NBSIR 76-1194

A Study of Fire Spread in

Multi-Family Residences:

The Causes — The Remedies

Bertram M. Vogel

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

February 1977

Final Report

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NBSIR 76-1194

A STUDY OF FIRE SPREAD IN

MULTI—FAMILY RESIDENCES:

THE CAUSES — THE REMEDIES

Bertram M. Vogel

Center for Fire Research

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

February 1977

Final Report

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Betsy Ancker-Johnson. Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

CONTENTS

Page

Abstract 1

1. INTRODUCTION 1

2. CONSTRUCTION DEFICIENCIES 4

2.1. Faulty Chase Construction 4

2.2. Violation of Fire Wall 4

2.3. Lack of Firestopping 4

2.4. Faulty Construction 5

2.5. Faulty Design 5

2.6. Exterior Walls 6

3. CODE GAPS AND RECOMMENDATIONS 7

4. REFERENCES 11

APPENDIX A. EXCERPTS FROM TWO TABLES FROM THE 1975

EDITION OF THE BOCA BASIC BUILDING CODE . 12

APPENDIX B. EXCERPTS FROM FIRE PROTECTION AND

FIRESTOPPING PROVISIONS OF THE BASIC

BUILDING CODE 15

APPENDIX C. SUMMARY OF INCIDENTS WHERE MULTIPLE

DEFICIENCIES WERE APPARENT 18

iii
,

.

'
A STUDY OF FIRE SPREAD IN MULTI-FAMILY

RESIDENCES: THE CAUSES THE REMEDIES

Bertram M. Vogel

Abstract

This report identifies the major elements

contributing to the spread of fire in multi-family

buildings, where the fire is beyond the area of

origin. The data has been collected from 84

separate fires involving low-rise (garden apartments) residential buildings in the Washington, D.C.

metropolitan area. This report categorizes the

contributing factors of the fire spread into construction deficiencies, design deficiencies, and

possible code violations; and suggests the need

for specific revisions to building codes.

Key words: Apartments; building codes; fire; fire

resistivity; firestopping; fire walls; garden

apartments; multi-family residences.

1. INTRODUCTION

Since January 1971, the Center for Fire Research,

Institute for Applied Technology, the National Bureau of

Standards, has retained under contract, Mr. Francis L.

Brannigan (Associate Professor, Fire Science Coordinator at

Montgomery College, Rockville, Maryland), [1]-*- for the purpose

of investigating serious multiple dwelling residential fires

occurring in the Maryland and Virginia jurisdictions adjacent

to Washington, D.C., a metropolitan area of 2-1/2 million

people. Among several objectives of these investigations is

the determination of those structural elements or construction

practices contributing to the extension of fire beyond the

area of origin. At a symposium on fire safety research held

at NBS on August 22, 1973, Mr. Brannigan presented a paper

[2] which summarized his observations on a number of fires

that had occurred between January 1971 and August 1973.

Numbers in brackets refer to the literature references

listed at the end of this paper.

1
Subsequently, additional reports on these multiple dwelling

fires have been received; they now number some 84 separate

cases. The reports are limited to fires in the D.C. metropolitan area and pertain only to multi-family residences in

which the fire left the apartment of origin.

This paper is an extension of the work reported in NBS

Special Publication 411, bringing these investigations of

fires in multiple dwellings up to date and containing an

analysis of the data for application to existing code requirements. In addition, the various in situ conditions contributing to the extension of the fires beyond the area of origin,

as identified by the investigator, are categorized.

While the majority of the subject buildings are relatively

new (erected within the last 10 years) no attempt has been

made here to ascertain specific information such as:

(1) What building code, if any, the building was built

under;

(2) Date of construction and first occupancy;

(3) Fire loading;

(4) Estimation of length of time fire was underway

before detection; and

(5) Length of time for fire department response

subsequent to detection.

The predominant building code now in effect in the jurisdictions involved in this study is some form of the "Basic

Building Code." [3] For this reason the Basic Building Code

is used as an example and the discussion that follows centers

on the provisions in the Basic Building Code. However, the

discussions and suggestions are equally applicable to other

model codes.

The Basic Building Code divides building construction

into four categories: Type 1 (fire proof), Type 2 (noncombustible) , Type 3 (ordinary) , and Type 4 (frame) . The

Code tabulates the fire resistance requirements for structural

elements according to the type of construction used. The

requirements for fire resistance are contained in Table A1

(see Appendix A) . Table A2 identifies the building height

and fire area limitations for various occupancy use groups

and types of construction (see Appendix A)

2
Attention is directed to these tables to point out the specific regulatory limitations and requirements for R-2 multi-family

residential buildings.

2

Except for five cases, the buildings in this study were

garden-type low-rise apartment houses or row-type townhouses

with wood floor joists, wood roof framing, and either masonry,

brick veneer, or wood frame exterior walls. The Basic Building

Code defines these types of construction as Type 3B (ordinary

protected) in the case of masonry exterior walls with wood

joists and roof framing; and Type 4A (frame-protected) in

the case of brick veneer or wood frame exterior walls with

wood joists and roof framing.

In all types of construction, fire protection and firestopping of the various building elements are major deterrents

to the spread of fire. In buildings of Type 1 (fireproof) or

Type 2 (noncombustible) construction these requirements are

not as critical as in Type 3 (ordinary) or Type 4 (frame)

construction where the resistance of the partitions to fire

penetration is lower and combustible materials in the partitions may contribute to flame spread.

Excerpts of the Basic Building Code's fire protection

and firestopping provisions are contained in Appendix B.

Similar or comparable provisions exist in the other model

building codes [4-6] in wide use throughout the United States.

These requirements, if clearly understood and strictly

enforced, constitute the major deterrents to the spread of

fire from one apartment to another in a multi-family residential building.

Unfortunately, in real life we may find poor enforcement, poor workmanship and a lack of understanding by designers and builders of the basic philosophy of fire protection.

The lack of appreciation of these factors relating to fire

spread is a primary contributor to major losses of life and

property. These factors become readily apparent during the

review of Brannigan's investigations, 84 of which are pertinent to this report. These 84 fires resulted in 14 fatalities.

Seventy-nine of the fires investigated involved fires

which extended vertically, horizontally or, in some cases, in

both horizontal and vertical directions to another apartment.

In 18 of these incidents the fire spread was abetted by more

than one apparent deficiency in design, construction or workmanship. (See Appendix C for summary of multiple deficiencies.)

Similar provisions are contained in other model building

codes (see references [4-6]).

3
In four incidents operation of sprinkler systems in

storage rooms (the room of fire origin) prevented the extension

of fire. The requirement of sprinklered storage rooms in

multiple family residential buildings is a relatively new

building code requirement and, therefore, was not a mandatory

requirement for all buildings involved in these investigations.

2. CONSTRUCTION DEFICIENCIES

This section is a breakdown of the apparent construction

or workmanship deficiencies responsible for spread of fire

and the number of incidents resulting from each type of deficiency. If the deficiencies violate sections of the Basic

Building Code, the specific sections are noted.

2.1.

Faulty Chase Construction

(1) Wood stud partitions used to conceal utility piping

or ductwork, in which the fire protective exterior

sheathing was penetrated by the pipe or duct - 20 incidents (24%) (violates Sections 875. 10 3 and

919.1 of the Basic Building Code.)

(2) Omission of fire protective sheathing above ductwork where ductwork was boxed-in below ceiling -

4 incidents ( 5% )

.

2.2.

Violation of Fire Wall

(1) Through penetrations of the fire wall construction

by joists and beams - 2 incidents (2.4%) (violates

Section 875.2 of the Basic Building Code.)

2.3.

Lack of Firestopping

(1) Partitions stacked one above the other without

proper firestopping at intervening floor or ceiling

levels, providing direct channels to floor, ceiling

or attic framing — 24 incidents (29%) (violates

Sections 875.1, 875.10 and 919.1 of the Basic

Building Code.)

Section citations refer to sections of the Basic Building

Code contained in Appendix B.

4
(2)

Omission of fire protective sheathing over or in

back of kitchen cabinets, or in back of bathtubs, providing direct access to floor/ceiling framing —

5 incidents (6% )

.

2.4. Faulty Construction

(1) Improper attachment of drywall or sheetrock —

6 incidents (7%) (code violation since fire resistance rating for drywall or sheetrock assemblies are

based on screw or nail types and sizes, and spacing.)

(2) Improper installation of required sprinkler heads — 1 incident (1%)

.

(3) Improper firestopping for required subdivision of

attic spaces (i.e., sheetrock improperly nailed,

and joints not taped, spackled and properly finished) — 2 incidents (2%) (violates Section 875.6 of the

Basic Building Code.)

2.5. Faulty Design

(1) Combustible surface finishes in corridor materials

which appeared to have flame-spread rating of greater

than 75 were installed — 2 incidents (2%)

(violation of Table 920 of the Basic Building

Code .

)

(2) Nonconforming construction in stairway —

1 incident (1%) (exposed wood framed stairs

installed in top story stairway.

)

(3) Omission of basement ceiling — 1 incident (1%)

.

(4) Installation of combustible room finishes — one

incident (1%) (this plywood paneling attached

directly to wood studs — thickness of paneling

undetermined but if less than 1/4 inch thickness

this paneling would have been required to be

applied directly to noncombustible backing in

accordance with Sections 921.5 and 921.6 of the

Basic Building Code.)

5
2.6. Exterior Walls

(1) Interior side of wall

(a) Omission of firestopping in furred-out areas

of exterior walls — 1 incident (1%)

.

(Violates Section 875.8 of the Basic Building

Code .

)

(b) Mansard roof framed to provide direct connection to attic space without intervening

firestopping — 2 incidents (2%) (violation

of Section 925.6 of the Basic Building Code.)

(2) Exterior side of yrall

(a) Vertical extension from floor to floor via

window openings in exterior walls without

apparent involvement of exterior surface

finish — 2 incidents (2%)

.

(b) Fire extension due to combustible balconies

or exterior surface finish — 13 incidents

(15%). (This- is an area where code revision

may be desirable since the Basic Building

Code addresses only "Exterior Trim Restrictions . " )

(c) Fire extension to combustible materials or

soffits of roof overhangs; or exposed roof

framing without firestopping at exterior wall

line — 21 incidents (25%)

.

(Note: in these cases fires originating below

roof level extended vertically into attic via

involvement of combustible exposed roof framing,

combustible soffits of roof overhang or through

vent openings in roof overhang.) (This is an

area where code revision may be desirable.)

It is readily apparent that each of these identified

deficiencies could fall into one or more of the following

categories, i.e.:

(1) Improper code enforcement;

(2) Poor workmanship;

(3) Building design that does not respond to basic fire

protection philosophy;

(4) Code gaps.

6
I

While the cases described above involve construction in

those jurisdictions of Maryland and Virginia adjacent to the

District of Columbia/ these conditions are not unique to

these jurisdictions. These conditions suggest that the design

professions , regulatory community and contractors need to

reassess the existing state-of-the-art of low-rise, multipledwelling design and construction with regard to fire safety;

and make those changes that are needed in both regulation and

building practice to be conducive to reduction in life and

property losses. The following are some "Code Gaps" which

may be worth considering.

3. CODE GAPS AND RECOMMENDATIONS

A. A review of information available on partition assemblies tested by Underwriters' Laboratories, Inc., Ohio

State University and other testing facilities does not

identify any partition assemblies (bearing or noribearing) which have been tested and rated with utility

services penetrating the fire protective membrane on

either or both sides of the assembly. This lack is in

contrast to a number of floor-ceiling assemblies wherein

te;st reports indicate maximum permissible areas of penetration. Yet it is common practice of the regulatory

authorities to permit penetrations in the field which

may negate the fire resistance ratings of the assembly

assigned by the testing facility.

Performance criteria for building assemblies should be

based on sound fire protection engineering principles

or tests. Building officials could use these criteria

for establishing maximum permissible areas of penetrations of fire-rated wall and partition assemblies.

Meanwhile, the necessity of installing noncombustible

packing or other non-combustible materials in oversized

openings for utility services penetrating firestops or

fire protective sheathing should be emphasized.

B. We have previously identified in this study a relatively

high incidence of fires which have spread from exterior

windows and doors into attic spaces through the involvement of combustible roof overhangs or through vent

openings in the soffits of roof overhangs. In all cases,

these roof overhangs were directly connected to the open

attic spaces without intervening full depth firestopping

between the terminus of the exterior wall and the roof

sheathing

.

7
All existing building codes require venting of attic

spaces. The general design practice to accomplish this

venting is by the provision of soffit vents in the roof

overhangs, or in those cases where the roof overhang

soffits are not sheathed, by installation of screening

in the rafter spaces.

Several of the model building codes have recognized the

fire problems associated with these practices. The 1976

National Building Code in Section 530.6b provides

"Eaves constructed of fire retardant treated wood,

lumber, or plywood or of wood or other combustible

materials shall extend not more than three (3) feet

beyond exterior walls, and, where connected to attics,

shall be firestopped between the upper terminus of the

exterior wall and the bottom side of the roof deck."

The 1976 Uniform Building Code, in recognizing the

potential hazard of fires extending from door and window

openings directly into attic spaces through eave vents,

provides the following requirement in the second paragraph of Section 3205(c):

"Where eave or cornice vents are used to provide the

required ventilation of combustible attic spaces, vent

openings shall not be located within 3 feet measured

laterally above window or door openings in the wall of

the story immediately below." While this requirement

may provide adequate protection from the extension of

fire from a wall opening into the attic space by way of

eave or cornice vents under one set of fire conditions,

it may not provide sufficient protection under every set

of fire loading and wind conditions.

Consideration should be given to the prohibition of

venting of attic spaces by means of eave, cornice or

soffit vents.

Extension of fire into attic spaces through the involvement of combustible roof overhangs would still be

possible if full depth firestopping at the exterior

wall were not present. Therefore, the following two

additional code changes are suggested:

(1) "Eaves constructed of combustible materials, where

connected to attics, shall be firestopped between

the upper terminus of the exterior wall and the

bottom side of the roof deck or sheathing."

8
(2) "The soffits of all roof overhangs shall be sheathed

in noncombustible material not less than 1/2 inch

thick.

It should be noted that required attic ventilation

would have to be accomplished by either gravity- or

power-driven roof ventilators or where gable ends exist

by means of louvres in the gable ends, or by a combination or gable end louvres and roof ventilators.

C. While not totally pertinent to this report, there is a possible omission of fire resistance rating requirements

for the structural elements which support fire resistive

dividers, in Table 214 of the Basic Building Code (see

Table Al in Appendix A) . In Types 3C and 4B construction fire resistance rated partitions, i.e., Item 4,

fire separation assemblies. Item 5, fire enclosure of

exitways, etc., and Item 6, shafts other than exitways,

etc., partitions requiring fire resistance ratings of

either one or two hours could be wholly supported by

floor constructions (Item 10) which do not require fire

resistance ratings in Types 3C and 4B construction. A

note should be added to Item 10 and should read "Construction supporting walls and partitions shall have a fire resistance rating not less than the wall or partition

supported." This condition can also possibly exist in

application of the Uniform and Standard Building Codes.

D. While all of the model building codes have statements on

firestopping similar to that contained in Section 875.1

of the Basic Building Code, there is a definite need to

provide guidance to building officials on how they can

readily accomplish effective firestopping which would

preclude "free passage of flame through concealed

spaces" and would allow firestoppage of all vertical

and horizontal draft openings." This is specifically

the case in partitions which: (1) run from lower

levels to the ceiling of the top story; and (2) contain

utility runs that pierce the required firestopping at

each floor and ceiling level. These two conditions

create "draft openings" and afford "free passage of

flame through concealed spaces," which are interconnected at each floor level and the attic space. A

partial solution to this interconnection of partition/

floor-ceiling voids could be accomplished by the following

suggested revision to the Basic Building Code. (Similar

provisions already exist in other model building codes.)

9
"Joists in all types of construction shall be firestopped at the ends and over supports for the full

depth of the joists."

It shall be noted that earlier editions of a number of

building codes required that joists be doubled under

partitions running parallel to the joist span. Why this

requirement has been dropped in subsequent editions of

these codes is unknown. Construction of this type would

provide desirable firestopping in the joist space.

E. As previously indicated, in at least 15 percent of the

fires investigated, combustible balconies and exterior

finish contributed to the spread of fire on the exterior

surfaces of the buildings after the fires left the rooms

of origin through openings in exterior walls. Section

608.4 of the 1976 Standard Building Code and Section

1705(d) of the 1976 Uniform Building Code address the

subject of exposed exterior wood veneers or paneling

applied to exterior walls; but only in relation to the

separation from adjoining property lines. No consideration is given to the possible spread of fire along the

exterior walls from sources within the building, where

the location of the building with respect to other

buildings or property lines does not dictate opening

protectives. Section 924.4 of the 1975 Basic Building

Code requires that balconies on Type 3 and 4 buildings

have the same fire resistance rating as required for the

floors. Section 1108 of the 1976 Standard Building Code

while concerned with certain criteria for balcony construction does not address fire resistance ratings for

balconies. In Section 924, the 1975 Basic Building Code

establishes restrictions on exterior trim but not on

overall exterior finish. In discussions with staff personnel of several of the model code organizations, it is

their interpretation that the existing requirements of

their codes do not address the subject of exterior finish

requirements for exterior walls and balconies.

F. In view of the failures, due to exterior fire spread,

reasonable requirements should be provided to place some

flame spread limitations on the use of combustible

exterior finishes including balconies in Types III and V

q buildings. A suggested code requirement is as follows:

Types III and V construction as referred to in this section

are the respective designations for "Noncombustible Exterior

Wall" and "Combustible," as defined by the Model Codes

Standardization Council (MCSC) and are the typical types

of construction most generally used in multi-family gardentype apartments. This suggested code change may also be

appropriate for the other types of construction.

10
I

"All exterior finish, including balconies located within

5 feet measured horizontally or vertically, of openings

in the exterior walls of buildings of Types III and V

construction, shall have a flame spread rating not

exceeding 75."

4 . REFERENCES

[1] Brannigan, Francis, L. , Building Construction for the

Fire Service, NFPA No. FSP-33, National Fire Protection

Association (Nov. 1971)

.

[2] Brannigan, Francis L. , A Field Study of Non FireResistive Multiple Dwelling Fires, in Fire Safety

Research, Proceedings of a Symposium held August 1973.

eds: J. Slater and M. Butler, Nat. Bur. Stand. (U.S.)

SP-411 (Nov. 1974) pp. 178-194.

[3] Basic Building Code, promulgated by the Building

Officials and Code Administrators International, Inc.,

1313 East 60th Street, Chicago, Illinois 60637, Current

Edition is 1975.

[4] Standard Building Code, promulgated by the Southern

Building Code Congress International, Inc., 3617 Eighth

Avenue South, Birmingham, Alabama 35222, Current

Edition is 1976.

[5] Uniform Building Code, promulgated by the International

Conference of Building Officials, 5360 South Workman

Mill Road, Whittier, California 90601, Current Edition

is 1976.

[6] National Building Code, promulgated by the American

Insurance Association, 86 John Street, New York, N.Y.

10038, Current Edition is 1976.

I

11
APPENDIX A

Appendix A contains excerpts from two tables

from the 1975 Edition of the BOCA Basic Building

Code

.

Table A1 (Excerpts from Table 214 of the

Basic Building Code) provides the required fire

resistance ratings of structural elements of

buildings with relation to the type of construction . Table A2 (from Table 305) establishes the

height and fire area limitations of buildings

based on the occupancy use group and type of

construction. The garden-type multi-family

dwelling residential buildings identified in this

paper are classified as R-2 occupancy.

12
Table Al. (Excerpts from Table 214) Fire-resistance Ratings of Structural Elements (In Hours)

Type of Construction — Section 214.0 structural Element

Note a Type 3 Exterior masonry walls Type 4 Frame Protected Unprotected Protected Unprotected

3B 35 4a 4 B Exterior walls

On street lot lines

or with fire separa-

(Section 906.0

and Note b) Bearinq 2 2 1 0 tion of 30 1 or more

from interior lot lines or any building

Non-bearing 0 0 0 0

1 On interior lot lines

or less than 6 ' there- from or from any Bearinq 2 2 l i Note d building Non-bearing 2 2 l i Note d

6' or more but less Bearinq 2 2 l 0 than 11' Non-bearing 2 2 1 0

11' or more but less Bearinq 2 2 l 0 than 30' Non-bearing 1-1/2 1-1/2 l 0

2 Interior bearing

walls and partitions 1 0 l 0

3 Fire walls and party

walls (Section 907.0

2 2 2 Not less than fire grading

(See Table 902

2 of use group

.) 4 Fire separation assemblies

Note a Fire-resistance rating corresponding to fire grading of use group - (See Table 902.)

5 Fire enclosure of exitways,

exitway hallways and stairways

(Section 909.0 and Note f)

2 2 l 1

6 Shafts, other than exitways,

elevator hoistways (Section

910.0)

2 2 l 1

7 Exitway access corridors & vertical separation of tenant

spaces (Section 910.0)

1 0 l 0

Other non-bearing partitions 0 0 0 0 Supporting more

than one floor

1 0 1 0

8 Columns, girders,

trusses, (other than

roof trusses) and Supporting one floor only

1 0 1 0 framing (Section

911.0) Supporting a roof only

1 0 1 0

9 Structural members supporting

wall (Section 911.0)

10 1 Not less than fire-resistance rating

wall supported

0 of

10 Floor construction including

beams (Section 912.0 and Note g) 1 0 1 0 15' or less in height to lowest member

1 0 1 0

11 Roof construction

including beams, trusses and framing

arches and roof deck

(Section 912.0 and

More than 15 ' but

less than 20' in height to lowest member

0 0 1 0

Notes g and j) 20' or more in height to lowest member

0 0 0 0

Notes applicable to Table 214 Note a

.

Note b.

Note d. Note e

.

Note f.

Note g.

For special high hazard uses involving a higher degree of fire severity and higher

concentration of combustible contents, the fire-resistance rating requirements

for structural elements shall be increased accordingly (see Section 400.3). The fire separation or fire exposure in feet as herein limited applies to the distance

from other buildings on the site, or from an interior lot line or from the opposite

side of a street or other public space not less than thirty (30) feet wide to the building wall (see Definitions, Section 201.3). See Section 303.2. See Sections 213.0, 909.0 and 912.0.

In all buildings of Types 3 or 4 construction, the stairways and their enclosures may

be constructed of wood or other approved materials of similar characteristics and of adequate strength; except in school buildings (see Section 616.9.3).

In Type 3A construction, members which are of material other than heavy timber shall have a fire-resistance rating of not less than one (1) hour (see Section 853.2). Where the omission of fire protection from roof trusses, roof framing and decking

is permitted, the horizontal or sloping roofs in Type 1 and Type 2 buildings,

immediately above such members shall be constructed of noncombustible materials of the required strength without a specified fire-resistance rating, or of mill type construction

in buildings not over five (5) stories or sixty-five (65) feet in height (see Section 913.3).
Table A2.

(Excerpts from Table 305)

Height and Area Limitations of Buildings

Height limitations of buildings (shown in upper figure as stories and feet above grade) , and area limitations of one- or two-story buildings facing on one street or public space not.

less than 30 feet wide (shown in lower figure as area in square

feet per floor)

.

Use Group

Note a

Type of Construction

Type 3 Exterior masonry walls

Ordinary Joisted

Type 4 Frame

Protected Unprotected Protected Unprotected

3B 3C 4A 4B

R-l Residential

,

hotels 4 St. 50' 3 St. 40' 3 St. 40' 2-1/2 St. 35

13,200 9,600 10,200 4,800

R-2 Residential

,

multi-family 4 St. 50' 3 St. 40' 3 St. 40' 2-1/2 St. 35

13,200 9,600 10,200 4,800

Note f

R-3 Residential

,

1 & 2 family 4 St. 50' 3 St. 40' 3 St. 40' 2-1/2 St. 35

13,200 9,600 10,200 4,800

Notes applicable to Table 305

Note a. See the following sections for general exceptions to Table 305.

Section

Section

Section

Section

Section

Section

Section

305.4

Allowable area reduction for multi-story buildings.

306.2 Allowable area increase due to street frontage.

306.3 Allowable area increase due to automatic fire suppression

system installation.

306.4 Maximum building area.

306.4

Maximum building area. 307.0 Unlimited area one-story buildings.

308.1 Allowable height increase due to automatic fire suppression

system installation.

Note f. For exceptions to height and area limitations for high hazard use buildings, see Article 4 governing the specific use. For other

special fire-resistive requirements governing specific uses, see Section 905.0.

14
APPENDIX B

EXCERPTS FROM FIRE PROTECTION AND FIRESTOPPING

PROVISIONS OF THE BASIC BUILDING CODE

"Section 875.0 Fire Protection and Firestopping —

875.1 General: To prevent the free passage of flame

through concealed spaces or openings in event of fire,

provision shall be made to trim all combustible framing

away from sources of heat, to provide effective fire

barriers against the spread of fire between all subdivisions and' all stories of the building, to provide

adequate fire separation against exterior exposure, and

to firestop all vertical and horizontal draft openings

as specified herein.

875.2 Beam separation in ordinary construction (Types

3B and 3C) : All wood and other combustible floor, roof

and other structural members framing into masonry walls

shall be cut to a bevel of three (3) inches in the

depth and shall project not more than four (4) inches

into the wall; and the distance between embedded ends

of adjacent beams or joists entering into the wall from

opposite sides shall be not less than four (4) inches.

875.3 Girder separation in heavy timber construction

(Type 3A)

Wood girders framing into walls shall have

at least eight (8) inches of masonry between their ends

and the outside face of walls and at least eight (8)

inches of masonry between adjacent beams entering the

wall from opposite sides. The girders shall be firecut, supported in pockets or in self-releasing metal

boxes, or otherwise supported to minimize destruction

of the wall in the event of fire.

875.6 Concealed roof spaces: Concealed roof spaces

enclosed by combustible ceiling and roof construction

shall be subdivided into areas of not more than threethousand (3,000) square feet as provided in Section

314.0.

875.7 Architectural trim: Exterior cornices and other

exterior architectural elements, where permitted of

combustible construction in Section 924.0, or when

erected with combustible frames, shall be firestopped

at maximum intervals of twenty (20) feet. If noncontinuous, they shall have closed ends, with at least

four (4) inches separation between adjoining sections.

15
875.8 Wall furring: In masonry wall construction

(Types 3A, 3B, and 3C) and in frame construction (Types

4A and 4B) where walls are furred, the space between

the inside of the furring and the face of the wall for

the full depth of the combustible floor or roof joists

shall be firestopped.

875.9 Combustible trim and finish: The space behind

combustible trim and finish where permitted under this

code and all other hollow spaces where permitted in

fire-resistance rated construction shall be back-filled

with noncombustible materials or firestopped as required

in Section 920.0.

875.10 Firestopping: Firestopping meeting the requirements of Section 919.0 shall be provided in stud walls

and partitions at each floor level and between the

ceiling of the top story and roof space; in all furred

spaces of frame walls and studded off spaces of masonry

walls at maximum intervals of eight (8) feet; at the

top and bottom and at least once in the middle of each

run of stairs; in concealed wall pockets for sliding

doors; at openings for pipes, belts, shafting, chutes

and conveyors passing through combustible floors or

partitions with close-fitting noncombustible caps or

metal shutters or other approved noncombustible means;

and in all other locations that would permit the free

travel of flame."

"Section 919.0 Firestopping

919.1 Where required: Firestopping shall be designed

and constructed to close all concealed draft openings

and to form effectual fire barriers against the spread

of fire between stories of every building and in all

open structural spaces therein, including the following

locations: for the subdivision of attic spaces in

Section 314.0; for combustible wall, partition and

floor framing in Section 875.0; for ceiling spaces in

Section 912.0; for open spaces behind acoustical and

other finishes in Section 921.0; for floor sleeper

spaces in Section 922.0; and for pipe, duct and flue

openings in the mechanical code listed in Appendix B.

919.2 Firestopping materials: All firestopping shall

consist of approved noncombustible materials securely

fastened in place. Firestops of two (2) thicknesses

of one (1) inch lumber with broken lap joint or of two

(2) inch lumber installed with tight joints shall be

permitted in open spaces of wood framing.

16
919.3 Required inspection: Firestopping shall not be

concealed or covered from view until inspected and

approved by the building official.

921.5 Class II, and III material: Interior finish

materials, other than Class I material, which are less

than one-quarter (1/4) inch in thickness shall be

applied directly against a noncombustible backing unless

the tests under which such material has been classed

were made with the materials suspended from the noncombustible backing.

921.6 Noncombustible backing: Noncombustible backing

for interior finish materials shall be a continuous

surface with permanently tight joints, equal in area to

the area of the finish, and extending completely behind

such finish in all directions; and may be of any materials meeting the requirements of this code for noncombustible classification of material under Section 903.5.1

or of fire-retardant treated wood. When the noncombustible backing does not constitute an integral part

of the structural elements or system, it shall be*

attached directly to the structural elements or to

furring strips as required for the application of finish

according to Section 921.2, or may be suspended from

the structural members at any distance provided concealed spaces created thereby shall be firestopped in

accordance with the applicable requirements of this

code. Where Class III interior finish is applied to

a continuous noncombustible backing beneath wood joist

construction, the allowable area for firestopping

required in Section 912.4 may be increased to three

thousand (3,000) square feet."

17
APPENDIX C.

SUMMARY OF INCIDENTS WHERE MULTIPLE

DEFICIENCIES WERE APPARENT

I. Double Deficiencies

(a)

(b)

(c)

(d)

(e)

(f)

Unf irestopped partitions, duct or pipe shaft - combustible balcony or exterior finish - 2 fires.

Unf irestopped partitions, duct or pipe shaft - improper nailing or installation of sheetrock -

1 fire.

Omission of fire protective sheathing at kitchen

cabinets - roof soffit vents - 1 fire.

Omission of fire protective sheathing at kitchen

cabinets - ductwork not properly boxed out -

1 fire.

Improper installation of sprinklerhead - omission

of firestopping under partitions - 1 fire.

Combustible balcony or exterior finish - roof

soffit vents - 4 fires.

(g) Unf irestopped partitions, duct or pipe shaft - omission of fire protective sheathing at kitchen

cabinets, bathtubs - 2 fires.

(h) Unf irestopped partitions, duct or pipe shaft - omission of attic firestopping - 1 fire.

(i) Faulty firewall construction - mansard roof

construction - 1 fire.

(j)

Combustible balcony or exterior finish - omission

of attic firestopping - 1 fire.

II. Triple Deficiencies

(a) Combustible balcony or exterior finish - roof soffit

vents - unf irestopped partitions, duct or pipe

shaft - 2 fires.

(b) Unf irestopped partitions, duct or pipe shaft - combustible balcony or exterior finish - combustible room finish - 1 fire.

18
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

4. TITLE AND SUBTITLE

1. PUBLICATION OR REPORT NO. NBSIR 76-1194

2. Gov’t Accession

No.

A Study of Fire Spread in Multi-Family

Residences: The, Causes — The Remedies

3. Recipient’s Accession No.

5. Publication Date February 1977

6 . Performing Organization Code

7. AUTHOR(S)

Bertram M. Vogel 8 . Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4920685

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Same as No. 9

13. Type of Report & Period Covered

Final Report

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most si&iificant information. If document includes a significant

bibliography or literature survey, mention it here.)

This report identifies the major elements contributing

to the spread of fire in multi-family buildings, where the fire

is beyond the area of origin. The data has been collected from

84 separate fires involving low-rise (garden apartments)

residential buildings in the Washington, D.C. metropolitan area,

This report categorizes the contributing factors of the fire

spread into construction deficiencies, design deficiencies, and

possible code violations; and suggests the need for specific

revisions to building codes.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) . . , , . , r • . • , Apartments; building codes; fire; fire resistivity;

firestopping; fire walls; garden apartments; multi-family

residences

.

18. AVAILABILITY [2C Unlimited c For Official Distribution. Do Not Release to NTIS

|

I Order From Sup. of Doc., U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. C13

[X Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

21

22. Price

$3.50

U5COMM.DC 29042-P74
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