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NBSIR 78-1586

Fire Safety Guidelines for

Vehicles in a Downtown People

Mover System

Richard D. Peacock

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

Washington, D.C. 20234

January 1979

Final Report

'repared for: rban Mass Transportation Administration

J.S. Department of Transportation

Washington, D.C. 20591

Bnreao of Standards MAY 14 ym

NBSIR 78-1586

< i < FIRE SAFETY GUIDELINES FOR

VEHICLES IN A DOWNTOWN PEOPLE

MOVER SYSTEM

Richard D. Peacock

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

January 1 979

Final Report

Prepared for: Urban Mass Transportation Administration

U.S. Department of Transportation

Washington, D.C. 20591

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

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
; • :• K ,, * '

-• v, .- •vi
TABLE OF CONTENTS

Page

LIST OF FIGURES v LIST OF TABLES V

EXECUTIVE SUMMARY vi

Abstract 1

1. INTRODUCTION 1

2. EXISTING PEOPLE MOVER SYSTEMS 2 2.1 The Morgantown System 3 2.2 The AIRTRANS System 3 2.3 Materials of Construction 4 2.3.1 Interior Vehicle Design .... 4 2.3.2 Exterior Vehicle Design 4 2.4 Fire Detection/Suppression Provisions 5 2.5 Emergency Egress from Vehicles 5 2.6 Vehicle Voice Communications 6

3. PROPOSED DPM SYSTEMS 7 3.1 Proposed DPM System, Houston, Texas 7 3.2 Proposed DPM System, Los Angeles, California 7 3.3 Proposed DPM System, St. Paul, Minnesota ..... 8

4. PROPOSED DPM VEHICLES 8 4.1 Otis Elevator Company, Duke University Type Vehicle 9 4.1.1 Basic Vehicle Design 9 4.1.2 Fire Detection/Suppression Provisions 10

4.1.3 Emergency Egress 11

4.1.4 Voice Communications 11

4.2 DEMAG + MBB Cabintaxi Vehicle 11

4.2.1 Fire Detection/Suppression Provisions 11

4.2.2 Emergency Egress 11

4.2.3 Voice Communications 12

5. THE FIRE SAFE DPM VEHICLE 12

5.1 Fire Scenarios in a DPM Vehicle 12

5.1.1 Interior Ignitions 12

5.1.2 Exterior Ignitions 15

5.2 Vehicle Design to Minimize Fire Hazard 16

5.2.1 Interior Vehicle Design . 16

5.2.2 Exterior Vehicle Design 17

5.2.3 Emergency Egress 18

5.2.4 Voice Communications System 18

6. EVALUATION 19

6.1 Important Areas of Consideration 19

6.2 Test Methods for the Flammability of Materials

Used in DPM Systems 20

6.3 Fire Penetration Test 21

6.4 Ignition Resistance Tests 21

6.4.1 Motor Vehicle Safety Standard No. 302 21

6.4.2 Federal Aviation Regulation FAR-25.853 21

6.4.3 ASTM D 635 22

6.4.4 ASTM D 1692 22

iii
TABLE OF CONTENTS (Cont'd)

Page

6.4.5 Carpeting Tests 22

6. 4. 5.1 DOC FF 1-70 Pill Test 22

6. 4. 5.

2

NFPA 253-78 23

6.5 Smoke Density Test 23

6.6 Rate of Heat Release Tests 23

6.7 Flame Spread Tests 24

6.7.1 Radiant Panel Test, ASTM E 162 24

6.7.2 ASTM E 84 Tunnel Test 24

7. PROPOSED GUIDELINES 25

7.1 Materials Flammability 25

7.1.1 Ignition Resistance/Flame Spread Test 25

7. 1.1.1 Interior and Exterior Materials 25

7. 1.1.

2

Floor Covering Flammability Test 26

7. 1.1.

3

Seating Assemblies 26

7.1.2 Smoke Generation Test 26

7.1.3 Penetration Test 27

7.1.4 Rate of Heat Release Test 27

7.1.5 Combustion Products Toxicity 27

7.2 Fire Detection 28

7.2.1 System for Vehicle Interior 28

7.2.2 System for Vehicle Electrical and Mechanical

Equipment Bays 2 8 7.3 Fire Suppression 29

7.3.1 Portable Fire Extinguishers 29

7.3.2 Automatic Fire Suppression 29

7.4 Emergency Egress 30

7.5 Voice Communications 30

7.6 Vehicle Construction 30

7.6.1 Heating and Air Conditioning System 30

7.6.2 Electrical Fire Safety 30

7.7 Guidelines for Testing Protocol 31

8. SUMMARY AND CONCLUSIONS 31

9. REFERENCES 32

iv
LIST OF FIGURES

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Table

Table

Table

Table

Page

1. Morgantown passenger vehicle construction 40

2. AIRTRANS passenger vehicle construction 41

3. Morgantown emergency egress provisions 42

4. AIRTRANS emergency egress provisions 43

5. Otis passenger vehicle interior construction 44

6. Probable location of ignition sources in a DPM vehicle . . 45

7. Comparison of ignition source characteristics and

minimum ignition energies for various seat assemblies . . 46

8. Vehicle interior design features 47

9. Vehicle exterior design features 48

10. Vehicle flammability guidelines 49

LIST OF TABLES

Page

Worst case evacuation times from people mover vehicles ... 36

Potential for ignition of various seat assemblies by

some ignition sources 37

Summary of selected small-scale test results on transit

vehicle components 38

Recommended acceptance criteria test method ASTM E 162 ... 39

v
EXECUTIVE SUMMARY

The fire safety aspects of vehicles used in Downtown People Mover

systems has not been previously studied and considered in depth. This report,

prepared by the Center for Fire Research, National Bureau of Standards,

presents the results of a limited study to evaluate fire problems and to

recommend fire safety provisions for automated vehicles used for the

movement of people in a congested urban area.

This study was sponsored by the Urban Mass Transportation Administration

(UMTA) to provide reasonable fire safety guidelines to be required for the

systems to be deployed under the "Downtown People Mover" (DPM) program and to

update existing UMTA guidelines. The specific objectives of the project

were to:

• Review the Morgantown and AIRTRANS systems and any fire

experience with these systems.

• Review the vehicle design features and materials that are used by the various system manufacturers and those which

may be proposed for use in the DPM program.

• Propose criteria for acceptable levels of flammability,

smoke generation, and toxic gas generation for vehicle

interior materials and vehicle construction materials

involved in fires.

• Recommend preferred materials and methods of vehicle

construction to minimize fire risk for the different

types of DPM systems.

• Recommend fire and smoke detection and suppression

methods as appropriate.

By the review of existing vehicles similar to those expected to be used

in the DPM program, and by a review of systems that have been proposed by

several cities, a series of fire scenarios were developed for potential

interior and exterior ignition sources. In addition, a variety of fire

protection measures proposed by system manufacturers ranging from simple

hand-held fire extinguishers to completely automatic Halon 1301 extinguishment

systems were identified.

This report presents guidelines that are recommended for use in the design

of downtown people mover vehicles. Methods and criteria, based on established

test procedures, are proposed for material flammability and smoke generation.

vi
Specific limits are established with the intent to control ignition/fire

spread, smoke, and toxic gas generation with the following types of test

methods

:

1) A fire penetration test to determine the likelihood of an undercar fire

penetrating to the vehicle interior.

2) An ignition resistance test for nonmetallic materials.

3) A smoke density test to limit smoke build-up in the vehicle interior.

4) A rate of heat release test to measure fire growth in the event of an ignition

.

5) A test to screen out materials that generate highly toxic combustion

products

.

Recommendations for fire and smoke detection equipment for the vehicle

interior and undercarriage and automatic fire suppression equipment for the

vehicle undercarriage are discussed.

Emergency egress provisions must also be considered in the design of a DPM system. Sufficient emergency exits, recognizing the special needs of the

handicapped, should be included in the vehicle design along with provisions

to insure the safe evacuation of passengers to the guideway.

Requirements for emergency communications between vehicles and a system's central control facility are also proposed.

vii

FIRE SAFETY GUIDELINES FOR VEHICLES IN A DOWNTOWN

PEOPLE MOVER SYSTEM

Richard D. Peacock

Abstract

The results of a study to formulate fire safety

guidelines to be required for vehicles used in Downtown People Mover (DPM) systems for the movement of

people in a congested urban area are presented. Through

a review of the design features of existing people mover

vehicles and systems, and a review of proposed new systems,

fire scenarios are developed and guidelines suggested to

minimize the fire risk to passengers.

Methods and criteria, based on established test

procedures, are proposed for assessing the flammability

and smoke generation of interior finish and furnishing

materials. Fire and smoke detection and suppression

equipment are recommended, along with proposed guidelines

for emergency evacuation provisions and emergency com- munication requirements.

An extensive bibliography of flammability in fixed

guideway transit systems is included.

Keywords: Emergency communications; emergency evacuation;

fire detection; fire safety, fire suppression; mass transportation; material flammability; people movers; smoke.

1. INTRODUCTION

The fire safety aspects of vehicles used in fixed guideway transportation

systems have not been rigorously studied and considered. At the request

of the Urban Mass Transportation Administration (UMTA) , the Center for Fire

Research at the National Bureau of Standard has conducted a limited study

to explore and formulate fire safety guidelines to be recommended for automated vehicles used for the movement of people in congested urban areas. The results of this investigation are needed to set reasonable requirements

for the systems to be deployed under the "Downtown People Mover" (DPM)

1
program sponsored by UMTA, to replace existing guidelines, and to insure an acceptable level of fire safety [1]^.

As in any transportation system, a complete fire safety analysis would

include consideration of station design and placement, trackways, vehicle

storage and maintenance areas, as well as surrounding environmental factors

that may affect the system's performance. In this study, consideration is

limited to the vehicle used in a fixed guideway transit system and to the

trackway that may be used for emergency evacuation of passengers. The

elevated guidewavs and automated unmanned vehicles present unique problems

in fire safety. This report presents guidelines that are recommended for

the design of vehicles to be used in DPM systems. In order to obtain

appropriate criteria, based on available established test methods that

would provide an acceptable level of fire safety for DPM vehicles, a review

is included of two existing systems, of proposals presented to UMTA by cities

selected for initial DPM system deployment, and of proposed new vehicle

designs from potential DPM system manufacturers.

2. EXISTING PEOPLE MOVER SYSTEMS

Automated people mover systems consist of driverless vehicles of varying

sizes, capable of carrying from 20 to 200 passengers, that operate on exclusive, fixed-path guideways. A vehicle is comprised of two major components:

the chassis usually containing the vehicle control, power collection, propulsion, and heating/air conditioning systems and the body comprised of the

exterior shell and vehicle interior [2,3].

There are approximately twenty installations of people mover systems

currently in use. Of these twenty systems, more than half are located in

recreational parks. Several are also located in airport complexes, plus

at least one system operating in a downtown university campus [2], In the

analysis of existing systems, the description will concentrate on two

operating systems - one located on the campus of the University of West

Virginia at Morgantown (the Morgantown system) and one located at the Dallas/

Fort Worth Regional Airport (the AIRTRANS system) . These two systems are typical of the people mover systems in use today and provide detailed information on typical vehicle and guideway construction. Other systems in use

are described in references [4-9] .

Numbers in brackets refer to the literature references listed at the end

of this report.

2
2.1 The Morgantown System

The people mover system at Morgantown, West Virginia serves the campuses

of the University of West Virginia with a maximum of 45 vehicles operating

over 3.9 km (2.4 mi) of reinforced concrete guideway. About half of the

vehicles are in normal service at any one time [10] . Design specifications,

according to Boeing design criteria, require that the system conform to

"pertinent provisions of the National Electrical Safety Code, applicable

specifications and standards of the National Fire Protection Association,"

applicable Motor Vehicle Safety Standards promulgated by the National

Highway Safety Administration (notably Motor Vehicle Safety Standard No. 302

- Flammability of Interior Materials), and such other local, state and

Federal safety codes and standards applicable to the design of system

elements. Vehicle floor covering is required to be "self- extinguishing"

although no test method is specified. In addition, a hand-held fire

extinguisher is required in each vehicle passenger compartment for use by

passengers [11,12].

Only a few minor fire incidents have been noted in the operation of the

Morgantown system. There have been no incidents of fire on board the vehicles used in the system. Deicing of the guideway with an ethylene-glycol

solution combined with salt splashed from an adjacent roadway has caused

arcing of the power rails and ignition of plastic power rail insulation on several occasions during severe winter weather. Fires were reported either

by passengers or system personnel and extinguished [13]

.

2.2 The AIRTRANS System

With 21 km (13 mi) of guideway, 53 stations, and 68 vehicles, the

AIRTRANS system at the Dallas/Fort Worth airport is the largest operating

people mover system in the world to date. The system is designed to transport airline passengers, as well as airport personnel, baggage, supplies,

mail, and trash at the airport. In considering the flammability characteristics of materials used in the AIRTRANS vehicles, manufacturers were required

to meet flammability specifications developed by the system designer, Vought

Corporation [14].

The specification for the AIRTRANS system required the following:

• Vehicle insulation must be self-extinguishing and fire-resistant.

• Vehicle flooring must be fire-resistant with a flame spread rating of

less than 75 using ASTM E 84-68.

3
• Each vehicle must have a fire extinguisher.

• Each vehicle must have two emergency exits in addition to the normal

entrance/exit doors.

In the twelve million vehicle miles covered in the past 3 1/2 years of

operation, the AIRTRANS system has been relatively free of problems associated

with fire. In one incident, a burning tire, caused by spinning on a slick

guideway, necessitated the removal of passengers from a vehicle because of

smoke entering through the air conditioning system. However, there have

been no reported cases of fire propagating on board a vehicle [15]

.

2.3 Materials of Construction

2.3.1 Interior Vehicle Design

Morgantown vehicles are constructed of steel frames with rigid urethane

foam insulation sandwiched between inner and outer shells of molded flame

retarded glass fiber laminates. Seats and air conditioning ducting are molded integrally with the inner shell. The polyester resin used is reported

to have a flame spread classification of 20 and a smoke density of 250, as determined by test method ASTM E 84. Nylon carpeting used as floor covering

in the vehicles is reported to have an ASTM E 84 flame spread rating of less

than 75 but does not meet Motor Vehicle Safety Standard No. 302, Flammability

of Interior Materials [16]. Figure 1 illustrates the construction of a Morgantown vehicle.

Passenger vehicles used in the AIRTRANS system are constructed of reinforced, vacuum-formed acrylic sheet interior panels, acrylic-coated glass

fiber exterior panels with rigid polyurethane foam in between. The seats are upholstered and carpeting is provided on the floors over a base of plywood

treated for moisture resistance. No details of tests performed on any of

the materials was available and no detailed verification testing was performed [14],

2.3.2 Exterior Vehicle Design

The outer shell of flame-retardant glass reinforced polyester on the

Morgantown vehicles is supported on a steel frame. The vehicle is designed

so that all electrical systems except interior car lighting and vehicle

communications are located underneath the shell that forms the interior

of the vehicle. The major components that are located beneath the vehicle

interior shell include: (a) the vehicle propulsion and braking systems

including motor, motor controller, and four-wheel vehicle brakes, (b) the

4
heating and air conditioning systems, (c) the vehicle steering/guidance

system, (d) the vehicle power-pickup shoe (575 VAC, three phase), and (e) the

vehicle communications and control systems. Vehicle window material in

the Morgantown system is 0.6 cm (1/4 in) tempered glass.

Passenger vehicles used in the AIRTRANS transit system are constructed

as illustrated in figure 2. Exterior panels are acrylic-coated glass fiber

reinforced plastic with colors impregnated in the acrylic. Propulsion is

provided by a 60-hp (continuous rating) DC motor connected to the differential by an automotive drive shaft. The 480 volt AC power is rectified and

controlled by the motor controller. The propulsion system is mounted on the

chassis, as are the emergency storage batteries. The alternator that charges

the batteries and an air compressor for the suspension system, door operator,

brakes, and vehicle dock leveling system are suspended below the chassis.

Two heating and air conditioning units are also suspended below the chassis,

one on either side. Power collection is performed by articulated brushes, a set on each corner of the vehicle, with two sets in normal use and two for

redundancy [14]

.

2.4 Fire Detection/Suppression Provisions

Vehicle on-board fire fighting equipment on both the Morgantown and the

AIRTRANS systems consists of manually operated fire extinguishers. No automatic fire detection or suppression system is provided for either system.

However, several of the following excess-temperature sensors are included in

each system [14,16].

Brake temperature sensor. Propulsion motor temperature sensor. Propulsion transformer temperature sensor. Propulsion armature temperature sensor. Hydraulic fluid temperature sensor. Vehicle communications and control system air temperature sensor

(proposed for Morgantown system)

.

These sensors are linked to the central control console of the system for

further action at the discretion of the system operator.

2.5 Emergency Egress from Vehicles

Emergency egress procedures for both the Morgantown and the AIRTRANS

system require passengers to exit through emergency exits provided onto the

5
vehicle guideway. An estimate of passenger evacuation time was made for the

Morgantown and AIRTRANS systems assuming maximum vehicle velocity, normal

vehicle deceleration, the maximum station dwell time, and maximum stationto-station travel time [2]. This estimated time represents a worst case estimate using the assumptions that the vehicle would use only normal braking rate and would have to travel the entire station-to-station distance in

order to allow a safe stop. The estimated evacuation times were 198 seconds

and 91 seconds for Morgantown and AIRTRANS, respectively. It should be

noted that these estimates are not based on evacuation drills. Rather they

have been calculated from vehicle performance data supplied in reference [2]

.

In Morgantown vehicles, the left-hand door can be operated manually to

provide egress onto a fenced walkway, then to the guideway; the rear window

of the vehicle opens to provide an additional exit. This walkway egress

is illustrated in figure 3. Due to the special conditions that exist

at Morgantown, i.e., an elevated guideway without provisions on the right

side of the guideway for passengers to safely leave the car, it was decided

that an emergency exit on the right side of the vehicle would expose the

passengers to additional, unnecessary hazards [16].

AIRTRANS vehicles are provided with emergency escape doors, 0.6 m (2 ft)

wide, at each end of the vehicles, and are posted with a sign warning of

guideway hazards — moving vehicles, etc. This provides direct egress onto

the guideway as shown in figure 4. In addition, vehicle doors are provided

with means for emergency manual opening. In both systems, operation of

emergency exits causes emergency braking of the vehicle, if in motion, and

notification to Central Control. Guideway power in the vicinity of the

disabled vehicle is also cut off in the Morgantown system. For the AIRTRANS

system, the system's Central control operation shuts power off manually to

any segment that could be affected by an evacuation.

2.6 Vehicle Voice Communicatons

Two-way communications are provided in both the Morgantown and the

AIRTRANS systems to allow communcation between Central Control and the passenger vehicles in the system. There is a UHF radio on each Morgantown

vehicle which allows any passenger to communicate directly with Central

Control by merely pressing a "push-to- talk" button. The Central operator

can communicate separately with an individual vehicle or with the entire

fleet. Public announcements may be made to the passengers of the AIRTRANS

system via a two-way radio. Passengers request individual communication

with Central Control by pressing a button on the passenger service panel in

the vehicle.

6
3. PROPOSED DPM SYSTEMS

Proposals submitted to UMTA by cities selected as initial sites for the

deployment of people mover systems in urban environments, although only

preliminary system proposals, contain information about vehicle design.

In addition, some design concepts unique to these proposed systems require

careful consideration of fire safety. The three systems proposed, St. Paul,

Minnesota, Los Angeles, California, and Houston, Texas, present a variety of

operating characteristics and environments that may affect fire safety

considerations

.

3.1 Proposed DPM System, Houston, Texas

The proposed DPM system in Houston, Texas, is a 3.6 km (2.25 mi) route

through the city's central business district. The guideway is proposed to

be aerial throughout with a double guideway serving most of the route. A

total of eight stations, three in the double guideway, three in the single

guideway, and two stations interconnecting with Houston's bus system, are planned. These will be an average of 0.33 km (1080 ft) apart [17].

The Houston proposal provides general specifications for the proposed

system and vehicle design. Specifications require provisions for passenger

egress from stalled vehicles/trains at any point along the guideway, including provisions for handicapped passengers, with assistance from passengers

or system personnel. It is proposed that these requirements be met with

walkways along the guideway, special service vehicles operating on the

guideway, special street vehicles, or a combination of these.

A communications system is proposed for the system that will allow only

one-way voice communication to trains on a selected or group basis. Automatic monitoring of fire and smoke detectors in stations is also proposed

for the computerized communications subsystem, indicating the recognition

of a potential fire problem in such a system.

3.2 Proposed DPM System, Los Angeles, California

The City of Los Angeles, California, has proposed a DPM system consisting of approximately 4.8 km (3 mi) of guideway including 4.2 km (2.6 mi) of

elevated guideway and 0.6 km (0.4 mi) of guideway in an underground portion.

Ten elevated stations and one subway station are planned, spaced an average

of 0.4 km (1395 ft) apart [18]. The unique evacuation problems associated

with subway systems has been recognized and should be considered carefully

in the overall fire safety analysis of the proposed system [19,20].

7
Consistent with the UMTA DPM program objectives, the City of Los Angeles

proposes vehicles utilizing existing technology with minimum modifications

for adaptation for the downtown environment. Recognition of a potential fire

hazard is indicated through the requirement of flame- resistant carpeting to

be used in DPM vehicles; however, no definition is provided.

Central Control and the DPM vehicles in the proposed system will be

linked by a two-way voice communications system. The system will allow

Central Control to make public announcements to any combination of vehicles

or to communicate with individual vehicles. In addition, a telephone system

is proposed for direct communications between fixed locations throughout the

DPM system.

3.3 Proposed DPM System, St. Paul, Minnesota

A 2.6-mile, two-way aerial small vehicle transit system connecting ten

stations is proposed jointly by the Metropolitan Transit Commission and

the City of St. Paul, Minnesota. An aerial guideway through the downtown

area is to connect with a below-grade guideway that will utilize an existing

trolley tunnel, circa 1907, as well as an underground guideway to a planned

office complex. Two underground stations are planned. As mentioned above,

the importance of the fire safety consideration given to underground tunnels

and terminals, although not within the scope of this project, cannot be over stressed

.

The proposal includes provisions for hand-held fire extinguishers,

readily accessible to passengers, on every vehicle. In the event of fire or

an emergency evacuation, all power is to be turned off by the Central Control

system. Separate emergency doors, in addition to manual operation of

entrance/exit doors, are required.

During an emergency evacuation of a vehicle, the passenger evacuation

route is to be designed to "insure against the possibility of passengers

falling from the guideway and/or coming in contact with the power system" [21]

.

All vehicles and stations are to be equipped with two-way communications

for emergency use between patrons and Central Control.

4. PROPOSED DPM VEHICLES

Perhaps the most critical element in the protection of rapid transit

riders from fire is the passenger vehicle used on the system. A number of

8
potential suppliers of Downtown People Mover systems were contacted for

information regarding vehicle design and materials that may be proposed for use in the DPM program. Of the nine system manufacturers, replies were

received from six. Of these six, two, Ford Transportation Systems Operations

and Rohr Industries indicated they were no longer in the business of designing

and producing people mover systems [22,23]. The remaining four manufacturers,

however, provided information about the vehicles that may be proposed for use in a DPM system. These four manufacturers were Boeing, Vought, Otis

and DEMAG + MBB.

Plans proposed by Boeing Aerospace Company [16] and Vought Corporation

[8] for DPM vehicles were not finalized sufficiently to respond. However,

detailed information is available on the Morgantown (Boeing) and AIRTRANS

(Vought) systems (see section 2) . Materials that may be used in DPM

vehicles are expected to be similar to those used in these systems.

4.1 Otis Elevator Company, Duke University Type Vehicle [3]

4.1.1 Basic Vehicle Design

The Otis vehicle, like other people mover vehicles, is designed with the

major components necessary to operate the vehicle attached to the chassis,

below the passenger compartment. Equipment contained in the chassis includes

subsystems for:

Propulsion

Braking (service and emergency)

Suspension

Power collection

Control

Lateral guidance

Wireways have been provided for the major wire runs. Other system wiring

is routed in open wiring harnesses.

The vehicle body assembly is composed of the following major elements:

Body shell

Interior

Lighting

Heating, ventilating, and cooling

Doors, emergency exits, and glazing

The vehicle body shell is constructed of interior and exterior panels of

glass fiber reinforced plastic.

9
Interiors of the Otis, Duke- type vehicles, illustrated in figure 5, are composed almost entirely of glass fiber reinforced plastic with steel supports.

A molded reinforced plastic seat shell with reinforced plastic seat and back

inserts are provided with package storage under the seats. This open area beneath the seat has been a vulnerable area in other systems, providing an area for intentional ignition of seat assemblies. Enclosure of the underseat area would minimize the potential for ignition of seat assemblies.

Carpeting is provided for the vehicle floors.

Heating, ventilation and air conditioning duct work and outlet is

included in the ceiling assembly in the vehicles.

According to Otis personnel [3]

,

several fire protection items have been

incorporated in the Otis DPM vehicle system concept. These are summarized

and described in further detail below:

Fire-resistant materials.

Fire detection.

Fire suppression (option)

.

Fire extinguishers.

Two-way communications.

Emergency exits.

Emergency ventilation.

Fault isolation and monitoring.

Automatic power shutdown.

4.1.2 Fire Detection/Suppression Provisions

Each vehicle is to be equipped with two portable, hand-operated fire

extinguishers. The removal of an extinguisher will activate an alarm in

Central Control. As an option, automatic fire control equipment can be

incorporated in the chassis electrical power equipment bays. The chassis

equipment bays will be protected from fire by a halogenated gas fire suppression system. High temperature sensors will be used to detect the presence

of fire. Excessive temperature will cause the fire control system to release

the agent and signal a fire to Central Control. Fire suppressant discharge

lines, incorporating separate orifices, are routed to those compartments or equipment bays of the vehicle which contain electrical power equipment [3].

Smoke detectors are installed in two equipment bays in the vehicle

chassis and in the command and control equipment compartment in the vehicle

body. These smoke detectors are configured into a serial fire bus arrangement

that is monitored by the on-board safety system. Dirt and contamination

10
could lead to false alarm conditions with detectors mounted in undercar areas

.

This should be recognized in the design.

4.1.3 Emergency Egress

A hinged window in each end of the body serves as an emergency exit.

No railings on elevated portions of guideway to allow use of regular entrance/

exit doors are proposed. Emergency evacuation of handicapped persons, possibly

difficult through end windows, should be considered in the design.

4.1.4 Voice Communications

Two-way voice communications are planned for the Otis vehicles to permit

public address/monitor and intercom operation. Passengers will have access

to an intercom panel which operates in a push-to-talk mode.

4.2 DEMAG + MBB Cabintaxi Vehicle

Two West German engineering firms, DEMAG Fordertecknik and MesserschmittBolkow-Blohm Gmbh, have proposed a unique system currently under development

and planned for deployment in two German cities [24]

.

The Cabintaxi vehicles

operate on small guideways suspending vehicles below the guideway as well as on the upper surface. This system presents unique problems for the emergency

evacuation of passengers. Specific details of construction materials were

not available.

4.2.1 Fire Detection/Suppression Provisions

Automatic and manual suppression along with automatic detection methods

are proposed by DEMAG + MBB for the Cabintaxi vehicles. Ionization smoke

detectors and temperature detectors are proposed, linked to an automatic

Halon 1301 extinguishing system and distributed to the cabin interior,

heating, electronics, and undercarriage. Hand-held fire extinguishers

are also planned [25]

.

4.2.2 Emergency Egress

As mentioned above, emergency egress from vehicles suspended below the

guideway presents a special problem in fire safety. Because of the variety

of operating conditions that would exist in this system, different evacuation

procedures are proposed. These include:

11
An emergency walkway along the guideway.

Inflatable emergency slides for heights up to ten meters.

Emergency ropes for very short distances from ground.

A safe walkway directly adjacent to guideway.

Space limitations in a downtown environment, and the increasing pressure to design to accomodate the handicapped, would place limitations on the

feasibility of such egress procedures.

4.2.3 Voice Communications

Two-way communications through a radio-telephone link is planned.

Automatic monitoring of on-board detectors is also proposed.

5. THE FIRE SAFE DPM VEHICLE

It is virtually impossible to completely protect a system against the

occurrence and subsequent spread of a fire. However, from previous fire

incidents in existing people mover systems and from a knowledge of fire

experience in other transit systems, a series of fire scenarios can be

developed for DPM type vehicles. These scenarios, representing likely ways

in which ignition and subsequent fire spread can occur, suggest critical areas that must be protected in order to reduce the fire risk to passengers.

Throughout this analysis, primary consideration has been given to passenger

safety, and only secondarily to the protection of the vehicle.

While all portions of a vehicle are considered, two areas seem to be

of considerable importance from the standpoint of fire protection: (a) the

subfloor area, because it contains the majority of heat-producing electrical

components - vehicle propulsion, braking and control systems and (b) the vehicle interior because of the wide variety of potential combustible materials

that may be present [26]

,

and the presence of ignition sources associated with

human activity such as cigarettes, matches or intentional ignition sources.

5.1 Fire Scenarios in a DPM Vehicle

5.1.1 Interior Ignitions

Consider a DPM vehicle outfitted in a similar manner to those proposed

by various companies described earlier. The vehicle interior, usually less

than 100 m 3 in volume, may be constructed of various materials. Wall and

ceiling panels of aluminum, glass fiber reinforced plastic, FR glass fiber

12
resin/chopped glass fiber and the like are common. Seating is usually

provided for some passengers and the seats may or may not be upholstered.

Carpeting is usually provided on the floor.

For a DPM vehicle, there are three primary parameters that need to be

defined to permit a determination of the effect of an interior fire:

1) The characteristics of the ignition source (the rate of energy

release and the total energy released)

.

2) The location of the ignition source.

3) The behavior responses of passengers.

Because it was considered outside the scope of the project, no details are given on the third parameter.

Braun [19] developed a series of fire scenarios for vehicles used on the

San Francisco California Bay Area Rapid Transit System. The same principles

apply to DPM vehicles. The ignition sources characterized by Braun are summarized in table 2.

In a DPM vehicle interior, except for electrical fires, there are three

probable locations for an interior ignition source (fig. 6). They are:

1) On the floor - in the aisle.

2) On the floor - directly adjacent to a wall or seat or beneath a seat.

3) On a seat.

In the ignition sequence, the first item ignited would be either the

wall, ceiling, or seat assembly. For the ceiling to be the first item ignited,

an ignition source in the aisle would have to produce flame heights at least

equal to the floor to ceiling distance, about 2 m. Since this would require

an inordinately large amount of fuel, it is highly unlikely that this would

have a high probability of occurrence. No consideration will be given to

this specific scenario. However, intentional ignition of the ceiling panels

is possible with a hand-held flame. In this case, flames could spread either

to the edges of the ceiling, involving the walls and windows, or burning

plastic materials could melt and drip onto the seats, carpet, or walls.

For ignition adjacent to, beneath, or on a seat, probable flame spread

paths may be developed. If the ignition source is on the floor, directly

adjacent to or beneath a seat assembly, as shown in figure 6, there are two

13
possible paths for flame spread. One would be along the carpeting and the

other along the seat assemblies. Flame spread along the carpeting could

travel eventually either to the seat assemblies or to the lower wall lining

material, then involving the upper wall liners or window material and the

ceiling. However, floor covering material used in other transit system

vehicles has been shown to provide sufficient protection to ignition and

flame spread in full-scale tests in mass transit vehicles, and in an actual

fire incident in a subway car [19,27,28]. Carpeting in these systems complied

with either the ASTM E 84 (tunnel test) test method with a flame spread index

less than 75 or the proposed Flooring Radiant Panel Test with a critical

radiant flux of 0.5 W/cm2. If the first item to ignite were a seat assembly,

the fire would probably grow in intensity until the back of the seat, the

ceiling, and the upper wall liners became involved. Seats that are upholstered

have been shown in full-scale tests and actual fire incidents to be a particularly important link in the fire growth chain [19,27,28], Seating integrally

molded into the interior liner without an open space beneath the seats would

prevent intentional placement of an ignition source beneath the seat.

For an ignition source on the floor, near the wall, primary fire growth

would again involve either the carpeting or the seat assemblies as above.

However, the lower wall liner would ignite at a much earlier stage in the

fire development, contributing further to the total evolution of smoke and

heat

.

For fires originating on a seat, the fire development may be faster than

with an ignition source on the floor, since simultaneous involvement of

back and seat assemblies could occur. In addition, the wall liner, windows,

and ceiling would become involved at a much earlier stage. However, the

floor covering, if it would support flame spread, would not become involved

until a later stage from either falling or melting material or with sufficient

feedback energy from the developing fire to permit ignition of the flooring.

The characteristics of the ignition and the minimum energy necessary

for ignition are important in determining whether an ignition will occur. Possible ignition sources, ranging from smoldering cigarettes to flammable

liquids, differ in the rate of energy release and in the total energy released.

Braun [19] presented the relationship of energy release rate and total energy

for various ignition sources, with ignition levels for seating materials

indicated. The relationship developed by Braun is shown in figure 7. From

this, table 2 presents ignition levels of various seating materials along

with energy output of various ignition sources. Proper choice of seating

material, if upholstery is to be provided, can provide significant ignition

resistance

.

14
Smoke generation in such a small, confined volume also poses a significant

threat to life safety. Hill, et al. [29] presented smoke density measurements in full-scale tests on a simulated automated guideway transit vehicle

with a variety of ignition sources. Less than one percent light transmission

measured at the ceiling of the vehicle was reached in as little as 28 seconds

after ignition of a neoprene cushioned seat. Probable evacuation times for

people mover systems, shown in table 1, are calculated assuming maximum vehicle

velocity, normal vehicle deceleration, and maximum station dwell time based

on the estimated maximum time to evacuate passengers from a vehicle [2],

This estimated time represents a worst case estimate using the assumptions

that the vehicle would use only a normal braking rate and would be required

to travel the entire station-to-station distance in order to allow a safe

vehicle stop. Evacuation times ranged from a minimum of 41 seconds to a maximum of 449 seconds.

5.1.2 Exterior Ignitions

A majority of the fire incidents in other transit systems have originated

below the floor of the vehicles due to overheated brakes, tires, bearings,

etc. In addition, the majority of mechanical and electrical equipment in a people mover vehicle is located beneath the floor, providing a prime source

for electrical fires. Detection of subfloor fires is also difficult. A

number of mechanical and electrical failures can cause a vehicle to stop

on the guideway. A stalled vehicle in a subway or tunnel section of guideway

presents a particularly dangerous situation. Passenger evacuation and fire

suppression in an underground fire require special consideration and present

special difficulties to the design and operating personnel. Although subfloor

fires can originate from a wide variety of causes, some simple scenarios can

be developed describing their consequences. The critical parameters that

enter the description are:

1) The location of the vehicle at the time of detection - is it

at a station, between stations, or underground, etc.

2) The condition of the vehicle at the time of the failure - is

it operable.

3) The intensity of the fire, at the time of detection.

The first two conditions determine the nature of the response that

operating personnel must initiate; the third affects the time available for

passenger evacuation and suppression of the fire. The vehicle floor and any

bulkheads between mechanical and electrical equipment and the vehicle interior must provide penetration resistance and allow a habitable environment

15
long enough to allow safe passenger evacuation. Duct work through such bulkheads, particularly the air conditioning system, must also be designed to

prevent entrainment of smoke, heat, and toxic products into the vehicle

interior in the event of a fire.

5.2 Vehicle Design to Minimize Fire Hazard

From the fire scenarios developed above, utilizing several design aspects

of the various people mover systems already in existence, somewhat simplified

design features of a DPM vehicle can be proposed that would reduce the

potential risk of fire. These design features, developed primarily from

consideration of the fire safety of the vehicle, are not meant to be the only

approach, nor necessarily an economic one. In addition, no consideration was given to the actual construction of the vehicle and any difficulties that may

be encountered. It is presented merely to point out important areas that

must be considered in the fire safe design of a DPM system. The construction

details presented here are by no means the only way to achieve an acceptable

level of fire safety.

5.2.1 Interior Vehicle Design

A possible vehicle interior design is shown in figure 8. Seating is

provided along the sides of the vehicle. The space below the seats is

enclosed to prevent potential ignition beneath the seats. The interior

lining of the vehicle, wall liners, ceiling liners, and seat assemblies

would preferably be constructed of aluminum or similar metal. However, the use of metal throughout, in addition to providing a very stark interior and

added vehicle weight, would create additional problems with existing DOT

guidelines for noise and passenger safety in the event of collision. Fireretardant glass fiber laminates could possibly be used with the seats molded

integrally with the interior shell. No upholstery would be provided on

the seats.

A full door emergency exit would be provided on at least one end of the

vehicle to allow safe evacuation of passengers, including the handicapped,

onto the guideway in the event of an emergency. A push-out window exit on

the other end can serve as another exit. Release handles for emergency

exits in the interior are placed so that they may be reached from a wheelchair.

The opening of any door or emergency exit would lead to activation of an alarm at Central Control. For vehicles to be used in multi-car trains, an emergency door on the side or both ends may be preferable.

16
Carpeting (similar to that used in the WMATA Metrorail cars) would be

provided over flooring of plymetal (a plywood/aluminum sandwich) . This

plymetal construction is also provided at any bulkhead between mechanical

or electrical equipment and the vehicle interior. It has been estimated

that this construction would provide about a ten-minute endurance to a given

fire load [27]

.

This time should be ample to allow passenger evacuation.

The air conditioning system could be designed with the return ducts most

probably in the ceiling. Smoke detectors, either ionization or photoelectric,

are placed in the main airflow stream in the vehicle interior. It could

be possible, with such a small interior volume (less than 100 m 3 ), to place

the detectors in the return air ducts. Activation of the detectors would

trigger an alarm in Central Control. Such a system must be fairly insensitive

to avoid false alarms.

Hill, et al . [29], concluded that a five percent Halon 1301 system, using

an early-warning detection system, can safely extinguish fire in the passenger

compartment of a people mover vehicle without producing intolerable levels

of toxic decomposition products (notably hydrogen flouride) . It was noted,

however, that Halon-type systems do produce extremely loud noise levels during

discharge. For systems where evacuation is easily accomplished and an early

detection system is included, a Halon system would not likely be necessary.

However, for systems where evacuation would be difficult, particularly for

elevated or suspended systems, such an extinguishment system may be necessary.

Hand-held fire extinguishers would be provided in each vehicle, with an alarm to Central Control to indicate removal.

5.2.2 Exterior Vehicle Design

Figure 9 illustrates one possible design for the vehicle exterior. The

outer shell could be constructed of aluminum, stainless steel, enameled

metal, etc., at least halfway up the vehicle sides and end to prevent, to a large extent, ignition of the outer shell from an undercarriage fire. The

upper shell could be constructed of aluminum, reinforced plastic, or the like.

The undercarriage could contain all electrical and mechanical equipment

and would also be enclosed, subdivided, and compartmentalized as much as possible. The following detection equipment could be installed as appropriate

17
Brake temperature sensor. Propulsion motor temperature sensor. Propulsion transformer temperature sensor. Propulsion armature temperature sensor. Hydraulic fluid temperature sensor. A/C system temperature sensor. Vehicle communication system temperature sensor. Vehicle control system temperature sensor.

While smoke detectors could possibly be installed, they may not be

practical for this application. These detectors are sensitive to dirt and

contamination, potentially a problem beneath the car. Any detectors used

would be linked to alarms in Central Control.

Detector operation in the undercarriage could also be linked to an automatic Halon 1301-type extinguishment system for the undercarriage with

appropriate plumbing to carry the extinguishing agent to all major subsystems

to provide an additional measure of safety for the vehicle. An automatic

fire suppression system may be desirable for the undercar area because of the

difficulty of early detection and the potential for a fire to penetrate into

the interior. The system should be designed so that the detection system

used for initiating suppression is desensitized to minimize false alarms.

5.2.3 Emergency Egress

For the safe evacuation of passengers, including the handicapped, a full

door exiting directly onto the guideway is preferable to emergency window

exits or egress through normal entrance/exit doors onto a catwalk. Thus,

guideway design should prevent passengers from coming in contact with the

vehicle power rails, preferably by turning power off to the section of the

guideway affected by the evacuation.

5.2.4 Voice Communications System

The communications systems would be designed to allow two-way voice

communication between Central Control and the vehicles on the DPM system.

Designed to operate even if primary power was disconnected to the vehicle,

the system could allow one-way announcements to all vehicles from the Central

Control facilities and would allow two-way conversations with individual

vehicles

.

18
6. EVALUATION

6.1 Important Areas of Consideration

Based on the fire scenarios developed, the DPM design and systems

proposals reviewed, and the vehicle design exercise described above, several

factors were found to be important to the fire safety of a DPM vehicle.

These are summarized below.

Vehicle Interior

1) Vehicle interior wall and ceiling liners should be designed to prevent

ignition, flame propagation, and smoke build-up when exposed to an ignition

source or fire load from another burning material within the vehicle.

2) Vehicle seats and seat assemblies should be designed to prevent ignition

flame propagation, and smoke build-up when exposed to an ignition source

of fire load from another burning jmaterial within the vehicle.

3) Carpeting should not ignite from simple ignition sources or support

the spread of flames when exposed to an ignition source or fire load

from another burning material within the vehicle.

4) Window material and glazings, light diffusers, etc. should not increase

the rate of fire growth.

The requirements for the vehicle interior are determined by the vehicle

design, support, and use. Factors that are important for design are: (a)

the ease of exiting, (b) track location (tunnel versus open) , and (c) mode

of vehicle support (elevated, suspended, or on-grade)

.

Vehicle Exterior

1) Flooring and bulkheads that separate the passenger compartment from

electrical and mechanical equipment should be designed to prevent

penetration of an undercar fire to the interior long enough to insure

safe evacuation of passengers from the vehicle.

2) The exterior body shell, particularly the lower half, should not ignite

or support flame spread from an undercar fire.

3) Insulation material used throughout the vehicle should not contribute

to fire growth.

4) The induction system for the air conditioning/heating system in the

vehicle should be located and suitably protected/designed to prevent

the ingestion of smoke, heat, and toxic combustion products from the

exterior to the interior of the vehicle from fires in the vehicle

undercarriage

.

19
Fire Detection and Suppression

1) Smoke detection systems might be installed in the vehicle interior

to provide early warning of a developing fire, particularly in an unoccupied car with an alarm indication to Central Control. In an occupied car, the passengers may be assumed to detect a developing

fire more quickly than the desensitized smoke detectors.

2) High temperature detectors should be incorporated into the vehicle

underbody as appropriate to insure early detection of a fire in the

undercar area.

3) A Halon 1301-type suppression system could be incorporated into the

vehicle underbody along with sufficient compartmentalization to insure

effectiveness of the system, to further protect the vehicle.

4) Hand-held ABC fire extinguishers should be provided on each vehicle,

sized properly for different vehicle capacities, and protected from

theft and vandalism.

5) All fire detection and suppression systems should be linked to alarms

in the system's Central Control center and should be designed so that

any malfunction in the system triggers an alarm.

6) Appropriate detection and suppression systems should be linked, automatically or manually, to stopping of the vehicle.

Emergency Evacuation

1) Emergency exits should be provided to allow safe evacuation of all

passengers

.

Communications

)

1) A two-way voice communications system should be provided to allow both

P/A announcements to all vehicles and private communication with

individual vehicles in the event of an emergency.

2) All smoke and fire detection alarms should be linked in a serial

alarm bus to indicate to Central Control the alarm situation.

6.2 Test Methods for the Flammability

of Materials Used in DPM Systems

In order to insure acceptable levels of flammability, smoke, and toxic

gas generation, the following types of test methods are required:

20
1) A penetration resistance test for flooring and bulkhead assemblies.

2) A self extinguishing/ignition resistance test for nonmetallic

materials

.

3) A smoke density generation test for nonmetallic materials used

in the interior of the vehicle.

4) A rate of heat release test, and/or a flame spread test for non- metallic materials.

5) A test to permit screening materials that generate highly toxic

combustion products.

A review of test methods which are currently available for testing of

materials, such as those expected to be used in DPM systems, is presented

below.

6.3 Fire Penetration Test

ASTM test method E 119 is designed to determine the fire endurance of

materials and constructions used in buildings [30]. The complete construction

is subjected to heating in a furnace with a prescribed temperature-time curve

loaded to simulate actual use. The time to the first sign of structural fail- ure or transmission of excessive temperature through the specimen are among

the test results.

6.4 Ignition Resistance Tests

6.4.1 Motor Vehicle Safety Standard No. 302

Motor Vehicle Safety Standard 302 is a test for horizontal burn rate

used to evaluate materials in all passenger motor vehicles sold in the U.S.

The standard requires that all materials used in the occupant compartment of

automotive vehicles have a horizontal burn rate of less than four inches per

minute [31] . Table 3 shows results of materials tested under MVSS-302 in

other transit systems [19,27]. Fabrics and foams used for seating materials

in the BART subway system and WMATA buses meet this requirement, but have

been involved in a number of full-scale fires. These have been a significant

link in the fire growth chain [19,27].

6.4.2 Federal Aviation Regulation FAR-25.853

This standard, issued by the Federal Aviation Administration, defines

both a test procedure and acceptance criteria for small-scale fire performance

of compartment interior materials used in transport category airplanes [32].

The test procedure outlined in this standard is a vertical test with a 3.9 cm

21
(1.5 in) flame applied either for 12 seconds or for 60 seconds (determined by

the end use of the material) to the lower edge of a 5 cm (2 in) wide 30.5 cm

(12 in) long specimen. The test records the flame time, burn length, and

flaming time of dripping material. The test criteria require that specimens

self-extinguish with a burn length not exceeding 15 to 20 cm (6 to 8 in)

(depending on the end use) , a flame time not exceeding 15 seconds after

removal of the burner, and flaming on the floor of the cabinet not to exceed

three to five seconds (end use dependent) . Table 3 presents results of tests

of materials used in other transit systems [28]

.

6.4.3

ASTM D 635

This test is intended for the measurement of the rate of burning or the

extent of burning of self-supporting plastics [33]. A 12.5 cm x 1.25 cm specimen in its end use thickness is clamped with its long dimension in

the horizontal direction. A bunsen burner flame is applied to the unclamped

end of the specimen for 30 seconds. Average burning rate, average time of

burning, and average extent of burning for 10 or 20 samples are reported as test results. No acceptance criteria are provided. Test method ASTM D 635

has been used in the past for the evaluation of materials used in other

transit systems [19] . From the fire history of vehicles used in one such

system, BART, this test method would be inadequate for DPM vehicles. Seat

assemblies that meet the requirements of ASTM D 635 have been involved in a number of fires and have been particularly important in fire growth.

6.4.4

ASTM D 1692

Test method ASTM D 1692, discontinued by ASTM in 1978, has been used to

determine the rate of burning or extent of burning for cellular plastics

using a horizontal screen to support a 15 x 5 x 1.3 cm specimen [34]. A

propane bunsen burner with a flame spreader attached is the ignition source

and applied to one end of the specimen for 60 seconds. Average burning rate,

average extent of burning, and average time of burning are reported as test

results. Table 2 shows results of tests from other transit systems. Again,

from the fire history of vehicles in the BART system, this test method would

be inadequate for DPM systems.

6.4.5

Carpeting Tests

6. 4. 5.1 DOC FF 1-70 Pill Test

No carpets and rugs sold in the United States are permitted to spread a flame beyond a radius of 7.6 cm (3 in ) when exposed to the flame from a methenamine timed burning pill on its surface [35]. This standard is intended

22
to eliminate carpets or rugs as a means of flame spread from small ignition

sources

.

6. 4. 5. 2 NFPA 253-78

This test, the Standard Method of Test for Critical Radiant Flux of

Floor Covering Systems Using a Radiant Heat Energy Source, NFPA 253-78, exposes

a specimen placed horizontally to a radiant energy source that varies across

a one meter length from a maximum of 1.1 W/cm2 down to 0.1 W/cm2 [36]. The

specimen is ignited by a small flame at the high energy end. The distance at

which the burning flooring material extinguishes itself defines the critical

radiant flux (CRF) necessary to support continued flame propagation. The

higher the CRF, the better is the fire safety of the carpeting. Carpeting

taken from several large fatal fires, tested according to this method, was

found to have CRF ' s of less than 0.1 W/cm2

. A wood floor would have a CRF

between 0.4 and 0.5 W/cm2

, while vinyl floor materials have values greater

than 1.1 W/cm2. Results of tests of carpeting taken from other transit

vehicles are shown in table 3 [27,28]. Acceptance criteria of 0.25 W/cm 2 for

residential and commercial occupancies and 0.5 W/cm2 CRF for institutional

occupancies have been suggested [37,38]. The carpeting tested from transit

systems meets both of the criteria.

6.5 Smoke Density Test

The smoke density chamber, NFPA 258-76, measures the smoke generation of

solid specimens exposed to a radiant flux level of 2.5 W/cm 2 [39]. The smoke

produced by the burning specimen in the chamber is measured by a light sourcephotometer combination. The maximum attenuation of the light beam by the smoke

is a measure of the optical density or "quantity of smoke" that a material

will generate under the given conditions of the test. The maximum optical

density, Dm

, is useful primarily in ranking relative smoke production of the

material used, and in identifying likely sources of severe smoke production

in a full-scale fire. Table 3 presents maximum optical density values under

flaming exposure conditions of materials used in other transit systems

[27,28,40]

.

6.6 Rate of Heat Release Tests

The rate of heat release for materials provides a measure of a material's

contribution to the growth of a fire. If an ignition occurs, then a test

method must be provided to insure that other items do not subsequently become

involved. Unfortunately, no established test methods exist to measure rate

23
of heat release. Several tests have been proposed and are in the process of

adoption with standards organizations. Smith has proposed one test method

that allows measurement of rate of heat, smoke, and toxic gas release of

materials. The apparatus measure release rate, in a flow system, of a material

exposed to piloted ignition at various heat flux exposures. Release rates

are determined by measuring the concentration of heat, smoke, and toxic gases

leaving an environmental chamber containing the sample [42] . Smith has also

proposed criteria and methodology for testing of materials used in transit

systems [43]

.

6.7 Flame Spread Tests

6.7.1 Radiant Panel Test, ASTM E 162

This method measures flame spread and rate of energy release under a varying radiant flux ranging from 4. to 0.3 W/cm2 [44]. The flame spread

factor, F , calculated from the flame spread velocity, and the heat evolution

factor of the burning sample, Q, are combined to yield a flammability index,

I , defined as

I s F

s Q

The higher the index, the greater is the flammability. An I value of

less than 75 is considered acceptable for the walls and ceilings of corridors

in commercial buildings, but a value of less than 25 is commonly required

for corridor linings in institutional buildings. There is, however, no generally accepted level of performance based on this test method since it

is not a prescriptive standard. Table 3 also presents results of tests by

this method for materials used in other transit systems [27,28,45,46].

6.7.2 ASTM E 84 Tunnel Test

The purpose of this test is to determine the surface burning characteristics of various building materials [47,48]. A specimen 51 cm wide by 7.3 m

long (20 in x 25 ft) is mounted and supported on the ceiling of a long test

chamber. Two gas burners pointing up at one end of the chamber impinge flame

on the exposed surface of the specimen. The test evaluates a material's

flame spread, fuel contribution, and smoke development. Results of tests on materials used in other transit systems are presented in table 3 [16,19].

24
7. PROPOSED GUIDELINES

The following guidelines are proposed for use in the design specifications for vehicles to be used in Downtown People Mover systems. Specific

test methods are proposed as guidelines for material flammability specifications. In addition, general guidelines are presented as recommendations

for fire detection and suppression, emergency passenger evacuation, and

vehicle communications. Different vehicle and system designs will require

different levels of protection in the vehicle design. A number of trade-offs

exist for different system types. For elevated or suspended systems, safe

passenger evacuation may be a problem. If passengers cannot evacuate a vehicle in an emergency, then the floor and all panels that provide separation between the vehicle interior and electrical or mechanical equipment

must be fire-hardened to provide resistance to penetration of an undercar

fire. For such a system, consideration should also be given to the inclusion

of automatic detection and suppression systems to provide further protection.

On the other hand, for systems where egress during an emergency is easily

accomplished, the fire penetration resistance of the floor, etc. becomes less

important and automatic detection and suppression provisions may not be

needed. These provisions are included in the recommended requirements

below.

7.1

Materials Flammability

The test methods reviewed in section 6 have been used to test materials

in other transit systems. Some of these tests, however, have not been

adequate based on the fire experience of the systems. The test methods

outlined below, with recommended acceptance criteria, were chosen based on the

review. These are recommended as guidelines for design specifications for

DPM system vehicles.

7.1.1

Ignition Resistance/Flame Spread Test

7.

1.1.1

Interior and Exterior Materials

Materials made into interior and exterior components as described below

should be tested in accordance with test method ASTM E 162 or ASTM D 3675.

The recommended acceptance criteria are included for the materials and

presented in table 4.

• Wall and ceiling lining, including partitions, door linings, etc.

• Hard-molded seats.

• Cushioned seats, including upholstered or self-skinned cushions.

• Seat cushion coverings.

25
• Window glazings.

• Thermal and acoustical insulation.

• Exterior vehicle shell.

• Air conditioning duct work with outlets into the vehicle interior.

7. 1.1.2 Floor Covering Flammability Test

Carpeting or other material used as a floor covering over the structural

floor should be capable of passing test method NFPA 253-78 [36] with a minimum

critical radiant flux of >_ 0.25 W/cm2

. Flooring should be tested together

with any underlay that may be used.

7. 1.1. 3 Seating Assemblies

Seating assemblies should be evaluated using a full-scale mockup of the

finished seat constructed utilizing the same upholstery materials, assembled

in the order used in the finished seating product. No established test

methods are available to evaluate seating in the end-use configuration. Test

methods are currently being developed for adoption as standard test methods

[49]. If these tests become available, they should be adopted with appropriate acceptance criteria to prevent the ignition and contribution to fire

growth of seating assemblies.

7.1.2 Smoke Generation Test

Interior finish materials and exterior materials which may, when ignited,

generate smoke which could be ingested by the heating/air conditioning system

and carried into the vehicle interior should be tested in accordance with

test method NFPA 258-76. The maximum optical density when testing in the

flaming mode should not exceed 300. Materials made into the following com- ponents should be tested:

• Wall and ceiling lining, including partitions, door linings, etc.

• Hard-molded seats.

• Seat cushions.

• Seat cushion coverings.

• Window glazings.

• Thermal and acoustical insulation.

• Air conditioning duct work with outlets directly into the vehicle

interior

.

• The exterior vehicle shell if smoke can be entrained by the

air conditioning system and carried to the vehicle interior.

26
However, the hazard of a particular material in its end-use configuration

may not be predicted by a single ’test method. The amount of smoke generated

by a material in actual use and the hazard presented by the smoke depends on

a number of properties, such as the amount of material present, the rate of

smoke generation, the ventilation characteristics of the vehicle, and the

potential for egress from the vehicle.

7.1.3

Penetration Test

The structural flooring and all panels that provide separation between

the vehicle interior and any electrical or mechanical equipment other than

communication panels, light switches, destination switches, etc., should be

designed to have sufficient resistance to prevent the penetration of fire to

the interior of the vehicle for a period of time to allow safe evacuation

of passengers from a vehicle. A fire endurance test such as the fire

exposure test in ASTM E 119 is recommended. The recommended fire test exposure duration should be at least two times the period of time necessary for a vehicle to come to a complete, safe stop from maximum velocity, plus the time

necessary to evacuate all passengers from the vehicle to a safe area. This

duration may be shortened if automatic fire detection and suppression equipment is included in the vehicle. A minimum of ten minutes protection is

recommended. While test method ASTM E 119 may not be appropriate for

extremely short evacuation times, no appropriate alternate exists for such

short times. One should be adopted if it becomes available.

7.1.4

Rate of Heat Release Test

A rate of heat release test is recommended for the evaluation of all

nonmetallic materials used in DPM vehicles, particularly vehicle interior

wall and ceiling panels, seats, and seat upholstery. No established test

methods are available to evaluate a material's rate of heat release.

Test methods are currently under consideration for adoption as standard

test methods. When these tests become available, they should be adopted

with appropriate acceptance criteria to prevent the excessive contribution

of materials to fire within a vehicle.

7.1.5

Combustion Products Toxicity

No accepted protocol has been established to evaluate materials that may

produce highly toxic combustion products. If test protocols become available,

they should be adopted for all nonmetallic materials used in the interior of

the vehicle to eliminate the use of materials that produce highly toxic

products of combustion. The toxicity of the combustion products generated

27
by a burning material in its end-use configuration depends on a number of

properties including the amount of material involved, the rate of toxic

product generation, the rate of flame spread, and the ventilation characteristics of the vehicle. Actual acceptance criteria of a prospective test

method would vary depending on these properties and the particular test

method in question.

7.2 Fire Detection

7.2.1 System for Vehicle Interior

An automatic smoke detection system could be included in the vehicle

interior to allow detection of a fire in the early stage of development.

Two problems, however, are encountered in the use of fire detectors: what

type of detector to use and where to install the detectors.

The type of detector to be installed is dictated by the environment in

which it will be used and its tolerance for false alarms. The location of

the detector in the vehicle is also critical to the proper operation of the

system. An investigation of the flow patterns in a vehicle must be made

in order to properly determine correct placement of the detectors. This is

necessary to insure that the detectors are placed in the main air stream - not in an area of stagnant air, and to preclude placement of the detectors

adjacent to a fresh air inlet within the vehicle.

The detectors should be connected via communication lines to an alarm

in Central Control.

References [50] through [54] provide information on detector siting

and studies on the effects of room geometry, ceiling configuration, fire

type, and detector spacing in dwellings, mobile homes, and commercial establishments. While the environment within the interior of a DPM vehicle is

obviously different from those in dwellings, important parameters necessary

for study are presented. The National Fire Protection Association also

provides guidelines for detector installation [55,56]. Fire detection

equipment should be installed and maintained in accordance with NFPA Standard

72 E-1975.

7.2.2 System for Vehicle Electrical and Mechanical Equipment Bays

Major vehicle electrical and mechanical equipment bays should be protected

by an automatic fire detection system. The following detection equipment should

be installed as appropriate.

28
Brake over-temperature detectors.

Propulsion motor over- temperature detector.

Propulsion transformer over-temperature detector.

Propulsion armature over-temperature detector.

Hydraulic fluid over-temperature detectors.

Air conditioning compressor over- temperature detector.

Air conditioning fan motor over-temperature detector.

Vehicle communications electronics over-temperature detector.

Vehicle control electronics over-temperature detector.

In addition, fixed temperature heat detectors should be included in

major equipment bays, and the possibility of the installation of smoke

detectors in major equipment bays should be investigated.

All detectors in the vehicle electrical and mechanical equipment bays

should also be connected via communications lines to alarms in the Central

Control facility of the system. Consideration should also be given to

provisions designed to automatically stop the vehicle and open emergency

exits if detectors indicate that a risk to life safety exists. Fire detection equipment should be installed and maintained in accordance with NFPA

Standard 72 E, [56]. The undercar area should be compartmentalized as appropriate to insure the effectiveness of the system.

7.3 Fire Suppression

7.3.1 Portable Fire Extinguishers

Every vehicle should be equipped with at least one approved multipurpose

(ABC) fire extinguisher accessible to system rescue personnel. The extinguisher can be mounted in a cabinet located on the outside of the vehicle to

be accessible only to rescue personnel. If the authority having jurisdiction

deems it necessary for passengers to have access to the extinguishers, they

can be located within the vehicle and provided with appropriate theft protection to prevent loss of the extinguishers. References [57] and [58]

provide recommendations on sizing, installation, and maintenance of

extinguishers

.

7.3.2 Automatic Fire Suppression

The fire detection system in vehicle equipment bays could be linked to an automatic fire suppression system for all vehicle equipment and mechanical

bays. The system, if included, should be designed to provide automatic suppression of fires in the undercarriage to prevent the penetration of undercar

29
fires to the vehicle interior. Release of the extinguishing agent should be

indicated to the Central Control center. Sufficient compartmental ization of

the undercar area must be included to insure the effectiveness of the system. 7.4

Emergency Egress

Provisions for the safe emergency evacuation of all passengers from a vehicle must be included in the system design. Federal Vehicle Safety

Standard 217, Bus Window Retention and Release, contains requirements detailing minimum number, type, and area of exits that are applicable for DPM

vehicles [59]

.

The safe evacuation of handicapped passengers must also be

considered. For the safe emergency egress of handicapped passengers, a full

door exiting directly onto the guideway is preferable to emergency window

exits or egress through normal entrance/exit doors onto a catwalk. Guideway

design should also prevent passengers from coming in contact with guideway

power rails and vehicle electrical pickups.

Emergency exits should be clearly marked both on the inside and outside

of the vehicle.

7.5 Voice Communications

The voice communications system should be designed to allow two-way

voice communications between Central Control and the vehicles in the DPM

system. The voice communications system should be designed to allow one-way

announcements to all vehicles from Central Control and to allow two-way

communications between Central Control and individual vehicles in the system.

7.6 Vehicle Construction

7.6.1 Heating and Air Conditioning System

Duct work in the heating and air conditioning system should be designed

to prevent the ingestion of heat, smoke, and toxic combustion products and

the conveying of these products to the vehicle interior. The fresh air

makeup inlet from the vehicle exterior should be placed to minimize ingestion

of products from undercar fires.

7.6.2 Electrical Fire Safety

All electrical systems and wiring should be designed in accordance with

applicable Federal, state, and local electrical codes. It is important to

provide fire stops for electrical cabling that penetrates to the interior

from electrical equipment bays to protect passengers from an undercar fire.

30
7.7 Guidelines for Testing Protocol

The guidelines presented above for material fire properties, fire

detection and suppression, emergency egress, and vehicle communications

provide for a number of trade-offs between detection and suppression provisions and material flammability requirements. In order to provide a realistic testing protocol both for system specification and system designers,

figure 10 describes a logical sequence that should be followed for the

design specification and acceptance of material design for flammability of

DPM vehicle materials. The logic analysis provides a step-by-step procedure

for the design of materials to be used in DPM systems.

8. SUMMARY AND CONCLUSIONS

Based upon a review of existing people mover systems, proposed DPM

vehicles, and DPM systems proposed by several cities, a series of possible

fire scenarios for DPM vehicles has been developed. The small enclosed

volume of a DPM vehicle and likelihood that elevated guideways will be used

presents a unique problem in the potential rapid development of hazardous

conditions within and around vehicles. Thus, the fire safety design of DPM

vehicles is a particularly important aspect in the design of a DPM system.

Guidelines are presented that are recommended for use in the design of

vehicles and systems to be deployed under the Downtown People Mover program.

Test methods for seating assemblies, rate of heat release, and toxicity of

materials as recommended in this report should also be adopted as they become

available

.

The test methods and criteria presented are based on a review of the

design, construction, and operation of typical DPM systems. Additional

testing of actual vehicles and materials would, of course, be needed to

provide support and validation for the recommended tests and criteria. In

addition, a study of methods to reduce the false alarms of smoke detectors

in ‘such a hostile environment should be initiated.

31
9. REFERENCES

[1] Downtown People Mover Project Implementation Guidelines, Appendix C,

Section 3.4.5, U.S. Urban Mass Transportation Administration UTD

Document 77-10, Revision 01 (March 1977).

[2] People Mover Profile, Urban Mass Transportation Administration,

Transportation Systems Center, 1976.

[3] Donlon, R. H., Otis Elevator Company, Transportation Technology Division, letter to R. D. Peacock (October 26, 1977).

[4] Yen, A. M. , et al, Assessment of the UMI Type II Tourister AGT System

at King's Dominion, Urban Mass Transportation Administration, Report

No. UMTA- IT-06-0135-77-6 (December 1977)

.

[5] Yen, A. M. , et al. Assessment of the Tunnel Train System at the

Houston Intercontinental Airport, UMTA, Report UMTA-IT-06-0135-77-3

(December 1977 )

.

[6] Yen, A. M. , et al, Assessment of the Automatically Controlled Transportation (ACT) System at Fairlane Town Center, UMTA-IT-06-0135-77-2

(December 1977)

.

[7] Yen, A. M. , et al, Assessment of the Satellite Transit System (STS)

at the Seattle-Tacoma International Airport, UMTA-IT-06-01 35-77-1

(December 1977)

.

[8] Yen, A. M. , et al , Assessment of the Passenger Shuttle System (PSS)

at Tampa International Airport, UMTA-IT-06-0135-77-4 (December 1977)

.

[9] Yen, A. M. , et al, Assessment of the WEDway Peoplemover System at

Walt Disney World, UMTA-IT-06-0135-77-5 (December 1977).

[10] Demoro, H. W. , People Movers, Mass Transit, Vol. IV, 52-58 (July/

August 1977 )

.

[11] Performance/Design and Qualification for the Phase II Morgantown

Operational Personal Rapid Transit System, General Specification

for (Boeing Document WVBOR-TD-OOl ) , Boeing Aerospace Company, Seattle

(January 1977 )

.

[12] Morgantown Personal Rapid Transit Final Report, (Boeing Document

D191-60016-1) , Boeing Aerospace Company, Seattle.

[13] Morgantown, WVU PRT personnel, personal communication.

[14] Kangas , R. , et al, Assessment of Operation Automated Guideway Systems - AIRTRANS (Phase 1), Transportation System Center, Report No.

UMTA-MA-06-0069-1 , (1976).

[15] Corbin, A., AIRTRANS Program Manager, Vought Corporation, letter to

R. D. Peacock (October 31, 1977).

[16] Davidson, T. M. , Automated Transportation Systems, Boeing Aerospace

Company, letter to R. D. Peacock (November 14, 1977).

[17] Houston Downtown People Mover, A proposal to the Urban Mass Transportation Administration, submitted by the City of Houston (1976) .

32
[18] Downtown People Mover Element of the Circulation Distribution System.

A proposal to the Urban Mass Transportation Administration, submitted

by the City of Los Angeles (1976) .

[19] Braun, E. , Fire hazard evaluation of BART vehicles, Nat. Bur. Stand.

(U.S.), NBSIR 78-1421 (March 1978).

[20] Troy, J. J. , Fire Protection for Rapid Transit Systems, Fire International, Vol. 5, No. 55 (March 1977).

[21] Proposal to the Urban Mass Transportation Administration for a Downtown People Mover System, St. Paul, Minnesota, Metropolitan

Transit Commission and the City of St. Paul, Minnesota, Report Mo.

76-08 (1976).

[22] Esmer, G. P. , Transportation Systems Operations, Ford Motor Company,

letter to R. D. Peacock (September 9, 1977).

[23] Tantlinger, K. W. , Rohr Industries, letter to R. D. Peacock (October 12.

1977)

.

[24] Germany's Automated People Mover, Civil Engineering, ASCE (July 1977).

[25] Arbeitsgemeinschaf t Cabinentaxi DEMAG+MBB personnel, personal

communication

.

[26] National Academy of Sciences (U.S.), Fire Safety and Fire Hazards

Related to Polymeric Materials in Cars of Washington Metropolitan

Area Transit Authority (1975) .

[27] Braun, E., Report of fire test on an AM General Metro Bus, Nat. Bur.

Stand. (U.S.), NBSIR 75-718 (1975).

[28] Braun, E., A fire hazard evaluation of the interior of WMATA Metrorail

cars, Nat. Bur. Stand. (U.S.), NBSIR 75-971 (1975).

[29] Hill, R. G., et al. Fire Detection, Extinguishment, and Material Tests

for an Automated Guideway Transit Vehicle, National Aviation Facilities

Experimental Center (U.S.), Report No. FAA-NA-76-52 (1977).

[30] Fire Tests of Building Construction and Materials, E 119, American

Society for Testing and Materials, Philadelphia (1974).

[31] Motor Vehicle Safety Standard - 302, National Highway Traffic Safety

Administration, Federal Register, Vol. 36, No. 5, 70 (1972).

[32] Federal Aviation Regulation - FAA Crash Worthiness Standard, Part 25,

Section 25.853, Federal Register, Vol. 34, p. 130 (August 12, 1969).

'[33] Test for Flammability of Self Supporting Plastics, D 635, American

Society for Testing and Materials, Philadelphia (1974).

[34] Test for Rate of Burning or Extent of Burning of Cellular Plastics

Using a Supported Specimen by a Horizontal Screen, D 1692, American

Society for Testing and Materials, Philadelphia (1974).

[35] Standard for the Surface Flammability of Carpets and Rugs, FF-1-70,

Federal Register, Vol. 35, No. 74, 6211-6212 (April 16, 1970).

[36] Hartzell, L. G. Development of a radiant panel test for flooring

materials, Nat. Bur. Stand. (U.S.), NBSIR 74-495 (May 1974).

33
[37] Benjamin, I. A., and Adams, C. H., The Flooring Radiant Panel Test

and Proposed Criteria, Fire Journal (March 1976).

[38] Benjamin, I. A. and Adams, C. H., Proposed criteria for use of the

critical radiant flux test method, Nat. Bur. Stand. (U.S.),

NBSIR 75-950 (1975)

.

[39] Standard Test Method for Measuring The Smoke Generated by Solid

Materials, NFPA 258-1976, National Fire Codes, Vol. 10, National

Fire Protection Association, Boston (1977)

.

[40] Lee, T. G., The smoke density chamber method for evaluation of the

potential smoke generation of building materials, Nat. Bur. Stand.

(U.S.), NBS Tech. Note 757 (1973).

[41] Smith, E. E., Heat Release Rate of Building Materials, Symposium on Ignition, Heat Release, and Noncombustibility of Materials, ASTM

STP 502, American Society for Testing and Materials, Philadelphia,

Pa. (1972).

[42] Smith, E. E., Measuring Rate of Heat, Smoke and Toxic Gas Release,

Fire Technology, Vol. 8, No. 3 (August 1972).

[43] Smith, E. E., Transit Vehicle Material Specification Using Release

Rate Tests for Flammability and Smoke, Phase I Report, prepared for

Transit Development Corporation, Washington, D.C., unpublished

(Oct. 1976)

.

[44] Surface Flammability of Materials Using a Radiant Heat Energy Source,

E 162, American Society for Testing and Materials, Philadelphia (1977).

[45] Robertson, A. F., Surface Flammability Measurements by the Radiant

Panel Method, ASTM Symposium on Fire Test Methods, Special Technical

Publications, 344-1962 (1962).

[46] Rose, A., Comparison of Flame-Spread Ratings by Radiant Panel, Tunnel

Furnace, and Pittsburgh Corning Apparatus, National Research Council

of Canada, NRC 10788 (1969)

.

[47] Test for Surface Burning Characteristics of Building Materials, E 84,

American Society for Testing and Materials, Philadelphia (1977).

[48] Lee, T. G., and Huggett, C., Interlaboratory Evaluation of ASTM E 84-70

Tunnel Test Applied to Flooring, Journal of Testing and Evaluation,

Vol. 3, No. 1 (1975) .

[49] Draft for Development, Tests for the Ignitability of Upholstered

Seating, BSI No. DD58:1978, British Standards Institution (May 1978).

[50] Gawin, W. M. and Bright, R. G., Mobile home smoke detector siting

study, Nat. Bur. Stand. (U.S.), NBSIR 76-1016 (May 1976).

[51] Bukowski, R. W. , Christian, W. J., and Waterman, T. E., Detector

sensitivity and siting requirements for dwellings, Nat. Bur. Stand.

(U.S.), NBS-GCR 75-51 (August 1975).

[52] Harpe, S. W., Waterman, T. E., and Christian, W. J. , Detector sen- sitivity and siting requirements for dwellings, Phase 2, Nat. Bur.

Stand. (U.S.), NBS-GCR-77- 82 (February 1977).

34
[ 53 ] Heskestad, G. and Delichatsios , M. A., Environments of fire detectors. - Phase 1: Effect of fire size, ceiling height and material, Vol. 1,

Measurements, Nat. Bur. Stand. (U.S.), NBS-GCR-77-86 (May 1977).

[54] Heskestad, G. and Delichatsios, M. A., Environments of fire detectors - Phase 1: Effect of fire size, ceiling, height and material, Vol. 2,

Analysis, Nat. Bur. Stand. (U.S.), NBS-GCR-77-9 5 (July 1977).

[55] Standard for the Installation, Maintenance and Use of Local Protective

Signaling Systems for Watchmen, Fire Alarm and Supervisory Service,

NFPA 72C-1975, National Fire Codes, Vol. 7, National Fire Protection

Association, Boston (1977)

.

[56] Standard on Automatic Fire Detectors, NFPA 72E-1974, National Fire

Codes, Vol. 7, National Fire Protection Association, Boston (1977).

[57] Fire Protection Handbook, 14th Edition, Section 16, National Fire

Protection Association, Boston (1977)

.

[58] Standard for Portable Fire Extinguishers, NFPA 10-1975, National Fire

Code, Vol. 1, National Fire Protection Association, Boston (1977).

[59] Federal Vehicle Safety Standard 217, Bus Window Retention and Release,

National Highway Safety Bureau, Department of Transportation (U.S.).

35
Table

1.

Worst

case

evacuation

times

from

people

mover

vehicles c • o -H

•h

g

+j

(0 o

+j

44 01 i—i

(N in ro 00 KD in 3 *r rH rH 00 in 3 »-4 44 o i—1

iH CN ro CN CN CN rH o (0 0 <D 1 1 1 (0 3

cn r^ > tr tn v—

in (N CN

0) 0)C rH ro CN •H

u o 3 o

4-1 M-4 o

4-1 33 cm O3

44o

Eh

0)

0) 00 Oh ro 00 cr. rH in

01 Oh r- in O' Oh ' rH rH1 ro l rH 1 l Oh

Oh VO in cO 44 •H

4-1 T3

<0

C

4-> 3

cn

<DO > 01

(0 01 U — £ o 0 CD !h 0) 44 •

c

01 0

CD 44 •H E rH 1—1

44

•rH o (0 (0 44 0 g V4

f-H

u cd tr <u 0 1—1 C > c CD *H

CL

g

CL 3 O

<D T)

VI

X3

VO

r-~ ro

vo o o CN o C

ro r- 00 00 <D 1—1 U 1 l 1 1 Q) o in 'cr 44

ro in •^r (1) Vh

CM

CM

ro

04

>1

44 •H

14 0 01 c

<1) £ 01 3 > c 3 o s CQ r—1 0 >i g g 0 CQ 3 U1 x 44

<D 44 S 01 £ cn •H

<U 44 c + U < >1 c O i—1 01 3 a CD 2 (1) •H 0

a- >i P> rt* 'p S4 > Eh c 44 rH O 0) Sh >4 X, •rH a 01 01 Q)

a)O

W o 0 c H •H 01 >

CL

a t. OCD < a s iHE0

V4 44c

ai -X3

4-1

01

a)E

•r4

4-1

CD?

T)c0

•r4 44

(0 44

01

13

36

Based

on

normal

deceleration,

station

dwell

time,

and

maximum

inter-station

travel

time
05

0)OU3O

05co

•Hx

-rHc

Cr> •H

05E0

05

>i

XI

cn05

•rH

»-4

0505

<0

4-> (0

<15 05

0)3O

•rHP3>XOco

•rH

4-> •Hc

tr> •rHPo

>44

a)u c oj r4 05 r4 1 05 05 05 05 0 s <15 <D a) o>

a) 05 >< ^4 O 3 0

14

O CO 3O

05cO 14 0

•h q) a) X a, 05 H 3 1 0 05 05 0) c as C CD 05 <15 tp 05 £4 >- >i

•rH 05 VO C ?" 3

£>1 XC cr> o 0 3 05 •H XI 05

4-5 1 •rH x s 0 0 05 05 c 05 c c 05 0

tp 3 O >4 >1 *H 14 X’

E4

140

<44

r-43

•rH

U

X

X 0) c O 05

aiX 1 0 0 0 05 -p 3 S c c c 0) o r >1 a o

<N

T3

o> X3E

•H 0) o x X 05

05

X 05

w 0) 1 0 0 0 0

>4 S c c c c 3

<po

•H ro U vo

05

143

O'- •H

>44 3

•H

4-> C

<15 4-1 0

Cb

rs

a) i—i

xi3

E4

a OS •H a &4 V

OP OP 0) O O X

ro iH c

0) 0) ». «• 0) 05 I—1 c 0) 0) C 05 3 05 c c 3 P

•rH P 3 3 X

a

p

a

X

X

X

0) 0 X

X 05 3 X 0) 05 05 14 X 3 s 14 p D 3 E D D \ T)

rH

G

XCC 0 G 3 c •H •H rH 0

05 •H

XX >i

C/3 > 05 05 Tl 1 1 05 X X 05 eX rH 3

0) 05 03

C/3 C/5 1“1

37
Summary

of

selected

small-scale

test

results

on

transit

vehicle

components

00

LO

CM Q

H

00 fa C «CM

•H fa 0

H ^ CJ o ^ O -u S

i—I CO fa a) H

2 <r H oo

co

<J w

CM

vO

onC W

co

<J

CM

O'

vO

3 2-g

(3 "eo

4=

4-> ^oo s

C U

fa% inCM

« aj kJ

d) \ 6 a) a

co S d) H rl (/) n H ^

m

oo

k oo g

3 3 o

(23 0) ^

rJ

a

CO CM tH

co o e

J> CO ^

2 6a

on -<j- pH on

CO vO

VO

VO

m

co

vO

2

Q

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<03 C & 3 5

3 0 o

0) 4-1 4-1

1 c c < CO 03 H 00 H fa 1

o <3 s «

HO2

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oo co

vO vO

iH <r o <f o

iH O O P*> rH H CM vO CO

o in m

cn CM V V

CMCO w

CO

w

CO

<J\ o

CO VO

CO Cn. VO

2 2

a a

«n o <r

av co co oo\vomvo«j

ON <r vO O uo CM CM

a

cs

<u

coco

4)U

CcC fa

<D 03 o 00 rH O ^ 4-1 4J CL C a) a) 03 e rH •H QJ cd

<u u Li o d 2 C *H cd rH ^ rH

Q- 0) cd *H cd cd pH rH 03 3 *H 3

Li a cj u X rH -c o rH CM 3 L» lu 03 pH cd H cn *H u u <J •H O T3 Li O 3

CO CJ cd 00 3 H e 0) c 0) cd Li s S pa CO O a) aj W

•H CJ c CJ hp cd Li •H Li pa JO cd Cd CM fa iH I cn H H •H cd o =3 > 3 cd o o 03 pH Li u n T3

01 O rH rH 4J fa fa u fa fa fa g>

0) T3 0) > c

4J O rH •H cd i i cd 1 l 1 <y cd •u &4 U 3

.3 i—l cd a) a> 03 •H Q) C O

fa 3 CJ co CO CO 2 2 M CO

38

-‘-Mixture

of

different

types

of

foam

^Styrene/butadiene

coated

with

Ethylene-ethylaciylate

copolymer

3Tests

on

WMATA

bus

and

subway

materials

were

performed

by

NBS;

tests

on

BART

materials

were

from

reference

[19];

tests

on

Morgantown

materials

reported

by

[16],
Table 4. Recommended acceptance criteria test method ASTM E 162

Acceptance

Material Criteria

Interior

Wall and ceiling linings 35

Window glazings 35

Thermal and acoustical insulation 35

Air conditioning duct work 35

Seats

Hard-molded seats

Cushioned seats

Cushion coverings

Padding

25

Exterior:

Exterior vehicle shell 35

Seat cushion coverings should be tested in conjunction with seat cushions.

Acceptance criteria is for composite assembly.

2 ASTM D 3675-78, a variant of ASTM E 162, has been developed specifically

for flexible cellular materials.

39
WELDED

STEEL

FRAME

40

Figure

1.

Morgantown

passenger

vehicle

construction
ANTENNA

DOOM OPERATION

INSTALLATION EMERGENCY DOOR OPEN

EMERGENCY BRAKE MAGNET VALVES LOW

SWITCH

, COMPRESSOR

, OH. TANK

-ALTERNATOR BRAKE PRESSURE SWITCH-' C0*fm?

L tmlT HEIGHT CONTROL VALVE—' 5^J^^K^^^~-SOLENO» SELECTOR VALVE DOCKING VALVES ' /ZtZZZZ 7% mtssURE swnroT

RESERVOIR

UTILITY MOTOR

REFLECTIVE

i SCANNER

SIGNAL BRUSH

GROUND BRUSH

RGENCV BRAKE MAGNET VALVE

- REVERSING ACTUATOR

MOTOR CONTROLLER

ROLLBACK SENSOR MOTOR BUMPER

INSTALLATION

Figure 2. AIRTRANS passenger vehicle construction

41
42

^'^-'jure

3

.

Morgantown

emergency

egress

provisions
Figure 4. AIRTRANS emergency egress provisions

43
ELECTRONICS

CLOSET

44

Figure

5.

Otis

passenger

vehicle

interior

construction
ON

SEAT

ADJACENT TO

OR BENEATH

SEAT

;r y

X

AISLE

IGNITION

X POTENTIAL LOCATION

OF IGNITION

SOURCE

Figure 6. Probable location of ignition sources

in a DPM vehicle

45
CO

UJz

UJ

ccQ.oUJz

>

Z

>

2

o

in

r*

(j < Z

cn$i-

°o,w

(/) UJ w £/) l>t<

z UJ — vl lzo5 2LUH-2

00

UJz

<

X

I- a:

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*

UJ

c/>

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Ulz

<

X

t- a:

Ul u. D*

Z®

to

UJV)

UlZ

<

X

t—

Ui

CCD

z

o_J>

z

5

o

o

55

it

5

o

<2, %

c,°

: &

A? >X ^ '

- O'

oUJ

(/) <

£

OUJ

(/)

I 1=<

O

UJ

C/) <Ul

_JUl

oc

>•a

x

UJz

ui

_J<

h-o

.2*c

(0E

"5c

]g> o

o

(S11VM) 3SV313U ADW3N3 30 3±VU

CD 5

46

Figure

7.

Comparison

of

ignition

source

characteristics

and

minimum

ignition

energies

for

various

seat

assemblies
47
END

DOOR

EMERGENCY

EXIT

FOR

EGRESS

DIRECTLY

ONTO

GUIDEWAY

UPPER

EXTERIOR

SHELL

OF

ALUMINUM o

48

Figure

9.

Vehicle

exterior

design

feature

VEHICLE FLAMMABILITY

GUIDELINES
NBS-1 14A (REV. 9-761

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 78-1586

3. Recipient $ Accession! No.

4. TITLE AND SUBTITLE

FIRE SAFETY GUIDELINES FOR VEHICLES IN A

DOWNTOWN PEOPLE MOVER SYSTEM

5. Publication Date January 1979

7. AUTHOR(S)

Richard D. Peacock

i. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS TT

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, zip)

Urban Mass Transportation Administration

U.S. Department of Transportation

Washington, D.C. 20591

13. Type of Report & Period Covered Final Report

: 15. SUPPLEMENTARY NOTES

|

] Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or less factual summary of most si gnificant information. If document includes a si gni ficant bibliography or Yrfeto/ur#4 |S/Arvey # mention it here.) The results of a study to formulate fire safety guidelines to

be required for vehicles used in Downtown People Mover (DPM) systems

' * ''“f'or the movement of people in a congested urban area are presented.

Through a review of the design features of existing people mover

vehicles and systems, and a review of proposed new systems, fire

scenarios are developed and guidelines suggested to minimize the

fire risk to passengers.

Methods and criteria, based on established test procedures, are proposed for assessing the flammability and smoke generation of interior

finish and furnishing materials. Fire and smoke detection and suppression

equipment are recommended, along with proposed guidelines for emergency

evacuation provisions and emergency communication requirements.

An extensive bibliography of flammability in fixed guideway

transit systems is included.

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)

Emergency communications; emergency evacuation; fire detection;

fire safety; fire suppression; mass transportation; material flammability;

people movers; smoke.

18. AVAILABILITY [x] Unlimited

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A 1 1 1 3 R R b 7 b 3

PUBLICATIONS

NBSIR 79-1588

Interlaboratory Evaluation of

the Attic Floor Radiant Panel

Test and Smoldering

Combustion Test for Cellulose

Thermal Insulation

J. Randall Lawson

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

February 1 979

Final Report

Prepared for: onsumer Product Safety Commission

extile and Mechanical Engineering Group

100 ethesda, Maryland 20202

,1156

WaflcMl wmi af Stancaj'ds

MAY

NBSIR 79-1588

- r 1 INTERLABORATORY EVALUATION OF

THE ATTIC FLOOR RADIANT PANEL

TEST AND SMOLDERING

COMBUSTION TEST FOR CELLULOSE

THERMAL INSULATION

J. Randall Lawson

Center for Fire Research

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

February 1979

Final Report

Prepared for: Consumer Product Safety Commission

Textile and Mechanical Engineering Group

Bethesda, Maryland 20202

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

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
• J >

'

.

<*•

• y

v ' •

• - • , v*
TABLE OF CONTENTS

Page

LIST OF FIGURES iv

LIST OF TABLES iv

Abstract . 1

1. INTRODUCTION 2

2. TEST APPARATUS AND METHODS 3 2.1 Attic Floor Radiant Panel 3 2.2 Smoldering Combustion 3

3. LABORATORY QUALIFICATION 4

4. PARTICIPANTS 5

5. MATERIALS AND SAMPLE PREPARATION 5

6. EXPERIMENTAL DESIGN 6

7. TEST RESULTS AND DISCUSSION 7 7.1 Critical Radiant Flux Test 7 7.2 Smoldering Combustion Test 9

8 . SUMMARY AND CONCLUSIONS 10

9. RECOMMENDATIONS 10

10. ACKNOWLEDGMENTS 11

11. REFERENCES 11

APPENDIX A - PARTICIPANTS IN THE INTERLABORATORY FIRE TEST PROGRAM . . A-l

APPENDIX B - STATISTICAL METHODS B-l

APPENDIX C - CELL AVERAGES AND STANDARD DEVIATIONS FOR

CRITICAL RADIANT FLUX AND SMOLDERING COMBUSTION C-l

iii
LIST OF FIGURES

Page

Figure 1. Attic floor radiant panel tester schematic - side evaluation 12

Figure 2. Standard radiant heat energy flux profile 13

Figure 3. Commercially built attic floor radiant panel 14

Figure 4. Home built attic floor radiant panel 15

Figure 5. Smoldering combustion test (materials before testing) ... 16

Figure 6. Smoldering combustion test (materials after testing) ... 17

LIST OF TABLES

Page

Table 1. Critical radiant flux data . 18

Table 2. Pass and fail tabulation (critical radiant flux) by

materials and laboratories 19

Table 3. Precision estimates of critical radiant flux measurements . 20

Table 4. Comparison of precision estimates for fire test methods . . 21

Table 5. Percent weight loss - smoldering combustion test 22

Table 6. Pass and fail tabulation (smoldering combustion) by

materials and laboratories 23

Table 7. Precision estimates of percent weight loss (smoldering

combustion) for materials without split test results .... 24

IV
INTERLABORATORY EVALUATION OF THE ATTIC FLOOR RADIANT

PANEL TEST AND SMOLDERING COMBUSTION TEST FOR

CELLULOSE THERMAL INSULATION

J. Randall Lawson

Abstract

An interlaboratory test program was conducted to

provide estimates of repeatability and reproducibility

of fire tests for cellulose loose fill insulation. The

test methods evaluated were for critical radiant flux,

using the Attic Floor Radiant Panel, and for smoldering

combustion; they were based on Federal Specification

HH-I-515D. Seven commercially manufactured cellulose

thermal insulations marketed for residential use were

evaluated by each procedure. An additional set of four

replicate hardboard specimens were tested by each participant using the Attic Floor Radiant Panel. Nine

laboratories conducted the Attic Floor Radiant Panel

test, and ten conducted tests for smoldering combustion.

The testing was conducted during the month of June 1978.

The participating laboratories were surveyed prior to

testing in order to ensure conformance to the critical

details of the test apparatus and procedures.

The between-laboratory coefficient of variation

for critical radiant flux ranged from 13 to 30 percent

with an average for seven insulation materials of 21

percent. Estimated precision levels of repeatability

and reproducibility for the Attic Floor Radiant Panel

test when compared to other standard flame spread tests

and materials are favorable. Data from the Smoldering

Combustion test was evaluated on a pass/fail basis with

agreement by nine of ten laboratories for six of the seven materials tested. Seven of ten laboratories also

agreed on the seventh material.

Based on work of this study, there is reasonable

assurance that results from different laboratories

evaluating the same material for compliance with Federal

Specification HH-I-515D will be consistent.

1
Key words: Attic floor radiant panel; cellulose

thermal insulation; critical radiant flux; flame spread;

test methods; smoldering combustion.

1. INTRODUCTION

Loose fill cellulose thermal insulation has been manufactured and used

in the United States for several decades. With the increasing need to

respond to the demand for energy conservation through reducing residential

heat losses, the industry has grown at a rapid rate. With this growth,

several problems have become apparent. As stated at the Consumer Product

Safety Commission's (CPSC) public meeting of August 22, 1977, some of these

problems were related to the fire properties of the materials. Only one fire

test method has been used by regulatory bodies to evaluate the fire properties of cellulose insulation. This is the ASTM E 84 Steiner Tunnel Test [l]"*". It is apparent that the test is not designed for evaluating attic insulations

since insulation is generally exposed on an attic floor and the tunnel test

evaluates it on the ceiling. Additionally, the insulation sample must be

supported by a fine mesh screen wire which further alters the natural environment. It was also recognized that the procedure did not take into account

the smoldering combustion process. A separate test method was developed for

the evaluation of this fire property. These problems with fire testing and

the fire incidence noted in Denver, Colorado and other areas resulted in the

updating of performance specifications for insulation.

The investigation of thermal insulation-related fires identified a significant fire scenario which had not been addressed. It was found that

many insulation-related fires were initiated by the overheating of recessed

light fixtures covered with insulation. The initial mode of combustion

was a slowly propagating smoldering of the insulation. In some cases the

smoldering material would involve other building materials and open flaming

would occur. A review of fire scenarios and laboratory mockup tests on insulations showed that relatively rapid flame spread on the exposed surface

of attic insulation could also be caused by ignition from open flaming

sources [2]. As a result, a new standard was written, Federal Specification

HH-I-515D which replaced HH-I-515C, and new test methods were included to

evaluate the fire properties of the materials [3]. The Attic Floor Radiant

Panel test is an adaptation of an established test method for flooring

'"Numbers in brackets refer to the literature references listed at the end of

this paper.

2
materials [4,5]. The Smoldering Combustion test is a newly developed test

for evaluating the tendency of thermal insulation to initiate and propagate

a smoldering reaction.

As part of the test development, an interlaboratory test program was

2 3 conducted to evaluate the repeatability and reproducibility of the Critical

Radiant Flux and Smoldering Combustion tests for cellulose thermal insulation

materials

.

2. TEST APPARATUS AND METHODS

2.1 Attic Floor Radiant Panel

Briefly, the basic elements of the test apparatus are a horizontallymounted 100 cm long specimen tray which receives radiant energy from an airgas fueled radiant panel mounted above the specimen and inclined at an angle

of 30° (see figure 1) . A pilot burner is used to initiate the test by open

flame ignition of the specimen. The gas panel generates a flux profile along

the length of the specimen ranging from a maximum of 1.1 W/cm2 to 0.1 W/cm 2 minimum [4]. The standard flux profile is shown in figure 2.

After the test chamber has been preheated to equilibrium conditions, the

specimen is placed into test position and the chamber is closed. Following

a two-minute preheat, the ignition flame is applied to the end of the specimen

located under the radiant panel. The test is continued until the specimen

flaming goes out (extinguishment) . The distance burned to the point of

extinguishment is converted to W/cm2 from the calibrated flux profile graph

and the result is reported as a critical radiant flux, W/cm 2 [4]. For a material to pass the test, the critical radiant flux must be equal to or greater than 0.12 W/cm2 [3].

2.2 Smoldering Combustion

The specimen holder is an open-top 20 cm square stainless steel box which

is 10 cm high. During the test the specimen holder rests upon a glass fiberboard pad which is approximately 2.5 cm thick (see figure 5). The ignition

source is a cigarette without a filter tip which is 85 mm long.

2 . . Repeatability precision - repeatability or within- laboratory precision is

defined in terms of the variability between test results obtained in the same laboratory on the same material [6],

3 . . Reproducibility precision - reproducibility or between-laboratory precision

is defined in terms of the variability between test results obtained in

different laboratories on the same material [6]

.

3
The weight of material necessary to fill the holder at a settled density

is determined. The specimen holder is filled to the top with the required

amount of material. An 8 mm diameter vertical hole is made in the center of

the material, and a well-lit cigarette is inserted in the formed cavity. The

lit end of the cigarette is upward and flush with the sample surface. The

cigarette and specimen are allowed to burn for at least two hours or until

smoldering is no longer progressing. After the specimen holder has cooled

down to 25° C, the holder with its material residue is weighed and the weight

loss is determined. For a material to pass, there must be no evidence of

flaming combustion and the weight loss must be <_ 15 percent of the initial

weight [3]

.

3. LABORATORY QUALIFICATION

Prior to initiating the round robin test program, Mr. David E. Swanson

of the National Bureau of Standards visited a number of laboratories to check

the operation of their radiant panel apparatus. Special attention was given

to checking the calibration of the radiant flux meters and flux profiles.

The following is a discussion of the survey findings.

The calibration of the radiant flux meters, used for adjusting the

radiant flux profile for the test, was compared to that of an NBS calibrated

flux meter. Out of eleven laboratories checked, one was found to be using an incorrect flux meter calibration value. A correct calibration constant was provided for use by the laboratory. The laboratory survey indicated a general

pattern of initial difficulties in adjusting the radiant panels for the

specified radiant flux profile. In some of these laboratories, this may be

attributed to the lack of experience with the apparatus because the units

had been recently acquired, rather than an insufficient description of the

test procedure. In order to correct this problem, adjustments were required

on sample to panel distance, radiant panel angle, and gas and airflow rates.

Gas and airflow rates were difficult to adjust on several test instruments.

This was mainly due to the coarseness of the flow' control valves. One panel

was being operated without airflow control to the burner, relying only on the

adjustment of gas flow for control. Another laboratory did not have the

optical pyrometer used for standardizing the thermal output of the radiant

panel. Several laboratories had experienced trouble with the temperatureactivated safety gas cut-off system on the panels. The thermocouples con- trolling the automatic shutdown were not located in the proper position.

Sporadic cooling of these thermocouples resulted in the gas flow to the

panels being cut off. These thermocouples were repositioned. The only other

significant problem noted was associated with airflow through the test chamber.

4
In one laboratory, the building exhaust duct was connected directly to the

test chamber stack by a flexible hose. This induced an unusually large

airflow through the test chamber which substantially lowered the chamber

temperature and also affected the radiant flux profile. The flexible hose was removed allowing natural convection to remove the products of combustion,

and the unit was recalibrated.

After the laboratory investigations were completed, the nine participants

were selected for the test program. Of these, two had assembled the apparatus

from drawings in the specification, and seven had commercially manufactured

test apparatus. Of the commercial instruments, two manufacturers were represented. Figures 3 and 4 show representative examples of commercial and

home-built test instruments that were used in this test program.

4. PARTICIPANTS

The laboratories who collaborated in this study are listed in appendix A.

The degree of experience among laboratories in using the insulation test

methods varied from one month to one year. Five of the participating laboratories provide commercial test services for the public while the others are government laboratories. In order to remain consistent with the usual practice in interlaboratory studies, the laboratories are identified in this report

only by code letters. It should be noted that one laboratory conducted only

the Smoldering Combustion test.

5. MATERIALS AND SAMPLE PREPARATION

Seven cellulose thermal insulation materials were obtained from

manufacturers for the test program. The basic ingredient in six of the

materials was ground waste paper while the seventh was cotton. The manufacturers indicated that all of the materials were treated with fire-retardant

chemicals. The fire-retardant chemicals in one material were added through a wet process while the chemicals for the six other materials were added by

mechanical dry blending. All of the materials were produced primarily for

the home insulation market. The materials are typically installed by being

blown into building spaces, attic floors and wall cavities by blowing machines.

The materials were received in bags containing insulation whose nominal weights

ranged from 9.1 to 18.2 kg (20 to 40 lbs). Before the insulation was separated into sample batches and blended, each product was given a code letter,

A through G, which was used throughout the program for identification.

5
After the bags were weighed, each material used in the test program was removed from its original bag and mixed separately. Mixing was accomplished

by blowing the insulation through 30.3 m (100 ft) of hose into a 1.8 m 3

(65 ft 3

) blending chamber using a commercial blowing machine. Depending on

the properties of the materials, two or three bags were fed through the blowing machine and into the mixing chamber before samples were taken from the

lot. Samples weighing a nominal 4.5 kg (10 lbs) were bagged separately and

code labeled for shipment to the participating laboratories. Before the bags were sealed, a 454 g (1 lb) sample was taken from each. These samples were

placed into a separate bag for each product and kept as a composite to be

tested by NBS . After each lot was mixed, the mixing system was thoroughly

cleaned before the next material was blended. When all the materials were

bagged, they were placed into groups for shipment and lot numbers were recorded

along with the laboratory identification number. The samples were then boxed

with a set of four hardboard specimens and a four-pronged pick, which was used

for fluffing the insulation, and shipped to the participants. For simplicity

and consistency, slight modifications were made in a few procedures and uniform

instructions were sent to the participants (see section 6).

6. EXPERIMENTAL DESIGN

Each laboratory participating in the test program received seven cellulose insulation materials and one set of four hardboard specimens. The

fire test procedures used by the participants in this interlaboratory test

program were slight modifications of tests found in Federal Specification

HH-I-515D [3]. The tests conducted were for Critical Radiant Flux (section

4.8.7 of HH-I-515D) and Smoldering Combustion (section 4.8.8 of HH-I-515D)

.

Both tests were performed on each of the cellulosic insulation specimens. The

hardboard specimens served as a reference material for Critical Radiant Flux

method only.

In order to maintain consistency in the test evaluation, minor changes

were made in the test procedures. It was requested that all laboratories

test their specimens at a fixed density instead of the settled density called

for in the specification. Tests on all insulation materials except C were

conducted at a nominal 48 Kg/m 3 (3.0 lbs/ft 3

) density with an allowable range

between 46.5 and 49.7 Kg/m 3 (2.9 and 3.1 lbs/ft 3

) . Because the blown density

of material C was much less than the others, it was requested that tests be

performed at a nominal density of 24 Kg/m 3 (1.5 lbs/ft 3

) with a range from

22.4 to 25.6 Kg/m 3 (1.4 to 1.6 lbs/ft 3 ).

6
Specimen preparation also varied somewhat from the procedure called for

in the specification. It was found that repeated passes of cellulose insulation through a blowing machine results in damage to the cellulose fiber and

alteration of its properties. Since the materials had already been blown

through a commercial insulation blowing machine when they were blended at

NBS, it was requested that the test specimens be prepared by hand, filling

the test containers to the weight required for the specified densities.

Care was to be taken to break up any lumps and to fluff the material using

the pick until the specimens evenly filled the test container.

The conditioning procedure for the Smoldering Combustion test was also

altered to conform with the procedure required for the Critical Radiant Flux

test. All materials and cigarettes were to be conditioned for a minimum of

48 hours in an environment of 21 + 3° C (69.8 + 5.4° F) and 50% R.H. before

testing.

7. TEST RESULTS AND DISCUSSION

Nine laboratories conducted tests and provided data on the Critical

Radiant Flux test. Ten laboratories conducted Smoldering Combustion tests

and supplied data. The data were compiled and compared with the requirements

set forth in the Federal Specification HH-I-515D. The specification states

in paragraph 3.1.9 that for a material to pass, the critical radiant flux

shall be equal to or greater than 0.12 W/cm2

. For smoldering combustion,

paragraph 3.1.10 states that a material must show no evidence of flaming

combustion and must have a weight loss <_ 15 percent of the initial weight in

order to be accepted.

7.1 Critical Radiant Flux Test

Three tests were conducted by each laboratory on each cellulose

insulation material; four hardboard specimens were also tested. Since loose

fill cellulose insulation and its properties are known to be variable, the use of a fairly uniform hardboard sheet, which has been used in other testing

programs, was included to provide a reference measure of test repeatability

and reproducibility. Table 1 lists the test results for critical radiant

flux provided by each laboratory.

Material D experienced five individual tests in two laboratories where

the specimen did not ignite; eight laboratories reported data for materials B

and F in which some or all of the specimens burned the entire length. The

results contained in these ten data cells were not included in the statistical

7
treatment. Two hardboard tests from laboratory number 2 were excluded from

analysis also because the laboratory indicated that the radiant panel

extinguished while the tests were in progress.

, Table 2 shows the Critical Radiant Flux test results ordered from pass to

fail tabulation. Material B failed in seven of the the nine laboratories and

exhibited relatively low critical radiant flux values in the laboratories

where it passed (see table 1) . Materials E and F experienced failures in one

and two laboratories, respectively. In summary, the results of four materials

had full agreement in all nine laboratories. The results of one material

agreed in eight of nine laboratories, and the results of two materials agreed

in seven of nine laboratories.

Table 3 exhibits the results of a statistical evaluation which provides

information related to the precision of the Critical Radiant Flux test. The

test results were evaluated using statistical methods found in the "Tentative

Recommended Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods" being prepared by ASTM Committee E 11 [6].

A brief presentation of the statistical methods used in this report is given

in appendix B. The table presents the overall laboratory average for critical

radiant flux, pooled repeatability standard deviation, reproducibility standard

deviation and the coefficients of variation for repeatability and reproducibility. (See appendix C for cell averages and standard deviations.) Although

material B exhibited the best repeatability with a coefficient of variation of

7.7 percent, it should be noted that this value was calculated using the

critical radiant flux results reported from only two laboratories. Material E

exhibited the greatest coefficient of variation for repeatability with a value

of 14.8 percent. The coefficient of variation for reproducibility ranged from

13 to 30 percent. The overall average coefficient of variation for repeatability for seven cellulose insulation materials was 12 percent; the average

coefficient of variation for reproducibility between laboratories for seven materials was 21 percent. These values were fairly close to the values for

the hardboard sheet material and also compare favorably with values for carpeting materials tested by the Floor Radiant Panel [4] and E 84 Flame Spread

tests [7] (see table 4). As shown, the range and median coefficients of

variation of the Attic Floor Radiant Panel are reasonable when compared to

similar estimates available for other test methods. Furthermore, it was expected

that the precision estimates for loose fill cellulose would be somewhat higher

than that for carpeting. Thus, the testing of loose fill cellulose insulation

materials by this test method does not introduce exceptionally high levels of

variability. Also, a comparison of hardboard test results from this interlaboratory program shows better reproducibility than that obtained from an

8
uncontrolled program involving 21 laboratories using the Floor Radiant Panel

test. An informal "calibration" experiment was carried out before an attempt

was made to standardize various test parameters. This work was done in order

to determine the extent of between-laboratory variability. (The results of

the calibration experiment resulted in a tightening of the test procedure.)

The data show that the average critical radiant flux obtained for hardboard in

the present program was 0.20 W/cm2 and the earlier calibration experiment was

0.19 W/cm2

. The repeatability coefficient of variation for hardboard in this

project was 12.7 with a reproducibility coefficient of variation of 19.5 (see

table 3) . The repeatability coefficient of variation for the hardboard in the

uncontrolled calibration experiment was 13.1 with a reproducibility coefficient

of variation of 91.5.

7.2 Smoldering Combustion Test

4 Ten laboratories supplied Smoldering Combustion test data. Each cell

consisted of three determinations as required by Federal Specification

HH-I-515D. Table 6 shows a tabulation of percent weight loss of the test

specimens as reported by the laboratories. Because of the split test results,

some pass and some fail, noted in a number of data cells exhibited in table 5,

calculations of repeatability and reproducibility were made for only three

materials

.

Figures 5 and 6 show examples of materials prepared for testing and the

specimens two hours after the cigarettes were ignited. It is evident that

where smoldering combustion was initiated and propagated readily a significant

weight loss occurred; where it was not initiated the weight loss was very

small. The chemical composition of the sample and the extent of separation

of the fire-retardant chemicals are principal determining factors in the

propagation of smoldering combustion.

Three laboratories experienced split test results within a single set of

tests. This can be seen in table 5 and is noted in table 6 by the asterisks.

There were six cells with split results out of a total of 70 cells. Four

materials experienced this phenomenon, C, E, F and G; materials E and F show

split results in two different laboratories. Material E exhibited the greatest inconsistency, passing in three laboratories and failing in seven. Within

the seven failing laboratories two data cells show passing results. This

variation appears to be directly related to the physical separation of fireretardant chemicals from the ground paper. A deposit of granular chemicals

Cell - each of p laboratories makes measurements on each of q materials.

This gives rise to p x q "cells". Each cell consists of n measurements [6].

9
was observed in the bottom of sample bags containing material E. Materials

F and G failed in nine of the ten laboratories with F exhibiting split results

in two data cells and G with split results in one. Materials B and D were

failures in all laboratories. Material C exhibited two failures in one data

cell and passed in the remaining nine. For statistical data on materials

without split results, see table 7.

Further analysis of table 6 provides some information associated with

reproducibility. Agreement among the laboratories was relatively good. The

results of three materials had full agreement in all ten laboratories. The

results of three materials agreed in nine of ten laboratories and the results

of one material had agreement in seven of the ten laboratories. It appears

that some variation in laboratory operations contributed to the scatter of

data

.

8. SUMMARY AND CONCLUSIONS

j An interlaboratory program was carried out to determine the repeatability

and reproducibility of the Critical Radiant Flux and Smoldering Combustion

tests referenced in Federal Specification HH-I-515D. Seven cellulose thermal

insulation products were evaluated in ten laboratories. The results indicate

that the estimated precision levels of repeatability and reproducibility for

the Attic Floor Radiant Panel test were not significantly greater for loose

fill cellulose materials than for other materials, and compare favorably with

precision estimates available from other standard fire test methods. Physical

separation of chemical fire-retardants was quite noticeable in one of the seven materials and the likely cause of variability noted in the test results,

particularly for the Smoldering Combustion test. Based on the work of this

study, there is reasonable assurance that results from different laboratories

evaluating the same material for compliance with Federal Specification

HH-I-515D will be consistent.

9 . RECOMMENDATIONS

In view of the variation experienced with the Smoldering Combustion test,

it would be appropriate to further study the possibilities of improving the

test procedure.

10
10. ACKNOWLEDGMENTS

Appreciation is extended to the manufacturers who freely provided

materials for this test program and the participating laboratories who

conducted the testing without compensation. Mr. Bernard Schwartz of the

Consumer Product Safety Commission and the field offices assisted in obtaining the test materials. Statistical consultation was provided by Mrs.

Mary G. Natrella, Statistical Engineering Division, National Bureau of

Standards. Appreciation is also extended to Mr. Sanford Davis, Furnishings

Flammability Research, National Bureau of Standards, who provided assistance

through the test program, and to Mr. David E. Swanson for conducting the

laboratory survey.

11. REFERENCES

[1] Standard Test Method for Surface Burning Characteristics of Building

Materials, ASTM E 84-77, American Society for Testing and Materials,

Philadelphia, Pa. (1977).

[2] Gross, D. , A preliminary study of the fire safety of thermal insulation

for use in attic or enclosed spaces in residential housing, Nat. Bur.

Stand. (U.S.), NBSIR 78-1497 (1978).

[3] Insulation Thermal (Loose Fill for Pneumatic or Poured Application):

Cellulosic or Wood Fiber, Federal Specification HH-I-515D (June 15, 1978).

[4] Benjamin, I. A. and Adams, C. H., Proposed criteria for use of the

critical radiant flux test method, Nat. Bur. Stand. (U.S.), NBSIR 75-950

’ (Dec. 1975) .

[5] Standard Method of Test for Critical Radiant Flux for Floor Covering

Systems Using a Radiant Heat Energy Source, NFPA 253, National Fire

Protection Association, Boston, Mass. (1978).

[6] Tentative Recommended Practice for Conducting an Interlaboratory Test

Program to Determine the Precision of Test Methods, ASTM Committee E 11,

American Society for Testing and Materials, Philadelphia, Pa. (1978).

[7] Lee, T. G. and Huggett, Clayton, Interlaboratory Evaluation of ASTM

E 84-70, Tunnel Test Applied to Floor Coverings, Journal of Testing and

Evaluation, Vol. 3, No. 1, American Society for Testing and Materials,

Philadelphia, Pa. (1975) .

11
Figure 1. Attic floor radiant panel tester schematic - side evaluation

12
o

u

UJo

z mo/SiiVM

13

Figure

2.

Standard

radiant

heat

energy

flux

profile
14

Figure

3.

Commercially

built

attic

floor

radiant

panel
15

Figure

4.

Home

built

attic

floor

radiant

panel
16

Figure

5.

Smoldering

combustion

test

(materials

before

testing)
17

Figure

6.

Smoldering

combustion

test

(materials

after

testing)
Table 1. Critical radiant flux data

Lab Material

A B C D E F G Hardboard

1 0.19 <0. n

a

0 . 16 0.51 0.10 0.14 0.15 0.21

0.20 < 0.11 0.18 0.39 0.11 0.15 0.16 0.19

0 .18 < 0.11 0.20 0.41 0.12 0.13 0.15 0.23

0.19

2 0.24 <o.na 0.20 0.49 0.18 0.21 0.26 c 0.25 0.12 0.21 0.49 0.17 0.18 0.24 c 0.22 < 0.11 0.19 0.53 0.19 0.16 0.25 0.22

0.21

3 0.29 0.14 0.25 0.46 0.21 0.16 0.38 0.17

0.24 0.15 0.27 0.41 0.20 0.18 0.35 0.15

0.34 0.17 0.28 0.46 0.21 0.15 0.41 0.14

0.13

4 0.18 <o.na 0.16 DNI b 0.18 <o.na 0.21 0.22

0.19 < 0.11 0.14 DNI 0.14 0.11 0.19 0.22

0.22 < 0.11 0.13 DNI 0 . 15 < 0.11 0.19 0.22

0.23

5 0.23 <o.na 0.27 0.39 0.13 0.14 0.25 0.21

0.25 < 0.11 0.28 0.45 0.15 0.13 0.22 0.22

0.24 < 0.11 0.30 0.41 0.15 0.12 0.19 0.15

0.12

6 0.21 o.na 0.26 0.55 0.17 0.13 0.24 0.21

0.12 0.11 0.21 DNI 0.15 0.16 0.20 0.22

0.16 < 0.11 0.24 DNI 0.12 0.14 0.24 0.20

0.25

7 0.20 0.13 0.32 0.62 0.17 0.12 0.27 0.23

0.23 0.13 0.31 0.49 0.21 0.19 0.37 0.23

0.20 0.13 0.31 0.44 0.22 0.13 0.26 0.23

0.21

8 0.27 < 0 . 12 a 0.22 0.55 0.27 0.14 0.21 0.22

0.27 < 0.12 0.28 0.54 0.18 < 0 . 12 a 0.22 0.25

0.27 < 0.12 0.25 0.53 0.18 < 0.12 0.21 0.27

0.28

9 0.18 0.10 0.18 0.60 0.20 0.16 0.18 0.20

0.20 0.10 0.20 0.43 0.16 0.17 0.22 0.17

0.17 0.10 0.24 0.40 0.16 0.14 0.18 0.20

0.12

c In the statistical treatment of the data, data cells containing

values designated by the less than sign "<" were not included in

the analysis.

DNI = did not ignite. These data cells were not included in the

statistical treatment.

Q'Two tests were not included because the radiant panel went out

while the tests were in progress.

18
Table 2 Pass and fail tabulation (critical radiant flux)

by materials and laboratories

Lab

G

P

P

P

P

P

P

P

P

P

C

P

P

P

P

P

P

P

P

P

A

P

P

P

P

P

P

P

P

P

E

F

P

P

P

P

P

P

P

P

No. of

Failures 0

19
Table

3.

Precision

estimates

of

critical

radiant

flux

measurements

>i

44 X

0 34 -H 0 •—

I

4-1 4-1 -H C XI

03 c •H LD

•H 0 0

0 •H p co <£> ro •H X T3 r—

1

rH CM 44 id 0

44 •H 34

0) 34 a

O (0 (D u > a;

CO ID ro LO in

rH rr <J> <T> 0

C4 CM CM rH rH CM

03

(0

>4 X c

•H 0

rH *H H X

x id •H *rH Os LO 0 r- r~ rH 00 0

O > rH CM in r- P 0) O O O 0 0 0 0 O

T3 Q

Repro Std

.

O 0 O 0 0 0 O O

•r4 r~ 34

<D 44 4-1 O id s

0)Cn C

id O

34 *H o 4-> > (0 I—

I

p

03c

44O >4 >4 O 44 X 4-1 *r4 C 1-4 03 G -H X O X

O -H Id •H 44 44 44 rd rO

4-. -H (1) id 4 a

O id CD CJ > K

00 00 CG t~~ 00 0 r-~ [-

CO rH CO rH CO CM rH

rH rH rH rH rH rH rH

03 F—

I

(d

r~- >403 44 44 O fO

>1 0

X X

--4 X

rH fC

03U1 c

id 0

>4 -H

•H *H rH rH VD 0 00 CM VD 0) X x > rH CM fN CM CM CM CM > id

id 03 O O O O O O O 0 rH X Q p

Repea Std

. O 0 O O O 0 O O 03CM

03Cn

1—1 rd rH H CM CM O O rH r- V£> id 03 in CM CO CO r- 0

34 > rH rH rH CM CM CM CM

03 <C Ov

Lab 0 O 0 O O O 0 0

fd

•1—

I

S4

ai 44

id £

•c

34

idO CQfcWCUOQ'OX

34

id X

2 0
Table

4.

Comparison

of

precision

estimates

for

fire

test

methods

i-' IN c c o id •H -H

4J T3

TO (1) >1-H S

4-» P

•H <0

r-4 >

•P

ja 44 •H O o3 4-> •P C O <D P -P

O.

U

0) -P

05 4-1 <U 44 tT

<D0u

a omo

•P op

m

•3*o

4J c c o id •H •H IN r-4 00

4J 'O r4

H

id 0

>1-P £

•P

p

•P 10 ft !> •P

XI 44

id 0 P

«d

v

<u c

a. <n O -P

05

O in a. r~ •P •—i

*H IN

4-1 <D 44 cn

O 0 0 0 e P p> 4-1 0 id u 05 00 00

tP (U »—1 rp m

id

H 0 4J 4J •P Cn >—i

<D a) P 3 a, cr

<u 0) r-4

u

p

p

W rP <d id id O O U U s 0 u

.J

4-> m

a) 4J P h C 0 id 4-i O r-4 •r4 M 00

43 i-l 0) T3 Q) -p 0 Cn C id E-i

w

m £ id 05

<u -p

O CU r-4 s

•H

p a)

H s P 4-> o c ca

4-1

C o id <

rP C4 •H Cn T3

id 05

21
Table 5. Percent weight loss - smoldering combustion test

Lab Material

A B C D E F G

1 0.8 66.8 0.7 57.5 54.5 47.5 54.9

0.3 66.4 0.1 52.9 52.4 43.2 55.2

0.2 67.3 0.2 49.1 49.7 46.3 54.4

2 0.5 62.5 -0.1 70.8 0.2 0.0 0.2

0.4 62.4 -0.2 50.8 0.2 0.1 1.3

0.6 64.5 -0.1 46.6 0.1 0.2 0.1

3 2.4 61.3 1.5 54.2 -0.2 49.3 51.7

3.4 60.7 1.3 54.0 -0.5 46.8 51.8

2.9 60.3 1.3 55.7 0.2 48.7 51.3

4 1.0 60.0 25.3 77.4 46.5 2.5 57.4

1.0 62.1 0.9 62.6 40.0 40.0 55.4

1.0 60.0 40.7 68.9 45.0 35.0 50.0

5 0.3 67.9 0.3 78.6 0.3 62.2 1.5

0.2 69.9 0.3 81.2 0.3 80.4 71.7

0.2 68.3 0.1 79.6 61.3 79.6 0.9

6 9 .

4

a 53.3 0.07 74.1 50.0 32.7 60.0

0.9 57.0 -1.1 51.1 47.8 35.3 58.9

0.5 61.5 0.1 56.6 42.5 29.7 53.2

7 0.5 52.9 0.7 40.4 40.2 34.0 38.0

0.7 55.1 0.8 44.9 43.7 37.0 48.6

0.2 61.2 1.5 48.7 41.1 35.0 47.3

8 0.6 73.1 0.1 77.3 50.7 74.4 57.7

0.7 70.8 0.0 84.0 50.4 75.3 64.3

0.5 73.3 0.0 73.8 48.6 69.6 51.5

9 0.6 62.3 1.4 81.1 50.5 0.6 62.0

0.5 63.5, 1.3 77.0 57.2 0.5 50.5

0.3 70.3 1.4 73.4 0.5 70.8 53.2

10 0.0 61.9 0.0 48.9 - 1.0 51.1 31.5

0.0 63.7 0.4 62.4' 0.0 34.1 54.2

0.4 60.4 -1.2 73.7 0.1 35.7 56.6

a This value was considered to be outlier and was not used in the statistical

evaluation.
Table 6. Pass and fail tabulation (smoldering combustion)

by materials and laboratories

Lab

1

2

3

4

5

6

7

8

9

10

No . of

Failures

P

P

P

F*

P

P

P

P

P

P

F

P

P

F

F*

F

F

F

F*

P

F

P

F

F*

F

F

F

F

F*

F

F

P

F

F

F*

F

F

F

F

F

F

F

F

F

F

F

F

F

F

F

10

F

F

F

F

F

F

F

F

F

F

10

*0f 3 tests, 1 or 2 are close to zero, and the other much above 15%.

23
Table

7.

Precision

estimates

of

percent

weight

lossGo

*H

4-1 CO3E0O

CncHG

<U 32I—I o£

CO

to G

r—I 3

to i 0)g

4-1 to

CD 44

44 •H

pHa

to

4430

x:

44 •H

CO I—I 3

•H

1-1 <D 443£G0

44

>i 44 G 44 o 0 •H

44 i—1

44 •H C c 12

CD 0 •H

•H •H o o 4-> 3 H fd 32

44 •H 0

44 P G

0) fda 0 > 0) u &

cm

cr\ t

>i

4-1

C

•H

O

•H 44 12 <0 •H *H o > 3 <D rd o o

14 • a32

CD 44 & 02

440 G >, 0 -P 44 4-1 -H G rH

(1)

C -H •H O 12 0 •H 3

•H 44 44 44 3 3

44 •H Q2

0)ga 0 3 a> u > K

>i c

44 0

•rH •H

r—1

44 •H 3

12 •H 3 >

44 cu 3 Q

CDa • 0) 32 a 4402

<n in r~ o cm r-~

<D

tji r4 3

pH

G 3 (1) G >

ai < >O 123J

r- 40 • • • o m ro

40 40 3

•HG

ai

4-1 3s < CQ

Q

24
APPENDIX A

PARTICIPANTS IN THE INTERLABORATORY FIRE TEST PROGRAM

Certified Testing Laboratories, Inc.

Dalton, Georgia 30720

Commercial Testing Company, Inc.

Dalton, Georgia 30720

Consumer Product Safety Commission

Engineering Laboratory

Bethesda, Maryland 20720

General Services Administration, FSS FML

Washington, D.C. 20405

Hauser Laboratories

Boulder, Colorado 80306

Independent Textile Testing Service, Inc.

Dalton, Georgia 30720

National Bureau of Standards

Center for Fire Research

Washington, D.C. 20234

Oak Ridge National Laboratory

Operated by Union Carbide Corporation

Oak Ridge, Tennessee 37830

Ontario Research Foundation

Sheridan Park, Mississauga, Ontario

Canada L5K 1B3

Southwest Research Institute

San Antonio, Texas 78284

(Results received 8-28-78, too late for inclusion in the analysis.)

Underwriters' Laboratories, Inc.

Northbrook, Illinois 60062

(Results received 12-27-78, too late for inclusion in the analysis.)

United States Testing Company, Inc.

Hoboken, New Jersey 07030

A1
.
APPENDIX B

STATISTICAL METHODS

(cv

r

)

(CV

i:

s . . 1J

(S L>j

( Vj

'Vj

( s _)x j X . . 1 D

Nomenclature

Coefficient of variation for repeatability (within-laboratory)

Coefficient of variation for reproducibility (betweenlaboratories)

Cell deviations from average

Number of replicates per cell

Total number of laboratories

Cell standard deviation

Component of variance between laboratories

Pooled standard deviation for repeatability

Standard deviation for reproducibility

Intermediate variance quantity

Average for cell (i,j) where i represents the laboratory

and j the material

Average for one material for all laboratories

B-l
Pooled Standard Deviation for Repeatability:

(s . ^fl i. s

2

. )

. = V — 1 i- r 1 f P

( 1 )

Equation (1) is applicable only when the number of replicates is the same for

each laboratory for a given material. Where there are missing replicates

in one or more laboratories use equation (la)

.

V

I. (n. ,-l)s? . 1 ^ U Z* (n, .-1}

i il

(la)

Coefficient of Variation for Repeatability:

(CV ) = 100 (s r

} j

Standard Deviation for Reproducibility:

First Calculate the "deviations from average" for each cell (i,j):

( 2 )

d . . = x . . - x . il il 1 (3)

Then calculate the intermediate variance quantity where:

( s _)x j

E . (d . .

)

i i]

P-1

(4)

Using (s_) and (s )

.

calculate the "component of variance" between laboratories,

x j r J where

(s L

), = (s_)

X j

(s ) 2

. r j n

(5)

The variance of the total variability of a test results including both within

and between laboratory variability is given by:

(s R

) j V

<S r’j +

2 ‘l’j (6)

B-2
Coefficient of Variation for Reproducibility:

(CVj

100

( Vi (7)

B-3

APPENDIX C

CELL AVERAGES AND STANDARD DEVIATIONS FOR

CRITICAL RADIANT FLUX AND SMOLDERING COMBUSTION

C-l
Critical

Radiant

Flux

T)p

!oo3

p

m

sc

*

in in 00 CN in o in m CN O rH CN CN CN in o

CN CM .H CN rH CN CN CN rH CN CTi O o O O o O o O o o

•PW

<D X

Cn •H

SCOP

r- oo oo o r- r' o T" lO oo o ** o rH f—

1

rH -d* n- rin •^r rH <T> in in r-~ o o o r-\ c O O o o o

A A

oo o o I''- o o co oo r~

in in oo CN CN o i—

i

O' n

i—

i

CN oo rH CN CN oo CN rH CN <T«

• • • . • • • . • • o o o o o o O O o o

o o 00 00 1" CO o O' rH

CO o VO ^r 00 00 rH in o 00

rH CN CN rH CN CN CO CN CN CN CT>

• • • • • • • • • . o o o o o o o o o o

O t-» o r- o 00 o o 00 o

cr> 00 c\ o\ 1

0

rH O' 00 CN rH CN CN rH CN rH CN CN rH CN

. • e . • • • • • • o o o o o o o o o O

UJ I—

I

m

•HP

(1) -P

(0 S

C-2

*Only

2

values

were

used

to

calculate

the

average.

Two

tests

were

discarded

because

the

radiant

panel

went

out.
Estimated

Cell

coG0

•P

•P

cr) P>

<1> Q

73P

(0 E5G

(fl -P

CD

-p

to

CD Si

Cn •PEO

-P

•P fa

CO

CD -P S G o m

•J -P

El

g <c O fa p

fal .p

to T3 U

CD -P P -P

<D tP U o

03

•rHp

CD P

Elp *

cd cn I'' t" in 00 CN

O ID 00 ID 0 rH o o CN cH CN cn CN

XI o o o o o o o O o O

El • p o o o o o o o’ o o o

03 E

”3*

n cn r-H CO o 00 CN

ID CN CN CO <n rH o ID

QO o o 1 o 1 o o rH

O • • • e • • • • o o o o o o o O

ID o o CN o CO rH ID CO 00 O rH CO rH ro CN ID O CN CN

UO o o o o o O

O o o • • • • • • • • • • o o o o o o o o o o o o in in in in CD o o o

CN rH rH r-H rH CN

O CO CO CN

U o o o o o o o o o O • • • • • « « • • • o o o o o o o o o o o in o rH o in r- o in ID

r—1rH in CN rH N* rH o rH CN

<c o o o o o o o o o O • • t • • • • • • • o o o o o o o o o o o o ID rH CN m ID CN CO

rH rH

O CN rH CN CN in CN CN

fa o o O o o o O o o O • 0 • • • • • • • • o o o o o o O o o o o in m o in 00 in rH

rH CN rH rH rH co rH CN

lit o o o 1 o o o 1 o O • • • • • 6 • • o o o o o o o o

in o rH

rH o rH

BQ 1 1 o 1 1 ! o 1 1 o

•8

pi CN ro in ID CD cn

COC

El o P -P

>om -p

CD t HJ >—I C *P o m > o -P CD fa CD Q

C-3

*Only 2

values

were

used

to

calculate

the

standard

deviation.

Two

tests

were

discarded

because

the

radiant

panel

went

out.
Cell

Averages

Percent

Weight

Loss

Smoldering

Combustion

Test

r" m m O o r" O' 00

«

H

o vO vO CD VO vO n vO in

• • • • • • • • • • • cn vO *3* Cv OV o 00 [" iH CO m If) in vO r* VO t" r~ vO vO

w

(0 n CO o o r" o o t" O VO •H CO iH r~ CN n O

U CQ • • • • • • • • • • • 0) VO CO o o 00 r* VO CN in CN m

-p

f0 s

VO KD VO vO vO m in VO vO VO

CO o o o ro

nJO r* o r~ CO CN in o CN r~ v VO < • • • • • • • • • • • o o CN rH O o o o o o o

£>i 0P

nJ0

n

n3

CN vO CO 01

W

0)C'm

L

<D

ou

C-4

The

9.4

in

the

original

data

is

treated

as

an

outlier.

The

average

is

of

2

cell

values

only.
Cell

Standard

Deviat:

Smoldering

Combustion

rH co co co rH rH in CO in CN Q CN O' CO o pH rH 00 r>

<N O r-» rH CN rf in co CN rrH rH rH

rH

+j (C w U5 •H LO 00 o rH lO rH O <n rH in rH c 0) >H CQ *3“ rH in <N O rH CO CO CO lo in 0 Eh cu • • • • • • • • • • • H p o rH o rH rH *3* rH *3“ rH CN

CN o o o 10 00 in o in CO CO rH in o o CN CN rH rH CN

• • • • • • • • • • o o o o o o o o o o

>1uo

4J

ftj Sh0

s

CN ro in lO co <n o

pH

C-5

Pooled

Standard

0.24
NBS-1 1 4A (REV. 9-76)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO.

NBSIR 79-1588

3. Recipient’ $ Accession No.

4. TITLE AND SUBTITLE

Interlaboratory Evaluation of the Attic Floor Radiant

Panel Test and Smoldering Combustion Test for Cellulose

Thermal Insulation

5. Publication Date February 1979

7. AUTHOR(S)

J. Randall Lawson

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS Mm.

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, city, State. ZIP)

Consumer Product Safety Commission

Textile and Mechanical Engineering Group

Bethesda, Maryland 20202

13. Type of Report & Period Covered

Final Report

15. SUPPLEMENTARY NOTES

| | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or leas factual summary ol most significant information. If document includes a significant bibliography or

literature survey, mention it here.) An i nterlaboratory test program was conducted to provide estimates of repeatability and reproducibility of fire tests for cellulose loose fill insulation. The test methods evaluated were for critical radiant flux, using the Attic

Floor Radiant Panel, and for smoldering combustion; they were based on Federal Specification HH-I-515D. Seven commercially manufactured cellulose thermal insulations marketed

for residential use were evaluated by each procedure. An additional set of four replicate hardboard specimens were tested by each participant using the Attic Floor Radiant

Panel. Nine laboratories conducted the Attic Floor Radiant Panel test, and ten con- ducted tests for smoldering combustion. The testing was conducted during the month of

June 1978. The participating laboratories were surveyed prior to testing in order to ensure conformance to the critical details of the test apparatus and procedures.

The between-laboratory coefficient of variation for critical radiant flux ranged

from 13 to 30 percent with an average for seven insulation materials of 21 percent.

Estimated precision levels of repeatability and reproducibility for the Attic Floor

Radiant Panel test when compared to other standard flame spread tests and materials are favorable. Data from the Smoldering Combustion test was evaluated on a pass/fail basis

with agreement by nine of ten laboratories for six of the seven materials tested. Sever

of ten laboratories also agreed on the seventh material.

Based on work of this study, there is reasonable assurance that results from different laboratories evaluating the same material for compliance with Federal Specifica17. 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)

Attic floor radiant panel; cellulose thermal insulation; critical radiant flux; flame

spread; test methods; smoldering combustion.

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