4 Shelter Types, Location, 
and Siting Concepts 

A community shelter either will be used solely as a shelter or will have 
multiple purposes, uses, or occupancies. This chapter discusses community 
shelter design concepts that relate to the type of shelter being designed and 
where it may be located. This chapter also discusses how shelter use (either 
single or multiple) may affect the type of shelter selected and the location of 
that shelter on a particular site. 

4.1 Shelter Types 
This manual provides design guidance on two types of shelters: 

 
stand-alone shelters: shelters that are separate buildings 
 
internal shelters: shelter areas that are within or part of a larger building, but 
that have been designed to be structurally independent. 
This is not meant to imply that these are the only two types of shelters that 
should be considered. Other shelter options, such as groups of smaller, often 
proprietary shelter systems, may be appropriate for residential communities, 
hospitals, schools, or at places of business. It is not possible to provide 
guidance concerning all sheltering options for all shelter locations. The 
guidance provided in this manual for stand-alone and internal shelters, 
including the design criteria, may be applied to other shelter options. If other 
shelter systems and types of shelters are designed to meet the criteria in this 
manual, they should be capable of providing near-absolute protection as well. 


NOTE 

The guidance provided in this manual is for the design and construction of 
new shelters, not for the addition of shelters to existing buildings (i.e., This manual provides guidance 
retrofitting). Because of the variety of structural types and the number of for the design and construcdifferent 
configurations of existing buildings, only a limited amount of tion of new shelters. The 
guidance is provided on modifying existing buildings to create a shelter where design professional perform-
none existed previously. However, a design professional engaged in a shelter ing retrofit work on existing 
retrofitting project should be able to use the guidance in this manual to buildings should apply the new 
determine the risk at the site and calculate the loads acting on the building. In design guidance presented in 
addition, the checklists in Appendix B and information presented in the case this manual to the retrofit 
studies in Appendixes C and D may be helpful in a shelter retrofitting project. design. 

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CROSS-REFERENCE 

Tornado Refuge Evaluation 
Checklists are discussed in 
Chapter 2 and presented in 
Appendix B. A risk assessment 
plan that uses these checklists 
can help determine which type 
of shelter is best suited to a 
given site. 

4.1.1 Stand-Alone Shelters 
The results of the risk and site assessments discussed in Chapter 2 may show 
that the best solution to providing protection for large numbers of people is to 
build a new, separate (i.e., stand-alone) building specifically designed and 
constructed to serve as a tornado or hurricane shelter. 

Potential advantages of a stand-alone shelter include the following: 

 
The shelter may be sited away from potential debris hazards. 
 
The shelter will be structurally separate from any building and therefore not 
vulnerable to being weakened if part of an adjacent structure collapses. 
 
The shelter does not need to be integrated into an existing building design. 
Case Study I (see Appendix C) shows the calculated wind loads for a shelter 
in Zone III (200 mph) and how the design requirements were met for a standalone 
shelter. This shelter was designed to serve communities in North 
Carolina that housed families displaced by flooding caused by Hurricane 
Floyd. 

4.1.2 Internal Shelters 
The results of the risk and site assessments presented in Chapter 2 may show 
that a specifically designed and constructed shelter area within or connected 
to a building is a more attractive alternative than a stand-alone shelter, 
especially when the shelter is to be used by the occupants of the building. This 
section concentrates on design considerations that are important for internal 
shelters. 

Potential advantages of an internal shelter include the following: 

 
A shelter that is partially shielded by the surrounding building may not 
experience the full force of the tornado or hurricane wind. (Note, however, 
that any protection provided by the surrounding building should not be 
considered in the shelter design.) 
 
A shelter designed to be within a new building may be located in an area of 
the building that the building occupants can reach quickly, easily, and 
without having to go outside. 
 
Incorporating the shelter into a planned renovation or building project may 
reduce the shelter cost. 
Case Study II (see Appendix D) shows the calculated wind loads for a shelter 
in Zone IV (250 mph) and how the design requirements were met for a shelter 
connected to an existing building. This shelter was designed for a school in 
Wichita, Kansas, and replaced a portion of the school building that was 
damaged by the tornadoes of May 3, 1999. 

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4.2 Single-Use and Multi-Use Shelters 
A stand-alone or internal shelter may serve as a shelter only, or it may have 
multiple usesfor example, a multi-use shelter at a school could also 
function as a classroom, lunchroom, or laboratory; a multi-use shelter 
intended to serve a manufactured housing community or single-family-home 
subdivision could also function as a community center. The decision to design 
and construct a single-use or a multi-use shelter will likely be made by the 
prospective client or the owner of the shelter. To help the designer respond to 
non-engineering and non-architectural needs of shelter owners, this section 
discusses how shelter use may affect the type of shelter selected. 

4.2.1 Single-Use Shelters 
Single-use shelters are, as the name implies, used only in the event of a 
natural hazard event. One advantage of single-use shelters is a potentially 
simplified design that may be readily accepted by a local building official or 
fire marshal. Single-use shelters typically have simplified electrical and 
mechanical systems because they are not required to provide normal daily 
accommodations for people. Single-use shelters are always ready for 
occupants and will not be cluttered with furnishings and storage items, which 
is a concern with multi-use shelters. Simplified, single-use shelters may have 
a lower total cost of construction than multi-use shelters. Examples of single-
use shelters were observed during the BPAT investigation of the May 3, 1999, 
tornadoes, primarily in residential communities (FEMA 1999a). Small, 
single-use shelters were used in residential areas with a shelter-to-house ratio 
of 1:1 or ratios of up to 1:4. One example of a large, single-use community 
shelter was observed in a manufactured housing park in Wichita, Kansas. 

The cost of building a single-use shelter is much higher than the additional 
cost of including shelter protection in a multi-use room. Existing maintenance 
plans will usually consider multi-use rooms, but single-use shelters can be 
expected to require an additional annual maintenance cost. 

4.2.2 Multi-Use Shelters 
The ability to use a shelter for more than one purpose often makes a multi-use 
stand-alone or internal shelter appealing to a shelter owner or operator. Multiuse 
shelters also allow immediate return on investment for owners/operators; 
the shelter space is used for daily business when the shelter is not being used 
during a tornado or hurricane. Hospitals, assisted living facilities, and special 
needs centers would benefit from multi-use internal shelters, such as hardened 
intensive care units or surgical suites. Internal multi-use shelters in these types 
of facilities allow optimization of space while providing near-absolute 
protection with easy access for non-ambulatory persons. In new buildings 
being designed and constructed, recent FEMA-sponsored projects have 

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indicated that the construction cost of hardening a small area or room in a 
building is 1025 percent higher than the construction cost for a non-hardened 
version of the same area or room. 

BPAT investigations of the May 3, 1999, tornadoes, as well as investigations 
conducted after numerous hurricanes in the 1990s, found many examples of 
multi-use areas designed and retrofitted for use as shelters, such as the 
following: 

fi 
in school buildings  cafeterias, classrooms, hallways, music rooms, and 
laboratories 

fi 
in public and private buildings  cafeterias/lunchrooms, hallways, and 
bathrooms (see Figure 4-1) 

fi 
in hospitals  lunchrooms, hallways, and surgical suites 

Figure 4-1 

The Denver International 
Airport (a public-use facility) 
evaluated the tornado risk at 
the airport site and identified 
the best available areas of 
refuge. Signs were placed at 
these areas to clearly 
identify the refuge areas to 
the public. 


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CHAPTER 4 
4.3 Modifying and Retrofitting Existing Space 
If a tornado or hurricane shelter is designed and constructed to the criteria 
presented in this manual, the shelter will provide its occupants with near-
absolute protection during a high-wind event. 

4.3.1 General Retrofitting Issues 
Although retrofitting existing buildings to include a shelter can be expensive 
and disruptive to users of the space being retrofitted, it may be the only option 
available. When retrofitting existing space within a building is considered, 
corridors are often designated as the safest areas because of their short roof 
spans and the obstruction-free area they provide. Recent shelter evaluation 
projects have indicated that, although hallways may provide the best refuge in 
an existing building, retrofitting hallways to provide a near-absolute level of 
protection may be extremely difficult. Hallways usually have a large number 
of doors that will need to be upgraded or replaced before near-absolute 
protection can be achieved based on the criteria outlined in Chapters 5 and 6. 
Designers should be aware that an area of a building currently used for refuge 
may not necessarily be the best candidate for retrofitting when the goal is to 
provide near-absolute protection. 

Examples of interior spaces within buildings where people can take refuge 
from tornadoes and hurricanes were listed in Section 4.2.2; additional 
examples include, interior offices, workrooms, and lounges. Guidelines for 
choosing the best available space are provided in Chapter 2. The design 
modifications that might be required should follow the recommendations of 
this manual for new construction (see Appendixes E and F for examples of 
wall sections, doors, and door hardware that are capable of withstanding the 
impact of the 100-mph, 15-lb design missile). 

Upgrades to improve levels of protection (until a shelter can be designed and 
constructed) may include the following retrofits: 

 
replacing existing doors (and door hardware) with metal door systems 
described in Chapters 5 and 6 
 
adding metal door systems to replace glazing that is vulnerable to failure 
from wind pressures or missile impacts 
 
adding metal door systems to sections of rooms, hallways, and other 
spaces, and creating protected refuge areas 
 
removing all glazing, or retrofitting or replacing glazing with either impact-
resistant glazing systems or wall sections that meet impact criteria defined 
in Chapter 6 
 
adding alcoves to protect existing doors from the direct impact of 
windborne debris, as described in Chapter 6 
CROSS-REFERENCE 

The checklists in Appendix B 
may be used to identify refuge 
areas as candidates for retrofit 
projects. 

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NOTE 

An existing area that has been 
retrofitted to serve as a shelter 
is unlikely to provide the same 
level of protection as a shelter 
designed according to the 
guidance presented in this 
manual. Also, the additional 
cost of providing shelter in a 
new, multi-purpose room is 
less than the cost of retrofitting 
an existing space. 
However, limited space at the 
proposed shelter site or other 
constraints may make 
retrofitting a practical alternative 
in some situations. 


CROSS-REFERENCE 

Design criteria for shelter 
systems are provided in 
Chapters 5 and 6. Examples of 
wall and door systems that 
have passed missile impact 
tests are presented in Appendixes 
E and F, respectively. 

4.3.2 Specific Retrofitting Issues 
An existing area that has been retrofitted to serve as a shelter is unlikely to 
provide the same level of protection as a shelter designed according to the 
guidance presented in this manual. BPAT investigations and FEMA-funded 
projects have indicated that when existing space is retrofitted for shelter use, 
issues have arisen that have challenged both designers and shelter operators. 
These issues arise when attempts are made to improve the level of protection 
in areas not designed originally for shelter or refuge use. When retrofit 
projects call for improving levels of protection through retrofitting doors, 
windows, and other openings to meet the missile impact requirements of 
Chapter 6, the designer should look carefully at the area being retrofitted. For 
example, protecting the openings of a refuge area that is structurally unable to 
withstand wind pressures and impact loads will not be a wise retrofit project. 

Issues related to the retrofitting of existing refuge areas (e.g., hallways/ 
corridors, bathrooms, workrooms, laboratory areas, kitchens, and mechanical 
rooms) that should be considered include the following: 

 
The roof system. Is the roof system over the proposed refuge area 
structurally independent of the remainder of the building? If not, is it 
capable of resisting the expected wind and debris loads? Are there openings 
in the roof system for mechanical equipment or lighting that cannot be 
protected during a high-wind event? It may not be reasonable to retrofit the 
rest of the proposed shelter area if the roof system is part of a building that 
was not designed for high wind load requirements. 
 
The wall system. Can the wall systems be accessed so that they can be 
retrofitted for resistance to wind pressure and missile impact? It may not be 
reasonable to retrofit a proposed shelter area to protect openings if the walls 
systems (loadbearing or non-loadbearing) cannot withstand wind pressures 
or cannot be retrofitted in a reasonable manner to withstand wind pressures 
and missile impacts. 
 
Openings. Windows and doors are extremely vulnerable to wind pressures 
and debris impact. Shutter systems may be used on hurricane shelters but 
should not be relied upon to provide protection for tornado shelters. There 
is often only minimal warning time before a tornado; therefore, a shelter 
design that relies on manually installed shutters is impractical. Automated 
shutter systems may be considered, but they would require a protected 
backup power system to ensure that the shutters are closed before an event. 
Doors should be constructed of impact-resistant materials (e.g., steel doors) 
and secured with six points of connection (typically three hinges and three 
latching mechanisms). Door frames should be constructed of at least 16gauge 
metal and adequately secured to the walls to prevent the complete 
failure of the door/frame assemblies. 
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The contents of the refuge area. What are the contents of the refuge area? 
For example, bathrooms have been used as refuge areas during tornadoes 
and hurricanes since they often have a minimal number of openings to 
protect. However, emergency managers may find it difficult to persuade 
people to sit on the floor of a bathroom when the sanitary condition of the 
floor cannot be guaranteed. Also, mechanical rooms that are noisy and may 
contain hot or dangerous machinery should be avoided as refuge areas 
when possible. The contents of a proposed shelter area (e.g., permanent 
tables, cabinets, sinks, large furniture) may occupy what was expected to 
be available space within the shelter, may make the shelter uncomfortable 
for its occupants, or may pose a hazard to the occupants. These types of 
shelter areas should be used only when a better option is not available. 
4.4 Community Shelters for Neighborhoods 
Community shelters intended to provide protection for the residents of 
neighborhoods require designers to focus on a number of issues in addition to 
structural design, including ownership, rules for admission, pets, parking, 
ensuring user access while preventing unauthorized use, and liability. FEMA 
post-disaster investigations have revealed issues that need to be addressed in 
the planning of such community shelters. Many of these issues are addressed 
in the sample Shelter Operations Plans in Chapter 9 and Appendix C for 
community shelters. The following are additional considerations: 

 
Access and Entry. Confusion has occurred during past tornado events 
when residents evacuated their homes to go to a community shelter but 
could not get in. During the Midwest tornadoes of May 3, 1999, residents 
in a Wichita community went to their assigned shelter only to find it 
locked. Eventually, the shelter was opened prior to the event, but had there 
been less warning time for the residents, loss of life could have occurred. 
The Shelter Operations Plan should clearly state who is to open the shelter 
and should identify the backup personnel necessary to respond during 
every possible event. 
 
Signage. Signage is critical for users to be able to readily find and enter the 
shelter. In addition to directing users to the shelter, signs can also identify 
the area the shelter is intended to serve. Confusion about who may use the 
shelter could result in overcrowding in the shelter, or, worse, people being 
turned away from the shelter. Signs can also inform the residents of the 
neighborhood served by the shelter about the occupancy limitations during 
any given event. Examples of tornado shelter signage are presented in 
Chapter 9 and the North Carolina shelter case study in Appendix C. 
 
Warning Signals. It is extremely important that shelter users know the 
warning signal that means they should report to the shelter. The owners/ 
operators of shelters should conduct public information efforts (e.g., mass 
mailings, meetings, flyer distribution) to ensure that the residents of the 
CROSS-REFERENCE 

Sample community Shelter 
Operations Plans are 
presented in Chapter 9 and the 
case study in Appendix C. 

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neighborhood served by the shelter know the meaning of any warning
signals to be used.


 
Parking. Parking at residential shelters can be a problem. Neighborhood 
residents, who are expected to walk, may instead drive to the shelter from 
their homes. Residents returning home from work may drive directly to the 
shelter. Parking problems can adversely affect access to the shelter, again 
preventing occupants from getting to the shelter before a tornado or 
hurricane strikes. The Shelter Operations Plan should clearly discuss 
parking limitations. 
 
Pets. Many people do not want to leave their pets during a disaster. 
However, tornado and hurricane shelters are typically not prepared to 
accommodate pets. The policy regarding pets in a community shelter 
should be clearly stated in the Shelter Operations Plan and posted to avoid 
misunderstandings and hostility when residents arrive at the shelter. 
 
Maximum Recommended Occupancy. In determining the maximum 
recommended number of people who will use the shelter, the design 
professional should assume that the shelter will be used at the time of day 
when the maximum number of residents are present. A community may 
also wish to consider increasing the maximum recommended occupancy to 
accommodate additional occupants such as visitors to the community who 
may be looking for shelter during a wind event. The maximum 
recommended occupancy should be posted within the shelter area. 
4.5 Community Shelters at Public Facilities 
Community shelters at public facilities also require designers to focus on 
issues other than structural design requirements for high winds. Some issues 
that have arisen from post-disaster investigation include: 

 
Protecting Additional Areas. If the shelter is at a special needs facility 
such as a nursing home or hospital, additional areas within the facility may 
need to be protected. These include medical and pharmaceutical supply 
storage areas and intensive/critical care areas with non-ambulatory patients. 
A shelter should address all the needs of its users. 
 
Signage. Signage is critical for users of public facilities to be able to 
readily find and enter the shelter. However, signage can be confusing. For 
example, tornado shelters in schools in the Midwest are often designed for 
use only by the school population, but aggressive signage on the outside of 
the school may cause surrounding residents to assume that they may use 
the shelter as well. This may cause overcrowding in the shelter, or, worse, 
people being turned away from the shelter. Similar problems may occur at 
hospitals, where the public may go seeking refuge from a tornado or 
hurricane. The owners/operators of shelters in public-use facilities such as 
these should inform all users of the facility about the occupancy limitations 
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of the shelter during any given event. Examples of tornado shelter 

signage may be found in Chapter 9 and the North Carolina shelter 

case study in Appendix C. 

 
Warning Signals. It is extremely important that shelter users know 
the warning signal that means they should report to the shelter. In 
schools, work places, and hospitals, storm refuge drills and fire drills 
should be practiced to ensure that all persons know when to seek 
refuge in the shelter and when to evacuate the building during a fire. 
 
Pets. Many people do not want to leave their pets during a disaster. 
This is the same problem as identified for the community shelters in 
neighborhoods. Hurricane and tornado shelters are typically not 
prepared to accommodate pets. The policy regarding pets in a 
neighborhood shelter should be clearly stated in the Shelter 
Operations Plan and posted to avoid misunderstandings and hostility 
when residents arrive at the shelter. 
 
Off-hours Shelter Expectations. It is important for shelter owners 
and operators to clearly indicate to the shelter users when the shelter 
will be open. For example, at a school, will the shelter be accessible 
after the regular school day? At places of business, will the shelter be 
accessible after normal work hours? At hospitals, can employees 
bring their families to the hospital shelter? These types of questions 
should be anticipated in the design and operation of a community 
shelter. 
4.6 Locating Shelters on Building Sites 
The location of a shelter on a building site is an important part of the 
design process for tornado shelters. The shelter should be located such 
that all persons designated to take refuge may reach the shelter with 
minimal travel time. Shelters located at one end of a building or one end 
of a community, office complex, or school may be difficult for some 
users at a site to reach in a timely fashion. Routes to the shelter should 
be easily accessible and well marked. 

Shelters should be located outside areas known to be floodprone, 
including areas within the 500-year floodplain. Shelters in floodprone 
areas will be susceptible to damage from hydrostatic and hydrodynamic 
forces associated with rising flood waters. Damage may also be caused 
by debris floating in the water. Most importantly, flooding of occupied 
shelters may well result in injuries or deaths. Furthermore, shelters 
located in floodprone areas but properly elevated above the 500-year 
flood elevation and the elevations of any floods of record will become 
isolated if access routes are flooded. As a result, shelter occupants could 
be injured and no emergency services would be available. 

DESIGN AND CONSTRUCTION GUIDANCE FOR COMMUNITY SHELTERS



CROSS-REFERENCE 

Additional human factors 
criteria are presented in 
Chapter 8. In addition, sample 
community Shelter Operations 
Plans are presented in Chapter 
9 and Appendix C. 


WARNING 

Shelters should be located 
outside known floodprone 
areas, including the 500-year 
floodplain, and away from any 
potential large debris sources. 

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Figure 4-2 

Improperly sited shelter  in 
an SFHA (Zone AE in this 
figure), adjacent to light 
towers that could become 
falling debris, at the 
periphery of the community. 


NOTE 

500-year floodplains are 
shown as either Zone B or 
shaded Zone X on FIRMs. 

Where possible, the shelter should be located away from large objects and 
multi-story buildings. Light towers, antennas, satellite dishes, and roof-mounted 
mechanical equipment may be toppled or become airborne during tornadoes 
or hurricanes. Multi-story buildings adjacent to a shelter may be damaged or 
may fail structurally during tornadoes and hurricanes. When these types of 
objects or structures fail, they may damage the shelter by collapsing onto it or 
impacting it. The impact forces associated with these objects are well outside 
the design parameters of any building code. Some limited debris impact testing 
was performed in the preparation of this manual and is discussed in Chapter 6. 

Examples of improper and proper locations of tornado or hurricane shelters on 
residential sites are presented in Figures 4-2 and 4-3. Figure 4-2 shows an 
improperly sited community shelter in a residential area. The shelter is within 
an SFHA, near large light towers that may fall on the shelter, and near an 
outside boundary of the community. Figure 4-3 shows a properly sited shelter 
that is outside the SFHA, away from the towers, and more centrally located 
within the community. 


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Figure 4-3 

Properly sited shelter  
outside the SFHA and 500year floodplain, away from 
potential falling debris, and 
centrally located within the 
community. 


NOTE 

500-year floodplains are 
shown as either Zone B or 
shaded Zone X on FIRMs. 

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