupants in a school during a hurricane, because the missile 
requirements only pertain to glazing. Hence, a code-compliant school can be 
designed, yet still allow the entrance of missiles through the roof or walls. To account 
for this deficiency, recommendations are given below regarding missile penetration 
through exterior walls and the roof. For a more conservative hurricane shelter, refer 
to FEMA 361.

Publication 4496 by the American Red Cross (ARC) provides information regarding 
assessing existing buildings for use as hurricane shelters. Unless a school has been 
specifically designed for use as a shelter, it should only be used as a last resort and 
only if the school meets the criteria given in ARC 4496.
Schools located in hurricane-prone regions should receive special design attention 
because of the unique characteristics of this type of windstorm. In addition to being 
capable of delivering very high winds, hurricanes can cause strong winds for many 
hours, which can eventually lead to fatigue failure. The direction of the wind can also 
change, thereby increasing the probability that the wind will approach the school at 
the most critical angle. Hurricanes also typically generate a large amount of missiles, 
which can be very damaging to schools and cause injury or death.  
For schools in hurricane-prone regions that will be used for a hurricane shelter 
and/or for emergency response after a storm, the following design parameters are 
recommended (these recommendations are in addition to the recommendations 
previously given in Sections 6.8 through 6.14):

1.   During the design phase, the architect should determine from the school district 
whether or not the school will be designated or used as a shelter or emergency 
response facility. The school should only be used for a shelter if it was designed 
for that purpose.  

2.   For schools in coastal Alaska and other areas that experience frequent high wind 
events (such as parts of Colorado), several of the following recommendations are 
also applicable to these schools, with the exception of the wind-borne debris 
recommendations.


6.15.1 Design Loads  

For the importance factor, use a value of 1.15.


6.15.2 Structural Systems
  
Because of the exceptionally good wind performance that reinforced cast-in-place 
concrete structures offer, a reinforced concrete roof deck and reinforced concrete 
and/or reinforced and fully grouted CMU exterior walls are recommended.  
In order to achieve enhanced missile resistance, the following roof decks are 
recommended, in descending order of preference: cast-in-place concrete, precast 
concrete, and concrete topping over steel decking. For exterior walls, the following 
are recommended: 6-inch (minimum) thick concrete reinforced with #4 rebars at 12 
inches on center each way, or 8-inch (minimum) thick fully grouted CMU reinforced 
with #4 rebars in each cell.


6.15.3 Exterior Doors

For glazing in doors, see the recommendations in Section 6.15.6.

Although the ASCE-7 wind-borne debris provisions only apply to glazing within a 
portion of hurricane-prone regions, it is recommended that all schools that will be 
used for evacuation shelters within the entire hurricane-prone region comply with 
the following recommendation: To minimize the potential of missiles penetrating 
exterior doors and striking people within the school, it is recommended that doors 
without glazing and the unglazed portions of doors with glazing  be designed to 
resist the missile loads specified in ASTM E 1996 and that they be tested in 
accordance with ASTM E 1886. The test assembly should include the door, door frame 
and hardware. Further information on missile resistance of doors is found in FEMA 
361, Design and Construction Guidance for Community Shelters.
6.15.4Non-load Bearing Walls, Wall Coverings, and Soffits  
In order to achieve enhanced missile resistance, the following types of exterior walls 
are recommended: reinforced cast-in-place concrete, or reinforced and fully grouted 
CMU. 

To minimize long-term problems with non-load bearing walls, wall coverings, and 
soffits, it is recommended that non-load bearing exterior walls, wall coverings, and 
soffits be avoided to the extent possible. Reinforced concrete or CMU offers greater 
reliability (i.e., they have no coverings that can be blown off). 

 
6.15.5 Roof Systems

The following types of roof systems are recommended on schools in hurricane-prone 
regions because they are more likely to avoid water infiltration if the roof is hit by 
wind-borne debris.  Also, the following systems are less likely to become sources of 
wind-borne debris:

 In tropical climates where insulation is not needed above the roof deck: 1) liquid-
applied membrane over cast-in-place concrete deck, or 2) modified bitumen 
membrane torched directly to cast-in-place concrete deck.
 Install a secondary membrane over a concrete deck (if another type of deck is 
specified, a cover board may be needed over the deck). Seal the secondary 
membrane at perimeters and penetrations. Specify a minimum 2-inch thick rigid 
insulation and a layer of 5/8-inch thick glass mat gypsum roof board over the 
secondary membrane to absorb missile energy. If the primary membrane is 
punctured during a storm, the secondary membrane should provide watertight 
protection unless the roof is hit with missiles of very high energy. A modified 
bitumen membrane is recommended for the primary membrane because of its 
enhanced resistance to puncture by small missiles.
 For an SPF roof system over a concrete deck, specify that the foam be a minimum of 
3 inches thick to avoid missile penetration through the entire layer of foam.
 For a PMR, it is recommended that pavers weighing a minimum of 22 psf be 
specified. In addition, base flashings should be protected with metal. Parapets are 
recommended at roof edges. The parapet should be at least 3 feet high or higher if 
so indicated by ANSI/SPRI RP-4. Note: If the basic wind speed exceeds 130 mph, a 
PMR is not recommended on schools in hurricane-prone regions.
 For structural metal roof panels with concealed clips, it is recommended that 
mechanically seamed ribs spaced at 12 inches on center over a concrete deck be 
specified. If a steel deck is specified, specify a self-adhering modified bitumen 
membrane and 3-inch thick rigid insulation, followed by the metal panels 
installed on wood nailers. At the self-adhering membrane laps, specify metal strips 
over the deck where the laps do not occur over the deck ribs, or specify a suitable 
cover board between the deck and self-adhering membrane. If the metal panels are 
punctured during a storm, the secondary membrane should provide watertight 
protection unless the roof is hit with missiles of very high energy. Note:  
Architectural metal panels are not recommended on schools in hurricane-prone 
regions.

In order to avoid the possibility of roofing debris blowing off and striking people 
arriving at the school during the storm, the following types of roof coverings are not 
recommended:  aggregate surfacings (either on BUR [shown in Figure 6-11], single-
plies [shown in Figure 6-8] or SPF), lightweight concrete pavers, cementitious-coated 
insulation boards, slate, and tile (see Figure 6-52). Wind-borne debris from heavy roof 
coverings such as tiles have great potential to cause serious injury to people arriving 
at a school during a hurricane or other high wind event.

Because mechanically attached and air-pressure equalized single-ply membrane 
systems are susceptible to massive progressive failure after missile impact (see Figure 
6-53), these systems are not recommended on schools in hurricane-prone regions. 
Fully adhered single-ply membranes are also very vulnerable to missiles (see Figure 6-
54); therefore, they also are not recommended unless they are ballasted with pavers. 


6.15.6 Windows and Skylights

ASCE 7 requires the use of impact-resistant glazing (i.e., laminated glass) or shutters 
in wind-borne debris regions. ASCE 7 refers to ASTM E 1996 for missile loads and to 
ASTM E 1886 for the test method to be used to demonstrate compliance with the E 
1996 load criteria. In addition to testing for impact resistance, the window unit is 
subjected to pressure cycling after missile impact to evaluate whether or not the 
window can still resist wind loads.
If wind-borne debris glazing protection is provided by shutters, the glazing is still 
required by ASCE 7 to meet the positive and negative design air pressures.
For those schools that desire to provide blast-resistant glazing, the windows and 
glazed doors can be designed to accommodate wind pressure, missile loads, and blast 
pressure. However, the window and door units need to be tested for missile loads and 
cyclic air pressure, as well as for blast. A unit that meets blast criteria will not 
necessarily meet the E 1996 and E 1886 criteria, and vice versa. 
With the advent of building codes requiring glazing protection in wind-borne debris 
regions, a variety of shutter designs have entered the market. Figure 6-55 illustrates an 
effective shutter. A metal track was permanently mounted to the wall above and below 
the window frame. Upon notification of an approaching hurricane, the metal shutter 
panels were inserted into the frame and locked into position with wing nuts. 
Shutters typically have a lower initial cost than laminated glass. However, unless the 
shutter is permanently anchored to the school (e.g., an accordion shutter), space will 
be needed to store the shutters. Also, when a hurricane is forecast, costs will also be 
incurred each time shutters are installed and removed afterward. To avoid the 
difficulty of installing shutters on upper-level glazing, motorized shutters could be 
specified, although laminated glass may be more economical in these locations. 


6.15.7 Emergency Power

Schools intended for use as shelters and/or emergency response after a storm should 
be equipped with an emergency generator.


6.15.8 Construction Contract Administration

It is important for the school district to obtain the services of a professional 
contractor who will execute the work described in the contract documents in a 
diligent and technically proficient manner.  
The frequency of field observations and extent of special inspections and testing 
should be greater than those employed on schools that are not designated as shelters.


6.15.9 Periodic Inspections, Maintenance, and Repair

The recommendations previously given for periodic and post-storm inspections, 
maintenance, and repair are critically important for schools used as shelters and 
emergency response after a storm because, if failure occurs, the risk of injury or death 
to occupants is great, and the needed continued operation of the school would be 
jeopardized.
The recommendations given in Section 6.15 are summarized in Table 6-2.  These 
recommendations are in addition to those given in Sections 6.8 to 6.14, as 
summarized in Table 6-1.




 
6.16 DESIGN FOR TORNADO SHELTERS

Tornado risk assessment and tornado-prone regions were discussed in Section 6.7 
and the cost of tornado shelters was discussed in Section 6.5.2. Following up on those 
discussions, strong and violent tornadoes produce wind speeds that are substantially 
greater than those delivered by the strongest hurricanes; hence, the wind pressures 
that these tornadoes exert on buildings is tremendous and far exceed the minimum 
pressures required by building codes. In addition, strong and violent tornadoes can 
generate very powerful missiles (see Figure 6-56), including vehicles. The missile 
sticking out of the roof in the foreground of Figure 6-56 is a double 2-inch by 6-inch. 
The portion sticking out of the roof is 13 feet long. It penetrated a ballasted ethylene 
propylene diene monomer (EPDM) membrane and approximately 3 inches of 
polyisocyanurate roof insulation and the steel roof deck. The missile laying on the 
roof just beyond is 2 inches by 10 inches by 16 feet long. 
Missile loads that are used for the design of tornado shelters are significantly greater 
than the missile loads used for the design of glazing protection in wind-borne debris 
regions of hurricane-prone regions.

As discussed in Section 6.5.2, FEMA 361, Design and Construction Guidance for Community 
Shelters, includes software for assessing the benefit/cost ratio of incorporating 
specially designed tornado shelters within schools. In addition, it includes 
comprehensive information regarding the design of shelters. If shelter design is 
contemplated, use of FEMA 361 is recommended. 

Existing Schools without Tornado Shelters. Where the number of recorded F3, F4,  and 
F5 tornadoes per 3,700 square miles is one or greater (see Figure 6-2), if the school 
does not have a tornado shelter, the best available refuge areas should be identified. 
FEMA 431, Tornado Protection, Selecting Refuge Areas in Buildings provides useful 
information for school administrators, and for architects and engineers who perform 
evaluations of existing schools.

To minimize deaths and injuries of students, faculty, and other occupants, it is 
critically important that the best available refuge areas be pre-identified by a qualified 
architect/engineer.8  Once identified, those areas need to be clearly marked so that 
occupants can quickly seek refuge. Don't wait for the arrival of a tornado on the 
school grounds to try to find the best available refuge areas; by that time, it is too late. 
If refuge areas have not been pre-identified, occupants can easily take cover in areas 
that can become death traps (see Figure 6-57).
When a true shelter is desired for a school that does not have one, retrofitting a 
shelter within the school can be very expensive. An economical alternative is an 
addition to the existing school that can function as a shelter as well as serve another 
purpose. This approach works well for smaller schools, but, for a very large school, 
construction of two or more shelter additions should be considered in order to 
reduce the time it takes to reach the shelter (often there is ample warning time, but 
sometimes an approaching tornado is not noticed until a couple of minutes before it 
strikes).

The recommendations given in Section 6.16 are summarized in Table 6-3 .





 
6.17 REMEDIAL WORK ON EXISTING SCHOOLS

Section 6.6.1 discussed prioritizing and Section 6.6.2 discussed cost. Following up on 
those discussions, many existing schools need building envelope component 
strengthening or structural strengthening. The need for this work is due either to 
deterioration over time and/or inadequate facility strength at the time the school was 
built.
  
It is prudent for school districts to have their existing facilities evaluated. This also 
applies to recently constructed schools that are located in an area where the basic 
wind speed is greater than 90 mph (peak gust), and those schools that will be used for 
emergency response after a storm and schools that will be used for a hurricane 
shelter.
For new schools, areas of concern would typically be the building envelope and 
exterior-mounted mechanical, electrical, and communications equipment. By 
identifying weaknesses and prioritizing and executing the work, many failures can be 
averted. A proactive approach can save significant sums of money and decrease the 
number of instances when schools are impaired or immobilized after a storm.  
For roofs with weak metal edge flashing or coping attachment, face-attachment of 
the edge flashing/coping (as shown in Figure 6-39) is a cost-effective approach to 
greatly improve wind-resistance of the roof system. Fastening rooftop equipment to 
curbs is a cost-effective approach to avoid the type of problems shown in Figure 6-19.
During planned roof covering replacement, by tearing off the existing roof covering 
rather than re-covering, there is the opportunity to evaluate the structural integrity of 
the deck and deck attachment and upgrade its attachment if necessary. Many older 
decks are poorly attached (Figure 6-58); hence, if their attachment is not upgraded, 
blow-off of the deck and the new roof covering could occur. The two deck panels 
shown in Figure 6-58 blew away because their attachment to the roof structure was 
inadequate. An SPF roof covering was over the deck panels that blew away because of 
the characteristics of this type of covering, membrane propagation failure did not 
occur, as would have been the case with built-up, modified bitumen, or single-ply roof 
membranes. Cementitious wood-fiber decks were commonly used on schools built in 
the 1950s and 1960s. Decks constructed during that era typically had very limited 
uplift resistance due to weak connections to the support structure. 
Design guidance pertaining to existing decks is presented in "Uplift Resistance of 
Existing Roof Decks:  Recommendations for Enhanced Attachment During Reroofing Work," RCI 
Interface, Thomas L. Smith, January 2003, pp. 14.
Weak non-load bearing masonry walls, poorly connected precast concrete panels, 
long-span structures (e.g., at gyms) with limited uplift resistance, and weak glass 
curtain walls are common problems with many older schools. Although the technical 
solutions to these problems are not difficult, the cost of the remedial work is 
normally quite expensive. If remediation funds are not available, it is important to 
minimize the risk of injury and death by evacuating areas that have this type of 
construction when winds above 60 mph are forecast. 
For schools located in wind-borne debris regions, if the exterior glazing is not 
missile-resistant, equipping the openings with shutters is a cost-effective approach to 
provide protection.

The recommendations given in Section 6.17 are summarized in Table 6-4.





6.18 REFERENCES AND SOURCES OF ADDITIONAL INFORMATION 

American Institute of Architects, Buildings at Risk: Wind Design Basics for Practicing 
Architects, 1997.
 
Federal Emergency Management Agency, Building Performance: Hurricane Andrew in 
Florida, FEMA FIA-22, Washington, DC, December 1992.

Federal Emergency Management Agency, Building Performance: Hurricane Iniki in 
Hawaii, FEMA FIA-23, Washington, DC, January 1993.

Federal Emergency Management Agency, Corrosion Protection for Metal Connectors in 
Coastal Areas, FEMA Technical Bulletin 8-96, Washington, DC, August 1996.

Federal Emergency Management Agency, Typhoon Paka: Observations and 
Recommendations on Building Performance and Electrical Power Distribution System, Guam, 
U.S.A., FEMA-1193-DR-GU, Washington, DC, March 1998.

Federal Emergency Management Agency, Hurricane Georges in Puerto Rico, FEMA 339, 
Washington, DC, March 1999.

Federal Emergency Management Agency, Oklahoma and Kansas Midwest Tornadoes of 
May 3, 1999, FEMA 342, Washington, DC, October 1999.

Federal Emergency Management Agency, Coastal Construction Manual, Third Edition, 
FEMA 55, Washington, DC, 2000.

Federal Emergency Management Agency, Design and Construction Guidance for 
Community Shelters, FEMA 361, Washington, DC, July 2000.

Federal Emergency Management Agency, Primer to Design Safe School Projects in Case of 
Terrorist Attacks, FEMA 428, Washington, DC, October 2003.

Federal Emergency Management Agency, Tornado Protection, Selecting Safe Areas in 
Buildings, FEMA 431, Washington, DC, October 2003.

National Research Council of Canada, Institute for Research in Construction, Wind 
Design Guide for Mechanically Attached Flexible Membrane Roofs, B1049, 2004.

Rousseau, M.Z., Facts and Fictions of Rain-Screen Walls, Construction Canada, 1990, pp. 40.
Smith, Thomas L., "Insights on Metal Roof Performance in High-wind Regions,"  
Professional Roofing, February 1995, pp. 12 (available on-line at www.nrca.net).

Smith, Thomas L., "Integrating a Lightning Protection System in a Roof System," 
12th International Roofing and Waterproofing Conference Proceedings (CD), 
National Roofing Contractors Association, 2002.

Smith, Thomas L., "Honing in on hangars,"  Professional Roofing, October 2002, pp. 32 
(available on-line at www.nrca.net).

Smith, Thomas L., "Uplift Resistance of Existing Roof Decks:  Recommendations for 
Enhanced Attachment During Reroofing Work," RCI Interface, January 2003, pp. 14.
Smith, Thomas L., "Detailing ASCE 7's changes," Professional Roofing, July 2003, pp. 26 
(available on-line at www.nrca.net).





6.19 GLOSSARY OF WIND TERMS

Basic wind speed. A 3-second gust speed at 33 feet above the ground in Exposure C.   
(Exposure C is flat open terrain with scattered obstructions having heights generally 
less than 30 feet.) Note: Since 1995, ASCE 7 has used a 3-second peak gust measuring 
time.  A 3-second peak gust is the maximum instantaneous speed with a duration of 
approximately 3 seconds. A 3-second peak gust speed could be associated with a given 
windstorm (e.g., a particular storm could have a 40-mile per hour peak gust speed), or 
a 3-second peak gust speed could be associated with a design-level event (e.g., the 
basic wind speed prescribed in ASCE 7).

Building, enclosed. A building that does not comply with the requirements for open or 
partially enclosed buildings.

Building, open. A building having each wall at least 80 percent open. This condition 
is expressed by an equation in ASCE 7.

Building, partially enclosed. A building that complies with both of the following 
conditions:
1. The total area of openings in a wall that receives positive external pressure exceeds 
the sum of the areas of openings in the balance of the building envelope (walls 
and roof) by more than 10 percent, and   
2. The total area of openings in a wall that receives positive external pressure exceeds 
4 square feet or 1 percent of the area of that wall, whichever is smaller, and the 
percentage of openings in the balance of the building envelope does not exceed 
20 percent.
These conditions are expressed by equations in ASCE 7.

Building, regular shaped. A building having no unusual geometrical irregularity in 
spatial form.
Building, simple diaphragm. An enclosed or partially enclosed building in which wind 
loads are transmitted through floor and roof diaphragms to the vertical main wind-
force resisting system.

Components and cladding. Elements of the building envelope that do not qualify as 
part of the main wind-force resisting system.
Escarpment. Also known as a scarp, with respect to topographic effects, a cliff or steep 
slope generally separating two levels or gently sloping areas. 

Exposure. The characteristics of the ground roughness and surface irregularities in 
the vicinity of a building. ASCE 7 defines three exposure categories - Exposures B, C, 
and D. 

Glazing. Glass or transparent or translucent plastic sheet used in windows, doors, and 
skylights.

Glazing, impact-resistant. Glazing that has been shown by an approved test method to 
withstand the impact of wind-borne missiles likely to be generated in wind-borne 
debris regions during design winds.
Hill. With respect to topographic effects, a land surface characterized by strong relief 
in any horizontal direction.

Hurricane-prone regions. Areas vulnerable to hurricanes; in the U.S. and its territories 
defined as:
1. The U.S. Atlantic Ocean and Gulf of Mexico coasts where the basic wind speed is 
greater than 90 miles per hour, and
2. Hawaii, Puerto Rico, Guam, U.S. Virgin Islands, and American Samoa.

Impact-resistant covering. A covering designed to protect glazing, which has been 
shown by an approved test method to withstand the impact of wind-borne missiles 
likely to be generated in wind-borne debris regions during design winds.
Importance factor, I. A factor that accounts for the degree of hazard to human life 
and damage to property. The importance factor adjusts the mean recurrence interval.  
Importance factors are given in ASCE 7.

Main wind-force resisting system. An assemblage of structural elements assigned to 
provide support and stability for the overall structure. The system generally receives 
wind loading from more than one surface.

Mean roof height, h. The average of the roof eave height and the height to the highest 
point on the roof surface, except that, for roof angles of less than or equal to 10 
degrees, the mean roof height shall be the roof eave height.

Missiles. Debris that became or could become ingested into the wind stream.  

Openings. Apertures or holes in the building envelope that allow air to flow through 
the building envelope and that are designed as "open" during design winds. A door 
that is intended to be in the closed position during a windstorm would not be 
considered an opening. Glazed openings are also not typically considered an 
opening. However, if the building is located in a wind-borne debris region and the 
glazing is not impact-resistant or protected with an impact-resistant covering, the 
glazing is considered an opening.

Ridge. With respect to topographic effects, an elongated crest of a hill characterized 
by strong relief in two directions.

Wind-borne debris regions. Areas within hurricane-prone regions located:
1. Within 1 mile of the coastal mean high water line where the basic wind speed is 
equal to or greater than 110 mph and in Hawaii; or
2.  In areas where the basic wind speed is equal to or greater than 120 mph







ACRONYMS     A



A

AASHTO American Association of State Highway and Transportation Officials

ACSA Association of Collegiate Schools of Architecture

ADA Americans with Disabilities Act

AHJ Authority Having Jurisdiction

AIA American Institute of Architects

AK Alaska

AL Alabama

ANSI American National Standards Institute

ARC American Red Cross

ASCE American Society of Civil Engineers

ASTMA merican Society for Testing and Materials

ATC Applied Technology Council



B

BFE base flood elevation

BOCA Building Officials and Code Administrators International

BSSC Building Seismic Safety Council

BUR built-up roof




C

CA California

CBR chemical, biological, or radiological

CMU concrete masonry unit



D

DE Delaware

DFE design flood elevation



E

EIFS exterior insulation finish system

ELF Equivalent Lateral Force

EPDM ethylene propylene diene monomer

EPS expanded polystyrene system




F

FEA finite element analysis

FEMA Federal Emergency Management Agency

FIRM Flood Insurance Rate Map

FIS Flood Insurance Study

FL Florida

FM Factory Mutual

FMG Factory Mutual Global

FMR Factory Mutual Research




G

GIS Geographic Information System

Gpm gallons per minute



H

HazMat hazardous materials

HAZUS Hazards U.S.

HAZUS-MH Hazards U.S. - Multihazards

HID high intensity

HVAC heating, ventilating, and air conditioning



I
IBC International Building Code

ICBO International Conference of Building Officials

ICC International Code Council

Id identification

IL Illinois

IT Information Technology



K

K-12 kindergarten to grade 12

Km kilometer 



L

LA Louisiana

LCD liquid crystal display



M

MA Massachusetts

MD Maryland

M/E/P Mechanical/Electrical/Plumbing

Mph miles per hour

MT Montana

MWFRS main wind-force resisting system




N

NBC National Building Code

NC North Carolina

NEHRP National Earthquake Hazards Reduction Program

NFIP National Flood Insurance Program

NFPA National Fire Protection Association

NIBS National Institute of Building Sciences




O

O&M operations and maintenance

OH Ohio

OSB oriented strand board



P

PA Pennsylvania

PMR protected membrane roof

Psf pounds per square foot



R

RC reinforced concrete

RSP Rapid Screening Procedure



S

SBC Standard Building Code

SBCCI Southern Building Code Congress International

SC South Carolina

SEACO Structural Engineers Association of California

SFPE Society of Fire Protection Engineers

SPF sprayed polyurethane foam

SUG Seismic Use Group




T

TN Tennessee

Tv television

TX Texas