CECW-PF

Engineer

Pamphlet

1165-2-314

Department of the Army

U.S. Army Corps of Engineers

Washington, DC 20314-1000

EP 1165-2-314

15 December

1995

FLOOD PROOFING

Distribution Restriction Statement

Approved for public release; distribution is unlimited.
EP1165-2-314

15 Dec1995

GASKET SEAL -\ i BOND BEAM OR LINTEL

WOOD FILLER 4 x“

NAIL ‘ J’

r’ [“Ad.- WINDOW IS REMOVED

II>’ STEEL

t

,:” ~ -’rNR?LTwAsHER

FLOOO SHIELD- ..:!

1/,” WE LD ---–

Li$

2 PER WINDOW

$/

SEAT /

[

i

L.A GA5KETSEAL-JX ./ 2-2,X4

$/ MASONRY UNIT

REINFORCING

FOR MASONRY- - ‘S’LL

CORNER ANGLE ~. 1/2’ / M FLOOD SHIELD

B

-SEE NOTE

-.JJ

ANCHOR BOLTS x.

,/’ ,. -,,

SEAL --–.

‘h

/ b >’ \

31/2,3.3/8 ~<’- ‘ ii,

LEL

\

“A \

\

\

GLASS CURTAIN \, “

WALL FRAMING \

\

\

\

\

.-

GLASS

“c SEAL

i

‘STIF

‘— 1)2 ALUh! FLOOD SHIELD

L -- sTIFFENER /

~ 31/2x3x318

SECTION A-A

CLOSURE PANEL FOR BASEMENT WINDOW

FOR SMALL WIN DOWSAND SHALLOW DEPTH OF FLOODING ER 3 1/2 X3 x 3/8 I@)1-6,

DETfilL B

DETAIL A

-—

LIDING FLOOD SHIELD FOR DOOR

FLOOD

SHIELD

SEALINI

FRAME

—

DISPLAY WINDOW

FLOOD SHIELD DETAILS

~*A I

DETAIL A I

COUNTERwEIGHT

,.

SEALING

FRAME

LA SECTION A-A Y DETAIL B

ELEVATION

II

L_———_ _._L__ —————— .4

FLOOD SHIELD BEHIND WINDOW

LOWERED INTO POSITION & ATTACHED TO

FRAME WITH QUICK DISCONNECT TYPE FASTENERS

[i)

US Army Corps

of Engineers

L

Washington, D.C. 20314-1000
Preface

The original EP 1165-2-314, Flood-Proofing Regulations, was published in June of 1972. It has been

distributed worldwide as an administrative and technical model for code design and enforcement. Over the

years, it has been adopted by direct reference in thousands of local building codes across the United States. It

also has served as the framework for the preparation of numerous other flood proofing publications, the flood

resistant design criteria of the National Flood Insurance Program, and the development of similar design

standards within the major national building code organizations.

The U. S. Army Corps of Engineers National Flood Proofing Committee completely revised the original 1972

document to reflect almost 20 years of field experience, research, and advances in engineering and building

practices. The revision, EP 1165-2-314, Flood Proofing Regulations, dated31 March 1992, made numerous

technical and editorial changes to most of the original chapters, updated the terminology, and addressed the

minimum flood plain management requirements of the National Flood Insurance Program @FIP) in relation

to flood proofing regulations, particularly with respect to NFIP policy on residential flood proofing and wet

flood proofing.

This publication supersedes the revised edition. However, with the exception of some clari~ing changes to

Chapter 2, Section 210, Classification and Posting of Buildings and Structures, it is the same as the superseded

document. Changes have been made to the FP2 and FP4 space classification in Table 1 of Section 210.1

General on page 2-8 and to the classification descriptions in Sec. 210,3.1 FP3 and Sec. 210.3.2 FP4 on pages

2-8 and 2-9, respectively. These were needed to correct unclear statements on the classification of partially

flood proofed structures. They distinguish between those structures that require “human intervention” to

implement a contingency plan in order to achieve protection (FP4) and those that do not (FP3).

NQTICE: States aIId local governnleuts tlzat kave used Table 1 antUor tlte FP3 and FP4

classification descriptions fronz Sectioil 210 of tlte superseded 31 MarcIt 1992 docttntcnt in tkeir

buildi~~g codes aild regulations sllouid take appropriate actio!ls to correct tlleln.

As with its predecessor, this publication retains the format of the original 1972 docu]ment as model code

language which can continue to be used by direct reference in local codes, It specifies the flood proofing

measures and techniques that can be followed to regulate private and public building construction in nverine

flood hazard areas. It contains implications for changes in existing building and housing codes and provides

for a diversity of flood proofing methods and techniques, Chapters 2 through 13 have been prepared in a form

that can be used to supplement existing building codes and regulations. If, on the other band, a separate “flood

proofing code” for direct adoption by States and local governments is desired, the flood proofing information

contained herein also is sufficient for that purpose,

The Corps of Engineers is distributing this publication to continue the interest and application of flood prooting

that, together with other flood plain management tools, will assist in reducing the threat to life, health, and

property of users of flood hazard areas.

ROBERT H. GRIFF~

Colonel, Corps of Engineers

Chief of Staff
This publication supersedes EP 1165-2-314 dated 31 March 1992. As with

its predecessors, it was drafied for the Chief of Engineers by the U. S. Army

Engineer District, Pittsburgh, PA.
Table of Contents

Chapter l-Introduction .,,,... . . . . . . . . . . . . . . . . . . . . . ., ...,...,1-1

Section 100.OFlood Proofing and Building Cdes . . . . . . . . . . . . . . . . . . . . . . , .1-1

Chapter 2-Administration, ... . . . . . . . . . . . . . . . . . . . . . , .,.,,,....2-1

Section 200. OPurpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...2-1

201.0Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2-1

202.0 Alternate Materials and Methods of Construction . . . . . . . . . . . . , . . .2-2

203.0 Tests . . . . . . . . . . . . . . .

204.0 Organization and Enforcement .

205.0 Permits . . . . . . . . . . . . . .

206.0 Inspections . . . . . . . . . . . .

207.0 Certificate of Use and Occupancy

208.0 Public Notice of Flood Hazard .

209.0 Provision of Safe Refuge . . . .

. . . . . . . . . . . . . . . . . . . . . . . . .2-2

. . . . . . . . . . . . . . . . . . . . . . . . .2-2

. . . . . . . . . . . . . . . . . . . . . . . . .2-3

. . . . . . . . . . . . . . . . . . . . . . . . .2-6

. . . . . . . . . . . . . . . . . . . . . . . . .2-6

. . . . . . . . . . . . . . . . . . . . . . . . .2-7

. . . . . . . . . . . . . . . . . . . . . . . . .2-7

210.0 Classification and Posting of Buildings and Structures . . . . . . . . . . . . . .2-8

Chapter 3-Definitions of Terms. . . . . . . . . . . . . . . . . . . . . . .,, , . . . . ...3-1

Section 300.0Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-1

301.0 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3-1

Chapter 4-Flood Proofing Classification of Spaces

Below the Regulatory Flood Datum . ., ., . . . . . . . . ,. , ., . , . . , . . . . . . . .4-1

Section 400.0Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...,...4-1

401.0 Descriptions of Flood Proofing Classes . . . . . . . . . . . . . . . . . . . . . .4-1

402.0The Space Classification Chart . . . . . . . . . . . . . . . . . . . . . . . . . .4-2

Chapter S-Waterproofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-1

Section 500. OScope ..,...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-1

501. OType A Constructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-1

502.0Type BConstructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-5

503.0Type CConstructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...5-6

Chapter 6-Structural Requirements . , , . . . . , . . , , . . . . . . . , , . , . . . . . . . ,6-1

Section 600.0Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-1

601.0Classes of L,oads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-1

602.0 Water ~adso. ..c, o.o . . . .. < O. . . . . . . . . . . . . . . . . ...6-1

603.01mpact baas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-3

604.0Soil hads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..6-3

605.0Hurricane and Tidal Wave Loads . . . . . . . . . . . . . . . . . . . . . . . . .6-3

606. OLoading@nditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-4

607. OCombined Loads ..,..... . . . . . . . . . . . . . . . . . . . . . . . ...6-4

608. OAllowable Stresses, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-4

609.0 Allowable Soil Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-4

610. OStability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...6-4

611. OReduction of Uplift Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . .6-5

612.0 Requirements for Other Flood Proofing Methods . . . . . . . . . . . . . . . . .6-6
Chapter 7-CIosure of Openings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..7. I

Section 700. OScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...7-1

701.0 Types of Closures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...7-1

702. ORequirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...7-1

703. OSpecial Applications of Closure Assemblies . . . . . . . . . . . . . . . . . . . 7-2

Chapter 8-Internal Flooding and Drainage . . , , , . , , . . , . , . . . . . . . . . . . , . 8-1

Section 800. OScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...8-1

801.0 Intentional Flooding with Potable Water . . . . . . . . . . . . . . . . . . . . 8-1

802. OAutomatic Flooding with Floodwater . . . . . . . . . . . . . . . . . . . . . . 8-1

803.0 Emergency Flooding of Waterproofed Spaces . . . . . . . . . . . . . . . . . . 8-2

Chapter 9-Flooring . . . . . . . . . . . . . . . . . . . . . ., . . . . . . . . . . . . . ...9-1

Section 900. OScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...9-1

901. OFIooring Classifications . . . . . . . . . . . . . . . . . . . . . . . . . . ...9-1

Chapter 10-Walls and Ceilings .,, . . . . . . . . . . . . . . . . . . . . . , .,.,....10-1

Section 1000. OScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...10-1

1001.0 Wall/~ iling Classifications . . . . . . . . . . . . . . . . . . . . . . . . . .10-1

Chapter n-Contents of Buildings and Structures , . , , . , . , , . , . , . , , . . . ...11-1

Section 1100.0 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...11-1

llO1.OClasses of Intents . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...11-1

Chapter 12-Electrical, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...12-1

Section 1200. OScope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...12-1

1201.0 Requirements at Locations Above and Below the RFD . . . . . . . . . . . .12-1

Chapter 13-Mechanical, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...13-1

Section 1300,0 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...13-1

1301.0 Heating, Air Conditioning, and Ventilation Systems . . . . . . . . . . . . . .13-1

1302.0 Plumbing Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...13-2

Chapter 14-Procedures ..,... . . . . . . . . . . . . . . . . . . . . . ., .,.,.,,,14-1

Section 1400. O Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...14-1

1401. OCritical Aspects ofa Flood . . . . . . . . . . . . . . . . . . . . . . . . . . .14-1

1402. O Flood Damages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...14-2

1403.0bads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...14-2

1404. OStructural Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...14-3

1405.OAtternate Methods of Flood Proofing . . . . . . . . . . . . . . . . . . . . . .14-7

1406. OTotal Approach .,...... . . . . . . . . . . . . . . . . . . . . . . ..14-21

List of Tables

TabIe

1 Classification of Buildings and Structures . . . . . . . . . . . . . . . . . . . . 2-8

2 Flood Proofing Classification of Spaces . . . . . . . . . . . . . . . . . . , . . 4-2
List of Illustrations

Figure

1

2

3

4

5

6

7

8,9

10, 11

12

13

14

15

16

17, 18, 19

20,21

22,23

24,25, 26

27

28,29

30

References

Application for Permit . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...2-5

Placard Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-10

Flood Hazard Areas and Regulatory Flood Datum . . . . . . . . . , . . . 2-11

Type A Membrane Waterproofing in Floor Slabs . . . . . . . , . . . . . . . .5-2

Non-Rigid Perimeter Wall and Floor Slab Connections . . . . . . . . . .5-4

Typical Foundation Drainage and Waterproofing . . . . . . . . . . . , . 14-5

Recommended Reinforcement Around Small Openings . . . . . . . . . . 14-8

Typical Flood Shields for Windows. , . . . . . . . . . . . . . . . . . . . 14-9

Bond Beams & Vertical Reinforcement at Large Openings . . . . . . . 14-10

Typical Door Shield, . . . . . . . . . . . . . . . . . . . . . . . . . . ...14-11

Display Window Floor Shield Details . . . . . . . . . . . . . . . . . . . . 14-12

Closures For Horizontal Openings Below RFD . . . . . . . . . . . . . . . 14-13

Closure Panel Assembly Fastening Methods . . . . . . . . . . . . 14-14

Flood Proofing Closure For Large Horizontal Opening Below RFD . 14-15

Flood Shield Installations . . . . . . . . . . . . . . . . . . . . . . . . . .. 14-16

Other Flood Protection Methods. . , . . . . . . . . . . . . . . . . . . . 14-17

Flood Protection With Floodwalls and Dikes . . . . . . . . . . . . . 14-19

Dikeor Levee Protection . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14-20

VariousFloo dWallType s...... . . . . . . . . . . . . . . . . . . . . . 14-22

Structures with Restricted Use. . . . . . . . . . . . . . . . . . . . 14-23

Prevention of Backflow Through Sewer System . . . . . . . . . . . . . 14-24
Chapter 1

Introduction

Section 100.0 Flood Proofiig and Building Codes

Sec. 100.1 General: Many thousanb of structures and ptential building sites are located in the flood plains

of our Nation and are susceptible to flooding. Fl@ control projects have partially protected some of these

structures and building sites through reduction of the flocd threat. However, the residual threat to partially

protected sites and the total threat to unprotected sites remain as major problems. Evidence of this is given

every year by the millions of words and hundreds of headlines that dramatically describ floods and their

resulting damage and loss of life. When floods strike developed areas, whole cities maybe disrupted and their

productive capacities impaired. Strategic transportation lines are cut. Public service facilities are sapped,

homes and crops are destroyed, and soils are erc)ded. Yet, in spite of this, flocd vulnerable lands are the setting

for continued urban growth in the United States.

Studies of flood plain use show that some encroachment is undertaken in ignoranu of the hazard, that some

occurs in anticipation of increased Federal protection, and that some takes place beeause, by shifting the cost

of the hazard to society, it becomes profitable for private owners to do so. Even if full information on the flocd

hazard were available to all owners or users of flood plain property, there would still be conscious decisions

for some reason or another to build in areas that are subject to flooding. In order to escape this dismal cycle

of losses, partial protection, further induced development, and more unnecessary losses, old attitudes must be

transformed into positive actions.

Primary among these actions is the revision of development policies and the enactment of a regulatory program

to encourage and/or restrict the direction of growth or change neeessary to achieve flood plain management

objectives. Information programs are essential to this revision. They foster the development of more

appropriate policies and involve the gathering and dissemination of data on past floods, on estimates of future

floods, and information on alternate ways of dealing with flood losses in areas where intensive development

has taken place or is anticipated. The latter has led to an expanded approach to flood damage reduction and

prevention, recognizing the need to control or regulate the use of lands adjacent to watercourses and the need

to provide guidance in the design of flood plain structures through the planned management and development

of the flood hazard areas.

Regulation of the use of flood plain lands is a responsibility of State and local governments and can be

accomplished by a variety of means, such as establishment of designated floodways and encroachment lines,

zoning ordinances, subdivision regulations, and building @es. These land use controls, most often known

as “Flood Plain Regulations,” do not attempt to reduce or eliminate flooding but instead are intended to guide

and regulate flmd plain development to lessen the adverse effects of floods. Flood prone communities in the

United States participating in the National Flood Insurance Program (NFIP) are required to adopt and enforce

such flood plain regulations to qualify for the sale of federally-backed flood insurance to its residents.

Flood proofing standards applied through building codes and regulations to flood plain structures can permit

economic development in the lower risk areas by holding flood damages and other adverse effects within

acceptable limits. Flood prmfing requires adjustments both to structures and to building contents and involves

keeping water out as well as reducing the effects of water entry. Such adjustments ean be applied by the

individual or as part of collective action either when buildings are under construction or during remodeling or

expansion of existing structures. They may be permanent or temporary.

Flmd proofing, like other methods of adjusting to floods, has its limitations, however. For example, in addition

to reducing loss potentials, a main purpse of flood proofing habitable structures is to provide for early return

to normalcy after floods have receded rather than for continuit y of occupance. Through a false sense of securit y,

oeeupants may choose to remain during a flood and risk being stranded or losing their lives. Also, unless

correctly used, flood proofing can tend to increase uneconomical use of flood plains. If applied to structural] y

unsound buildings, it can result in more damage than would have occurred without flood proofing. Generally

it is applied to individual structures, so unless flood proofing is also applied to means of access, it is only

partially effective in an area context. Accordingly, access ways should b passable at least in floods up to the

magnitude used in setting flood proofing elevations.

1-1
Flood Proofing Regulations

These recommended regulations are intended for direct use or for incorporation into existing building codes

which properly enforced should effectively reduce flood damages to buildings and structures located in the

flood plain. ~mpliance should be a mandatory requirement for approval of plans or issuance of permits for

construction of all new buildings and structures, and for existing buildings that will be subjected to major

alterations, additions, or reconstruction in the defined flood hazard areas.

These recommended regulations neither contain nor are referenced to other regulations pertinent to flood plain

management that may be provided by separate statute or involve political decisions relative to land use, zoning,

subdivision regulations, occupancy restrictions, creation of flood zones, flood warning, or floodwa y encroachment. The intent here is to establish the special design and construction provisions that should be required for

buildings, structures, and support facilities that are or may be subjected to flooding, relying upon zoning

regulations to establish the areas of application. Other aspects of flood plain regulations, such as Flood Plain

Zoning and Subdivision Regulations, are treated in “Regulation of Flood Hazard Areas to Reduce Flood

Losses”, Volumes 1 and 2 (1972), and Volume 3 (1982), Water Resources ~uncil, Washington, D.C.

This publication deals with the treatment of hydrostatic and hydrodynamic forces and waterproofing associated

with riverine flooding only. To the extent that coastline structures are subject to these semistatic conditions,

these provisions will be applicable to coastal or tidal flooding situations; however, no consideration is given

to the special problems of wave impact, corrosion, and erosion associated with coastal flooding. Similarly, the

problems of impact from floating debris and velocit y introduce dynamic considerations Yhich are not treated

in detail and mud slide and high density fluid problems that are prevalent in West Coast communities are

omitted entirely.

The design and construction criteria contained herein for riverine flooding conditions should be of substantial

benefit to many communities. Future development of more comprehensive coverage including the treatment

of special dynamic problems should be implemented where warranted by others more directly involved with

tbe particular flood damage situations.

Sec. 100.2 National Flood Insurance PrWram:Tbe National Flood Insurance Program (NFIP) was created

by Congress in 1968 to provide federally-backed flood insurance coverage that was generally not available

from private sector companies, and to promote wise flood plain management practices in the Nation’s

floodprone areas. One of the goals of this program is to reduce future flood losses by establishing guidelines

for protecting existing and new development. The NFIP operates on a mutual agreement with communities

which have been identified as flood-prone. ~mmunity-wide flood insurance coverage is provides if the

community adopts and enforces flood plain management ordinances and regulations which meet or exceed

the specific minimum program requirements. The NFIP is administered by the Federal Insurance Administration (FIA) of the Federal Emergency Management Agency (FEMA) under the aut hority of the National Flood

Insurance Act of 1968 and Flood Disaster Protection Act of 1973; U.S.C. 4001-4128.

me NFIP insurance coverage is available only in communities that agree to implement comprehensive flood

plain management regulations to reduce the likelihood of future flood damage. This is often done through

zoning ordinances that can be more restrictive than those required by the NFIP.

The NFIP is administered in two phases: the Emergency Program and the Regular Program. The function of

the Emergency Program is to make flwd insurance readily available to property owners in flood prone

communities which are identified by the ~ by the issuance of a Flood Hazard Boundary Map (FHBM). This

map is a preliminary delineation of Special Flood Hazard Areas within the community with a definite likelihood

of inundation. No elevations are shown. U~n entering the Emergency Program, limited amounts of flood

insurance become available and the community is required to apply minimal flood plain management

regulations based on the FHBM, and is encouraged to reasonably use any additional data that maybe available

from other sources.

A community generally enters the Regular Program after the completion of a detailed technical study which

determines elevations of floods of varying intensity, including the base flood, areas inundated by the various

magnitudes of flooding, and floodway boundaries. This information is presented on a Flcod Insurance Rate

Map (FIRM) and Flood Boundary and Floodway Map (FBFM). A FIRM generally shows flood prone areas

as either A-Zones or V- Zones. The flood prone areas on the Flccd Insurance Rate Maps are generally divided

into two general hazard zones:

1-2
A-Zones: Riverine flood prone areas and coastal flood prone areas subject to storm surges

with velocity waves of less than three feet. New construction or substantial improvements

to structures are generally required to have the top of their lowest floor elevated to or above

the Base Flood Elevation.

V-Zones: Coastal high hazard area, which is the portion of the coastal flood plain subject

to storm surges with velocity waves of three feet or more during the 100-year flood. The

bottom of the lowest horizontal structural member of the lowest flmr must be elevated on

pilings or columns to or above the Base Fl@ Elevation. The space below the lowest floor

may not be used for human habitation and must be free of obstructions or constructed with

non-sup~rting breakaway walls, open wd latticework, or insect screening. Insect screening designed to collapse under wind and water loads less than those which would occur

during a 100-year flood.

Communities should recognize that there are differences between current NFIP minimum flood plain

management requirements and those of this publication. Several of the flood proofing techniques covered by

this publication are not permitted by the NFfP unless a variance is issued by the community or are permitted

only for some structure types or in some communities. Despite these differences, the provisions are retained

herein because they do reduce flood damages and their use may by appropriate under some circumstances.

NFIP regulations require that the lowest floor of new and substantially improved residential structures by

elevated to or above the base (100-year) flood elevation. However, non- residential structures may be flood

proofed to that elevation provided that the structure is watertight with walls that are impermeable to

floodwaters. Flood proofed basements (which also must be watertight with walls that are impermeable to

floodwaters) for new residential constructions are also permitted @in a community which has been granted

an exception in accordance with 44 CFR 60.6 of the NFIP regulations. Structures that do not meet these

requirements are generally violations of lml flmd plain management regulations and can be subject to

extremely high flood insurance premiums. Structures which are flmd proofed in accordance with NFIP

regulations must therefore meet the standards corresponding to the W-1 space classification in these flood

proofing Regulations,

FEMA has undertaken an effort to incorporate flood damage resistant design standards into building codes

which are adopted by either states or lccal communities. These generally follow one of the three national

model building codes, which are:

BOCA National Building Code, Building Officials and Code Administrators (BOCA),

generally adopted by eastern and Midwestern states.

Standard Building Code, Southern Building Code Congress International (SBCII), generally

adopted by southern states.

Uniform Building Code, International Council of Building Officials (ICBO), generally

adopted by western states.

This has involved the revision of specific building criteria from the NFIP flood plain management requirements

(44 CFR, Parts 59 and 60) into proposed code change ]anguage for submittal to the model building code groups.

These code submittals on] y cover the sections of the NFIP regulations that deal directly with buildingstandards.

Other NFIP requirements such as those applicable to floodways and subdivisions and certain required

administrative provisions are generally beyond the scope of most building codes and are more properly

addressed in zoning ordinances, subdivision ordinances, or special purpose regulations such as sanitary codes.

For this reason, the model building codes generally are not a substitute for a wmmunity adopting flood plain

management regulations that meet NFIP minimum standards. Once a decision is made to allow a structure to

be built in a flood plain, the model building codes can assist the community in assuring the structure is

adequately protected from flood damages.

1-3
Chapter 2

Administration

Section 200.0 Purpose

Sec. 200.1 Application: The provisions contained herein shall constitute the minimum building standards

and requirements that are applicable to safeguard life or limb, health, propert y, and public welfare by regulating

and controlling the design, construction, and quality of materials of all buildings and structures which are or

will be located in all lands shown within Special Flood Hazard Areas, or A Zones, indicated on either a Flood

Hazard Boundary Map or a Flood Insurance Rate Map published by the Federal Insurance Administration of

the Federal Emergency Management Agency, or other such Official Flood Plain Zoning Map. Hereinafter

these provisions will be referred to as the “Flood Proofing Regulations” part of “me Building Code,” or in

short as “these Regulations.”If adopting the provisions of these “Regulations” would result in a lesser degree

of flood protection than that which would be provided by the minimum flood plain management regulations

adopted by a community as a condition of participating in the NFIP, the latter shall have precedence.

Sec. 200.2 Special Flood Hazard Areas: The lands adjoining the channel of a river, stream, or watercourse

which would be covered by flood water during a base fld (100-year Flood). Flood Hazard Boundary Maps

or Flood Insurance Rate Maps published by the Federal Insurance Administration of the Federal Emergency

Management Agency, or other such Official Flood Plain ~ning Maps which identify S~cial Flood Hazard

Areas are hereby declared and established as a part of these Regulations.

Sec. 200.3 Regulatory Flood Datum: For the purpose of these Regulations, The Regulatory Flood Datum,

or as hereinafter referred to as the “RFD,” is hereby declared and established for use as the elevation above

the National Geodetic Vertical Datum (NGVD) to which flood proofing protection shall be provided. It shall

always be at least equal to the elevation of the base flood, but can be higher after the addition of a freeboard

height differential.

Section 201.0 Scope

Sec. 201.1 Application: These Regulations shall apply to the construction, alteration, and repair of any

building or parts of a building or structure in Special Flood Hazard Areas. Additions, alterations, repairs, and

changes of use or occupancy shall comply with all provisions for new buildings and structures as otherwise

required in “The Building Code,” exeept as specifically provided in these Regulations.

Sec. 201.2 Nonconforming Use: A structure or the use of a structure or premises which was lawful before

the passage or amendment of the ordinan~ but which is not in conformity with the provisions of these

Regulations may be continued subject to the following conditions:

(1) No such use shall be expanded, changed, enlarged, or altered in a way which increases

its nonconformist y.

(2) No structural alteration, addition, or repair to any conforming structure over the life of

the structure shall exceed _per cent of its value at the time of its becoming a nonconforming

use, unless the structure is permanently changed to a conforming use.

(3) If such use is discontinued for_ consecutive months, any future use of the building

premises shall eortform to these Regulations. The assessor shall notify the zoning administrator in writing of instanws of nonconforming uses which have been discontinued for

a period of — months.

(4) If any nonconforming use or structure is destroyed by any means, including floods, to

an extent of _ per cent or more of its value, it shall not be reconstructed except in

conformance with the provisions of these Regulations; provided, the Board of Adjustment

may permit reconstruction if the use or structure is located outside the floodway and is

adequate] y and safe] y flood proofed, elevated, or otherwise protected in conformance with

these Regulations.

2-1
Flood Proofing Regulations

(5) Uses or adjuncts thereof which are or become nuisances shall not be entitled to continue

as nonconforming uses.

(6) Except asprovided in’’The Building ~e,” any use which has been permitted as a

special exception shall not be deemed a nonconforming use but shall be considered a

conforming use.

(7) Any alteration, addition, or repair to any nonconforming structure which would result

in substantially increasing its flood damage or flood hazard potential shall be protected as

required by these Regulations.

(8) The Building Official shall maintain a list of nonconforming uses including the date of

becoming nonconforming, assessed value at the time of its becoming a nonconforming use,

and the nature and extent of nonconformity. This list shall be brought up to date annually.

(9) The Building Official shall prepare a list of those nonconforming uses which have been

flood proofed or otherwise protected in conformance with these Regulations. The Building

Official shall present such list to the Board of Adjustment which may issue a certificate to

the owner stating that such uses, as a result of these corrective measures, are in conformance

with these Regulations.

Section 202.0 Alternate Materials and Methods of Construction

Sec. 202.1 Application: These Regulations are not intended to prevent the use of any materials or methcds

of construction not specifically prescribed herein or by “The Building ~de,” provided any such alternate has

been approved and its use authorized by the Building Official prior to its incorporation or use in the

construction.

Sec. 202.2 Approval: The Building Official may approve any such alternate design proposed that is found

to be satisfactory and complies with the provisions of “The Building Code” and that the material, method, or

work offered is, for the purpose intended, at least equivalent to that prescribed in “The Building Code” in

quality, strength, effectiveness, fire resistance, durability, and safety. The Building Official shall require that

sufficient evidence or proof be submitted to substantiate any claim that may be made regarding its use. If, in

the opinion of the Building Official, the evidence and/or proof is not sufficient to justify approval, the owner

or an agent of the owner may refer the entire matter to the Board of Appeals.

Section 203.0 Tests

Sec. 203.1 Proof of Compliance: Whenever there is insufficient evidena or proof of compliance with the

provisions of these Regulations, or evidence that any material or any construction does not conform to the

requirements of these Regulations, or in order to substantiate claims for alternate materials or methods of

construction, the Building Official may require tests or test reports as proof of compliance. Tests, if required,

are to be made at the expense of the owner, by an approved testing laboratory or other approved agency, and

in accordance with approved rules or accepted standards as prescribed in “The Building Code.”

Sec. 203.2 Absence of Approved Rules: In the absence of approved rules or other accepted standards, the

Building Official shall determine the test procedure or, by election, shall accept duly authenticated reports

from recognized testing authorities or agencies in respect to the quality and manner of use of new materials.

Sec. 203.3 Records: ~pies of such tests, reports, certifications, or the results of such tests shall be kept on

file in the office of the Building Official for a period of not less than — years after the approval and acceptance

of the completed structure for beneficial occupancy,

Section 204.0 Organization and Enforcement

Sec. 204.1 Rnles and Regulations: The Building Official is hereby authorized and directed to enforce the

provisions of these Regulations as part of “The Building Code”, and for such purpose shall have the powers

of a police officer.

2-2
Sec. 204.2 Deputies: The Building Official may appoint such number of officers, inspectors, and assistants

as required and may deputize such employees as needed to perform the functions of the Building Department.

Sec. 204.3 Official Records: The Building Official shall establish and maintain an official record of all

business and activities of the department relating to these Regulations, and all such records shall be open to

public inspection. The Building Official shall keep a permanent, accurate account of all fees and other monies

collected and received under these Regulations. The Building Official shall, at least once a year, submit a

report to the proper cit y official covering the work of the Department during the preceding period. Said report

shall include detailed information regarding the administration and enforcement of these Regulations.

Sec. 204,4 Right-of-Entry: Whenever it maybe necessary to make an inspection to enforce the provisions

of these Regulations, the Building Official or an authorized representative may enter such building or premises

at all reasonable times to inspect all parts that are or may be subject to flooding or where the potential for flood

damage exists.

Sec. 204.5 Stop Work Order: Whenever any building work is found to k done contrary to these Regulations,

the Building Official shall order the work stopped by notice in writing to the person doing the work.

Sec. 204.6 Board of Appeals: In order to cletermine the suitability of alternate materials and methods of

construction and to provide reasonable interpretations of the provisions herein, there shall be and is hereby

created a Board of Appeals of — members. Each member of the Board shall be a licensed professional

architect or engineer, or a builder or superintendent of building construction with at least 10 years experience,

of which five years shall have been spent in responsible charge of work. At no time shall there be more than

two members from the same profession. At least one of the members shall be a licensed structural or civil

engineer with architectural engineering experience. The Board shall adopt reasonable rules for its investigations and shall render written decisions to the Building Official.

Sec. 204.7 Validity: It shall be unlawful for any person, firm, or corporation to erect, construct, enlarge, alter,

repair, move, improve, remove, convert, or demolish any building or structure in Special Flood Hazard Areas,

or cause the same to be done, contrary to or in violation of any of the provisions of these Regulations and/or

“The Building Code.”

Sec. 204.8 Violations and Penalties: Any person, firm, or corporat ion violating any of these provisions shall

be deemed guilty of a misdemeanor, and upon conviction thereof shall be punished by a fine or by imprisonment

as provided in the laws of the municipality for such misdemeanor, or as specified in “The Building Code.”

Section 205.0 Permits

Sec. 205,1 Statement of Intention to Improve: The Owner or any registered architect or licensed professional

engineer authorized to represent the Owner shall, before preparing final plans for any improvement in a Special

Flood Hazard Area, file with the Building Official a Statement of Intention to Improve, including a brief

description of the type of improvement being considered and giving its precise location, on a form provided

by the Building Official. The Building Official shall note on two copies the elevation of the RFD at the location

of the proposed improvement, One copy of the Statement of Intention to Improve shall be retained by the

Building Official until a permit for improvement on the site is approved or one year has elapsed; a second copy

shall be returned to the Owner for use in final site selection and design of the improvement. Assignments of

RFD elevations at all locations shall be based on determination of the Base Flood Elevation from a Flood

Insurance Rate Map published by the Federal Insurance Administration of the Federal Emergency Management Agency, or from site flood elevations and/or profiles provided by other technical sources, such as the

U.S. Army brps of Engineers, U.S. Geological Survey, Tennessee Valley Authority and Soil Conservation

Servim, or from qualified registered professional engineer firms. This information shall be open to public

examination at all reasonable times.

Sec. 205.2 Permits Required: No person, firm, or corporation shall erect, construct, enlarge, alter, repair,

move, remove, mnvert, or demolish any building or structure or any part thereof, or make any other

improvement within a Special Flood Hazard Area, or cause same to be done, without first obtaining a separate

building flood proofing permit for any such improvement from the Building Official. Ordinary minor repairs

may be made with the approval of the Building Official without a permit, provided that such repairs shall not

violate any provision of these Regulations or of “The Building ~de,”

2-3
Flood Proofing Regulations

Sec. 205.3 Applications: To obtain a permit, the applicant shall first file an application therefor which shall

consist ofi

(1) A description of the work to be covered by the prmit including a list of all spaces

affected by these Regulations giving flood proofing class, elevation of RFD, floor elevation(s), proposed uses and contents, and references to drawings and specifications which

explain the fld proofing measures that apply to each spaw. The description shall include

an estimate of the total value of the improvement. This description shall be made on a form

provided by the Building Official (Figure 1).

(2) sets of complete plans and specifications, in addition to plans and specifications

requ~d by “The Building Code,” except that plans and specifications for any and all

proposed improvements in a Special Flood Hazard Area shall be prepared by an engineer

or architect licensed by the State to practice as such. All drawings and specifications shall

bear the name of the author thereof in that person’s true name, followed by such title as that

person may be lawfully authorized to use. All plans and sections shall be noted with the

proposed flood proofing class of each space below the RFD including detail drawings of

walls and wall openings.

(3) copies of the Owner’s Contingency Plan, which shall describe in detail all

proce~es for temporary pla~ment and removal of mntingent protection proposed for

items in spaces affected by these Regulations including:

(a) Plans and schedules for items to be removed and locations of places above the

RFD to which they will be removed if these contents violate restrictions associated

with the flood proofing class of the space in which they are placed temporarily,

including specific organizational responsibilities for accomplishing this removal.

(b) Procedures, materials, and equipment for protecting items required to have

protection by their flood proofing class but for which this protection is proposed

to be provided contingently, including specific organizational responsibilities for

ammplishing this protection.

Waivers of restrictions implicitly requested by submission of the Owner’s Contingency Plan

may be granted by the Building Official as provided by 1101.2.

(4) Any other information as reasonably maybe required by the Building Official, including

computations, stress diagrams, and other data sufficient to show the correctness of the plans.

Sec. 205.4 Action on Permit Applications: The complete application filed by an applicant for a flood

proofing permit, including all of the above listed items, shall be checked by the Building Official. Such plans

may be reviewed by other Departments to check complianu with the laws and ordinances under their

jurisdiction. The Building Official shall determine that the RFD elevation noted in the application is correct

in accordanm with the Statement of Intention to Improve and that all requirements for the flood proofing

classes selected by the Owner are met. If it is determined that for any space affected by these Regulations,

any requirement for the particular flood proofing class, or any other requirement of these Regulations has not

been met, the Building Official shall so indicate on the drawings and a permit shall not be granted. If the

Building Official is satisfied that the work described in all parts of the application conform to the requirements

of these Regulations and “The Building me” and other pertinent laws and ordinances, and that the fees

specified in the “The Building Code” have been paid, a permit shall be issued therefor to the applicant. The

Building Official shall also endorse sets of written descriptions, plans and specifications, and the Owner’s

Contingency Plan by writing or stam~ng “APPROVED” and shall sign and date this endorsement. _ sets

of the complete application as approved shall be retained by the Building Official for a period of not less than

two years after the approval or issuance of a certificate of occupancy for the completed improvement. _ sets

of the complete application as approved shall be returned to the applicant, of which one set shall be kept at the

building site and available for review by the Building Official at all reasonable times.

2-4
(Suggested Format)

I

t

I

❑

(

SuDplamentary BUILDING OR STRWTURE IN FLOOO NhZARO AREA

APCIllcatlon (To Accompany Appllcatlon for Bulldlng Parmll)

City or TIJ. n

County

Locat Ion

Intended use Value Of Improvement $

Type of Cons truct Ion No. of Storlcs

Owns r kddrosa_

[xlst. Ground Elev USL; Fin. liround Elev. MSL; Reg. Flood Oatum Elav. at SIto

_F loor Elav ML: Proposad u$@

MSL; RFO Velocity Ft/Scc

Floor Elev ,— MSL: Propoatd Uao

_F1oor Elav

.—

MS L ?roposed Uae ;— Floor Elev. USL; Propos@d Uso

Maximum [oad, ng ~“ Wa I IS Hydrostatlp (UUl Ift) Prossuro on Floor Slaba(Matlmum)_ PSF

Non Flood Load PSF Foundation Type(s)

Hjdrostatlc Load PsF Lowcsl Footer Elov. (Bottom) NSL

Hydrodynamic Load PSF Sevaga Olsposa I _Sopt Ic Tank ,_ Pub. Syst, _Othcr(Etplaln)

Impact Load PS F Potabla Qator”_lndlvldual Woll_Pub, Syst. ,_ Otfrer(Elplaln)

Total Flood Load _PSF

Extarlor Wall COnstr UCt iOn T~W($)i Floor Construction TYPS($):

&bov8 Floor Flnor

\bovo Floor —Floor

Abova Floor Floor

Above Floor I Ioor

Tygea of !latarprooflng

Typa(s) of Joints: Walls Floors ; Watarstops/S@a ls(Typos)[ Uallo Floor

Sump Locattion Sump Typa

All Tanka and/or Bouyant Equipment Are Arc Not Anchorwd To Prwvgrrt Flotatlon

Altarnatc Powar Sourca Is 1$. Not_ Provldcd For Ewrargoncy Opwratlon Of SumO Pump

Sanitary, Dralnago t Watar Sup PlY Facllltlas Ara_ Aro Not Protoctod From Contamlnatlon U Back Flow by Flood Water

Rata lnlng Wall(s) Ara Ara Not Used 10 Protoct Bulldlng/Structura

Intentional Floodlng la IS Not Plannwd For Thla Build lrrg/Structuro

Tomoorary And/Or Emarg8ncy Flood Proofing la Is Not Plannwd For This Bulldlng/Structura

Bulldlng Structure la Is Not Protwct@d Agalnat Erosion By Flood Flows

Slta la 1$ Not Protwctcd Against Eroalon By Flood Flows

Clasalflcatlon 01 Bulldlng/S tructur@: FP ._* Primary Sacondary Flood Hazard Araa.

SPACES’ Llat balow all apacaa of the building or structure below the Regulatory Flnod Oatuiw includlng thclr nama, room numbar, and proposad flood-o roofing classification (1, s 11, 12 ate.), List al I contsnts of sach space (aoo Chaptwr 10 of tho

Flood-Proofing Regulations). Mark all Items which arw to bo olthar protsctod contlngontly or ramovod to aafc rofugc upon

racalpt of a flood warrslng wlfh an astarlsk (*); all such Items must bo merit ionad In tho Oarrwr’s Contlngorrcy Plan. Attach

additional shaola If nacassary,

Tha appl!cant haraby cart iflas that tha abova Information Is corract and that tho plana submlttad haraulth conform to

ho$a submit tad tor occupancy parmlt appl!catl on, Tha applicant agroos to comply with tho provlalona of tha Zoning Ordl -

lanca, tho Bulldlng Coda and all othar laws and ordlnancws affoctlng tha construction and occupancy of this proooswd bulldIng

S#gnatura Of Arch ltact/Englnaar Addrasa

Thw undtralgntd wI II suparvlaa tha Construct Ion of tha vork

abovo.

Slgnaturw

;EAL

Tltla

lat8

Addrwss

:Iark

(Slgnaturo)

APPROVEO FOR COMPLIANCE U I TH BU I LOING COOE

Oatw

Figure 1

2-5
Flood Proofing Regulations

Sec. 205.5 Issuance of Permit: The Building Official shall not issue a permit for the partial execution of any

improvement until the complete application for the entire improvement has been submitted and approved. The

issuance or granting of a permit or approval of an application shall not be construed to k a permit for, or

approval of, any violation of these Regulations or of “The Building Gale.” The issuance of a permit based

upon an approved application shall not prevent the Building Official from thereafter requiring correction in

such application or any part thereof or from preventing work related to the execution of any improvement from

being carried on thereunder when in violation of these Regulations, “The Building Code,” or of any other

ordinance.

Sec. 205.6 Expiration: Every permit issued by the Building Official shall expire by limitation and shall

become null and void if the work authorized by such permit is not commenced within 60 days after the issuance

date of such permit, or if the work authorized by prmit is suspended or abandoned for a period of 120 days

at any time after the work is commenced . Before such work is resumed, a new prmit shall first be obtained,

and the fee therefor shall be one-half the amount required for the original permit for such work; and provided,

further, that such suspension or abandonment has not exceeded one year, after which, a new application for

permit must be submitted and the permit fee shall be based on the total value of all construction work for which

the permit is issued.

Sec. 205.7 Revocation of Permit: The Building Official may revoke a permit or approval issued under these

Regulations in case of any false statement or misrepresentation of fact in the application or on the plans,

whenever the permit is issued in error, or whenever the permit is issued in violation of any ordinance or

regulation, “The Building Code,” or these Regulations.

Sec. 205.8 Permit Fees: Building permit fees shall be paid to the Building Official as required and set forth

in “The Building bale,” and in accordance with the determination of value or valuation under any provision

of these Regulations that shall be made by the Building Official.

Sec. 205.9 Posting of Permit: The building permit shall b posted at the site of operations in a conspicuous

place open to public inspection during the entire time of prosecution of the work and until completion of the

same.

Section 206.0 Inspections

Sec. 206.1 Inspections Required: All construction or work for which a permit is required shall be subject

to inspection by the Building Official.

Sec. 206.2 Periodic Inspections: Buildings or structures and parts thereof that contain or utilize contingent

or emergency (temporary) type flood proofing elements or devices shall be subject to inspection by the Building

Official at intervals of three years or less. The Owner or the owners agent shall be notified at least 10 days in

advance of the inspection date and shall be present at the inspection and shall be responsible for demonstrating

the availability y, installation, and proper functioning, anchorage, and support of all closure assemblies and other

contingent or emergency (temporary) flood proofing items. All necessary correction of deficiencies shall be

performed within 90 calendar days of the inspection date and at the Owner’s expense. Failure to perform the

required remedial work within the prescribed time shall be a violation of these Regulations and the applicable

part(s) of “The Building Code.”

Section 207.0 Certificate of Use and Occupancy

Sec. 207.1 New Buildings and Structures: No building or structure hereafter constructed in a Special Flood

Hazard Area, or any portion thereof, shall be used or occupied until the Building Official shall have issued a

certificate of use and occupancy.

Sec. 207.2 Buildings or Structures FIereafter Altered: No building or structure in a Special Flood Hazard

Area, hereafter enlarged, extended, or altered, or any portion thereof, shall be used or occupied; and no change

in use or occupancy shall be made, until the Building Official shall have issued the certificate of use and

occupancy, except that; the Building Official may permit lawful use or occupancy to continue upon the

submission of evidence that the flood hazard or flood vulnerability of any occupied portions of the structure

and its contents will not be increased during the execution of the improvements.

2-6
Chapter 2

Sec. 207.3 Existing Buildings and Structures: The Building Official shall issue a certificate of use and

occupancy for an existing building or structure located in a Special Flood Hazard Area upon receipt of a written

request from the Owner, provided:

(1) There are no violations of law or orders of the Building Official pending.

(2) It is established after inspection and investigation that the alleged use or occupancy of

the building or structure has heretofore existed,

(3) That the continued use or occupancy of a lawfully existing building or structure in the

Special Flood Hazard Area, and without requiring alterations, rehabilitation, or reconstruction, does not endanger public safety and welfare.

The Building Official shall refuse to issue a certificate of use or occupancy for any existing building or structure

in a Special Flood Hazard Area whenever it is found that the building or structure, or any portion thereof or

appurtenant thereto, is in an unsafe condition and/or would be potentially unsafe when subjected to floods up

to the RFD. The Building Official shall, in writing, so notify the Owner, lessee, tenant, occupant and/or agent

thereof describing said condition and ordering the abatement thereof withina reasonable length of time. Failure

to comply with the order of the Building Official shall be a violation of these Regulations and the applicable

part(s) of “The Building Code.”

Sec. 207.4 Contents of Certificate: When a building or structure is entitled thereto, the Building Official

shall issue a certificate of use and occupancy that shall certify compliance with the provisions of these

Regulations and “The Building @de.” huance of a certificate does not asign liability to the community.

Section 208.0 Public Notice of Flood Hazard

Sec. 208.1 Procedure: On or shut the anniversary date of the flood of record, the Building Official shall

alert the public of the existing flood hazard and shall publish or cause to be published a public notice which

shall indicate the elevations of the flood of record together with depths and approximate areas of inundation

(if known). Said public notice will also contain similar information about the RFD that is established for

purposes of these Regulations.

Sec. 208.2 Other Information: The public notice shall emphasize the necessity for maintenance and repair

of all contingent flood proofing measures and the probability of occurrence of a flood that would reach

elevations high than the RFD. It shall advise owners and/or occupnts to operate all mechanically and manually

operated closure assemblies for doors, windows, and utilities openings, emergency electrical generating units,

sump pumps, etc. and to check the availability and condition of all temporary closure panels, gaskets, and

anchorage devices, etc. Ml organizational, volunteer, or assistance groups having responsibilities to act at

times of flood emergencies shall be advised to review their state of readiness for effective mobilization and

implementation of the flood emergency plan.

Section 209.0 Provision of Safe Refuge

Sec. 209.1 New Buildings and Structures: Every building or structure hereafter erected that is located in a

Special Flood Hazard Areas where the ground surface is _ feet or more below the RFD, or where floodwater

velocities may exceed five feet per second, shall be provided with an enclosed refuge space ahve the RFD

of sufficient area to provide for the occupancy load with a minimum of 12 square feet per person. It shall be

provided with one or more exits through the exterior walls ahve the RFD to an exterior platform and stairway

not less than three feet wide.

Sec. 209.2 Buildings or Structures Hereafter Altered: Existing buildings and structures in Special Flood

Hazard Areas that are subject to flood conditions described in 209.1, and which are hereafter enlarged,

extended, or altered, or where change of use or occupancy shall be made, shall conform to all provisions for

new buildings and structures required by 2W.1

Sec. 209.3 Use of Space Below the Regulatory Flood Datum: No flood level or portion of the building or

structure that is below the RFD regardless of structure or space classification shall be used for human

occupancy, or for storage of any property, materials, or equipment that might constitute a safet y hazard when

contacted by flmdwaters.

2-7
Flood Proofing Regulations

Section 210.0 Classification and Posting of Buildings and Structures

Sec. 210.1 General: For administration of these Regulations and the coordinated enforcement and conduct

of zoning regulations, inspection of structures, and emergency public safety operations, all buildings or

structures in Special Flood Hazard Areas, whether existing or hereafter erecte~ shall be classified and posted

in accordance with this Section. Building and structure classifications FP1, FP2, FP3, FP4 and FP5, as shown

in Table 1, are based upon flood proofing classifications W 1, W2, W3, W4 and W5 of each constituent space

of the stmcture below the RFD (see Chapter 4) and the means by which these classifications are achieved.

Posting would be accomplished by placards mounted on internal walls at building entrances. For public safety

operations, a designation to include the address of the building and its classification according to this Section

shall be displayed on the outside of the building, at a level at least three feet above the RFD, and of a size to

be readily visible from a distance of fifty (50) feet.

Table 1

,

CLASSIFICATION OF BUILDINGS AND STRUCTURES I

Building or

Structure

Classification

FP 1

FP2

FP3

FP4

FP5

W1

Completely Dry

Without *HI

x

x

With *HI

x

x

SPACE CLASSIFICATION

W2 I W3

x

x

x

x

x

x

W4

Flooded with

Flood Water

x

x

W5

Non-FloodProofed

x

*Human Intervention

Sec. 210.2 Completely Flood Proofed Structures (FPl, FP2):

Sec. 210.2.1 FP1 - Any building or structure located in a Special Flood Hazard Area with

no spaces below the RFD or in which all enclosed spaces below the RFD are classified W1

or W2 without employing any contingent closure, removal, protection, or other measure

which requires human intervention for effectiveness in a flood event to obtain those

classifications shall be known as a Completely Flood Proofed Structure and classified FP 1.

It shall be posted by the Owner with a Type 1 placard, which shall be fastened securely to

the structure in a readily visible place above the RFD.

Sec. 210.2.2 FP2 - Any building or structure located in a Special Flood Hazard Area with

any spaces below the RFD and in which all such enclosed spaces are classified W1 or W2,

but for which at least one or more of the spaces employ any contingent closure, removal,

protection, or other measure which requires human intervention for effectiveness in a flood

event to obtain those classifications shall be known as a Completely Flood Proofed Structure

and classified FP2. It shall be posted by the Owner with a Type 2 placard, which shall be

fastened securely to the structure in a readily visible place above the RFD.

Sec. 210.3 Partially Flood Proofed Structures @P3, FP4):

Sec. 210.3.1 FP3 - Any building or structure located in a Special Flood Hazard Area which

contains a combination of spaces below the RFD that are classified W 1 or W2 and/or one

or more spaces that will be flooded internally, neither of which require human intervention

to achieve the required degree of flood protection, shall be known as a Partially Flood

Proofed structure and be classified FP3. It shall be posted by the Owner with a Type 3 placard

which shall be fastened securely to the structure in a readily visible place above the RFD.

2-8
Sec. 210.3.2 FP4 - Any building or structure located in the Special Flood Hazard Area which

contains a combination of spaces below the RFD that are classified W 1 or W2 which is

achieved with human intervention, andfor one or more spaces that will be flooded internally

(W3 and/or W4), either of which require human intervention to achieve the required degree

of flood protection, shall be known as a Partially Flood Proofed structure and be classified

FP4. It shall be posted by the Owner with a Type 4 placard which shall be fastened securely

to the structure in a readily visible place above the RFD,

Sec. 210.4 Non-Flood Proofed Structures ~P5): Any existing building or structure located in a Special

Flood Hazard Area which contains one or more spaces below the RFD that are not flood proofed (W5) shall

be known as a Non-Flood Proofed Structure and classified FP5. It shall be posted by the Owner with a Type

5 placard which shall be securely fastened to the structure in a readily visible place.

Sec. 210.5 Safe Refuge Areas: Buildings or structures located in a Special Flood Hazard Area that are

provided with area(s) of safe refuge shall have said area(s) posted by the Owner with a Type 6 placard, which

shall be securely fastened to the structure in a readily visible place above the RFD.

Sec. 210.6 Placards: All placards shall be furnished by the Building Official and installed by the Owner and

shall be replaced immediately if removed, or defaced.

Sec. 210.7 Placard Types: Placards shall be white rigid plastic or other non-water susceptible material, _

inches long and _ inches wide, and shall have printed thereon in black letters the information shown in Figure

2.

Sec. 210.8 Violations: Failure to comply with the requirements of this section shall be a violation of these

Regulations and the applicable part(s) of “The Building Code.”

2-9
PLACARD TYPES

COMPLETELYF1OOD-PROOF[DSTRUCTURE ●I +.

F1OOO-RESISTIV[STRUCTURE

lhishuilding/structrrre is completely flood”proofed

lhisbrrilding/structure contains areas below the

RFOwhich require implementation of an approved

to withstand flooding to the RFO. contingency plan to achieve their required degree

RE6U1ATORYF1OOODATUM_ F[ET MS1 of protection

Areas htlow RFD arc tIlhori2tt for ,*-m, Ist R[6U1A1ORYF1OOOOATUM_ FEETMS1

ts a~preved b! Isle Areas belaw RfO are aalberiled fer ,k,w, ese

,,..,..,.,!t.,!. * k.!,,“ as approved hy Bate

f100B [l[VJTIOH Al THIS POIN1._ fr brsl

!,.d,,M!..*! .!W..* ...

f100RE1[VAIIOHAT TIPISPOINT_ fT. Msl

Type 1 Type 2

PARTIALLYF1OOD-PROOF[DSTRUCTURE ●-”1

PARTIALLYF1OOO-PROOFEOSTRUCTURE

Structural integrity during floods to the RFDwill Structural integrity during floods to the RFDwill be

be achieved by internal flooding of spaces achieved by internal flooding of -., spaces when

when flood waters reach____ feet MS1. flood waters reach _feet MS1. Some areas

REGULATORYF1OODOATUM_ FEETMS1 require implementation of an approved contingency

Aleas belaw UfTl are ip~rove~ for ese plan to achieve their required degree of protection. !,,”!,,,!

as ap~revet by Oate RE6U1ATORYF1OOOOATUM— FEETMS1

,....,0!,.!h.,!..?..’,,,<,, , Areas belew RfB are ap~rovet fer ase

f100R[l[VITIOMAI THISPOINT il. MS1 as a~~reved by Oate

Floot [lEVAIIOH11 THISPOINT_fT. Usl +

Type 3 Type 4

I

NON.F1OOO-PROOFEOSTRUCTUR[ AREA0FSAF[REFU6E

This building/structureis not flood-proofed. This space is authorized as an area of safe refuge

RE6U1ATORYF1OODDATUM FEETMS1 above the RFDand will accommodate— persons.

Areas b~low UFO ale amtherizedfor ,,.,,,,,

RE6U1ATORYF1OODOATUM FEETMS1

ese

as approred by Oate Ap~roved by Oale.

,...,,,,.. 0,,!. !., ,,,.!,4,, ,.,.,,!!,,).,!,!,.,!.,,,,!,.!,

fT, NS1 f100R[lIVATIONAl T&$ POINT fl. Msl

Type 5 Type 6

Figure 2

2-1o
Figure 3

FLOOD HAZARD AREAS AND REGULATORY FLOOD DATUM

SECONDARY SECONDARY~

FLOOD HAZARD ,

AREA PRIMARY FLOOD HAZARD

i

-

FLOODWAY

FRINGE

Perspective View

(b)

SECONDARY SECONDARY

FLOOD HAZARD AREA (a) FLOOD HAZARD AREA

PRIMARY

FLOOD HAZARD AREA L k

FLOODWAY FLOODWAY FLOODWAY

REGULATORY - FRINGE I FRINGE

I

FLOOD

DATUM—’— — 9

BASE FLOOD—J—

NORMAL CHANNEL FLOW———

(a)

(b)

Croas Seotion

Primary Flood Hazard Area: Under the Unified National Program for Flood Plain Management, this area is the base or 100-year flood plain.

Secondary Flood Hazard Area: Areas of potential flooding beyond the base or 100-year flood

within which special design criteria should be applied to critical uses, such as hospitals, elderly

housing, prisons, etc. Critical uses like hospitals, schools and the like often require protection or

access to the 500-year flood. Lower floors or basements built below the base fllod may be required

to prevent damage due to groundwater related flooding.

2-11
Chapter 3

Definitions of Terms

Section 300.0 Scope

Sec. 300,1 Purpose: For the purpose of these Regulations, certain abbreviations, words, and their derivatives

shall be construed as set forth in this Chapter.

Section 301.0 Definitions

Sec. 301.1 Accessory Use or Structure - a use or structure on the same lot with, and of a nature customarily

incidental and subordinate to, the principal use or structure.

Sec. 301,2 Artificial obstruction - artificial obstruction shall mean any obstruction which is not a natural

obstruct ion.

Sec. 301.3 Base Flood - a flood which is representative of large floods known to have recurred generally in

the area or reasonabl y characteristic of what can be expected to occur on a particular stream or other body of

water. This flood is general] y being recognized and accepted nationally by Federal and non-Federal interests

as one with an average frequency of occurrenw on the order of once in 100 years (see 100-Year Frequency

Flood and Figure 3).

Sec. 301,4 Building Code - the regulations adopted by a local governing body setting forth standards for the

construction, addition, modification, and repair of buildings and other structures for the purpose of protecting

the health, safety, and general welfare of the public.

Sec. 301.5 Building Official - the officer charged with the administration and enforcement of the Building

Code and these Flood Proofing Regulations or a regularly authorized deputy.

Sec. 301.6 Channel - a natural or artificial watermurse of perceptible extent, with definite bed and banks to

confine and conduct continuously or periodically flowing water. Channel flow thus is that water which is

flowing within the limits of the defined channel (see Figure 3).

Sec. 301.7 Encroachment Lines - the lateral limits or line drawn along each side and generally parallel to a

watercourse or body of water, to preserve the flccd carrying capacity of the stream or other body of water and

its flood plain, and to assure attainment of the basic objective of improvement plans that may be considered

or proposed. Their location should be such that the floodway between them will effectively carry and discharge

the base flood, or 100-year frequency flood (see Figure 3).

Sec. 301,8 Fill - the placing, storing, or dumping of any material, such as (by way of illustration but not of

limitation) earth, clay, sand, concrete, rubble, or waste of any kind upon the surface of the ground which results

in increasing the natural ground surface elevation.

Sec. 301.9 Flood - an overflow of lands adjamnt to a river, stream, ocean, lake, etc., not normally covered by

water. Otherwise it is normally considered as any temporary rise in stream flow or stage that results in

significant adverse effects in the vicinity. Adverse effects may include damages from overflow of land areas,

backwater effects in sewers and local drainage channels, creation of unsanitary conditions, soil erosion,

deposition of materials during flood recessions, rise of groundwater coincident with increased streamflow,

contamination of domestic water supplies, subsidence or collapse of land along a body of water, and other

problems.

Sec. 301.10 Flood Crest - the maximum stage or elevation reached by the waters of a flood at a given location.

Sec. 301.11 Flood Plain - the area, usually low lands, adjoining the channel of a river, stream or watercourse

or ocean, lake, or other My of standing water, which has been or may be covered by floodwater.

Sec. 301.12 Flood Plain Management - a term applied to the full range of public policy and action for ensuring

wise use of floodplains. It includes the operation of an overall program of corrective and preventat ive measures

for reducing flood damage, including, but not limited to emergency preparedness, plans flood control works

and flood plain management.

3-1
Flood Proofing Regulations

Sec. 301.13 Flood Plain Regulations - a general term applied to the full range of codes, ordinances, and other

regulations relating to the use of land and construction within flood plain limits. The term encompasses zoning

ordinances, subdivision regulations, building and housing codes, encroachment laws, open area (space) and

health regulations, grading and erosion mntrol ordinanws for purposes of reducing or preventing flood

damage.

Sec. 301.14 Flood Profile - a graph or a longitudinal profile showing the relationship of the water surface

elevation of a flood to location along a stream.

Sec. 301.15 Flood Proofing - a combination of structural changes and/or adjustments incorporated in the

design and/or construction and alteration of individual buildings, structures or properties subject to flooding

primarily for the reduction or elimination of flood damages.

Sec. 301.15.1 Permanent Flood Proofing - permanent protection would be provided

against flooding which does not depend upon any judgment, flood forecast, or action to put

flood protection measures into effect.

Sec. 301.15.2 Contingent (Partial) Flood Proofing - contingent measures would not be

effective unless, upon receipt of a warning or foreeast, some minimal action would be

required to make the flood proofing measures operational.

Sec. 301.15.3 Emergency (Temporary) Flood Proofing - emergency measures would be,

upon receipt of a warning or forecast, either improvised just prior to or during an actual flood

or carried out according to an established emergency plan of action.

Sec. 301.16 Floodway - the channel of the stream or body of water and those portions of the flood plain which

are reasonably required to carry and discharge floodwater or fl~ flow of the base flood or 100-year frequency

flood (see Figure 3).

Sec. 301,17 Floodway Fringe - the area of the flood plain not lying within a floodway which may hereafter

be covered by floodwaters up to the Base Flood (see Figure 3).

Sec. 301,18 Freeboard - a factor of safety usually exprewed in feet above a design flood level for flood

protection or control works. Freeboard tends to compensate for the many unknown factors that could

contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions

such as wave action, bridge opening and floodway obstructions, and the hydrological effects of urbanization

of the watershed (see figure 1).

Sec. 301.19 Habitable Room - a space used for living, sleeping, eating or cooking, or a combination thereof,

but not including bathrooms, toilet compartments, closets, halls, storage rooms, laundry and utility rooms,

basement recreation rooms and similar spaces.

Sec. 301.20 Natural Obstruction - natural obstruction shall mean any rock, tree, gravel, or analogous natural

matter that is an obstruction and has been located within the floodway by a nonhuman cause.

Sec. 301.21 Nonconforming Use - a building or structure, or the use thereof, which was lawful before the

passage or amendment of the (ordinanm, resolution, act) but which is not in conformance with the provisions

of these Regulations.

Sec. 301.22 100-Year Frequency Flood - a flood having an average frequency of occurrence on the order of

once in 100 years although the flood may occur in any year (a one percent chance of being exceeded in any

year). It is based on statistical analyses of streamflow records available for the watershed and analyses of

rainfall and runoff characteristics in the general region of the watershed and is a statistical means of estimating

the probability y of flooding for insuran~ and land use planning. Over the life of a 30-year mortgage, there is

approximately a 25- percent chance that this flood or one of a greater magnitude will occur. For these and

NFIP regulations the base flood is the 100-year frequency flood.

Sec. 301,23 Owner - owner shall mean any person who has dominion over, control of, or title to land and

improvements.

Sec. 301,24 Reach - a hydraulic engineering term to describe longitudinal segments of a stream or river. A

reach will generally include the segment of the flood plain where flood heights are primarily controlled by

3-2
Chapter 3

man-made or natural flood plain obstructions or restrictions. In an urban area, the segment of a stream or river

between two physically identifiable points on the stream center line would most likely be designated as a reach.

Sec. 301.25 Regulatory Flood Datum (RFD) - established plane of reference from which elevation and depth

of fl~ing may be determined for specific locations in the flood plain. It is the Base Rood plus a freeboard

factor of safety established for each particular area which tends to compensate for the many unknown and

incalculable factors that could contribute to greater flood heights than that computed for a Base Flood. (See

Base Flood and Freeboard definitions for clarification of cumulative definition of Regulatory Flood Datum,

and Figure 3.)

Sec. 301,26 Special Flood Hazard Areas: The lands adjoining the channel of a river, stream, or watercourse

which would be covered by flood water during a base flood (100-year Flood). Flood Hazard Boundary Maps

or Flood Insurance Rate Maps published by the Federal Insurance Administration of the Federal Emergency

Management Agency identify Special Flood Hazard Areas. These can also be determined from flood hazard

studies performed by agencies such as the U.S. Army Corps of Engineers, U.S. Geological Survey, Tennessee

Valley Authority, Soil Conservation Service and from qualified professional engineer firms. Elevation

differences should be clarified for community use and referenced to appropriate agency.

Sec. 301.27 Subdivision - the partitioning or dividing of a parcel or tract of land.

Sec. 301,28 Subdivision Regulations - regulations and standards established by a local unit of government

with authority granted under a state enabling law, for the subdivision of land in order to secure coordinated

land development, including adequate building sites and land for vital community services and facilities such

as streets, utilities, schools, and parks.

Sec. 301.29 UndercIearance - the lowest point of a bridge or other structure over or across a river, stream, or

watercourse that limits the opening through which water flows. This is referred to as “low steel” in some

regions.

Sec. 301.30 Watercourse - any natural or man-made depression with a bed and well-defined banks below the

surrounding land serving to give direction to a current of water or pattern of runoff from a drainage area of

any size.

3-3
Chapter 4

Flood Proofing Classification of Spaces

Below the Regulatory Flood Datum

Section 400.0 Scope

Sec. 400.1 General: The flood proofing classification of a space is determined by the degree of protection

required under these Regulations to permit its intended use. (Classification of entire buildings or structures

for administrative and posting purposes, which is based jointly on the flood proofing classes of its constit ucnt

spaces and the means by which their classifications are obtained, is explained in 210.0.) The flood proofing

class of a space for which temporary placement or contingent protection measures are approved assumes that

these measures are in effect during a flood and defines the resulting relationship of protection to use.

Sec. 400.2 Assignment of Flood Proofing Classes: Assignment is made by the Owner at the time of

application for a permit and is subject to the approval of the Building Official as indicated in 205.0. Every

space of an improvement in a Special Flood Iiazard Area which impinges in whole or part upon the RFD shall

have a flood proofing class assigned to it, and all requirements associated with a flood proofing class shall bc

met by the space to which they appl y in addition to all other requirements of these Regulations and the Building

Code.

Section 401.0 Descriptions of Flood Proofing Classes

Sec. 401.1 Classifications: The following descriptions of the five flood prmfing classes are approximate and

general; more precise specification of the requirements associated with each class are set forth in Table 2 of

Section 402.0.

Sec. 401.2 Completely Dry Spaces (W1): These spaces shall remain completely dry during flooding to the

RFD; walls shall be impermeable to pa~age of water and water vapor. Permitted contents and interior finish

materials are virtual] y unrestricted, except for high hazard typ uses or human habitation as provided in 209.3.

Structural components shall have the capability of resisting hydrostatic and hydrodynamic loads and the effects

of buoyancy.

Sec. 401.3 Essentially Dry Spaces (W2): These spaces shall remain essentially dry during flooding to the

RFD; walls shall be substantially impermeable to water, but may pass some water vapor or seep slightly.

Gntents and interior finish materials are restricted when hazardous or vulnerable under these conditions.

Structural components shall have the capability of resisting hydrostatic and hydrodynamic loads and the effects

of buoyancy. WI and W2 flood proofing classes herein are comparable to the NFIP flood proofing standards

in CFR 60.3 (c)(3) (ii), 60.3 (c)(8)(ii), and 60.6 (c)(2)(i).

Sec. 401,4 Spaces Intentionally Flooded With Potable Water (W3): These spaces will be flooded internally

with potable water provided by the Owner in order to maintain the building’s structural integrity by equalizing

pressures on structural components during flooding to the RFD; walls shall be sufficiently impermeable to

prevent the passage, infiltration or seepage of contaminated floodwaters. ~ntcnts and interior finish materials

are restricted when hazardous or vulnerable under intentional flcoding conditions. This is also known as wet

flood proofing.

Sec. 401.5 Spaces Flooded With Floodwater (W4): These spaces will be flooded with floodwater (contaminated) by automatic means, or are otherwise partially exposed to the unmitigated effects of lhe flood.

Although there are minimal structural requirements to be met for walls and other structural components,

contents and interior finish materials are restricted to types which are neither hazardous nor vulnerable to loss

under these flooding conditions. (Most spaces in existing buildings would have this classification if provided

with a suitable automatic flocding system. Carports, loading platforms, open crawl spaces, porches, and patios

would generally fall into this classification. This is also known as wet flood proofing.

Sec. 401,6 Non-Flood Proofed Spaces (W5): A non-fld proofed space in an existing building or structure

is defined as a space which fails to meet the requirements of any of the above described classifications.

4-1
Flood Proofing Regulations

401.7 Flood Prooting and the National Flood Insurance Program: National Flood Insurance Program

regulations require that new and substantially improved residential structures be elevated to or above the base

flood elevation. Non-residential structures may be flood proofed provided that the structure is watertight with

walls below that elevation substantially impermeable to floodwaters. Structures that do not meet these

requirements are generally violations of local fld plain management regulations and can be subject to

extremely high flood insurance premiums. The FEMA does remgnize that there may be other circumstances

where a “lesser degree” of flood pr~fing including “wet flood proofing” may k appropriate. Enclosures below

elevated buildings that are used sole] y for parking, building sass, or limited storage can be wet flood proofed

in accordance with NFIP regulations. Other examples include small accessory structures, some large commercial or industrial buildings containing low-damage uses, and certain agricultural structures. In these situations,

wet flood proofing is permitted only upon issuance of a variance by the mmmunity and only if the structure

meets the varian~ criteria in 44 CFR 60.6 (a) of the NFIP regulations. Wet flood proofing may also be

appropriate as a means of reducing damages to existing flood-prone structures.

Section 402.0 The Space Classification Chart

Sec. 402.1 General: Table 2 indicates the various degrees of protection required to permit uses of spaces for

each flood proofing class. Although spaces must meet the requirements shown for each element of flood

proofing, the chart in itself shall not be mnstrued as being exhaustive with respect to all requirements imposed

by these Regulations. In disputes arising over the interpretation of this chart, the written provisions of these

Regulations shall be considered as definitive. Succeeding chapters provide interpretive definitions for each

element of flood proofing.

Sec. 402.2 Separation of Spaces With Different Flood Proofing Classifications: Any two adjacent spaces

below the RFD having different flood proofing classes shall be separated by a barrier meeting the requirements

for the space with the Iower-num&red classification. In addition, any opening below the RFD between two

adjoining spaces shall be provided with a closure meeting the requirements for the space with the lower-numbered classification.

Table 2

SPACE CLASSIFICATION CHART

FloodProofing

Classes

W1

Completely

Dry

W2

Essentially

Dry

W3

Flooded

with Potaable Water

W4

Flooded

with

Flood

Water

W5

NonFloodProofing

FLOOD-PROOFING CLASSIFICATION OF SPACES

WaterProofing

Type A

Type B

Type A

Type C

—

structural

Loads

Class 1

Class 1

Class 2

Class 3

—

Closure

of

Openings

Type 1

Type 1

Type 3

Type 4

Type 5

MIN~UM REQUIREMENTS

Internal

Flooding

k Drainage Flooring

Class 1

Class 2

class 3

Class 4

Class 5

walls

and

Ceilings

Class 1

Class 2

Class 3

Class 4

Class 5

Contents

Class 1

Class 2

Class 3

Class 4

Class 5

Electrical Mechanical

4-2
Chapter 5

Waterproofing

Section 500.0 Scope

Sec. 500.1 Purpose: This chapter shall govern the design, use, and methods of construction and materials

with respect to obtaining, for a given space, the degree of protection against water, water vapor, and waterborne

contamination determined by the vulnerability or hazard potential of the contents and interior finish materials

to meet its flti pr~fing classification.

Sec. 500.2 Performance Standards: Three types of waterproofing are defined herein as to the degree to

which they satisfy a standard of dryness. If any material or methods of construction meets the functional

performance standard defining a type of waterproofing construction it shall be considered as satisfying the

requirements of this chapter. For the pur~e of these Regulations, the detailed specification of Type A

waterproofing construction, as contained in this chapter, shall be interpreted as a guide to measures which are

reasonable prerequisites for attaining this standard of dryness.

Section 501.0 Type A Constructions

Sec. 501.1 Permeability: Type A waterproofing constructions are completely impermeable to the passage of

external water and water vapor under hydrostatic pressure of flooding to the RFD. Type A waterproofing

construction shall consist of either a continuous membrane satisfying 501.2, integrally waterproofed concrete

satisfying 501.3, or a continuous interior lining satisfying 501.4.

Sec. 501.2 Type A Membrane Construction: Type A membrane waterproofing forms a continuous external

impervious lining to protect a structure with a concrete floor slab and concrete or reinforced concrete masonry

unit walls. It shall comply with the following requirements for structural prerequisites, materials, and

installation.

Sec. 501.2.1 Structural Prerequisites:

Sec. 501,2.1.1 Continuity of Structure: Structural slabs below grade shall be

continuous under perimeter walls to prevent differential settlement and shall be

designed to act monolithically with the walls; reinforced concrete masonry unit

walls shall be connected rigid] y to slabs with reinforcing steel. Where conventional

footings are necessary to achieve bearing below the frost line, the structural slab

shall be formed monolithically with the walls or anchored into the walls by means

of a keyway and reinforcing steel so as to act monolithically with the wall.

Sec. 501.2.1,2 Projection of Slab: Where a slab is continuous under perimeter

walls, it shall project not less than six inches beyond the outside of the wall in order

to provide space for joining horizontal and vertical membranes.

Sec. 501.2,1.3 Columns: Where columns recur, there shall be no vertical discontinuity or abrupt change in slab cross sections. Where slab thicknesses change, they

shall do so gradually, and the effects of pressure distribution on the thinner portions

of the slab cross section shall be considered.

Sec. 501,2.1,4 ProtectIon: All membranes shall be installed on exterior surfaces

of perimeter walls. For floor slabs, the membrane shall be installed between the

structural slab and wearing surface or otherwise placed on a non-structural concrete

subbase at least two inches in thickness to protect the membrane and ensure its

flatness; in the latter ease (Figure 4), a two-inch thick sand-cement screed shall be

placed over the membrane before laying reinforcing steel for the structural slab. If

a floor membrane is sandwiched between two structural slabs, the membrane shall

be positioned at a location that will not subject it to excessive overstress conditions.

5-1
Sec. 501.2.1.5 Pile Foundations: When spaces are supported on pile foundations,

there shall be complete separation between pile caps and floor slab; the membrane

shall be continuous and loads shall be transferred to the piles through basement

walls acting as deep beams or through isolated foundations. The pile caps shall be

interconnected with stabilizing beams and a reinforced concrete slab not less than

four-inches thick shall be provided over the entire area between the beams (and

monolithic with them) in order to rewive membrane.

[

REINFORCED CONCRETE COLUMN

REINFORCED CONCRETE :;.

STRUCTURAL FLOOR- “,; :,;

>, “’.

.9 .b

..

:: ;

b’

2“ PROTECTIVE SAND

& CEMENT SCREED

CONCRETE SUB BASE

WATER PROOFING

TYpE ‘lA” MEMBRANE WATER PRC)OFING IN FLOOR SLABS

Figure 4

Sec. 501.2.2 Materials: For the purpose of these Regulations, a membrane shall be any

layered sheet construction of tar/asphalt bitumen and felts, at least 3-ply in thickness

neoprene coated nylon fabric; other approved sheet material; or multiple applied hydrolithic

coatings of asphaltic bitumens. All applicable ASTM standards shall apply to Type A

membranes and their component parts. Relevant ASTM standards include the following

standard numbers: D4637, D3083, ~36, D2626, D3393, E96 and (%98.

Sec. 501.2.2,1 P1astic Waterproofing Materials: Various’ plastic materials, including among others, polyethylene, PVC, polyurethane, and polyisobutylene,

shall be permitted in sufficient thicknesses in sheets or coatings. In certain cases,

the Building Official may require less protection beneath the plastic than the

concrete subbase required in 501.2.1.4.

Sec. 501.2.3 Installation:

Sec. 501.2.3.1 Application: All Type A membrane waterproofing shall be applied

by a certified roofing or waterproofing contractor.

Sec. 501.2.3.2 Turns: Turns at corners, hth vertical and horizontal, shall be made

with chamfers or fillets of not less than two inches dimension on any side.

Sec. 501.2.3.3 Seams: Membrane seams or overlaps, if any, shall bc thoroughly

interleaved and protected in accordance with accepted practice, but in no case shall

seams or overlaps be less than two inches in any direction.

5-2
Chapter 5

Sec. 501.2.3.4 Pipes: Points where pipes or ducts penetrate waterproofed construction shall be designed to be watertight in accordance with accepted engineering

practice.

Sec. 501.2.3.5 Joints: Membranes shall be continuous across expansion, control,

and construction joints, which shall have waterstops of rubber, copper, plastic, or

other suitable materials.

Sec. 501.2.3.6 Protection: Membranes on walls shall extend at least three inches

above the RFD of the protected space and shall be attached with a reglet or covered

with protective masonry at its upper termination. To protect all wall membranes

during backfill operations, protection of not less than Vz-inch thickness of cement

parging, plastic sheets, or other rigid non-cellulose material, installed in a

workmanlike manner, shall be provided; however, in large projects or where the

aforementioned protection may not be adequate, [he Building Official may require

protection by some other means.

Sec. 501,2.3.7 Excavation: Excavation preceding construction shall extend a

minimum distance of 24 inches beyond the exterior wall lines to facilitate construction operations. In built-up areas where this requirement cannot be met, excavation

limits will be as designated by the Building Official.

Sec. 501.3 Type A Integrally Waterproofed Concrete Construction: Type A integrally waterproofed

concrete construction shall comply with the following requirements for structural prerequisites, materials, and

installation.

Sec. 501.3.1 Structural Prerequisites:

Sec. 501,3.1,1 Continuity of Structure: Structural slabs shall be continuous under

perimeter walls. Slabs shall be designed to act monolithically with perimeter walls,

or otherwise shall carry them nonrigidly in a recess with mastic V fillings and

watemtops. (Figure 5) Where conventional footings are necessary to achieve

bearing below the frost line, the structural slab shall be formed monolithically with

the walls or anchored into the walls by means of a keyway and reinforcing steel.

Sec. 501.3.1.2 Deflections: To prevent increases of permeability yin tension zones,

the maximum deflection of any structural slab or perimeter wall shall not exceed

1/500 of its shorter span.

Sec. 501.3,1.3 Columns: Where columns occur there shall be not vertical discontinuity or abrupt change in slab cross section. Where slab cross sections change,

they shall do so gradually, and the effects of pressure distribution on the thinner

portions of the slab cross section shall be considered.

Sec. 501.3.2 Materials:

Sec. 501.3.2.1 Strength: All Type A integrally waterproofed concrete shall have

a seven-day compressive strength of at least 3,000 psi and a 28-day compressive

strength of 4000 psi.

Sec. 501.3.2.2 Waterproofing Admixtures: If an approved waterproofing admixture is used, the cement content required to achieve the strength specifications may

not be reduced by more than 10 percent. Approved admixtures shall not reduce

the compressive strength of the mncrete and shall act as a densifier and to increase

workability y.

5-3
Flood Proofing Regulations

Sec. 501.3.2.3 Joints: Expansion joints shall be keyed and provided with

waterstops. Construction joints shall be provided with waterstops and shall be

thorough] y roughened and cleaned before continuation of concrete placement.

Sec. 501.3.2.4 Protection of Fresh Concrete: When potentially aggressive

groundwater conditions exist, the Building Official may require the protection of

fresh concrete from contact with groundwater for a minimum of 14 calendar days.

Protection shall be accomplished either by the removal of groundwater or by the

application of a temporary membrane or surface coating (e.g. bitumen or tar

emulsion) which, however, need not meet standards for prmanent protection.

&&

(a) (b)

NON-RIGID PERIMETER WALL AND FLOOR SLAB CONNECTIONS

Figure 5

Sec. 501.4 Type A Interior Linings: A Type A interior lining forms a continuous internal impervious barrier

to protect a structure with a concrete floor slab and concrete or reinforced mncrete masonry unit walls. All

Type A interior linings shall conform to the following requirements for structural prerequisites, materials, and

installation

Sec. 501.4.1 Structural Prerequisites

Sec. 501,4.1.1 Continuity of Structure: Structural slabs below grade shall be

continuous under perimeter walls to prevent differential settlement and shall be

designed to act monolithically with the walls; reinforced concrete masonry unit

walls shall be connected rigidly to slabs with reinforcing steel. Where mnventional

footings are necessary to achieve bearing below the frost line, the structural slab

shall be formed monolithically with the walls or anchored into the walls by means

of a keyway and reinforcing steel so as to act monolithically with the wall.

Sec. 501,4.1,2 Columns: Where columns occur, there shall be no vertical discontinuityy or abrupt change in slab cross sections. Where slab thicknesses change, they

shall do so gradually, and the effects of pressure distribution on the thinner portions

of the slab cross section shall be considered.

Sec. 501.4.1.3 Deflections: To prevent cracking of the interior lining, the maximum deflection of any structural slab or perimeter wall to which the lining is

applied shall not exceed 1/500 of its shorter span.

5-4
Chapter 5

Sec. 501.4.2 Materials: For the purpose of these Regulations, an interior lining shall be

any continuous coating, parging, or rendering of a cementitious, or other approved waterproofing material or compund with adequate structural strength and impermeability to

serve its intended purpose. All relevant ASTM standards shall apply to Type A interior

lining materials. Relevant ASTM standards include the following standard numbers:

D4637, D3083, C836, D2626, D3393, E96 and C898.

Sec. 501.4.3 Installation:

Sec. 501.4.3.1 Application: All Type A interior lining waterproofing shall be

applied by a certified roofing or waterproofing contractor.

Sec. 501,4.3.2 Turns: Turns at comers, both vertical and horizontal, shall be made

with fillets of not less than two inches dimension on any side.

Sec. 501.4.3.3 Pipes: Points where pipes or ducts penetrate waterproofed construction shall be designed to be watertight in accordance with accepted engineering

practice.

Sec. 501.4.3.4 Joints: Interior linings shall be continuous across expansion,

control, and construction joints which shall have waterstops of rubber, copper,

plastic, or other suitable material.

Sec. 501.4.3.5 Vertical Extent: Interior linings on walls shall extend at least three

inches above the RFD of the protected space.

Sec. 501.5 Existing Spaces: Spaces in existing buildings or structures which become subject to these

Regulations may be approved as having Type A waterproofing upon submission by the Owner of plans and

specifications for these spaws prepared by a licensed architect or engineer; however, the Building Official

shall make a thorough inspection of actual site conditions and may require that tests be made to demonstrate

the adequacy of the work before granting this approval.

Section 502.0 Type B Constructions

Sec. 502.1 Permeability: Type B waterproofing construction shall be substantially impermeable but may

pass water vapor and seep slightly during flooding to the RFD. Large cracks, openings, or other channels that

could permit unobstructed passage of water shall not be permitted. In no case shall there be permitted the

accumulation of more than four inches of water depth in such a space during a 24-hour period if there are no

devices provided for its removal. However, sump pump shall be required to control this seepage.

Sec. 502.2 Upgrading Existing Spaces: Spaces with Type B waterproofing construction may be upgraded

to Type A through the installation of a continuous exterior or interior lining or a combination of both which

the Building Official may approve as meeting the requirements for permeability of Type A waterproofing.

Sec. 502.2,1 Inspections: The Building Official shall make inspections prior to and upon

completion of this work before approving the completed work as meeting Type A waterproofing requirements. The Building Official may require that tests be made to demonstrate

the adequacy of the work before granting this approval.

5-5
Flood Proofing Regulations

Section 503.0 Type C Constructions

Sec. 503.1 Non-Waterproofed: Type C waterproofing constructions are any which do not satisfy the

requirements for Type A or B in 501.0 and 502.0, respectively.

Sec. 503.2 Upgrading of Spaces: Non-waterproofed spaces maybe upgraded to Ty~ A or B waterproofing

when the Building Official shall approve such work as meeting the standards for Type A or B in 501.0 and

502.0, respectively.

Sec. 503.2.1 Inspections: The Building Official shall make inspections prior to, during,

and upon completion of this work before approving the improvements as Type A or B

waterproofing, and may require testing be made to demonstrate the adequacy of the work

before granting this approval.

5-6
Chapter 6

Structural Requirements

Section 600.0 Scope

Sec. 600.1 General: All buildings and structures, covered by these Regulations and all parts thereof, shall be

capable of resisting all loads required by “The Building ~de” and, in addition, all loads prescribed in this

chapter, without exceeding the prescribed allowable stresses.

Section 601.0 Classes of Loads

Sec. 601.1 Class 1 hads - reflect the probable effects of flooding on structures which are waterproofed (WI

or W2). These loads shall be calculated in complete accordance with this Chapter and shall include all water,

impact, and soil loads specified herein.

Sec. 601.2 Class 2 bads - reflect the probable effects of flooding on structures which include internal flooding

as a means of structural protection and which shall be so flooded in accordance with Chapter 8. These loads

shall be calculated in accordance with this Chapter except that only hydrodynamic and impact loads must be

considered when the interior and exterior water levels are equal.

Sec. 601.3 Class 3 Loads - apply to fully enclosed spaces which are to be flooded with floodwater internally

by automatic means and to partially enclosed or external spaces. For such internal flooding, Class 3 loads

shall coincide with those of Class 2. For partially exposed spaces, however, any dependent or supporting

structural components shall be designed for Class 1 or 2 loads if they are also structural components of any

adjacent enclosed space, whichever is required; isolated or freestanding columns or walls shall meet all criteria

of 612.2.3.

Section 602.0 Water hads

Sec. 602.1 Types: Water loads, as defined herein, arc loads or pressures on surfaces of the buildings and

structures caused and induced by the presence of floodwaters. These loads are of two basic types: hydrost:i[ic

and hydrodynamic.

Sec. 602.2 Hydrostatic hads: Hydrostatic loads are th~e caused by water either above or below the ground

surface, free or confined, which is either stagnant or moves at very low velocities, or up to five feet per second.

These loads are equal to thee product of the water pressure multiplied by the surface area on which the pressure

acts. The pressure at any point is equal to the product of the unit weight of water (62.5 pounds per cubic fool)

multiplied by the height of water above the point or by the height to which confined water would rise if free

to do so. Hydrostatic pressures at any point are equal in all directions and always act perpendicular to the

surface on which they are applied. For the purpose of these Regulations, hydrostatic loads are subdivided into

the following types:

Sec. 602.2.1 Vertical Loads: These are loads acting vertically downward on horizontal or

inclined surfaces of buildings or structures, such as roofs, decks or floors, and walls caused

by the weight of floodwaters above them.

Sec. 602.2.2 Lateral hads: Lateral hydrostatic loads are those which act in a horizontal

direction, against vertical or inclined surfaces, both above and below the ground surface and

tend to cause lateral displacement and overturning of the building, structure, or parts thereof.

Sec. 602.2.3 Uplift: Uplift loads are those which act in a vertically upward direction on the

underside of horizontal or sloping surfaces of buildings or structures, such as basement slabs,

footings, floors, decks, roofs, and overhangs. Hydrostatic loads acting on inclined, rounded,

or irregular surfaces may be resolved into vertical or uplift loads and lateral loads based on

the geometry of the surfaces and the distribution of hydrostatic pressures.

6-1
Flood Proofing Regulations

Sec. 602.3 Hydrodynamic Loads: Hydrodynamic loads, for the purpose of these Regulations, are those

induced on buildings or structures by the flow of floodwater moving at moderate or high velocity around the

buildings or structures or parts thereof, above ground level. Such loads may occur below the ground level

when openings or conduits exist which allow free flow of floodwaters. Hydrodynamic loads are basically of

the lateral type and relate to direct impact loads by the moving mass of water, and to drag forces as the water

flows around the obstruction. Where application of hydrodynamic loads is required, the loads shall be

computed or estimated by recognized and authoritative methods. Methcds for evaluating water velocities and

related dynamic effects are beyond the scope of these Regulations, but shall be subject to review and approval

by the Building Official.

Sec. 602.3.1 Conversion to Equivalent Hydrostatic hads: For the purpose of these

Regulations and for cases when water velocities do not exceed 10 feet per second, dynamic

effects of the moving water maybe converted into equivalent hydrostatic loads by increasing

the elevation of the RFD for design purposes by an equivalent surcharge depth, dh, on the

headwater side and above the ground level only, equal to:

L

aV

‘h=~ , where

V is the average velocity of the water in feet per second; g is the acceleration of gravity,

32.2 feet per second per second;a is the coefficient of drag or shape factor. (The value of a,

unless otherwise evaluated, shall not be less than 1.25.)

The equivalent surcharge depth dh shall be added to the RFD design depth and the resultant

pressures applied to, and uniformly distributed across, the vertical projected area of the

building or structure which is perpendicular to the flow. Surfaces parallel to the flow or

surfaces wetted by the tailwater shall be considered subject to hydrostatic pressures for

depths to the RFD only.

Sec. 602,4 Intensity of Loads:

Sec. 602.4.1 Vertical Mads: Full intensity of hydrostatic pressures caused by a depth of

water to the level of the RFD applied over all surfaces involved, both above and below

ground level, except that for surfaces exposed to free water, the design depth shall be

increased by one foot.

Sec. 602.4.2 Lateral Loads: Full intensity of hydrostatic pressures caused by a depth of

water to the level of the RFD applied over all surfaces involved, both above and below

ground level, except that for surfaces exposed to free water, the design depth shall be

increased by one foot.

Sec. 602.4.3 Uplik Full intensity of hydrostatic pressures caused by a depth of water to

the level of the RFD acting on all surfaces involved, unless provisions are made to reduce

uplift intensities as permitted in 611.0.

Sec. 602.4.4 Hydrodynamic hads: Hydrodynamic loads, regardless of method of evaluation, shall be applied at full intensity over all above ground surfaces between the ground

level and the RFD.

Sec. 602.5 Applicability: For the purpose of these Regulations, hydrostatic loads shall ti used in the design

of buildings and structures exposed to water loads from stagnant floodwaters, for conditions when water

velocities do not exceed five feet per second, and for buildings and structures or parts thereof not exposed or

subject to flowing water. For buildings and structures, or parts thereof, which are exposed and subject to

flowing water having velocities greater than five feet per second, hydrostatic and hydrodynamic loads shall

apply.

6-2
Chapter 6

Section 603.0 Impact bads

Sec. 603.1 Types: For the purpose of these Regulations, impact loads are those which result from floating

debris, ice, and any floatable object or mass carried by floodwaters striking against buildings and structures

or parts thereof. These loads are of three basic types: normal, s~cial, and extreme.

Sec. 603.1.1 Normal Impact tiads: Normal impact loads are those which relate to isolated

occurrences of logs, ice blocks, or floatable objects of normally encountered sizes striking

buildings or parts thereof.

Sec. 603.1.2 Special Impact tiads: Special impact loads are those which relate to large

conglomerates of floatable objects, such as broken up ice floats and accumulation of floating

debris, either striking or resting against a building, structure, or parts thereof.

Sec. 603.1.3 Extreme Impact bads: Extreme impact loads are those which relate to large

floatable objects and masses such as runaway barges or collapsed buildings and structures,

striking the building, structure, or component under consideration.

Sec. 603,2 Applicability: Impact loads shall be considered in the design of buildings, structures, and parts

thereof as stipulated below:

Sec. 603,2,1 Normal Impact Loads: A concentrated load acting horizontally at the RFD

or at any point below it, equal to the impact force, produced by a 1,000-pound mass traveling

at the velocity of the floodwater and acting on a one square foot surface of the structure.

Sec. 603.2,2 Special Impact Loads: Where special impact loads are likely to occur, such

loads shall be considered in the design of buildings, structures, or parts thereof. Unless a

rational and detailed analysis is made and submitted for approval by the Building Official,

the intensity of load shall be taken as 100 pounds per foot acting horizontally over a one foot

wide horizontal strip at the RFD or at any level below it. Where natural or artificial barriers

exist which would effectively prevent these special impact loads from occurring, the loads

may be ignored in the design.

Sec. 602.2.3 Extreme Impact bads: It is considered impractical to design buildings

having adequate strength for resisting extreme impact loads. Accordingly, expect for special

cases when exposure to these loads is highly probable and the resulting damages are

extremely severe, no allowanws for these loads need be made in the design.

Section 604.0 Soil Loads

Sec. 604.1 Applicability: Full consideration shall & given in the design of buildings, structures, and parts

thereof, to the loads or pressures resulting from the presence of soils against or over the structure. bads or

pressures shall be computed in accordance with accepted engineering practice, giving full consideration to the

effects that the presence of floodwater, above or within the soil, has on loads and pressures. When expansive

soils are present, the Building Official may require that special provisions be made in foundation and wall

design and construction to safeguard against damage due to this expansiveness. The Building Official may

require a special investigation and re~rt to provide these design and instruction criteria.

Section 605.0 Hurricane and Tidal Wave bads

Sec. 605.1 Applicability: Coverage of loads caused by flooding related to hurricanes, tidal waves, and other

similar natural events is beyond the scope of these Regulations and no specific or detailed treatment is provided.

Concepts and requirements of these Regulations maybe used as a guide in developing suitable provisions for

flood proofing of buildings exposed to flooding from these sources. FEMAs “Construction Manual” for design

and construction criteria for coastal structures, NFIP regulations and other guidance is available for reference

use.

6-3
Flood Proofing Regulations

Section 606.0 Loading Conditions

Sec. 606.1 Applicability: Buildings and structures, covered by these Regulations, and all parts thereof, shall

be designed for all loads and loading conditions required by “The Building ~de” for the prevalent state of

loading when the structure is not subject to flood loads. In a separate analysis, the effects of flood related loads

and loading conditions shall be calculated. Maximum values of loads and member stresses shall then be

computed under the mm bined effects of the normal loads required by “The Building me” and those of flood

related loads. The buildings, structures, and all structural membem or components thereof shall be capable of

resisting these maximum loads and stresses without exceeding the prescribed allowable stresses.

Section 607.0 Combined Loads

Sec. 607.1 Applicability: All loads stipulated in “The Building Code” and all flood related loads shall be

applied on the structure and on structural components, alone and in combination, in such a manner that the

combined effect will result in maximum loads and stresses on the structure and members. Loads required by

“The Building Code” shall be used in combination with flood related loads defined in this chapter to the extent

and subject to the exceptions stated below.

(1) Dead bad, Use at full intensity.

(2) Live had. Use at reduced intensity as provided in “The Building ~de” for design of

columns, piers, walls, foundations, trusses, beams, and flat slabs. Live loads on floors at or

below the RFD and particularly on basement slabs, shall not be used if their omission results

in greater loading or stresses on such floors. Similarly, for storage tanks, pools, bins, silos,

and other similar structures designed to contain and store materials, which may be full or

empty when a flood occurs, both renditions shall be investigated in combination with flood

related loads of the containing structure being full or empty.

(3) Snow Load. Use at full intensity.

(4) Wind had. Use at full intensity as required in “The Building Code” on areas of the

building and structure above the RFD.

(5) Earthquake bad. ~mbined earthquake and flood related loads need not be considered.

Section 608.0 Allowable Stresses

Sec. 608.1 Applicability: Allowable stresses for all materials shall be as stipulated in “The Building @de.”

Except as otherwise permitted by “The Building Code,” only basic allowable stresses shall be used under flood

related loads or combined loads, and those allowable stresses shall in no way be increased or permitted to be

used in an “overstress” wndition.

Section 609.0 Allowable Soil Pressures

Sec. 609.1 Applicability: Under flood conditions, the bearing capacity of submerged soils is affected and

reduced by the buoyancy effect of the water on the soil. For foundations of buildings and structures covered

by these Regulations, the bearing capacity of soils shall be evaluated by a recognized acceptable method.

Expansive soils should be investigated with special care. Soils which lose all bearing capacit y when saturated,

or become “liquefied,” shall not be used for supporting foundations. If a detailed soils analysis and investigation

is not made, and if bearing capacities of the soils are not evaluated as required above, allowable soil pressures

permitted in “The Building me” maybe used, provided those values are reduced_ percent. @is reduction

should be determined for each local ity and soil type by the Building Official.)

Section 610.0 Stability

Sec. 610.1 Overturning: All buildings and structures covered by these Regulations and all parts or elements

thereof shall be proportioned to provide a minimum factor of safety of 1.50 against failure by sliding or

6-4
Chapter 6

overturning when subjected to flood related loads or combined loads defined under 607.0. The required

stability shall be provided by the normal resistive loads allowed by “The Building Code,” such as frictional

resistance between the foundations and the soil, passive earth pressure, batter and vertical piles and permanent

anchors which may be provided. For the purpose of providing stability, only the dead load shall be considered

effective. No use shall be made of any resistance, either as weight or frictional or passive, from soils which

could be removed or displaced by excavation, scour or other causes. Similarly, no use shall lx made of

frictional resistance between the foundation and the underlying soil in the case of structures supported on piles.

Sec. 610.2 Flotation: The building or structure, and all appurtenances or components thereof not rigidly

anchored to the structure, shall have enough weight (deadload) to resist the full or reduced hydrostatic pressures

and uplift from floodwater at the RFD with a factor of safety of 1.33. For provisions governing reduced uplift

intensities, see 611.0. In cases when it is not practical to provide the required factor of safety against flotation

by weight alone, the difference shall be made up by providing dependable and permanent anchors that meet

the approval of the Building Official. Elements which depend on anchorage to other portions of the structure

shall be anchored to a portion or portions of the structure which has the required factor of safety against flotation

from all contributing elements subject to uplift. Apportionment of uplift and resisting forces shall be made by

a recognized method of structural analysis in accordance with accepted engineering practice.

Sec. 610.3 Anchorage: Any building and structure as a whole, which lacks adequate weight and mass to

provide the required factors of safety against overturning, sliding, and flotation, shall be dependably and

permanently anchored to the ground and preferably to underlying sound rock formations. In addition, all

elements of a building or structure, such as walls, flood slabs, girders, beams, columns, and other members

shall be dependably connected or anchored to form an adequate structural system to support the individual

members and all the applied loads. Provision of adequate anchorage is also essential and required for all tanks

and vessels, sealed conduits and pipes, lined pits and sumps, and all similar structures which have negligible

weight of their own. (See also 1101,4, Underground Storage Tanks)

Section 611.0 Reduction of Uplift Pressures

Sec. 611.1 General: Uplift forces, in conjunction with lateral hydrostatic forces, constitute the most adverse

flood related loading on buildings and structures and elements thereof. Their combined effect determines to

a major extent the requirements for weight and anchorage of a structure as a whole to assure its stabilit y against

flotation, sliding, and overturning. When uplift forces are applied to structural elements of a building or

structure, such as footings, walls, and particularly basement slabs, they generally constitute the critical loading

on such elements. In the interest of providing economical solutions to the basic problem of structurally flocd

proofing buildings and structures, it is permissible under these Regulations to make provisions for effectively

reducing uplift forces acting under the structure. The plans and design data submitted to thee Building Official

for approval as required by 205.0, shall show complete and detailed procedures, assumptions, analyses and

design information, and specific provisions to be incorporated in the work for accomplishing the proposed

reduction in uplift. Data and design procedures shall be based on recognized and acceptable methods of

foundation drainage and waterproofing. Such provisions shall include, but are not limited to, the following

items, used alone or in combination, as conditions will dictate.

Sec. 611.2 Impervious Cutoffs: Impervious cutoffs are barriers installed below the ground line and externally

to the perimeter of the building or structure for the purpse of decreasing seepage quantities and/or reducing

exit gradients. Such cutoffs must, in all cases where fldwaters will rise above the ground level, be connected

by suitable impervious blankets or membranes to the walls of the building or structure. Cutoffs may consist

of interlocking steel sheeting, compacted barrier or impervious soil, grouted or injected cutoffs, impervious

wall of interconnected concrete piles or panels, and similar seepage barriers, used alone or in combination.

Sec. 611.3 Foundation Drainage: Where impervious cutoffi are provided or where suitable foundation

conditions exist, effective drainage and reliefof uplift pressures under buildings and structures can be achieved.

These foundation materials must be free-draining and have the desired degree of permeability. For the purpose

of these Regulations, foundation drainage is intended to consist of the provision of drainage blankets, trenches,

and in all cases, drain tiles or perforated drain pipes adjacent to footings and under floor slabs. Other methods

of foundation drainage, such as by means of sumps, well points, or deep wells can be used for special

applications. Drain pipes shall discharge into a sump or suitable collection structure, where the water is

collected and ejected by sump pumps.

6-5
Flood Proofing Regulations

Sec. 611.4 Sumps and Pumps: Spacing, sizing, and determinant ion of depth of sumps shall be consistent with

and correlated to the intended drainage system, the estimated amount of seepage and drainage yield.

Section 612.0 Requirements for Other Flood Proofing Methods

Sec. 612.1 Methods: A building shall be considered as being completely flood proofed if the lowest elevation

of all space(s) within the building perimeter including basement is above the RFD as achieved by:

(1) building on natural terrain beyond the limits of the bse flmd, on natural undisturbed

ground,

(2) building on fill,

(3) building on piles and or columns,

(4) protection by dikes, levees and/or flood walls.

These methods may be used alone or in combination to achieve the required degree of flood

prmfing. Data and design procedures shall, in all cases, be based on recognized and

acceptable methods of the applicable disciplines involved, and the following additional

requirements.

Sec. 612,2 Flood Proofing by Elevating the Building:

Sec. 612.2.1 Natural Terrain: In addition to the requirements of “The Building Cede,” the

building shall be located not less than feet back from the line of incidence of the base

flood on the ground. Assuming floodwater at the level of the RFD, foundation design shall

take into consideration the effects of soil saturation on the performance of the foundation,

and the effects of flood water on slope stability shall be investigated. Normal access to the

building shall be by direct connections with areas above the RFD and all utility service lines

shall be designed and constructed as required to protect the building and/or its components

from damage or failure during a flding event to the RFD.

Sec. 612,2,2 Building on Fill: The building and all parts thereof maybe constructed above

the RFD on an earth fill. Filling a flood hazard area within a designated floodway shall not

be permitted unless effects are mitigated and community variance is approved. Prior to

placement of any fill or embankment materials, the area upon which fill is to be placed,

including a five-foot strip measured horizontally beyond and contiguous to the toe line of

the fill, shall be cleared of standing trees and snags, stumps, brush, down timber, logs and

other growth, and all objects including structureson and above the ground surface or partially

buried. The area shall be stripped of topsoil and all other material which is considered

unsuitable by the Building Official as foundation material. All combustible and noncombustible materials and debris from the clearing, grubbing, and stripping operations shall k

removed from the proposed fill area and disposed of at locations above the RFD and/or in

the manner approved by the Building Official. Fill material shall be of a selected type,

preferably granular and free-draining and placed in compacted layers which are tested for

compaction density acmrding to ASTM D698 (Standard Proctor Density). Fill selection

and placement shall recognize the effects of saturation from floodwaters on slope stability,

uniform and differential settlement, and scour potential. The minimum elevation of the top

of slope for the fill section shall be at the RFD. The minimum distance from any point of

the building perimeter to the top of the fill slope shall be either 25 feet or twice the depth of

fill at that point, whichever is the greater distance. This requirement does not apply to

roadways, driveways, playgrounds, and other related features which are not integral and

functional parts of the building proper. Fill slopes for granular materials shall be no steeper

than one vertical on one and one-half horizontal, unless substantiating data justif ying steeper

slopes are submitted to the Building Official and approved, For slopes expsed to flood

velocities of less than five feet per second, grass or vine cover, weeds, bushes, and similar

6-6
vegetation undergrowth will be considered to provide adequate scour protection. For higher

velocities, stone, or rock slope protection shall be provided.

Sec. 612.2.3 Building on Piles or Columns: The building maybe constructed above the

RFD by supporting it on piles, piers, columns, and in certain cases, walls. Clear spacing of

support members, measured perpendicular to the general direction of flood flow shall not

be less than eight feet apart at the clmest point. The piles or columns shall, as far as

practicable, be compact and free from unnecessary appendages which would tend to trap or

restrict free passage of debris during a flood. Solid walls, or walled-in columns are

permissible if oriented with the longest dimension of the member parallel to the flow. Piles

or columns shall&capable of resisting all applied loads as required by “The Building Code”

and all applicable flood related loads as required herein. Bracing, where used to provide

lateral stability, shall be of a type that causes the least obstruction to the flow and the least

potential for trapping floating debris. Foundation supports may be of any approved type

capable of resisting all applied loads, such as spread footings, mats, and similar types. In

all cases, the effect of submergence of the soil and additional flmdwater related loads shall

be recognized. The potential of surface scour around the the piles or columns shall be

recognized and protective measures provided, as required.

Sec. 612.3 Protection by Dikes, hvees, and Floodwalls: The building shall be considered a flood proofed

type when it is protected from floodwaters to the RFD by means of dikes, levees, or floodwalls, either used

alone or in combination, as necessary. This protection may extend all around the building where all

surrounding ground is low, or on one or more sides where high ground (above the RFD) exists on the remaining

sides. Regardless of type and method of construction, dikes, levees, and floodwalls shall be designed and

constructed in accordance with recognized and accepted engineering practice and methods. They shall have

adequate strength and stability to resist all applied loads and shall provide an effective watertight barrier up

to the RFD. According to NFIP regulations, earthen dikes (levees) must be designed to a height of at least 3

feet above the BFE, and even higher in certain other situations. Areas behind dikes not built to provide

protection for the Base Flood, including the freeboard requirements, will not be recognized by FEMAas having

the level of protection intended by the construction, for purposes of the NFIP. FEMA design, operation, and

maintenance criteria for levee systems is set forth in 44 CRF 65.10. If a levee is built according to the provisions

in this regulation, the property protected by that levee may be removed from the SFHA.

If the levee or floodwall is a component of the flood proofing of an individual structure, it must be designed

such that below the BFE it is watertight, substantial] y impermeable to the passage of water, and be capable of

withstanding hydrodynamic and hydrostatic forces, and the effects of buoyancy. Thought there is no formal

requirement for freeboard for levees or floodwalls when used to flwdproof an individual structure, it is strong] y

urged to maintain a freeboard of one foot or greater. The levee or floodwall must, however, protect the

nonresidential structure to at least the base flood elevation level. As with other methods of flood proofing

nonresidential structures, the levee or floodwall must be designed (or have the design, plans and specifications

reviewed) by a registered professional engineer or architect. The design and methods of construction must be

certified that they are in accordanm with accepted standards of practice for meeting the provisions stated above

for being watertight and substantially impermeable to the passage of water.

Sec. 612.3,1 Dikes and Levees: Dikes and levees shall be constructed of suitable selected

materials, placed and compacted in layers to a section that has the required stability and

impermeability y. Prior to start of placement operations, the area on which the dike or levee

is to be constructed shall be prepared as required by 612.2.2. In cases where underlying

materials are highly pervious, it may be necessary to provide im~rvious cutoffs. A filter

blanket, drainage ditch and/or trench shall be provided along the interior toe of the

construction to collect seepage through the dike or levee. All seepage and storm drainage

shall be collected at a sump or sumps where it may be pumped out over the dike. Normal

surface runoff wit hin and into the diked area during nonflood periods may be discharged

through appropriate drainage pipes or culverts through the dike. Such culverts shall have a

dependable flap, slide gate, or backflow preventing device which would close either

automatically or manually to prevent backflow during a flood. Scour protection measures

for dikes and levees shall comply with the requirements of 612.2.2. Clearance from the toe

6-7
Flood Proofing Regulations

of the dike or levee to the building shall be a minimum of 20 feet or twice the height of the

dike or levee above the interior finished grade, whichever is greater.

Sec. 612.3.2 F1oodwalls: Floodwalls maybe constructed of concrete, steel sheet piling, or

other suitable structural materials. Regardless of type, the wall shall have adequate strength

and stability to resist the applied loads. The provisions of 612.3.1 shall be followed, as

applicable, regarding removal of unsuitable materials, provision of impervious cutoffs,

provision of seepage and storm drains, drainage ditches, sumps and sump pumps, and the

minimum clearances from the flocdwall to the building. It shall be recognized in the

drainage provisions that substantial amounts of leakage may occur through the interlock of

a steel sheet piling wall. Adequate expansion and contraction joints shall be provided in the

walls. Expansion joints will be provided for all changes in wall direction. ~ntraction and

expansion joints in concrete walls shall be provided with waterstops and joint sealing

material both in the stem and in the base. Steel sheet piling walls maybe encased in concrete

for corrosion protection or shall be coated with a coal tar epoxy coating system and

periodically inspected and maintained. Steel sheet piling walls may be used as the impervious core of a dike.

6-8
Chapter 7

Closure of Openings

Section 700.0 Scope

Sec. 700.1 General: Openings in exterior and interior walls of buildings or structures in a Special Flocd

Hazard Area which are wholly or in part below the RFD shall be provided with waterprmf closures meeting

the requirements of this chapter.

Section 701.0 ~pes of Closures

Sec. 701.1 Classification: Closures shall be classified into five types according to their compatibility with

the waterproofing standards of the various flood proofing classes.

Sec. 701,1,1 Type 1 Closures - shall forma complete sealed barrier over the opening that

is impermeable to the passage of water at the full hydrostatic pressure of a flood to the RFD.

Sec. 701.1.2 Type 2 Closures - shall form essentially dry barriers or seals, allowing only

slight seepage during the hydrostatic pressure conditions of flooding to the RFD.

Sec. 701.1.3 Type 3 Closures - shall form barriers or seals that are impermeable to the

passage of waterborne contamination under equalized pressure conditions.

Sec. 701.1,4 Type 4 Closures - shall form barriers to the passage of flood carried debris and

the loss of floating items from the interior, but are not required to form impermeable seals.

Sec. 701.1.5 Type 5 Closures - are those of existing spaces which do not meet the

requirements of any of the above described types, but are in use as required by “The Building

tide.”

Section 702.0 Requirements

Sec. 702.1 Design Standards for Closure Assemblies: The structural capacity of all closures shall be

adequate to support all flood loads acting u~n its surface. Closure assemblies may be fabricated of cast iron,

steel, aluminum, or other adequate and durable structural material, provided with a continuous support around

its perimeter, and shall be attached to the building or structure at its immediate location of use i.e.; hinged, on

slides, or in a vertical recess. The closure device shall be capable of bing set in place with minimal manual

effort. Seals, where required, shall be gasketed pressure ty~s permanently anchored or attached to the

structure or to the closure assembly. Closures designed to lift into vertical recesses for storage when not in

use, and/or located so that the open position of the assembly will not impede fire exit or the functioning of fire

closure assembly, shall be supported in the open position by auxiliary supports or safety latches that can be

released at times of flooding. In the closed ~ition, the closure assembly shall engage fixed wedging blocks

that will force the closure into a tight sealing position. The entire cl~ure assembly should be inspected by the

owner annually and suitably maintained to preserve its waterproof and structural quality or be replaced as

required.

Sec. 702.2 Frames for Openings: Each opening below the RFD shall have a metal frame suitable for

providing an adequate sealing surface and for supporting the flood proofing closure assembly. The frame shall

be connected to the adjacent walls and floors and provide adequate bearing surface and anchorage to transfer

the panel loading into the wall. It shall be supported upon adjacent floor or wall intersections or sufficient

reinforcement shall be provided around the opening in the concrete or masonry wall to transfer the panel load

to such intersections as required.

Sec. 702.3 Openings in Shafts: All buildings or structures which have enclosing walls, decks, or shafts with

horizontal or inclined openings at the top that are at or below the RFD and which would inundate WI or W2

spaces shall be provided with Type 1 closure assemblies that can be readily positioned and secured to prevent

7-1
Flood Proofing Regulations

entrance of floodwaters. Construction of such o~nings shall provide for permanently affixed doors, wall

extensions, gates, panels, etc., that are either hinged or on slide tracks to facilitate prompt and positive sealing

of the opening with only minimal manual effort. Windows, grilles, vents, door openings, etc. in the side walls

of a shaft and below the RFD shall be provided with flood proofing closures meeting the requirements of 701.0.

Sec. 702.4 Fire Resistivity of Closure Assemblies: All flood proofing closure assemblies shall have a fire

resistive rating that conforms to the requirements of “The Building me” and the particular fire protection

requirements for the oeeupancy group and building ty~ of the structure.

Section 703.0 Special Applications of Closure Assemblies

Sec. 703.1 Applicability: Residences, firms, businesses, or institutions with fewer than 10 permanent

employees; or spaces which are or would be unoccupied and unattended in their foreseeable normal operation

for periods of greater than 72 hours shall not have any window, doorway, or other such opening any part of

which is below the RFD unless at least one of the following conditions is met:

(1) Type 1 and 2 closures are utilized and are fully automatic types.

(2) Manually installed closure devices meeting the requirements of the appropriate flood

proofing class are provided and are installed in their protective position by the Owner at any

time in the season of high flood danger during which the space will be unoccupied and

unattended for periods of longer than eight hours. This requirement shall be considered in

the Owner’s tintingency Plan and noted by the Building Official on the permit and

Certificate of Occupancy.

(3) Watertight exterior walls, dikes, levees or fltiwalls of adequate design (as specified

in Chapter 6) are constructed to prevent floodwaters up to the RFD from entering the

structure or space.

7-2
Chapter 8

Internal Flooding and Drainage

Section 800.0 Scope

Sec. 800.1 General: The provisions of this chapter shall apply to the intentional flooding of buildings,

structures, and spaces with water from potable or floodwater sources for the purpose of balancing internal and

external pressures to protect a structure and/or its components from damage or failure during floods up to the

RFD.This is also known as wet flood proofing. (See also Sec. 401.7, Wet Flood Proofing and the National

Flood Insurance Program).

Section 801.0 Intentional Flooding with Potable Water

Sec. 801.1 Applicability: Spaces to k intentionally flooded (W3 spaces) to maintain a balanced internal and

external pressure condition shall be filled automatically with potable water from a source provided by the

Owner as required by 801.2 and approved by the Building Official. This level of filling shall & equal to that

of the external flood surface unless a reduction in the internal flooding level is requested in writing by the

Owner, and such approval is granted by the Building Official. The Owner shall, together with the written

request, submit sufficient evidence that full internal flooding is unnecessary to protect the structure. The

potable water flooding system shall activate and operate automatically and completely without human

intervention and shall act independently of the emergency flooding system utilizing floodwaters as required

for these spaces by 801.3 An automatic drainage system shall also be provided that will assure positive

drainage of the space(s) at a rate comparable to the reduction of exterior flood height when floodwaters are

receding.

Sec. 801.2 Potable Water Sources: At any lmation where disruption of water supply service from a public

utility may occur, or such service may be deemed inadequate, the Building Official shall require the Owner

to provide an independent source of potable water that will be stored at the location of the improvement. In

areas with history of multiple cresting, the Building Official may require that the supply of stored water be

increased by a specified amount to cover this condition.

Sec. 801.3 Safeguard Against Failure of Potable Water Flooding System: Where intentional floding with

a potable water flooding system is used for maintaining the structural integrity of buildings, structures, or

spaces during flood events to the RFD, an emergency (back up) flooding system utilizing flood waters shall

be provided and maintained in a state of readiness for automatic implementation in the event of failure of the

primary potable water flooding system. The emergency flooding system shall comply with all requirements

of 802.0.

Section 802.0 Automatic Flooding with Floodwater

Sec. 802.1 Applicability: Spaces to be intentionally floded with floodwater (W4) shall be provided with the

necessary equipment, devices, piping, controls, etc. necessary for automatic flooding during the flood event

and drainage of the space(s) when floodwaters recede. The automatic flooding and drainage system(s) shall

utilize approved piping materials and have sufficient capacity for raising or lowering the internal water level

at a rate comparable to the anticipated rate of rise and fall of a flood that would reach the RFD. These pipe

systems shall be directly connected to the external floodwaters to maintain a balanced internal and external

water pressure condition. Provisions shall be made for filling the lower portions of the structure first and for

interconnections through or around all floors and partitions to prevent unbalanced filling of chambers or parts

within the structures. All spaces below the RFD shall k provided with air vents extending to at least _ feet

ahve the elevation of the RFD to prevent the trapping of air by the rising water surface, All opnings to the

filling drainage systems shall be protected by screens or grills to prevent the entry or nesting of rodents or birds

in the system. The NFIP requires under 44 CFR 60.3 (c) (5) that such openings only be located below the

lowest flmr of the building, and be no higher than one fmt above grade. The lower area must have a minimum

of two openings having a total met area of not less that one square inch per foot of enclosed area subject to

flooding.

8-1
Flood Proofing Regulations

Section 803.0 Emergency Flooding of Waterproofed Spaces

Sec. 803,1 Applicability: Spaces which have been waterproofed (W1 or W2) to the RFD shall tx provided

with an automatic internal flooding system meeting al] requirements of 802.0 to maintain structural integrity

during floods which exceed the RFD elevation. Inverts shall be located at the RFD elevation unless an increase

in invert elevation(s) above the RFD is requested in writing by the Owner, and approval is granted by the

Building Official. Approvals shall not b granted by the Building Official until sufficient evidence has been

furnished by the Owner that automatic internal flooding at the RFD elevation is not necessary to maintain

structural integrity. Outlets for the drainage of water from waterprmfed spaces shall & located to properly

drain the water from all parts of the spaces. TO prevent the inflow of water at flocd levels below the RFD each

exterior drainage outlet shall be provided with a device for preventing backflow of water (flood) through the

drainage system. Auxiliary outlets shall be provided as required to evacuate all water from upper floor levels

before draining the lower spaces. All watertight walls shall be designed for an internal hydrostatic pressure

equal to at least two feet of differential head to provide for unknown factors that may cause malfunction of

the required drains.

8-2
Chapter 9

Floorinq

Section 900.0 Scope

Sec. 900.1 General: This chapter shall govern the design and use of floor systems and their constituent

materials for buildings and structures located in a Special Ftood Hazard Area.

Sec. 900.2 Basis for Restriction: Floor systems and flooring materials are restricted according to their

vulnerability to floodwater. For the purpose of these Regulations, vulnerability y of a given floor or floor

material may result from one or more of the following:

(1) Normal suspended-floor adhesives specified for above grade use are water-soluble or

are not resistant to alkali or acid in water, including ground seepage and vapor.

(2) Flooring material contains wood or paper products.

(3) Flooring material is not resistant to alkali or acid in water.

(4) Sheet type floor coverings (Linoleum, rubber, vinyl) restrict evaporation from non-Wl

slabs.

(5) Ftooring material is impervious but dimensionally unstable.

Section 901.0 Flooring Classifications

Sec. 901.1 Classes of Flooring: Floor systems and flooring materials are divided into five classes according

to their degree of vulnerability. Class 1 flmrings require conditions of drynes provided by W1 spaces. Class

2 floors require essentially dry spaces which may be subject to water vapor and slight seepage that is

characteristic of W2 spaces. Class 3 flooring may be submerged in clean water during ~riods of intentional

flooding as provided by W3 spaces. Class 4 floorings maybe exposed to and/or submerged in floodwaters in

interior spaces and do not require special waterproofing protection. Class 5 floors are permitted for partially

enclosed or outside uses with essentially unmitigated flood exposure.

Sec. 901.1.1: Ploors of a given class may be used in any application for which a lower-numbered class is permitted by these Regulations unless specifically restricted by notation in the

chart below. For example, concrete (a Class 5 floor) maybe used whenever floors of Classes

1,2,3,4, or 5 are permitted.

Sec 901.1.2 Classes of Typical Flooring Materials: The following chart is intended as an

aid to the Owner, Architect/Engineer and the Building Official in assessing the vulnerability

of typical materials with respect to the criteria stated in 900.2(1-5). In disputes arising over

the merits of particular materials or methods of construction, the Building Official shall be

guided by and decide on the basis of those criteria.

Asphalt tiles (A)

with asphaltic adhesives

Carpeting (glued-down types)

Cement/bituminous, formed-in-place

Cement/latex, formed-in-place

Ceramic tiles (A)

with acid and alkali-resistant grout

Chiphard

Class

1

3

1

4

4

1

3

1

9-1
Clay tile

Concrete, precast or in situ

@ncrete tile

Cork

Enamel felt-base floor coverings

Epoxy, formed-in-place

Linoleum

Magnesite (magnesium oxychloride)

Mastic felt-base flood coverings

Mastic flooring, formed-in-place

Polyurethane, formed-in-place

PVA emulsion cement

Rubber sheets (A)l

with chemical-set adhesives (B)

Rubber tiles (A)

with chemical-set adhesives (B)

Silicone floors, formed-in-place

Terrazzo

Vinyl sheets (homogeneous) (A)

with chemical-set adhesives (B)

Vinyl tile (homogeneous) (A)

with chemical-set adhesives (B)

Vinyl tile or sheets (mated on cork or wood product backings)

Vinyl-asbestos tiles (semiflexible vinyl) (A)

with asphaltic adhesives

Wmd flooring or underlay merits

Wood composition blocks, laid in cement mortar

Wood composition blocks, dipped

and laid in hot pitch or bitumen

Class

5

5

5

1

1

5

1

1

1

5

5

1

*5

1

4

5

4

1

*5

1

4

1

1

4

1

2

2

*Not permitted as Class 2 flooring

Notes: (A) Using normally-specified suspended floor (i.e., above grade) adhesives, includingsulfite liquor (Iignin or’’linoleum paste”), rubber/Asphaltic dispersions, or “alcohol” type

resinous adhesives (cumar, oleoresin).

(B) e.g. epoxy-polyamide adhesives or latex-hydraulic cement.

9-2
Chapter 10

Walls and Ceilings

Section 1000.0 Scope

Sec. 1000.1 General: This chapter shall govern the design and use of wall and ceiling systems and their

constituent materials for buildings and structures lmted in a Special Flood Hazard Area.

Sec. 1000.2 Basis for Restriction: Materials treated in this chapter are those which constitute interior walls

and ceilings including their finishes and structural constructions upon which they depend such as sheathing

and insulation, and are restricted according to their susceptibility to flood damage. For the purpose of these

Regulations, susceptibility of a given interior material or construction is dependent on one or more of the

following:

(1) Normal adhesives specified for above-grade use are water- soluble or are not resistant

to alkali or acid in water, including ground seepage and vapor.

(2) Wall or ceiling material contains wood, wood products, gypsum products, or other

material which dissolves or deteriorates, loses structural integrity, or is adversely affected

by water.

(3) Wall or ceiling material is not resistant to alkali or acid in water.

(4) Material is impervious but dimensionally unstable.

(5) Materials absorb or retain water excessively after submergence.

Section 1001.0 Wall/Ceiling Classifications

Sec. 1001.1 Classes of Wall/Ceiling: Wall and ceiling systems and materials are divided into five classes

according to the degree of vulnerability. Class 1 materials require conditions of dryness provided by WI

spaces. Class 2 materials require essentially dry spaces which maybe subject to water vapor and slight seepage

that is characteristic of W2 spaces. Class 3 wall and ceiling materials may be submerged in clean water during

pericds of intentional flooding as provided by W3 spaces. Class 4 materials may be exposed to and/or

submerged in floodwaters in interior spaces and do not require special waterproofing treatments or protection.

Class 5 wall and ceiling materials are permitted for partially enclosed or outside uses with essentially

unmitigated flood exposure.

Sec. 1001.1.1: Materials of a given class may be used in any application for which a

lower-numbered class is permitted by these Regulations, For example, concrete (a Class 5

wall/ceiling material) may be used whenever materials of Classes 1, 2, 3, 4, or 5 are

permitted.

Sec. 1001,2 Classes of Typical Wall/Ceiling Materials: The following chart is intended

as an aid to the Owner, Architect/Engineer, and the Building Official in assessing the

vulnerability of typical materials with respect to the criteria stated in 1000.2(1-5). In

disputes arising over the merits of particular products or of materials not listed below, the

Building Official shall be guided by and decide on the basis of those criteria.

Class

Asbestos-cement ~rd 5

Brick, face or glazed 5

common 2

Cabinets, built in

Wood 2

Metal 5

10-1
Cast stone (in waterproof mortar)

Chalkboards

Slate, porcelain glass, nucite glass

Cement-asbestos

Compmition, painted

Chiphard

Exterior Sheathing Grade

Clay tile

Structural glazed

@ramic veneer, ceramic wall tile-mortar set

Ceramic veneer, organic adhesives

~ncrete

tincrete block

~rkboard

Dmrs

Wood hollow

Wood, light weight panel construction

Wood, solid

Metal, hollow

Metal, Kalamein

Fiberboard panels, Vegetable types

Sheathing grade (asphalt coated or impregnated)

Otherwise

Gypsum products

Gypsum hard

Keene’s cement on plaster

Plaster, otherwise, including acoustical

Sheathing panels, exterior grade

Glass (sheets, colored tiles, panels)

Glass blocks

Hardkard

Tempered, enamel or plastic coated

All other types

Insulation

Foam or closed cell types

Batt or blanket types

All other types

Metals, non-ferrous (aluminum, copper, or zinc tiles)

Ferrous

Mineral fiberboard

Plastic wall tiles (polystyrene, urea formaldehyde, etc.)

waterprmf adhesives, pointed with waterproof grout

Set in water-soluble adhesives

Paint

Polyester-epoxy and other waterproof types

All other types

Paperboard

Partitions, folding

Metal

wood

Fabric-revered ty~s

Partitions, stationary

Wood frame

Metal

Class

5

5

2

2

1

2

5

4

2

5

5

2

2

2

2

5

2

2

1

2

2

2

2

4

5

2

2

4

1

2

3

5

1

3

2

4

1

1

4

2

1

4

5

10-2
Chapter 10

class

Glass, unreinforced 4

Reinforced 4

Gypsum, solid or block 1

Rubber, mouldings and trim with epoxy-polyamide

adhesive or latex-hydraulic cement. 4

All other applications 1

Steel, (panels, trim, tile) with waterproof applications 5

With non-waterproof adhesives 2

Stone, natural solid or veneer, waterproof grout 5

Stone, artificial non-absorbent solid or veneer, waterproof grout 5

All other applications 2

Strawboard

Exterior grade (asphalt-impregnated kraft paper) 2

All other types 1

Wall coverings

Paper, burlap, cloth types 1

wood

Solid (boards, sheets, or trim) 2

Plywood

Exterior grade 2

Otherwke 1

10-3
Chapter 11

Contents of Buildings and Structures

Section 1100.0 Scope

Sec. 1100.1 General: This chapter shall govern the types of contents permitted and protection requirements

for contents of spaces in buildings or structures lmted in Special Flood Hazard Areas.

Sec. 1100.1.1: The contents of an improvement consist of all items situated or placed within

the confines of a space not permanently and structurally integral with the improvement.

Electrical and mechanical equipment that is installed as a building services feature and/or

required to be in operation during a flood is covered in Chapters 12 and 13. Contents are

restricted by these Regulations whenever they are or potentially may be:

(1) Hazardous to the general public welfare due to the possibility of spreading highly

flammable, explosive, corrosive, or otherwise harmful substances in the event of a flood-induced spill.

(2) Hazardous to the welfare of other Owners due to the creation of projectiles which could

cause damage by impact.

(3) Hazardous as in (1) or (2) above when stockpiled in quantity, although such items may

be permitted if stored in lesser amounts for isolated or occasional use.

(4) Hazardous to the health or safety of the Owner or to other persons occupying or in the

vicinity of the improvement due to the possibility of explosion or electric shock caused by

floodwater contact with operating mechanical or electrial equipment.

(5) Vulnerable as a loss to the Owner, necessitating replacement, extensive repair, and/or

excessive period of inoperation resulting from prolonged exposure to moisture, clean water,

floodwater, or the unmitigated effects of flooding.

Section 1101.0 Classes of Contents

Sec. 1101.1 Applicability: ~ntents are divided into seven classes acmrding to the degree of flcod proofing

required to protect them from becoming hazards or losses as defined above.

(1) Class XX items are extremely hazardous or vulnerable to flood conditions and require

their prohibition in Special Flood Hazard Areas at all times.

(2) Class X items are sufficiently hazardous or vulnerable to require their prohibition in all

spaces below the RFD, i.e., requiring their placement atleast one floor level above the RFD.

(3) Class 1 items require the protection assured by W1 spaces.

(4) Class 2 items require the protection assured by W2 spaces.

(5) Class 3 items require only the protection assured by W3 spaces.

(6) Class 4 items are generally not damageable by floodwaters moving at low velocities

and require the minimum protection given by W4 spaces.

(7) Class 5 items are sufficiently non-hazardous and non- vulnerable to permit their

placement in spaces exposed to unmitigated flooding renditions.

11-1
Sec. 1101.2 Waiver of Restriction: Upon approval of the Owner’s ~ntingency Plan, which shall include

plans for temporary movement of items to a place of safe refuge above the RFD or in spaces below the RFD

where these items are permitted, the Building Official may waive specific content restrictions for non-Wl

spaces on non-hazardous items that are movable or for which the degree of waterproofing required by the flood

proofing class can be achieved upon receipt of a flood warning or alert. This waiver of restriction, however,

shall not apply to residences and their ancillary spaces; to firms, businesses, or institutions with fewer than 10

permanent employees and their ancillary spaces; or to any spaces which are or would be unoccupied and

unattended in their foreseeable normal yearly operation for periods greater than 72 hours; and in no case shall

a waiver of restriction be construed to permit the creation of spaces for human habitation.

Sec. 1101.3 Contents Classes for Typical Items: The following chart is intended as an aid to the Owner,

Architect/Engineer, and the Building Official in assessing the hazard potential and vulnerability to loss of

typical contents of an improvement with respect to criteria listed in 1100,1.1(1-5). In disputes arising over the

classification of particular items or of items not listed below, the Building Official shall be guided by and

decide on the basis of those criteria. In no case, however, shall changes of classification for items listed in

Classes X and XX be permitted.

Sec. 1101.3.1: Gntents of a given class may be situated or placed in any space for which

a lower-numbered class is permitted by these Regulations. For example, items which are

listed in Class 3 may also be placed in any spaces in which Class 1 or Class 2 contents are

permitted.

Sec. 1101.3.2: Temporary placement of items of a given contents class in a space with a

higher-numbered flood proofing class may be permitted in those cases where contingent

removal is approved by the Building Official, and in conformance with 1101.2. Temporary

placement may be permitted for certain items, subject further to the restrictions of 1101.2

as indicated by numbers in parenthesis in the list; in each case, the number in parenthesis is

that of the highest-numbered fld proofing class in which temporary placement may be

considered.

Acetone

Acetylene gas containers

AmmoniaXX

Animals (pets, livestock, laboratory specimens)

Appliances, electrical

Washers, dryers, unit air mnditioners, lamps,

refrigerators, sewing machines, electric clocks, etc.

Aft works (paintings, sculpture, etc.)

Barrels, buoyant (empty or non-hazardous contents

tinstrained and/or without tops or lids

Benzene

Books, magazines, publications

Cabinets

Solid wood or veneer

Metal

Calcium carbide

Carbon disulfide

Cardboard boxes

Carpeting and floor rugs

Celluloid

Chlorine

Clothing

@tton (loose) wadding or waste

Curtains and drapes

Fabric (Nonfast dyes)

Class

xx

x

x(5)

2

1

2

4

xx

1(3)

2

4

xx

xx

1

1(3)

xx

xx

2(3)

2

2

11-2
Flood Proofing Regulations

Fabric (Fast dyes)

Plastics

Drugs - in quantity

Electrical distribution equipment (Storage only)

Waterproof or submersible types

Nonwaterproof

Protected contingently (B)

Electronic equipment (Storage only)

Television, stereo equipment, radios

Computers, etc.

Fabri= ~extile Raw Materials)

Non water-soluble dyes

Otherwise

Food Products

Furniture

Upholstered

Unupholstered

Wood construction (A)

Metal construction, painted

Gasoline

Hydrochloric acid

Hydrocyanic (Prussic) acid

Magnesium

Matches and sulfur products (in quantity)

Mattresses & box springs

Musical instruments

Pianos, organs, violins, etc.

All other types

Nitric acid, oxides of nitrogen

Oxygen

Paints, enamels, varnishes (in quantity)

Paper or paper productsl

Petroleum products storage

(unless buried and constrained)

Phosphorous

Potassium

Recreation equipment

Sports gear, toys

Pool tables

Scrap metal, unstrained

Soaps, detergents (in quantity)

Sodium

Sulphur

Tires

(Open storage)

constrained

Wood products, raw or finished (in quantity)

Class

3

4

x

4

2

4

2(3)

1

3

2

x

1

2

4

x

xx

xx

xx

x

1(2)

1

2(3)

xx

2(3)

2

x

xx

xx

2(3)

1

5

x

xx

xx

x

4

x

Notes: (A) Solid wood construction with pinned joints, reinforced corners, and lacquered or factory-baked

finishes.

(B) Contingent protectior~shall be protection equal to that of 6 roils of polyethylene sealed to be watertight or

“moth-balled,”

Sec. 1101,4 Underground Storage TtlnM: The exclusion of Class X and XX contents from interior spaces

of buildings below the RFD recognizes that residual flood hazards may exist when a structure is only protected

to the RFD. However, a properly designed and constructed underground storage tank and dispensing system

11-3
Chapter 11

for Class X contents can be developed in a Special Flood Hazard Area, if such development is the only

practicable alternative and it is not contained within a flood proofed structure. In addition to design criteria

required by the tank manufacturers and applicable fire and safety codes, the tank awemblies should be designed

assuming groundwater levels fully at the ground surface, buoyant soils above the tanks, and the tanks empty.

They should also be designed assuming the tanks full with groundwater below the tanks. The tanks should be

set on and anchored to reinforced concrete pads. All vents should be above all possible floodwater entry levels.

The filling stack piping caps should be equipped with watertight seals if below the RFD and the dispensers

should be placed above the RFD.

11-4
Chapter 12

Electrical

Section 1200.0 Scope

Sec. 1200.1 General: Where buildings or parts of buildings and structures extend below the RFD, the electrical

materials, equipment, and installation shall conform to the requirements of this section of the Regulations.

Section 1201.0 Requirements at Locations Above and Below the RFD

Sec. 1201.1 Main Power Service: The incoming main mmmercial power service equipment, including all

metering equipment, shall be located above the RFD. Whenever a building or structure is not accessible by a

bridge, walkway, or other connecting means except by boat during periods of flooding to the RFD, a means

for disconnecting the incoming main commercial power service shall be provided at an accessible remote

location above the RFD.

Sec. 1201.2 Stationary and Portable Equipment: Switchgear, control centers, transformers, distribution,

and main lighting panels in addition to all other stationary equipment shall be located above the RFD. Portable

or movable electrical equipment maybe located in any space below the RFD provided that the equipment can

be disconnected by a single plug and socket assembly of the submersible type and rated by the manufacturer

as submersible for not less than 72 hours for the head of water above the assembly to the RFD. All dismnnect

assemblies shall be provided with submersible seals attached to the disconnect assembly by means of a

corrosion resistant metal chain for immediate use when needed to ensure safety to all personnel during a flood.

All portable or movable equipment should be de-energized and/or moved out of potentially flooded spaces

upon receipt of a flood warning and prior to floodwaters reaching floor levels where such equipment is located.

Sec. 1201.3 Normal and Emergency Elghting Circuits: All circuits except emergency lighting circuits,

extending into areas below the RFD shall be energized from a common distribution panel located above the

RFD. All emergency lighting circuits into areas below the RFD shall k energized from an independent

distribution panel also located above the RFD. Each distribution panel shall have the capability of being

de-energized by a separate single disconnecting device.

Sec. 1201.4 Emergency Lighting Requirements: All areas of the building or structure that are below the

RFD, where personnel may be required to mnduct emergency operations or work with water present on the

floor of the area during a flood, shall be provided with automatically operated emergency lighting facilities

and automatically operated electrical dismnnect equipment to ensure that all electrical circuits into these areas,

except emergency lighting circuits, are de-energized prior to personnel working in water. The electrical

circuits shall be de-energized prior to the presence of any water on the floor of the affected area. All

com~nents of emergency lighting systems installed below the RFD shall be so located that no component of

the emergency lighting system is within reach of personnel working at floor level in the areas where emergency

lighting systems are utilized unless the emergency lighting circuits are provided with ground-fault circuit

interrupters having a maximum leakage current to ground sensitivity of five milliamperes. The energy for

emergency lighting may be furnished by a storage battery(s), prime mover-generator system, a separate

commercial power supply system, the same mmmercial power system, or a combination thereof, subject to

the following provisions of this section.

Sec. 1201.4.1 Storage Battery (including battery operated lighting units): Battery

operated lighting units shall be completely self-contained and shall indinte the state of

charge of the battery at all times. Lighting units shall automatically provide light when the

normal source of lighting is de-energized. Sufficient number of emergency lighting units

shall be provided to enable personnel to ~rform their assigned emergency tasks and to

permit a safe exit to areas above the RFD.

Sec. 1201.4,2 Separate Commercial Power Supply System: This source of energy shall

have a degree of reliability satisfactory to the Building Official. A system fed from a

substation other than that used for the regular supply and not on the same poles (except

service pole) as the regular supply is deemed to have the required degree of reliability. A

12-1
Flood Proofing Regulations

secondary circuit fed from the same primary network circuit as the regular supply shall be

regarded as a separate system.

Sec. 1201.4.3 Same Commercial Power Supply System: The system shall be an underground secondary network system and a separate service shall k mnnected on the line side

of the service switch or breaker of the regular service.

Sec. 1201.5 Lighting Circuits Below Regulatory Flood Datum: Lighting circuit switches, receptacles, and

lighting fixtures operating at a maximum voltage of 120 volts to ground may be installed below the RFD,

provided that these circuits shall be de-energized as noted in 1201.4. Should any switch, receptacle, or lighting

fixture be flooded, its particular circuit shall not be re-energized until such circuits and devices, and/or any

part thereof, have been disassembled and thoroughly checked, cleaned, or replaced, and approved for use by

qualified personnel.

Sec. 1201.6 Submersible Equipment: Except for the switches, receptacles, and lighting fixtures noted herein,

all other electrical equipment permanently installed below the RFD shall be of the submersible type rated by

the manufacturer for submergenm for not less than 72 hours for a head of water above the equipment to the

RFD.

Sec. 1201.7 Submersible Wiring Requirements: All electrical wiring systems installed below the RFD shall

be suitable for continuous submergence in water and shall contain no fibrous components. Only submersible

type splices will be permitted in areas below the RFD. All mnduits located below the RFD shall be so installed

that they will be self-draining if subject to flooding conditions.

Sec. 1201.8 Elevators: All electric ~wer equipment and components of elevator systems shall be located

above the RFD. Automatic type elevators shall be provided with a home station to which the elevator will

automatically return after use, with home station located above the RFD.

Sec. 1201.9 Electric Heating Equipment: Electric unit heaters installed below the RFD shall be capable of

disconnection and removal in the manner described for portable electrical equipment in 1201.2. Electric

controls on gas and oil furnaces located below the RFD shall not exceed 120 volts to ground and the control

circuits shall be automatically de-energized prior to the presenm of any water on the floor of the affected area

in accordance with 1201.4.

Sec. 1201.10 Sump Pump Installation: Buildings and structures utilizing sump pumping equipment of any

type to keep areas within the structure free of water shall be provided with float operated warning alarms that

shall act independently of any other float actuating devices used to start and stop pumping equipment. All

buildings or structures utilizing sump pumping equipment shall be provided with automatic starting standby

electrical generating equipment located above the RFD. The standby generating equipment shall be capable

of remaining in continuous operation for a period of 125 percent of the anticipated duration of the design flood.

12-2
Chapter 13

Mechanical

Section 1300.0 Scope

Sec. 1300.1 General: All mechanical systems, including heating, air conditioning, ventilating, plumbing,

sanitary, and water systems, in or serving buildings or structures in a Special Flood Hazard Area shall be

designed and installed to compl y with the requirements of this chapter.

Section 1301.0 Heating, Air Conditioning, and Ventilation Systems

Sec. 1301.1 Applicability: Heating, air conditioning, and ventilation systems, including all appurtenances,

in buildings or structures in a Special Flood Hazard Area shall k designed and installed to comply with the

requirements of these Regulations.

Sec. 1301,2 Location: Heating, Air Gnditioning, and Ventilating Equipment should, to the maximum extent

possible, be installed in areas and spaces of buildings that are above the RFD. When not feasible, said

equipment shall be located in WI or W2 spaces (below the RFD) with direct access provided from a location

above the RFD, and shall conform to all requirements of this Section.

Sec. 1301.2.1: Heating systems utilizing gas or oil fired furnaces shall have a float operated

automatic control valve installed in the fuel supply line which shall beset to operate when

floodwaters reach an elevation equal to the floor level of the space where furnace equipment

is installed. A manually operated gate valve that can be operated from a location above the

RFD shall be provided in the fuel supply line to serve as a supplementary safety provision

for fuel cutoff. The heating equipment and fuel storage tanks shall be mounted on and

secure] y anchored to a foundation pad or pads of sufficient mass to overcome buoyancy and

prevent movement that could damage the fuel supply line. As an alternate means of

protection, elevation of heating equipment and fuel storage tanks above the RFD on

platforms or by suspension from overhead structural systems will be permitted, All unfired

pressure vessels will be accorded similar treatment. Fuel lines shall be attached to furnaces

by means of flexible or swing type couplings. All heating equipment and fuel storage tanks

shall be vented to an elevation of at least feet above the RFD. Air supply for combustion

shall be furnished if required for system~stalled in WI or W2 spaces, and piping or duct

work for such purpose shall be terminated at least — feet above the RFD.

Sec. 1301.2.1.1: All duct work for warm air heating systems which is lccated

below the RFD shall be provided with emergency openings for internal flooding

and drainage of the ducts with all openings having covers with gravity operators

for closure during normal operation. Where duct work must pass through a

watertight wall or floor below the RFD, the duct work shall be protected by a

mechanically operated closure assembly and shall be provided with the operator

control psition above the RFD. The closure assembly in its open position shall

not impede the normal function of the heating system.

Sec. 1301.2.1.2: Steam or hot water heating pipes located below the RFD shall be

provided with shut-offvalvessufficient to isolate the piping system when itislikely

that the forecasted flood crest level will expose the piping system to flooding.

Sec. 1301.2.1.3: Electric heating systems, where utilized in Special Fled Hazard

Areas, shall be installed in accordance with requirements of Chapter 12.

Sec. 1301.2.2: Air conditioning and ventilation systems that will be located below the RFD

shall be installed in W1 or W2 spaces only. All installation, piping, duct work, connections,

and safety features shall conform to the same requirements stated for Heating Systems in

1301.2.1.

13-1
Flood Proofing Regulations

Sec. 1301.2.3: Where heating, air conditioning, orventilatingsystems (as definedin 1301.2)

are installed in other than WI or W2 spaces, all bearings, seals, shafts, gears, clutches, valves,

or controls which are susceptible to damage from contact with water or silt, or are not capable

of withstanding hydrostatic or hydrodynamic loading, shall be provided with suitable

protective waterproofing enclosures as maybe required by the Building Official.

Sec. 1301.2.4: All fuel supply lines that originate either outside of WI or W2 spaces or pass

through areas that would be flooded, shall be equipped with automatic shut-off valves to

prevent loss of fuel in the event of a line breakage. The wall opening shall be flood proofed

by use of imbedded collars, sleeves, waterstops, or other means as may be approved by the

Building Official.

Sec. 1301.2.5: Electrical connections to all mechanical systems covered by this chapter

shall conform to the requirements of Chapter 12.

Section 1302.0 Plumbing Systems

Sec. 1302.1 Applicability: For the purpose of these Regulations, plumbing systems shall include sanitary and

storm drainage, sanitary facilities, water supply, storm water and sewage disposal systems.

Sec. 1302.1,1: Except as otherwise provided herein, nothing in these Regulations shall

require the removal, alteration, or abandonment of, nor prevent the continued use of, an

existing plumbing system.

Sec. 1302.1.2: Plumbing materials shall be selected with due consideration given to the

hydrostatic, hydrodynamic, and chemical actions of floodwaters on the interior of piping

systems, of the soil, fill, or other materials on the exterior of piping systems, on joints,

connections, valves, traps, seals (and caulking), and fixtures.

Sec. 1302,2: Systems below RFD: Sanitary sewer and storm drainage systems that have openings below the

RFD shall be provided with automatic backwater valves or other automatic backflow devices that are installed

in each discharge line passing through a building exterior wall, In W1 spaces, manually operated shut-off

valves that can be operated from a location above the RFD shall also be installed in such lines to serve as a

supplementary safety provision for preventing backflow in case of automatic backflow device failure or line

break between the space(s) and the device.

Sec. 1302,2.1: Spaces in buildings that are to be protected from floodwaters by implementation of the Owner’s Contingency Plan may utilize standpi~s attached to floor drains,

cleanouts, and other openings below the RFD, and/or manually operated shut-off valves or

closure devices.

Sec. 1302.2.2: Where the state of dryness of a space is dependent on a sump pump system,

or where the stability of a structure during a flood event depends on the relief of uplift

pressures on building components, all interior storm water drainage or seepage, applian~

drainage, and underslab drain tile systems shall be directly ~nnected to a sump (pump) and

discharged at an elevation at least — feet above the RFD.

Sec. 1302,2,3: Sanitary sewer systems, including septic systems, that are required to remain

in operation during a flood shall k provided with a sealed holding tank and the necessary

isolation and diversion piping, pumps, ejectors, and appurtenances required to prevent

sewage discharge during the flood. me holding tank shall be sized for storage of at least

150 percent of the anticipated demand for the duration of a flood to the RFD.

Sec. 1302.2.3.1: All vents shall extend to an elevation of at least feet above

the RFD.

13-2
Sec. 1302.2.3.2: All pipe openings through walls below the RFD shall be flocd

proofed to prevent floodwater backflow through spaces between pipes and wall

construction materials. (See 1301.2.4)

Sec. 1302.3 Sewage Dis~salflreatment: Individual sewage disposal and/or treatment facilities, except for

cesspools and seepage pits, will be permitted in a Special Flood Hazard Area but only at locations where

connection with a public sewer system is not possible or feasible. The design of such systems shall take into

consideration their l~tion with respect to wells or other sources of water supply, topography, water table,

soil characteristic, available area for improvements, and the effects of flooding to the RFD. Installations in

low swampy areas or areas with generally high water tables or which maybe subject to periodic flooding will

not be permitted.

Sec. 1302.3.1: Cesspools will not be permitted as permanent installations for sewage

disposal, except that in those instanms where connection to a public sewer system will be

possible within a one (1) year period, the Building Official may approve such an installation

as a temporary expedient. The one (1) year period shall expire on the anniversary date of

the written approval of the Building Official. Because of the public health hazard involved,

extreme care shall be exercised in locating the cesspool. Under no circumstances shall a

cesspool be located closer than 150 feet to a water supply well or be permitted to penetrate

the groundwater stratum.

Sec. 1302,3.2: Seepage pits shall, for purposes of these Regulations, conform to the same

requirements set forth above for cesspools.

Sec. 1302.4 Water Supply: Potable water supply systems that are located in a Special Flood Hazard Area shall

be designed and installed in such a manner as to prevent contamination from floodwaters up to the RFD. No

water supply well shall be located within the foundation walls of a building or structure located in a Special

Ftood Hazard Area used for human habitation, medical or educational services, food processing, or public

service type facilities.

Sec. 1302.4.1: Water supply wells, tanks, filters, softenem, heaters, and all appliances

located below the RFD shall be protected against contamination by covers, walls, copings,

or castings. All vents shall be extended to a minimum elevation of — feet above the RFD.

Sec. 1302.4.2: Approved backflow prevention devices shall be installed on main water

service lines at water wells and at all building entry locations to protect the system from

backflow or back siphonage of floodwaters or other mntaminants in the event of a line break.

Devices shall be installed at accessible locations and shall be maintained in good working

condition by the person(s) responsible for maintenance of the water supply system.

Sec. 1302.4.3: Individual water supply wells that are utilized inSpecial Flood Hazard Areas

shall be of either the drilled or driven type and located at a site slightly higher than

surrounding ground levels to assure Wsitive drainage from the well.

Sec. 1302,4.3,1: Private potable water well supplies shall not & developed from

a water table located lessthan 25 feet below the ground surface, nor from any deeper

supply which may be polluted by contamination entering through fissured or

crevice formations.

Sec. 1302.4,3.2: Each well shall be provided with a watertight casing to a distance

of at least 25 feet below the ground surface and shall extend at least one foot above

the well platform. Casings shall be large enough to permit installation of a separate

drop pi~ with a watertight seal between the drop pipe and the casing. Casings

shall be sealed at the bottom in an impermeable stratum or extend several feet into

the water bearing stratum.

13-3
Flood Proofing Regulations

Sec. 1302,4.4: In the event that floodwater wntamimtion occurs in the water

supply system, all potable water equipment, piping, water storage tanks, etc. shall

be disinfected in the manner prescribed by the National Plumbing me.

13-4
Chapter 14

Procedures

Section 1400.0 Scope

Sec,1400.1 Purpose: ~epurpose ofthischa~lter istopresent andexplain somepractical aspecSofflod

proofing and to show by means of examples and diagrams the effects of flood-related loads on structural

elements of a building and other protective constructions. The structural elements discussed include concrete

and masonry basement walls, concrete and masonry retaining walls, basement floor slabs, and closure panel

assemblies. Also included are some concepts of foundation drainage, examples of floodwalls and dikes, and

concepts of closure panels, devices, and axemblies.

Section 1401.0 Critical Aspects of a Flood

Sec. 1401.1 General: No attempt is made here to provide an elahrate definition of the term fled nor to

define a typical fld. Instead, critical aspects of a fl~ are listed below in the order of greatest importance

as related to flood damages and their impact on flmd proofing measures.

Sec. 1401,2 Depth: Depth of floodwaters around a structure is by far the most critical element to be considered

in planning and designing flood proofing measures. The depth of floodwaters determines to a great extent the

strength and stability requirements for the structure as a whole and for individual structural elements below

the design flood level. Except for very special structures and for massive or very high buildings, it is assumed

herein that the maximum practical flood depth for which flood proofing measures are economically effective

is ten (10) feet of free water above grade for a building or structure having a ten (lO)-foot space or basement

height below grade.

Sec. 1401,3 Velocity: The velocity of flmdwater during overbank flow conditions affects the amount of

scouring, sediment transport, debris loading, and dynamic loading on structures and obstructions. Flood

velocities vary from point to point in a flood plain and over the area of inundation. From a practical stand~int,

velocities up to five feet per second are not uncommon or unusual and their effects on structures may be dealt

with by application of normal design methods and procedures. Velocities up to 10 feet per second could occur,

particularly in close proximity to the channel, but are believed to be unusual and to require special methods

and techniques. A velocity of 10 feet per second is considered to be the upper limit for which flood proofing

measures are economically effective, except for special structures and facilities built at the edge of a channel,

where permitted.

Sec. 1401.4 Duration: The duration of a flood, as measured from the time the stream overflows its banks,

reaches its crest elevation, and then recedes to within its banks, is important from the standpoint of saturation

of soils and building materials, of seepage, achievement of full pressure in soils and under foundations, and

other time dependent effects. In addition, the duration of the flood affects the provisions for standby utilities

and services.

Sec. 1401.5 Rate of Rise and Fall: The rate of rise and fall of a flood to and from its crest affects the sizing

of flooding and draining provisions, where such are required. It also affects in certain cases the implementation

of contingent or emergency flood proofing measures, and must be recognized in investigations of slope stability

for a condition of quick drawdown.

Sec. 1401.6 Advance Warning: The length of advance warning available from flmd forecasting is all-important, particularly in relation to contingent flood proofing methods which require definite amounts of lead

time for protective measures to be placed into effect.

Sec. 1401.7 Debris had: The amount and type of floating debris carried by the floodwaters can result in

substantial loads against buildings and structures and can cause blockages of channels and passageways.

Debris typically includes such items as logs, tree branches and trees, lumber, displaced sections of frame

structures, drains, tanks, and runaway boats and barges. One type of floating solids borne by floodwaters

which is predominant in certain areas of the country during early spring floods consists of broken up ice blocks

and at times of large masses of broken up ice sheets. Ice blockage of channels or ice jams that frequent] y occur

in certain areas contribute significantly to the flood hazard and related problems.

14-1
Flood Proofing Regulations

Sec. 1401.8 Wave Action: A degree of wave action is inherent to all large expanses of water under the action

of the wind. For typical riverine floods, wave action is nominal and allowances can be made for it by providing

a suitable freehard. Wave action is most significant for coastal floods which are caused by persistent storms,

e.g. Nor’casters, tsunami waves or hurricanes. These cases are beyond the scope of the Flood Proofing

Regulations and require special design considerations and procedures.

Section 1402.0 Flood Damages

Sec. 1402.1 General: Floods are a natural and inevitable part of life in communities along the rivers of our

country, The transformation of tranquil rivers into destructive floods occurs hundreds of times each year. No

part of the United States is spared. Every year, some 300,000 Americans are driven from their homes by floods.

On the average, 200 persons are killed each year. These destructive overflows cause property damages that

currently average $2 billion a year. Damages to property, human suffering, and loss of life resulting from

floods have been increasing year by year in spite of the expenditure of billions of dollars for flood control

works. The increase in flood damages has been due primarily to the rapid growth of flood damageable

improvements in (he fld plains of the rivers and seacoasts. No dollar values can be assigned to human

suffering and loss of life caused by a flood. Flood damages to property can be assessed and are substantial.

As a rule, damages increase rapidly with depth of flooding. Damages to a building and its contents, as they

relate to damage to finishes, trirnwork, furniture, appliances, equipment, and storage materials represent a

substantial portion of the total lm. For the purpose of this publication however, major emphasis is placed on

structural damage to the building or structure or to structural elements thereof, including complete collapse or

displacement of the structure.

Sec. 1402.1,1: When floodwaters reach a structure, they induce unbalanced pre~ures and

loadings on all wetted surfaces which increase rapidly with increased depth. Once interior

spaces become flooded, water pressures are automatically equalized. Unbalanced lateral

pressures on walls may cause excessive lateral displacement, cracking, tilting, sliding, and

the eventual collapse of the wall. These same pressures can cause overloading and failure

of vertical and horizontal framing memkrs of the structure into which the walls are framed.

Uplift pressures under basement and floor slabs can displace and collapse the slabs.

Saturation of soils on which footings are sup~rted and uplift pressures under the footings

and within the soil can greatly reduce the bearing capacity of the soil and cause the footing

to become unstable and fail. Uplift pressures under raft or mat foundations with integral

walls can cause the entire structure to become buoyant and displa~ vertically upward, or to

become unstable and overturn. In this latter case, unbalanced lateral pressures are also often

at work. Dry, checked wooden beams and other structural materials lme their strength,

swell, and deflect excessively as they become water-logged. This can cause floors and

partitions to settle and sag, frames to become distorted, and plaster walls and ceilings to

crack. When the beams, for example, dry up and attempt to return to their original shape,

they are prevented from doing so by settled floors and partitions above, and can fail or cause

the failure or displacement of other supporting members. The following sections contain

examples of structural elements of buildings investigated under hydrostatic loads related to

floodwaters.

Section 1403.0 Loads

Sec. 1403.1 General: Fldwaters surrounding a structure induce hydrostatic and hydrodynamic loads on the

structure itself. Hydrostatic loads (pressures) are induced by water which is either stagnant or moving at low

velocity, Hydrodynamic loads result from the flow of water against and around a structure at moderate or high

velocities, Impact loads are im~ed on the structure by waterborne objects and their effects become greater

as the velocity of flow and the weight of objects increase,

Sec. 1403.2 Hydrostatic hads: These loads or pressures, at any point of floodwater contact with the

structure, are equal in all directions and always act perpendicular to the surface on which they are applied.

Pressures increase linearly with depth or “head” of water above the point under consideration. The summation

of pressures over the surface under consideration represents the load acting on that surface. For structural

analysis purposes, hydrostatic loads are defined to act vertieall y downward on structural elements such as

roofs, decks, and similar overhead members having a depth of water above them; vertically upward or in uplift

14-2
Chapter 14

when they act at the underside of generally horizontal members such as slabs and footings and the net effect

is upward; laterally when they act in a horizontal direction on walls, piers, and similar vertical structural

elements. For the purpose of these Regulations, it has been assumed that hydrostatic renditions prevail for

still water and water moving with a velocity of less than five feet per second. It is estimated that hydrodynamic

effects up to the stated velmit y can be conservative] y recognized in the freeboard allowance.

Sec. 1403.3 Hydrodynamic hads: As the floodwaters flow around a structure at moderate to high velocities,

they impose additional loads on the structure. These loads consist of frontal impact by the mass of moving

water against the projected width of the obstruction represented by the structure, drag effect along the sides

of the structure and eddies or negative pressures on the downstream side. For the range of velocities discussed

in 1401.3 (0-10 feet per second), it is considered most practical to make allowances for the hydrodynamic

effects by converting them into an equivalent hydrostatic condition. For s~cial structures, conditions, and

for velocities greater than 10 feet per second, a more detailed analysis and evaluation should be made utilizing

basic conc,epts of fluid mechanim and/or hydraulic models.

Sec. 1403.4 Impact Loads: These loads are induced on the structure by solid objects and masses carried by

or floating on the moving water surface. These loads are the most difficult to predict and define with any degree

of accuracy, yet reasonable allowances must be made for these loads in the design of affected buildings and

structures. To arrive at a realistic allowance, a great deal of judgment must be used, along with reliance on

the designer’s experience with debris problems at the site, and consideration of the degree of exposure of the

structure.

Section 1404.0 Structural Elements

Sec. 1404.1 General: The following sections present a discussion of loading assumptions and design criteria

for structural elements of buildings, such as basement and retaining walls, floor slabs, and closure panels, under

the effects of flood related loads. All the examples herein assume a “structurally” flood proofed structure.

(Classification W1 or W2 of the Regulations), where floodwaters are prevented from reaching interior spaces

and full imbalance hydrostatic loads attain on the exterior of the structure. Secondary loading effects

associated with floodwaters, such as wave action, debris loads, and hydrodynamic loads are not included in

this discussion. Under the requirements of the NFIP flood proofed basements for new residential construction

are permitted only in communities which have ken granted an exception according to 44 CFR 60.6.

Sec. 1402.2 Basement Slabs: Under flood conditions, and often under normal non-flood conditions in cases

where conditions of high water table prevail, basement slabs may be subjected to high uplift pressures. To

overcome this condition, the slab can be made thick enough to have sufficient weight to counteract the uplift

pressures. This solution is very seldom economical.

Sec. 1404.2.1: For relatively large, heavy structures, a more economical solution would be

to design thinner reinforced concrete slabs that are tied into the footings, walls, and columns,

such that the overall weight of the structure is utilized in resisting the uplift forces acting on

the floor slabs. This type of construction would then provide the additional stability required

to prevent flotation and overturning of the structure from other flood loads. The slab

(commonly referred to as mat or raft ty~ construction) mllst be capable of resisting all

applied loads and distributed pressures, either when uplift pressures are acting at full

intensity, as is the case during a flood, or when such loads are nonexistent, as could be the

case under normal conditions. Integral slab construction can be utilized equally well for

buildings supported on piles. In these cases, column and wall loads are supported by the

piles, and the uplift pressures are transferred by the reinformd slab to the columns and walls

so as to utilize the building loads (weight) as the downward resistive force.

Sec. 1404.2.2: In many cases, however, where uplifi pressures are excessive, the most

practical solution would be to relieve (or reduce) these uplift pressures under the slab by

providing adequate and dependable drainage, mmbined where necessary with impervious

blankets and cutoffs on the outside of the structure, Illustrations of foundation drainage

methods that may be used for relief of uplift pressures are shown on Figure 6. Where it is

found impractical to stabilize the slab and structure by one of the methods shown on Figure

6, or a combination thereof, it may be more expedient to anchor the slab and/or structure to

14-3
Flood Proofing Regulations

the ground (and preferably to an underlying rock formation) or to provide the required

protection by means of dikes, levees, retaining walls, or floodwalls.

Sec. 1404,3 Basement and Retaining Walls: Under normal or non-flood conditions, the primary loading on

basement and retaining walls consists of lateral soil pressures caused by the backfill material, For selected

granular backfills and normal heights of the wall, this load is relatively small. Other secondary or associated

loads on walls are lateral loads resulting from surcharge conditions, loads resulting from frost action, and any

vertical or other applied loads which the wall is intended to resist. Under flood conditions, by far the most

significant load on a wall is that caused by lateral hydrostatic pressures. This load amounts to several times

the intensity of the normal loads and as such will govern the strength and stability requirements for the wall.

Provisions for backfill drainage are commonly used to reduce water pressure behind a wall and are known to

be effective for groundwater control if carefully designed, constructed and maintained. In the case of walls

subject to flood loading, a reduction in water pressure behind the wall is not considered practical nor

dependable. When an infinite source of water exists and free water stands above grade, the most efficient

drainage provisions are likely to be inadequate. For cases where the wall is protected by impervious

membranes, blankets and cutoffs, even a minimal rupture, separation or failure of the membrane or blanket,

or cutoff, can cause the attainment of full hydrostatic pressures on the wall and cause failure of an inadequately

designed wall.

Sec. 1404.4 Closure of Openings: All exterior wall openings and other openings located below the RFD

should be closed and sealed for effective flcod protection. Existing structures shall & reviewed to assure that

walls and supporting members can safely support the added pressures induced by closing the openings. Under

no circumstances should a building be made watertight if the additional flood loads cannot be satisfactorily

transferred to the walls or supporting members. Closing the openings under these conditions may lead to a

structural failure that could be much more serious than the damages resulting from unrestricted flooding. In

designing new structures, all openings which are not necessary for proper functioning of the structure should

be omitted, or at least kept to a minimum, both in number and size.

Sec. 1404.4.1: Openings should be provided with either permanent closures or closure

assemblies that can be easily installed or positioned in an emergency flocding situation.

Openings that are no longer necessary for building operation should be permanently closed

and sealed. Permanent claures can be accomplished with reinforced concrete plugs,

concrete masonry units, or metal assemblies that are keyed or anchored to the existing wall

and supports. Additional support and strengthening may have to be provided to carry the

additional loads from floodwaters acting on the closure assemblies.

Sec. 1404.4.2: The clmure or closure assembly must be designed for the full water pressure

resulting from the heights calculated from the highest and lowest points of the closure to the

RFD. @nsideration must be given to loads resulting from debris impact and other loads as

specified in these Regulations. The closure should be supported along at least three edges

and be capable of being secured around the opening perimeter by some self-actuating means

or latching devices. Bolting may be used as a means of securing the closure in place;

however, it is recommended that such a procedure be avoided if at all possible and especially

for closures of large and/or critical openings. A bolted type closure would generally require

more lead time (flood warning) to assemble, transport, and install equipment held in storage,

generally require trained personnel to affect the installation, and might well depend on the

use of material handling equipment or additional personnel to handle large, heavy, or

cumbersome closure panels or assemblies.

Sec. 1404.4.3: The closure assembly should attach to a metal frame that surrounds the

opening and be of sufficient width to provide an adequate watertight sealing surface. The

frame may attach or be connected to the adjacent wall or supporting members or be

constructed as an integral part thereof and be strong enough to transfer the closure loads to

the building structural components without exceeding the allowable stresses. The walls are

to be designed to transfer the loads to the building structural system and conform to the

structural requirements of the Building Code. The seal maybe attached to the closure door

14-4
TYPE “A” SUMP

v —— Y4° CWP

; ,A

~ :b 4“ MIN. SLAB MAINTAIN AM IN.

. .

.. OF 9“ OF WATER

$.‘~ 1“ CWP

‘.

4

.. ,,

A

WATERSTOP Y

I

DRAIN PIPES

OPTIONAL

10” MIN. DfiAINAGE COURSE

L

L

o

0A PRESSURE SLAB

+

3 v +

u ——— ~

0

.,. eDAMPPROOFING

. b.

USE TYPE “A”

OR “C” SUMP

m

3+Oul

5g

PERFORATED

a< PIPE DRAINS

UJ

n~m 4“ SAND FILTER

CWP = CEMENT PLASTER

WATERPROOFING

MATERIAL FOR UNDER-FLOOR

DRAINAGE COURSE SHALL

CONSIST OF SOUND, CLEAN

GRAVEL OR CRUSHED ROCK,

3/4 IN. TO 2 IN. IN SIZE

FOR PRESSURE RELIEVED

SLAB, PROVIDE PERIPHERAL

DRAIN AT BASE OF

FOUNDATION WALL.

REPLACE CWP ON

FOUNDATION WALL WITH

DAMPPROOFING.

c

couRsE~ 10’’MIN DRAINAGE

@ RELIEVED SLAB

~ ~“cwp ‘-- LJSETYPE’’C’’SLJMP

1“.b]l 4“ MIN. SLAB ~ lot MIN. DRAINAGE COURSE

. . )

IF SOUND ROCK OR

IMPERVIOUS STRATUM IS

ENCOUNTERED AT SHALLOW

DEPTH BELOW FOUNDATION,

CARRY OUTSIDE WALL AS

CUTOFF. DISPENSE WITH

WALL DRAIN AND REPLACE

CWP ON FLOOR SLAB WITH

DAMPPROOFING. ARRANGE

DISCHARGE FROM DRAINAGE

SYSTEM TO PREVENT

AERATION OF DRAINAGE

COURSE

TYPICAL FOUNDATION DRAINAGE AND WATERPROOFING

ADAPTED FROM NAVFAC DM-7

Figure 6

14-5
Flood Proofing Regulations

(panel, etc.) or sealing frame and sealing should be achieved by applying pressure through

bolting or latching of the closure or some other self- acting and positive means.

Sec. 1404.4.4: All closures, whenever possible, should be external to the opening, such that

the water pressure helps in providing a continuous seal, thereby eliminating the need for

extensive anchors, blocking and bolting, as would be required for reverse loading cases.

Sec. 1404.4.5: Horizontal closures should be designed to support the full weight of water

above the closure assembly to the RFD. The closure should be sup~rted and have a

watertight seal along its entire perimeter, A frame with a smooth sealing surface and capable

of transferring the load to the structure is to be provided.

Sec. 1404,4.6: Permanent closures of an opening maybe accomplished by any structural

means or system that would not require further actions during a flood. These closures may

consist of walling an unneeded window, vent, chute, etc. with masonry units, reinforced

concrete plugs, metal shields, or other approved materials. All closure systems used shall

provide the required protection to the RFD.

Sec. 1404.4.7: Closures for openings in existing structures that would have to be assembled

and set in place in preparation for a flood would be classified as temporary or emergency

flood proofing closures. These openings are necessary for the continual operation of the

building and their functions will be disrupted when the closures are set. Clmures should be

of metal construction and sized for easy and quick assembly and installation. Closure panels

should be stored at a convenient location near the opening and should be properly marked

and identified for each opening. Bolts, latches, and other equipment used to install the

closures should be similarly stored and identified. Examples of emergency closures are

closures used to block doors, windows, vents, loading docks, or chutes.

Sec. 1404.4.8: Contingent closures may ~ set into position by either mechanical or manual

operation of the assembly. Design of the assembly must take into consideration the type of

placement operations, weight of the closure, space required, aesthetic considerations,

available work force, and total number of openings to be closed. Mechanical placement of

closures can be accomplished through rollers, cable and weights, levers, and hinges.

Sec. 1404.4.9: Seals on all closures should be watertight and preferably of rubber or

neoprene. The entire closure and frame should be inspected and tested periodically to ensure

that they are still functional and in good condition.

Sec. 1404,4.10: Some permanent closures may be designed to protect against floodwaters

and still maintain the functions of the opening. A window could be designed with intermediate supports consisting of reinforced concrete beams or structural members encased in

concrete. The window would then & made up of tempered plate glass sections capable of

withstanding impact loads spanning between intermediate supports, Metal doors can be

made to protect against fl~s by providing a watertight seal and adding stiffeners and

latching devices to the door, Examples of o~ning reinforcement, fastening methcds and

devices, and closures for typical conditions are illustrated in Figures 7 through 19.

Sec. 1404.5 Additional Considerations: Itshould be noted that the preceding design examples do not contain

coverage of several structural elements and framing methods used in normal practice, Included in this category

are wall and column footings, mats or rafts, integral or continuous wall and slab construction, horizontally

framed walls, and other similar items. Also omitted are examples of bearing masonry walls, curtain walls,

precast concrete, metal and “sandwich” panels, and similar items, These items either involve too many

variables, or are too complex for tabulated treatment, or relate to highly specialized technology. In all cases,

coverage of these topim dms not lend itself to a simplified treatment and are thereby omitted.

14-6
Chapter 14

Section 1405.0 Alternate Methods of Flood Proofing

Sec. 1405.1 Site Selection: The one method of assuring complete fl~ hazard protection of a building or

structure is to select a site or structure location which places all spaces in the structure above the RFD or BFE.

This could apply to sites both inside or outside the flood plain limits. titing a structure outside the flocd

plain would eliminate the need to consider floodwater loads in the building design. The building could be

located in the floodplain and be protected to design-flood level by dikes, levees, or floodwalls; also eliminating

the need for flood load consideration in the building design for floeding to a design-flood level.

Sec. 1405.2 Flood Proofing by Elevating the Building:

Sec. 1405.2.1 Natural Terrain - Structures constructed above the RFD and outside the

regulatory flood plain will not be subject to loads from regulatory floodwaters if basements

are not used. The effect of soil saturation on basement walls and foundations may still have

to be considered. Natural slopes should k investigated for stability and scour potential if

the structure is to he built near the run-out line of the Base Flood, on the ground surface. A

building located outside the Base Flood flood plain is shown at the left side in Figure 20.

Sec. 1405.2.2 Building on Fill - Buildings can be located within the flocd plain or

Special Flood Hazard Area on a fill constructed to an elevation above the RFD.

This method of protection ean be aamplished by constructing an earth fill either

partially or entirely with the flood plain, as also shown in Figure 20. Such a design

should provide assurances that the fill does not restrict or obstruct the flow of

floodwaters or reduce the hydraulic efficiency of the channel, which in turn could

cause floodwater back-up and resultant higher floodwater elevations upstream of

the filled building site. Fill is not permitted in the floodway as depicted in Figure

3.

Sec. 1405.2.2.1: The fill material should k suitable for the intended purpose as

determined by an investigation of the soil properties. The earth fill should b

compacted to provide the necessary permeability and resistance to erosion or scour.

Where velocities of floodwaters are such as to cause scour, adequate slope protection should be provided with vegetation or stone protection as required. Slope

stability should be analyzed by an experienced soils engineer to assure its adequacy.

Sec. 1405.2.2.2: Where the fill is partially within the flood plain, access and

utilities should be provided from the “dry” side. If the fill is entirely in the flood

plain, a-~and utilities could beprovidedbyconstructingan acecssroadorbridge

to an elevation above the RFD.

Sec. 1405.2.3 Building on Piles or Columns - Often it is geographically undesirable or

economically infeasible to locate a structure outside the flocd plain. Available land areas

are being developed rapidly and communities are finding it ne~ssary to permit construction

in the fringe areas of floodways. IrI these areas, structures can he built which place all

functional aspects above the RFD by building on piles or columns as shown in Figure 21.

Sec. 1405.2,3.1: In elevating a building on “stilts,” piles, columns, piers, and walls,

or other similar members are used to raise the functional floors or spaces of the

building above the R~ elevation. The design should consider the loads that result

from possible debris blockage between supporting members and impact of floating

debris,

Sec. 1405.2,3.2: The open space created at ground level below the functional floors

could be used as a plaza, parking area, materials handling, or recreational area, or

for storage of special nondamageable materials, equipment, etc. This open space

would be essentially free from the damaging effects of floodwater, except that

14-7
RECOMMENDED REINFORCEMENT AROUND SMALL OPENINGS

AND FOR SHALLOW DEPTH OF FLOODING

II

HEAD

~#4 BAR MINIMUM AROUND ALL WINDOWS.

REINFORCED

MASONRY OR

CONCRETE

DOORS OR OTHER

OPENINGS AND EXTENDING (WHERE POSS”IBLE) AT LEAST 24”

BEYOND CORNERS OF OPENING.

‘LINTEL REINFO RCEMENT

m●

JAMB

II

h

B

W BAR

---

SILL TYPICAL STEEL BASEMENT WINDOW

FOR REINFORCED MASONRY WALLS

NOTE:

IF OPENING BEG INS AT THE TOP OF A FOOTING, HORIZONTAL REIN FORC

ING SHALL BE PROVIDED AT THE TOP OF THE FOOTING.

Figure 7

14-8
Chapter 14

r

A

L A

ED

$EcTION A-A

CLOSURE PANEL FOR BASEMENT WINDOW

FOR SMALL WINDOWS AND SHALLOW DEPTH OF FLOODING

Figure 8

SEALING

FRAME

. . . . . . . . . . . . . .

-1

t

1

L F

L

4

. . . . . . . . . . . . . .

,.. . . . . . . . . . . .

: /

~ /

/

/

L ——— ——. ——— ——.

FLOOD SHIELD BEHIND WINDOW

LOWERED INTO POSITION & ATTACHED TO

STORED FLOOD SHIELD

WITH STIFFENERS

*

COUNTERWEIGHT

FRAME WITH QUICK DISCONNECT TYPE FASTENERS

Figure 9

14-9
Flood Proofing Regulations

BOND BEAMS & VERTICAL REINFORCEMENT AT LARGE OPENINGS

STEEL OR CONCRETE

STRUCTURALMEMBERS L

I

I

Figure 10

EDGE

REINFORCEMENT

WALL SHOULD BE

CONSTRUCTEDINTEGRAL

WITHSTRUCTURAL

MEMBERORSUFFICIENTLY

ANCHOREDTOIT.

II

. .

I*I

REINFORCING FOR BOND BEAMS AND VERTICAL STEEL MAY BE REDUCED

ARE TRANSMllTED TO STRUCTURAL MEMBERS BY THE FLOOD SHIELD FRAME AS

SHOWN ABOVE.

Figure 11

14-10
Chapter 14

STEEL OR

ALUMINUM

FLOOD SHIELD

ATTACH ED TO

FRAME WITH +

QUICK DISCONNECTI

TYPE FASTENERS

I

I

I

I

TYPICAL DOOR

●

● ☛ ✎ ✎

✎

✎

,!

,1

_l- “ 1~

\l/

Y STIFFENERS

I ti”f I

A

-

‘v” !P’i “ “, ,::, ~,..

M

SEAL-PERMANENTLY ATTACHED TO SHIELD

‘:;”b:~’;”

,,.. . 1.”. —METAL FRAME #b-,... ::

. . ‘, .&..

....... . ....”.. \

.,. , ,,, . .,.,

:* MORTAR BETWEEN MASONRY UNITS

- ... ,

;~. .,.“:

A

.,,......

.,.,, ;&,.’,

4 /(,,....,

B\

RI

~ ANCHORS& FLUSH HEAD BOLTS

FOR ATTACHING FRAME TO

MASONRY UNITS

.“!

““”IMI

...,

:“’O .,.

. . .. .. .. .

- FILL HOLLOW MASONRY WITH CONCRETE AROUND

DOOR FRAME

SECTION A–A

ALL CELLS AROUND OPENINGS IN HOLLOW MASONRY CONSTRUCTION SHOULD BE

FILLED WITH CONCRETE. LARGE OPENINGS SHOULD HAVE BOND BEAMS, VERTICAL

REINFORCEMENT, AND METAL FRAMES AROUND OPENING.

MORTAR JOINTS THAT LIE WITHIN FLOOD SHIELD SHOULD BE STRUCK FLUSH WITH

THE MASONRY UN ITS SO THERE WILL BE ABETTER SEAL.

Figure 12

14-11
Flood Proofing Regulations

DISPLAY WINDOW

FLOOD SHIELD DETAILS

1 DETAILA I

q

/

//

I [11 111 111 [[1111111111

,

I I I I

I I I I 1 1

[ I I I r

I

7’

/

OR

LA sECTION A–A ~DETAIL B

ELEVATION

,CORNER ANGLE - %“ ALUM. FLOOD SHIELD

L

‘STl FFENER3’/z x3x3/8 @l’-6°

‘/’2” ~LUM. FLOOD SHIELD

,,, .,

.,.

STIFFENER i

3%x3x318

DETAIL B

DETAIL A

NOTE

SUPPORT IS ASSUMED AT THIS LOCATION. WHERE SUPPORT IS NOT AVAILABLE,

INCREASE SIZE OR NUMBER OF STIFFENERS AND PROVIDE SUPPORT AT BOTTOM.

MEMBERS ARE SIZED FOR WATER LEVEL AT TOP OF DISPLAY WINDOW.

Figure 13

14-12
CLOSURES FOR HORIZONTAL OPENINGS BELOW RFD

[

NEOPRENE GASKET OR EQUIVALENT

~ ALUMINUM FLOOD SHIELD

\

L OPENING 7

THREADED

-1 4

ANCHORAGE

(a)

6!~“

.:..+“ “.,

.,

.“4 :“.

.

.,

. .

. .. .

. . .

. .. . .

b

.: 4”.

. . . . .

.:: ;

.. ..h .

,,. .

I

(b)

r

T-BOLT OR OTHER QUICK

DISCONNECT FASTENER

DETAI

F. +

h

(c)

CAST IRON FRAME & COVER RING

FOR SQUARE, RECTANGULAR GASKET IN MACHINED

OR CIRCULAR OPENINGS

COVERS FASTENED TO FRAME

,.

.~

. . .

P,’, :“. *.. ”

,.

.,.,

...“

“<

(d) CAST IRON FRAME & COVERS

GRAVITY TYPE COVERS

(HELD IN PLACE BY WEIGHT ALONE)

GROOVE

Figure 14

14-13
CLOSURE PANEL ASSEMBLY FASTENING METHODS

I

ANGLEFRAME* I

f t SLOllED

PIN

WALL

ANGLE FRAME

\

CLOSUREPANEL \

ASSEMBLY P \

\

(a) (b)

7

WALL v * CHANNEL

/ SEAL / FRAME

BUMPER

STRIP

FIBERWASHER

LATCHING

DOG

CLOSUREPANEL

ASSEMBLY

\

A u

(c)

& CHANNELFRAME

,.,.,,

BUMPER

STF”-&

~ THREADED

STUD

PAWL-SETWITH

RIP HAMMERBLOW

SLO~ED THREADED

P

STRIP

/

FRAME

CLOSUREPANEL

d

u

ASSEMBLY

(d)

SLOTTEDSTEEL

SELF-TAPPING

SCREWS

SEAL ~

L

NEOPRENEO-RING

ORSOLIDGASKETSEAL J

CLOSUREPANEL

ASSEMBLY :gg:pANEL y~~

(e) (9

Figure 15

14-14
Chapter 14

FLOOD-PROOFING CLOSURE FOR LARGE HORIZONTAL OPENING BELOW RFD

rremovable BAR

I IF–--” CL~URE

ASSEMBLY

-GASKET

~G”lDE HOLE

r

+ STIFFENERS

\CTABLE

ASSEMBLY

\> &ANGLE TRACK-ATTACHED

TO < FRAME AT OPENING

//// OPENING

/c

ANGLE FRAME

POSITIONING STUDS

*

(b) (c)

ALTERNATE POSITIONING METHODS

PROCEOURE

BEFORE FLOOO – Closure assembly rema[ns In stored position and rests on blocks to keep assembly weight off O-Ring or flat sealing gasket. wheels in an up pos!tion and operat!ng bars removed.

Wheel assembly is coated w,th heavy grease and covered with plastic or canvas sheet.

OURINGFLOOO –Wenfloodwarnlng i$received, operati~ bar(s) inserted in retractable wheel

asembly andwheel$ lowered to engage rails, raising closure assembly off storage blocks andhlgh

enough toclear position ingstuds; closure assembly rolled into positlontieregulde holes are d!.

rectly over pctsitioni”g studs; closure ~ssembly Iowered toengage studs unt!l all wheels are free-of

guide rails and contact established between gasket and frame, operating bars then removed from

wfteel assembly. Pmitive seal ismaintained during flo4bywelght ofclosure assembly and flwd

water weight ;poslt!oning studs prevent displacementor movement of closure assembly.

AFTER FLOOO-Closure as~blywash4 dwntoclear mudanddebrls, raised \ntorollingpositlon, rolled to storqe Iocatio” a“d pmitioned, inspected for possible damage, then “moth-balled”

for future use.

NOTE: This illustrates only oneofmany schemes that fnaybecons,dered forhor!zontal open, ng

flocd-proofing. Closure assemblies should ~ofdurable material$ forreWat type use, shouldre.

quirem)nlmum maintenance, andrequire minim alinstallat!on effort. Variations ma.f include

hinged andlor cwnter-balanced assembles; lever, ratchet or hydraulic systems for mmement and

Wsitionlng of assembly; positioniy lugs, wedges, recesses, etc. where expowd studs mnnot k tolerated; anduwof positive fastening methods and devices for special Iocatlonsor situations. The

methods, procedures, andeq”i~ent that may be utilized are limited only by the desfgner<s

imagination and the owner’s pocketbook.

Figure 16

14-15
Flood Proofing Regulations

FLOOD SHIELD INSTALLATIONS

~ ROLLER

L

FLOOD

SHIELD

–SEALING FRAME

SLIDING FLOOD SHIELD FOR DOOR

Figure 17

\\\\\\\\\\\ \

SEALS , L. m L

, t

\ LFLOOD SHIELD

\

\

\

\

\

\

\

\

‘-_

b

\\\\\\\\\\\

HINGED FLOOD SHIELD FOR LOADING DOCK

Figure 18

[

WATER PRESSURE

EQUALIZATION HOLE

b

mFLOOD

\

SEALING I

FRAME

SHIELD

STORED FLOOD SHIELD BEHIND WINDOW

Figure 19

SECURED TO SEALING FRAME BY LATCHING DOGS, WEDGE ASSEMBLIES,

OR OTHER QUICK DISCONNECT FASTENERS.

14-16
RFD LIMIT OF OVERLAND FLOODING

Doa

000

non

anon

REGULATORY FLOOD DATUM .— —. — —— . —. — — .

STRUCTURES ON NATURAL TERRAIN OR FILL

Figure 20

OPERATING

EQUIPMENT

RFD

BUILDING ON PILES OR COLUMNS

Figure 21

14-17
Flood Proofing Regulations

lobbies and entrance would have to be protected by some approved flood proofing

method.

Sec. 1405,2.3.3: The equipment necessary to maintain building functions should

be located safely a~ve the RFD. If access to the building were provided from a

location above the RFD, the normal building activities would not be disrupted and

the building could continue to function during the flood emergency.

Sec. 1405.3 Protection by Dikes, Levees, and F1oodwalls: ~ an alternative to providing flood protection

through building or structure modifications, the necessary protection may be achieved by detached dikes,

levees, or floodwalls. The primary purpose of these constructions is to prevent the flood from reaching the

structure and associated functional land areas. The choice of using a dike or flcodwall is made on the basis

of economic considerations when compared to structural flood proofing modifications, the abilit y of a structure

to be structural] ymodified, and the degree of protection to be provided. The type of protection barrier depends

on location, availability of material, foundation conditions, and right-of-way restrictions. Floodwalls would

be used in tight, restricted areas where foundation conditions are favorable. Dikes or levees would be used

where adequate space and material are available. The dike or floodwall may not have to completely surround

a structure. Protection maybe required only on the low sides as illustrated in Figures 22 and 23. The ends of

the works would be tied into the existing high ground or to the structure depending on local conditions.

Reference section 612.3 of these regulations for NFIP requirements

Sec. 1405.3.1 Dikes - If used, dikes should be constructed to a section capable of supporting

the imposed loads and providing the required im~rmeability. Suitable material preferably

should be available atthe site and should be tested and approved for use prior to constructing

the dike. An investigation should also be made of the foundation material to determine the

presence of, location, and extent of unsuitable materials, and necessity for drainage of cutoff

provisions.

Sec. 1405.3.1.1: At locations where the foundation material has a high degree of

permeability, an impervious cutoff maybe necessary to reduce seepage through

the in situ foundation materials. The cutoff may be a sheet pile wall, compacted

barrier of impervious soil, fabric reinforced membrane, concrete wall, or a grouted

cutoff. As no cutoff is totally impermeable, provisions should be made to collect

the excess seepage and any seepage from less permeable soils without cutoffi. The

excess seepage can be mllected with drainage blankets, pervious trenches, or

perforated pipe drains placed at the tm of the embankment and on the dry landward

side. Typical dike sections, cutofk, and drainage provisions are shown in Figures

24,25, and 26.

Sec. 1405.3.1.2: If any drain pipes or related structures are within a dike, they

should be designed to resist all applicable loads and be provided with gates to

prevent backflow to the dry side. Backflow through conduits can be prevented by

installing flap gates, manually operated valves, or slide gates that would be closed

when fl~waters would reach critical elevations.

Sec. 1405.3.2 Floodwalls -A floodwall issubject to hydraulic loading on one side with little

or no earth loading as a resisting force on the opposite side. Floodwalls can be constructed

as cantilever I-type sheetpiling walls, cellular walls, buttress walls, or gravity walls.

Sec. 1405.3,2,1: The walls should be founded on and keyed into rock where

suitable rock is encountered reasonably close to the founding elevations. Where

the soil provides inadequate bearing capacity and removal of unsuitable material

and replamment is mtly, an adequately designed system of piling should be

considered. Cutoff and drains should be used to intercept seepage as required in

612.3,2. Drain pips should not be placed directly under the wall base and any

drainage provided should not be mnsidered as a factor for reduction of uplift

14-18
—

‘—.\. ——— REGULATORY FLOOD DATUM

~\, A ————”

>

-FLOODWALL

-——. 1

L ——— —..

SHEETPILE_

CUTOFF

U

FLOOD PROTECTION WITH FLOODWALLS

Figure 22

‘%RXOPOFDI.E r*I

FLOOD PROTECTION BY DIKES

Figure 23
Flood Proofing Regulations

DIKE OR LEVEE PROTECTION

❑ 00

❑ un

REGULATORY FLOOD DATUM

------ ____

FILTER ‘ ----------

—- SHEETPILE

CUTOFF

LEVEE WITH SHEETPILE CUTOFF

Figure 24 -

THESE OR OTHER MEANS -

SHOULD BE PROVIDED TO

NEGATE EFFECTS OF

SEEPAGE ON BUILDING

.—. . ——— ——— —

BLANKET DRAIN

DIKE WITH BLANKET DRAIN

Figure 25

\ ----- -. --—- -

ROCK OR IMPERVIOUS FILTER ROCK OR IMPERVIOUS

STRATUM STRATUM

DIKE WITH IMPERVIOUS CORE

Figure 26

14-20
pressures. The problem of scour should be further investigated and corrective

measures provided where necessary.

Sec. 1405.3.2.2: Drainage features through floodwalls should be equipped with

the necessary devices to prevent backflow. Typical sections of various floodwall

types are shown in Figure 27.

Sec. 1405.4 Controlled or Intentional Flooding: In many situations, the basement walls and floor slab(s) of

existing buildings and structureslack the structural strength required to withstand flood loadings. The ex~nse

of reinforcing an existing structure or replacement with a new structure at the same location to withstand such

flood loadings is, in most cases, not justified. As an alternate means of flood proofing these structures,

provisions may be made for flooding of the structure interior to balance the external flood pressures on the

building components. This intentional flooding would have to be accomplished in such a manner as to keep

the unbalanced hydrostatic pressures safely within the load carrying capacity of the slab and walls. Provisions

must be made for interconnections through and around all flmrs and partitions in order to prevent unbalanced

filling of chambers or spaces within the structures, This is also known as wet flood proofing (See Section 401,7

Wet Flood Proffing and the National Flood Insurance Program).

Sec. 1405.4.1 Flooding: Flmding should be with potable water from a piping or storage

system of adequate capacity to fill the basement at a rate consistent with the anticipated

floodwater rise. The provisions should be such as to keep the internal water surface as nearly

even with the outside as pmsible. All spaces should b provided with air vents to prevent

the trapping of air by the rising water surface.

Sec. 1405.4.2 Draining: Outlets to drain the water as flood waters recede should k located

to completely drain the structure and all spaces at a uniform rate corresponding to that of

the receding waters. The water level in all interior spaces should be kept even and all spaces

should & completely drained. Upper spaces and levels should be drained before the lower

spaces. All watertight walls should be designed for an internal hydrostatic pressure resulting

when waters trapped in the building are higher than those of the receding floodwaters

outside, which is possible with the malfunction of required drains.

Sec. 1405.4.3 Use: Where provisions are made for internal flooding, all flmrs and spaces

below the RFD should be restricted as to types of use permitted. Examples of controlled

flooding of structures with restricted use are shown on Figures 28 and 29.

Sec. 1405.4.4 Backflow: Where intentional flooding with potable water is proposed (or

where floodwater backflow through the sewer system may occur), backflow preventers

should be instailed in the sewer lines. Various types of backflow preventers are illustrated

in Figure 30.

Section 1406.0 Total Approach

Sec. 1406.1 General: The design and implementation of flood proofing systems and procedures requires a

total approach, No element or item, regardle~ of how minute it might appear, should be overlooked or left to

chance. The most elaborate, extensive, and expensive flcod proofing system may be rendered useless by a

minor omission or by the failure of a weak link in the system,

Sec. 1406.2 Standard Operating Procedure: The same “in toto” approach is necessary in establishing

detailed procedures for making a contingently flood proofed system ready for an expected flood. Standard

operating procedure for mobilizing and implementing the flood proofing measures, referred to in these

Regulations as “The Owner’s Contingency Plan,” should be developed by the original designer of the system.

It requires a degree of completeness such that all details, sequen~s, and implementing personnel assignments

are fully spelled out. The building owners and all other personnel assigned to implement the Plan should be

thoroughly acquainted with all aspects of the o~ration and procedure. All personnel should periodically

inspect the system and participate in scheduled “dry runs” or exercises of the flood proofing plan. The standard

operating procedure should be in the format of a manual containing all descriptive information and operational

sequences, along with necessary illustrations, drawings, and maintenance requirements for all measures.

14-21
+ “’ ;

.

;i

:‘+: .> . .j:,, . ., i., .

Type 1 Type 2 Type 3

CANTILEVER l–TYPE SHEET PILING

CELLULAR

&...

BU~RESS AND COUNTERFORT

FLAT DAM

&...,,

&

!..8 ;.ea

8

..

A% .;. ””:. ..;..: “.;. b.

..~.a.

.A -e

:&;:.

~...;. b.. ~

‘.”i ..

.,.a.

A. .. .

. .

.#.A., ..bo..’. ,.’A, .*’.

.A ‘.”i!-; ?* ..:A, ●..A:b..b. .

f

. . . . . +.’’.;?A.. .

-= --

GRAVITY

VARIOUS FLOOD WALL TYPES

Figure 27

14-22
Chapter 14

STRUCTURES WITH RESTRICTED USE

OPERATING

EQUIPMENT 7 s\\\\\\\!

PARKING

LEVELS

RFD

I

STRUCTURE ON NATURAL TERRAiN OR FILL

Figure 28

.

I

OPERATING I

EQUIPMENT ~-—— RFD

— PARKING OR

REMOVABLE STORAGE

STRUCTURE ON NATURAL TERRAIN OR FILL

Figure 29

14-23
Flood Proofing Regulations

PREVENTION OF BACKFLOW THRU SEWER SYSTEM

(a) (b)

FLOOR DRAIN WITH INTEGRAL BACKWATER VALVE

*

BACKWATER VALVE – FLAPPER TYPE – AUTOMATIC

BACKWATER VALVE – GATE TYPE COMBINATION – MANUAL & AUTOMATIC

RFD

REMOVE GRATE AND

PIPE INSTALL STANDPIPE.

USE ONLY WHERE

yq.pq

FLOOR SLAB WILL TAKE

STEEL PLATE UP-LIFT PRESSURES

WITH GASKET

BOLT

. .

‘~.

EXISTING BASEMENT DRAIN FLOOD-PROOFING

Figure 30

14-24
Personnel designated to perform each task should be noted and, if possible, alternates should be assigned to

assist during times of emergencies or to take over and act if the regularly assigned personnel are absent or

unavailable for flmd emergency duties. In addition, summarized procedures should k pmted at prominent

building locations to facilitate and expedite the operation. Color-ceding of flood proofing implements, such

as closure panels, backflow valves, and similar features would be helpful in assuring the most efficient

implementation of the Plan.

Sec. 1406.2.1: As preparation of a building for a flood event often involves auxiliary

personnel, equipment, and materials, planning for simple logisti~ should be developed and

be closely keyed to available advance time. In this respect, information from flood forecasting and warning sources must be obtained at the earliest possible time. Since floods can

occur at any time of the day or night, on weekends or holidays, a plan for emergency

readiness must be established. It should include establishment of definite lines of communications and control, and identification of key personnel who can be counted on to

respond whenever needed.

Sec. 1406.2.2: AI systems and implements of flood proofing must be kept in a perfect state

of readiness and b easily accessible at all times. The emphasis on periodic inspection,

testing, and continued maintenanm cannot be adequately stressed.

14-25
References

1. Design of Welded Structures, Omer W. Blodgett, The James F. Lincoln Arc Welding Foundation,

Cleveland, Ohio

2. Introduction to Fld Prmfing, John R. Sheaffer, The Center of Urban Studies, 1967, University of

Chicago, Illinois

3. Wall Design, Flood Walls, Part CXXV Chapter 1,January 1948, Dept. of the Army, Corps of Engineers,

Office of the Chief of Engineers, Washington, D.C.

4. Design Manual -Soil Mechanics, Foundations and Earth Structures NAVFAC DM-7, March 1971, Dept.

of the Navy, Naval Facilities Engineering timmand, Washington, D.C. 20390

5. Flood-Proofing: An Element in a Flood Damaged Reduction Program, John R. Sheaffer, Chicago:

University of Chicago, Dept. of Geography, Research Paper No. 65,1960

6. Floods, Flash Ffoods and Warnings, U.S. Department of timmerce, NOAA-National Weather Service,

PA8101O, 1981.

7. Technical Standards Bulletin - Wet Floodproofing (Draft), Federal Emergency Management Agency,

Bulletin No. 85-1

8. National Flood Insurance Program (Regulations for Flood Plain Management and Ftood Hazard

Identification), Revised as of October 1,1988.

* U.S. @VERNMENT PRINTING OFFICE 1998-721 -096 I awl

References-1