U.S. Department

of Commerce

Technology

Administration

National Institute

of Standards and

Technology j

Impacts

NIST SP 838-4

NIST

Bulking &

File

Research

Laboratory

U.S. Department

of Commerce

Ronald H. Brown, Secretary

Technology

Administration

Mary L. Good,

Under Secretary for Technology

National Institute

of Standards and

Technology

Arati Prabhakar, Director

Noel J. Raufaste

August 1993
National Institute of Standards U.S. Goverment Printing Office

and Technology Washington: 1993

Special Publication 838-4,

Natl. Inst. Stand. Technol.

Spec. Publ. 838-4

40 pages (Aug. 1993)

CODEN: NSPUE2

For sale by the Superintendent

of Documents

U.S. Government Printing Office

Washington, DC 20402
Contents

I Introduction

Section 1 - IMPACTS

3 Structural Reliability

3 Nondestructive Testing of Concrete

4 Structural Failure Investigations

5 Seismic Design and Construction Standards

6 Rehabilitation Codes and Standards

7 Alternative Refrigerants Research

8 HVAC Simulation Models

10 Thermal Insulation

I I Residential Equipment Energy Efficiency

12 Residential Plumbing Standards

13 Computer Image Evaluation of Building

Materials

14 Corrosion-Protection for Reinforcing

Steel

15 Prediction of the Service Lives of Building Materials

16 Quality of Construction Materials Laboratory Testing

17 Roofing Standards

18 Simulating Fires with Computers

19 Fire Safety Evaluation System

20 Fire Investigations

21 Soot Formation and Evolution

22 Cone Calorimeter Development

23 Smoke Detector Standards

24 Standard for the Flammability of

Children's Sleepwear

24 Smoldering Insulation Fires

25 Wood Heating Safety Research

Section 2 - PRELIMINARY IMPACTS

27 In-Place Testing of Concrete

28 Communication Protocols for Building

Automation and Control Systems

29 Computer Simulation of the Properties of

Concrete and Other Porous Materials

30 Cigarette-Induced Furniture Fires

30 Carbon Monoxide Formation in Enclosure Fires

31 Halon Alternative Fire Extinguishing

Agents

32 Turbulent Mixing Research

33 Materials Fire Research

34 Furniture Flammability Testing

35 Standard for the Cigarette Ignition Resis- tance of Mattresses

36 Support of Navy Firefighter Trainer Program

37 Using Fire to Clean Up Oil Spills

Introduction

The Building and Fire Research Laboratory

(BFRL) of the National Institute of Standards

and Technology (NIST) is dedicated to the life cycle quality of constructed facilities. NIST is the only federal technology agency with the

specific mission of helping U.S. industry to strengthen its international competitiveness.

BFRL is the national laboratory for the building

and fire communities. BFRL's mission is to enhance the competitiveness of U.S. industry

and public safety through performance prediction and measurement technologies and technical advances that improve the life cycle quality

of constructed facilities. The Laboratory

performs and supports field, laboratory, and

analytical research on the performance of

construction materials, components, systems

and practices, and the fundamental processes

underlying the initiation, propagation, and

suppression of fires. BFRL produces technologies to predict, measure, and test the performance of construction and fire prevention and

control products and practices.

This report describes major effects of BFRL's

program on building and fire research. Scientific and economic impacts are cited in Section

1 ; preliminary impacts are cited in Section 2. Although in no instance did BFRL alone ac- complish the improvements in building and fire practices, BFRL has played a key role in improvements in building and fire practice producing annual savings amounting to tens of billions of dollars.

BFRL participates actively in about 1 50 national

standardization committees; provides leadership

in national and international standardization

organizations and chairs more than 20 voluntary standardization committees. BFRL annually publishes over 230 reports, articles for research journals, and articles for professional

and trade journals. BFRL staff annually makes

hundreds of presentations to professional and

technical meetings of building and fire community organizations. Over 70 guest researchers

from industry, academia, Federal agencies, and

international laboratories participate in 6 month

and longer assignments at BFRL. The Laboratory annually presents a series of Building Technology Symposia in cooperation with other

organizations concerned with building research

and practice and hosts Fire Research Seminars

for NIST staff and colleagues from the fire community. BFRL's Fire Research Information

Service (FRIS) is a national and international fire research library and FIREDOC is BFRL's automated database of fire research literature. FRIS

is the only comprehensive national library resource for the fire community.
SECTION 1 - IMPACTS
Structural Reliability

Problem. Quantitative knowledge of structural

reliability is required to assure that structures

are safe and serviceable throughout their

intended service lives and that alternative

structural materials and systems can compete

equitably in the marketplace.

Approach. BFRL conducts research into

structural loadings, structural resistance, and

reliability-based design procedures.

Findings. Research results include design load

criteria including live loads and live load reduction, distribution of extreme winds, gust factors

and pressure coefficients, and provisions for general structural integrity and avoidance of

progressive collapse.

Delivery Method. BFRL's findings are incorporated in building codes and standards e.g., ASCE 7- 1988 standard, Minimum Design

Loads for Buildings and Other Structures. This

Standard seeks to provide adequate and consistent reliability for all structural materials and

systems, types of loadings and locations in the

United States. It provides the technical basis for the loading provisions of the model building

codes, national standards for design with the

various structural materials and systems, loading provisions of state and local building codes,

and loading requirements for engineers dealing

with design situations not covered by local building codes.

Impact. These findings have provided consistent reliability across various types of materials

for structural systems and various environmental loading. Catastrophic failures are reduced

and costly excessive safety requirements are avoided.

Nondestructive Testing of Concrete

Problem. The present crisis to evaluate and

repair the Nation's aging infrastructure demands the development of reliable, cost-effective nondestructive testing (NDT) methods for

civil structures. The application of NDT methods to the inspection of civil structures has

lagged behind the developments in other fields,

such as the aerospace industry. Progress has

been especially slow in the development of

suitable NDT methods for complex heteroge- neous materials, such as reinforced concrete

and masonry.

Approach. BFRL established that the application of the principles of stress wave propagation held the potential for development of

versatile NDT methods for locating flaws within

concrete structures. Recent developments in signal processing and computational methods

indicate that significant advances could be

achieved. A multi-faceted research program

composed of analytical modeling, controlledexperimental studies, and field verification was

undertaken to establish the basis for this improved NDT method.

Findings. BFRL was successful in developing

the technical basis for a new test method,

which has become known as the "impact-echo

method." Laboratory and field studies demonstrated that the method is capable of locating a

variety of flaws within concrete, such as voids,

honeycombing, and delaminations.

Delivery Method. The research results have

been reported extensively in technical journals,

workshops held, e.g., the FHWA and State

highway agencies' Spring 1992 workshop on

nondestructive test equipment, and presentations made at professional meetings. Research

performed by one of the collaborators, who is currently at Cornell University, has expanded

BFRL's research and extended the applicability

of the method into development of a commercial test system.

Impact. This technique improved the reliability

of detecting flaws in concrete structural mem3
bers and bridge deck delaminations. BFRL's

research was recognized by the American

Concrete Institute (ACI); their prestigious ACI

Wason Medal for Materials Research was

awarded twice to BFRL researchers for papers

dealing with the impact-echo method.

Structural Failure Investigations

Problem. The physical causes of significant

structural failures should be ascertained and

made public so that future failures may be

avoided.

Approach. BFRL responds to requests from the

U.S. Occupational Safety and Health Administration and others to investigate important

failures during construction to determine their

most probable cause of failure. Several of these

investigations BFRL participated in are: the

1 973 failure of a 23 story apartment complex

in Fairfax County, Virginia that killed 1 4 workers and injured 34; the 1 978 failure of a cooling

tower in Willow Island, West Virginia that killed 51 workers; the 1981 failure of a 5 story

condominium in Cocoa Beach, Florida that killed

1 1 workers and injured 23; the 1981 collapse

of walkways at the Kansas City Hyatt Regency

Hotel that killed 1 1 4 persons and injured 1 86;

performed at the request of local officials and

the cognizant Congressional officials; the 1 982

failure of a highway interchange ramp in East

Chicago, Indiana that killed 1 3 workers; the

1 987 collapse of a building in Bridgeport, CT,

that killed 28 construction workers; the 1 988

collapse of a four million gallon capacity oil storage tank up river from Pittsburgh, PA.

Findings. Results of these, and other related,

investigations are published and disseminated

to designers, fabricators, contractors, building

officials, owners and the public to assist in avoiding future failures. Since many of the

failures resulted from premature reliance on the

load carrying capacity of immature concrete,

BFRL developed prediction and measurement

techniques for the strength of concrete at early

ages that have been incorporated into ASTM

Standards and Occupational Safety and Health

Administration regulations.

Delivery Method. BFRL's recommendations are acted on by the American Consulting Engineers

Council, the American Society of Civil Engi- neers (ASCE), the National Conference of

States on Building Codes and Standards

(NCSBCS), American National Standards

4
Institute (ANSI), ASTM, and other building

community organizations.

Impact. These results influenced the structural

engineering profession to reassess and revise

procedures for design review and quality

control of the construction process. Stimulated

by the reports of BFRL's failure investigations,

the American Society of Civil Engineers (professional society of over 1 00,000 civil engineers

worldwide) developed a quality control manual,

Quality in the Constructed Project. BFRL's

reputation for high quality post disaster investigations led to revising NIST's authorization

legislation for fiscal year 1 986: "The National

Bureau of Standards, on its own initiative, .... may initiate and conduct investigations to

determine the causes of structural failures in structures which are used or occupied by the

general public."

Seismic Design and Construction

Standards

Problem. A catastrophic earthquake poses

perhaps the greatest natural hazard faced by

the Nation. Dollar losses in one great earthquake (Richter magnitude 8 or greater, e.g., a

1 908 San Francisco magnitude earthquake)

could be many times the $10 billion losses

suffered from to the October 1 989 Loma Prieta

earthquake; fatalities and injuries could be in the tens of thousands.

Approach. In the National Earthquake Hazards

Reduction Program, established by Congress in 1977, BFRL is responsible for carrying out

research and development for improved build- ing codes and standards and practices for structures and lifelines. BFRL works closely

with national standards and model building

codes organizations to encourage implementation of research results, promotes better

building practices among architects and engi- neers, and works closely with national stan- dards organizations to develop seismic safety

standards and practices for new and existing

buildings and lifelines. BFRL provides technical

support, manages, and chairs the Interagency

Committee on Seismic Safety in Construction

(ICSSC). The ICSSC assists Federal agencies

involved in construction to develop earthquake

hazards reduction measures and incorporate

them in their ongoing programs. At the request

of Congress, BFRL in support of the Federal

Emergency Management Agency, developed a

plan, including precise timetables and budget

estimates, for developing and adopting, in consultation with appropriate private sector

organizations, design and construction stan- dards for lifelines.

Findings. BFRL staff developed analytical

procedures for selecting appropriate structural

systems for strengthening existing concrete

buildings, developed an analytical procedure to design and analyze bridge columns based on damage criteria, assessed the effectiveness of current design approach for masonry shear

walls and identified potential failure mechanisms of double-deck highway bridges similar

5
to the Oakland Nimitz Freeway which failed in the 1 989 Loma Prieta Earthquake.

Delivery Method. Seismic design and construction provisions recommended by the Building

Seismic Safety Council (BSSC) and the ICSSC

are adopted widely in national standards,

building codes, and requirements of Federal

agencies. Portions of these revisions are in use by the three model building codes, and Federal

agencies.

Impact. This work helped to create a consensus among the building community on a new

generation of provisions for the seismic resis- tant design and construction of buildings. The

model building codes have adopted these

provisions. ICSSC has formulated seismic

design guidelines for new Federal buildings,

practices for evaluation of site hazards, and

plans for cooperative Federal post-earthquake

response activities in the event of a damaging

earthquake. States and local jurisdictions can

update their existing seismic guidelines by

referencing the NEHRP recommended provisions. For a nominal increase in building

construction cost, use of these technologies are expected to result in fewer lives lost and

reduced property lost.

Rehabilitation Codes and Standards

Problem. During the late 1 970's, there was a surge in the rate of building rehabilitation due to

tax incentives, the high cost of new construction, and energy conservation retrofitting.

Building code constraints to rehabilitation were

a major roadblock to cost-effective rehabilitation.

Approach. BFRL provided technical support to

formulate a new regulatory approach to rehabili- tating existing buildings. The approach allows

repairs, alterations, and additions to existing

buildings without necessarily meeting new

construction requirements and without sacrificing safety concerns.

Findings. BFRL produced several publications

including 1 . NBS Special Publication 623,

Removing Regulatory Restraints to Building

Rehabilitation: The Massachusetts Experience;

2. NBSIR 80-21 71 , Selected Methods for

Condition Assessment of Structural, HVAC,

Plumbing, and Electrical Systems in Existing

Buildings (describes methods to determine the

condition of existing buildings), 3. Technical

Note 998, Impact of Building Regulations on

Rehabilitation - Status and Technical Needs

(documented the regulatory problems and

technical needs for effective rehabilitation).

Delivery Method. BFRL's technology was

adopted by the State of Massachusetts. The

National Institute of Building Sciences (NIBS)

included BFRL results in their 1 0 guidelines on

building rehabilitation prepared for the Department of Housing and Urban Development

(HUD). These guidelines were adopted in model building codes.

Impact. The model code organizations which

produce the widely used National Building

Code, Standard Building Code, and Uniform

Building Code have revised and developed new

provisions based on BFRL's work which permit a more rational approach to building rehabilitation while retaining essential requirements for health and safety. BFRL's reports provided the

technical basis for the American Society of Civil

6
Engineers Standard 1 1 -90, Guidelines for Structural Condition Assessment of Existing Buildings.

Alternative Refrigerants Research

Problem. The world faces an environmental

crisis with depletion of the stratospheric ozone

layer from the release of certain

chlorofluorocarbons (CFC's) into the atmosphere. Scientists need to find alternatives to

R-1 1 and R-12, CFC's commonly used as

refrigerants. Worldwide recognition of this

crisis resulted in 7 1 countries agreeing to elimi- nate world production of these CFC's by 1998.

Approach. BFRL and NIST's Chemical Science

and Technology Laboratory (CSTL) researchers

studied 860 industrial fluids to identify properties of new environmentally compatible refrigerants to help industry improve the effective- ness of air-conditioning systems and replace

the ozone damaging CFC's. Thermophysical

properties of the most promising environmentally acceptable replacements were measured.

Simulation models of refrigeration systems and

experimental equipment determined engineering

properties of the replacements. Research is supported by DuPont Corporation, TRANE Co.,

the Electric Power Research Institute (membership composed of electric utility companies),

the Air Conditioning and Refrigeration Institute

(U.S. equipment manufacturer's trade association), and the American Society of Heating, Refrigerating, and Air Conditioning Engineers (over

50,000 member professional engineering

society).

Findings. Mixtures of incompletely halogenated

methane and ethane molecules in the

chlorofluorocarbon family with little or no

chlorine proved to be the most promising

replacements. Scientists created a microcomputer-based predictive package REFPROP. showing thermophysical properties of the

leading replacements R123 and R134a.

REFPROP is in its third version and contains 25

other pure refrigerants and all possible combinations of up to five component mixtures of

these refrigerants. The boiling heat transfer

coefficient of R 123 and R134a also were determined to aid industry design refrigeration

system evaporators. The studies identified

changes in the refrigeration system design to
take optimum advantage of the characteristics

of the refrigerant mixtures.

Delivery Method. The Journal of the American

Society of Heating, Refrigerating, and Air- Conditioning Engineers (ASHRAE) published the

original characterization of 860 industrial fluids

and awarded this paper the best technical

paper of the year. This research won the 1 988

NIST Edward Uhler Condon Award for distin- guished publication. NIST's Office of Standard

Reference Data, in a special distribution agreement with the 170 members of the Air Conditioning and Refrigeration Institute (ARI), distrib- uted the microcomputer-based program of

thermophysical properties. BFRL staff published their data in the World Meteorological

Organization Alternative Fluorocarbon Environmental Acceptability Study (AFEAS). BFRL

staff authored a technical assessment of large

building air conditioning for the United Nations on how the international agreement on eliminating world production of CFC's would affect this

application of cooling. All these publications

resulted in many international requests for further information from chemists, physicists,

and engineers.

Impact. This research stimulated industrial

interest to produce replacements for CFC's.

These results helped avert losses in market

share for the U.S. chemical, refrigeration, and

machinery industries. More than 5,000 American companies rely on CFC's to produce goods

and services valued at more than $28 billion a

year. Also, these findings assisted industry

redesign the more than $135 billion worth of

installed CFC-dependent equipment.

HVAC Simulation Models

Problem. Many unsolved problems in building

energy conservation, indoor air quality, and

alternative refrigerants research require a wealth of data on equipment, system, and

building performance. One approach to solving

these problems is to conduct many experiments under a wide range of experimental

conditions and document the performance of

the proposed system or solution. Given current

constraints in time and resources, this approach

is not feasible.

Approach. BFRL researchers developed a

variety of simulation models that accurately

predict the performance of building heating,

ventilation, and air conditioning (HVAC) systems, and associated controls. The models

also predict performance of refrigeration equipment used as part of these systems, intra- building air and contaminant movement, and

moisture migration and accumulation in building

facades. BFRL validated these models under

controlled experimental conditions, BFRL and

other researchers around the world used these

models to propose solutions to energy conservation, indoor air quality, and alternative refrigerant problems.

Findings. BFRL developed HVACSIM+ , a modular program designed to simulate the

thermal performance of a building shell, its heating, ventilation, and air conditioning systems, and its building controls. Although other

modular programs preceded it, HVACSIM + uses variable-time-step, advanced equationsolving techniques that make it uniquely suited

for studying energy advances through control.

HPSIM was designed to simulate the thermodynamic performance of all refrigeration equipment operating on the vapor compression

cycle, such as heat pumps and air conditioners.

It simulates the behavior of the refrigerant and

the equipment components from first principles

and can account for such detailed phenomena

as heat transfer differences from tube to tube

in an air-to-refrigerant evaporator. Researchers

developed AIRNET to predict inter-room air- flows through building openings, such as doorways and through HVAC systems. Using new,

8
efficient mathematical techniques, AIRNET

solves a network of nonlinear equations

iteratively on a personal computer, something

that had only been done on a mainframe

computer prior to AIRNET'S development. Researchers developed CONTAM to build on the

capabilities of AIRNET. Unique contaminant

dispersal equations combined with AIRNET

now gives researchers a tool to predict both

interzone airflow and contaminant movement in multi-zone buildings. MOIST is a computer

simulation of moisture migration and accumulation within a multi-layer building facade. It predicts localized moisture levels throughout

the structural elements as a function of time of year, given material composition and weather

conditions for the year.

Delivery Method. Researchers validated all simulation models using experimental data,

documented them through users manuals and

publicized them through presentations and

technical papers for the American Society of

Heating, Refrigerating, and Air-Conditioning

Engineers (ASHRAE). Colleagues and researchers throughout the world received copies of the

programs. For example, more than 1 20 copies

of HVACSIM+ have been distributed since

1 984. Thirty-three copies of HPSIM. available

since 1 983, have been distributed to colleagues

during the past 3 years alone.

Impact. BFRL has used HVACSIM+to study

the dynamic performance of an 1 1 -story office

building on the NIST campus and to model

advanced heat pumps with built-in thermal

storage. In Europe, where controls research is prevalent in universities and government institu- tions, researchers use HVSIM+

extensively.

The International Energy Agency (IEA) has

adopted the program for use by seven countries which are cooperating to construct a

building emulator for testing advanced control

systems. BFRL has used HPSIM to suggest

modifications to conventional heat pumps that

improved their performance by more than

30%. At least five U.S. universities have used

HPSIM in graduate student research. Researchers from Canada, Brazil, and Singapore have

published numerous technical papers based on HPSIM simulations. AIRNET has been incorporated into the primary building energy research

program in Europe, the University of

Strathclyde's ESP program. It also has been

used as the main tool in three ASHRAE-sponsored research projects in U.S. universities. In one of the studies, AIRNET was the best of all available algorithms for airflow predictions in smoke control systems, reliably solving all test cases in an order of magnitude faster than

ASHRAE's previously recommended algorithms. BFRL has used MOIST to examine new

practices being considered by HUD in their

standards for the moisture control in the walls

and ceiling/roof cavities of manufactured

housing and to examine recommended designs

for the DOE Moisture Control Handbook now

under development.

i
Thermal Insulation

Problem. NIST research on heat transfer

through thermal insulation began in 1910 and

in 1 91 2 led to development of the first Guarded Hot Rate apparatus for precise measure- ment of heat transmission. This device and its successors have provided the basis for calibration of the measurement devices used by

industry and regulatory authorities for determining the thermal resistance of insulation. Twenty-five millimeter thick calibration transfer stan- dards were routinely supplied to industrial

laboratories for calibration purposes prior to the

1 970's. Concerns for energy efficiency after

the 1 973 Oil Embargo led to routine use of

thick 1 50 to 450-mm low density insulation in U.S. buildings. In 1978-79, the Federal Trade

Commission proposed requiring manufacturers

to label their products for thermal resistance at thickness representative of typical installation. Industry representatives, concerned for the

accuracy of labeling, requested that the rule be

deferred until their measurement devices could

be calibrated with full thickness, low-density

insulation calibration transfer standards.

Otherwise, industry estimated they would

need to use an additional 20 percent of material to be assured of the validity of the labeling

and would have to pass these costs on to their

customers.

SRM's have been sold and an additional 70

special calibrations have been completed for U.S. industry to support the accurate testing,

production, and labelling of thermal insulation.

Delivery Method. BFRL staff have presented

results of this research at conferences of the

American Society for Testing and Materials

(ASTM), the American Society of Heating,

Refrigerating, and Air-Conditioning Engineers

(ASHRAE), and International Thermal Conductivity Conferences (ITCC). BFRL staff have

published approximately 20 technical papers in the proceedings of these conferences and in the Journal of Thermal Insulation and Review

of Scientific Instruments. BFRL served as a major participant in a round-robin testing

program organized by the International Standards Organization (ISO) in 1983 and two

additional programs organized by ASTM in

1 987 and 1 990. The results of the latter round-robin programs were used to refine the

precision and bias statements in ASTM Standard C687.

Impact. In 1 984, The U.S. Chamber of Commerce testified to Congress that the measure- ment capability of the Guarded Hot Plate saves consumers $90 million per year.

Approach. In the late 1 960's, BFRL staff formulated a radical new approach for accurately measuring heat transmission through

thermal insulation, a circular line-source Guarded Hot Plate. At industry's and the Federal

Trade Commission's request, BFRL built a 1 m

diameter version of the Guarded Hot Rate

capable of full thickness measurements up to

380 mm to within one percent uncertainty and

made calibration transfer standards available to

industry.

Findings. BFRL completed the 1 -m circular line- source Guarded Hot Rate in 1981 that met

design specifications. BFRL subsequently

developed two standard reference materials

(SRM); a fibrous-glass blanket (SRM-1451) in 1985 and a fumed silica board (SRM-1449,

1 459) in 1 990. To date, approximately 60

10
Residential Equipment Energy

Efficiency

Problem. Residential energy consuming equipment accounts for 20 percent of our national

energy consumption. A goal of the Energy

Policy and Conservation Act of 1 975 was to provide for the improved energy efficiency of

this equipment. Under the Act, BFRL was

directed to develop test procedures for the

determination of their annual efficiency and

operating costs. The test procedures were to reflect energy

efficiency during a representative average use

cycle and not be unduly burdensome to conduct.

Approach. BFRL staff used simulation models,

laboratory tests, and field tests to understand

the principal independent variables affecting the

energy efficiency of the equipment. BFRL

proposed test procedures for each type of

equipment covered under the law. BFRL

worked closely with industry representatives

experienced in testing the equipment to obtain

their review and recommendations, particularly

for energy conserving innovations that were

being considered for future products.

Findings. BFRL staff developed entirely new

test procedures for central air conditioners,

central heat pumps, furnaces, and boilers that

accounted for the dynamic performance of the

equipment under transient or "part-load"

conditions. BFRL modified as necessary test procedures already used in industry for refriger- ators and refrigerator-freezers, water heaters, room air conditioners, home heaters, dishwashers, clothes washers, clothes dryers, television

sets, kitchen ranges and ovens, and humidifiers

and dehumidifiers.

Delivery Method. The test procedures are used

by manufacturers to label the annual operating

costs of their products in a mandatory program

administered by the Federal Trade Commission.

The test procedures for central furnaces and

boilers, and for central air conditioners and heat

pumps were adopted by the American Society

of Heating, Refrigerating and Air-Conditioning

Engineers (ASHRAE) as consensus standards.

The Gas Appliance Manufacturers Association

(GAMA) developed its efficiency certification

program for oil and gas furnaces based on the

test procedures. The Air-Conditioning and

Refrigeration Institute (ARI) standards and

certification program for central air conditioners

and heat pumps are similarly based on these

test procedures.

Impact. These test procedures have supported

substantial increases in appliance efficiency.

The American Council for an Energy Efficient

Economy (ACEEE) reports average efficiency

increases from 1972 to 1987 of 96% for

refrigerator-freezers, 35% for central air conditioners and heat pumps, 30% for room air conditioners, and 18% for gas furnaces. The

most efficient equipment now coming on the

market is shown by the test procedures to be as much as 75% more efficient than the

average new equipment. The test procedures

are stimulating even more energy efficiency for the future through the integration of more than one function in future equipment. Examples

are space heating boilers which also heat domestic hot water and central heat pumps that

provide domestic hot water through the use of

waste heat.
Residential Plumbing Standards

Problem. Because of the growing constraints

of land use and development for watersheds,

water shortages and drought, costly urban

infrastructure replacement financing, and environmental constraints on ground/water/land use and river water extraction limitations and waste

water treatment discharge limits, the Department of Housing and Urban Development

(HUD) and other Agencies requested BFRL to

provide research on water conservation in buildings. These findings are now being used in NIST's plumbing laboratory accreditation pro- gram.

Approach. For more than 6 decades, BFRL

studied demands for plumbing services and the

hydraulic performance of plumbing fixtures and

design/sizing of plumbing water supply, waste

water drains, and vents.

Findings. Results included: (Da computerbased design procedure for the drain-wastevent system that accurately solves the tran- sient transport of liquids and solids, (2)

plumbing standards flow rate recommendations

input for water savings fixtures; (3) drain sizing

for simultaneous and nonsimultaneous dis- charge loads with water saving fixtures; (4) test procedures for plumbing standards updates

and replacement with data derived from laboratory test measurements, and analytical derivations for water savings fixtures performance;

and (5) rational methods for sizing vents.

Delivery Method. The Department of Defense,

the National Association of Homebuilders and

HUD have transferred BFRL's plumbing technologies into building codes and standards.

Impact. These results permit safe and serviceable water-conserving residential plumbing

systems, and substantially reduce previous

requirements for the sizes of water supply and

drainage piping. Results of BFRL's plumbing

research continue to be incorporated into

plumbing standards. The American National

Standards Institute (ANSI) standards revisions

for water-conserving fixtures continue to

incorporate BFRL's recommendations for test

procedures and include recommendations for test procedures for adequate transport of

wastes through the total plumbing system.

BFRL's recommendations for water supply and

sizing of venting were incorporated in 1 983

and 1 984 changes to the model plumbing code

of the Building Official and Code Administrators, International. The 1 986 One and Two

Family Dwelling Code of the Council of Ameri- can Building Officials, which applies to one and

two family housing, adopted BFRL's findings

for drainage loads and methods for sizing water

supply, drain and vent piping. The National

Association of Home Builders' economic

assessment of the revised provisions indicated

savings of about $500 per home in plumbing

system costs. This amounts to an annual

savings of $500 million in an ordinary year of

new home construction. Further savings to the

home owner will accrue from annual savings in water used, and urban development will be less

constrained by our limited water resources.

12
Computer Image Evaluation of

Building Materials

Problem. The behavior of a construction

material reflects its chemical composition,

internal structure, and surface condition.

Qualitative and quantitative information about

its structure is often obtained by human observation using a microscope following careful

sample preparation, a tedious and time-consuming task. As a result, potentially important

information may not be obtained.

Approach. To overcome barriers to routine

analysis of images of building materials by

direct human observation, BFRL has shown

that computers can be used to perform quantitative analysis of images of building materials

obtained with a microscope or other instrument. A computer analyzes infrared images to

detect corrosion products under a coating

before they become visible to the naked eye

and determines the extent of the corroded area. This has important implications for increasing

research productivity. For example, BFRL re- searchers have shown that computer image

analysis can be used to determine: 1 . the

surface roughness of a metal; 2. the area of

corrosion under paint on a metal surface; 3. a contaminated area of rubber roofing material

which could interfere with proper adhesive

bonding; and 4. the area of peeling paint on the

surface of a large building. The development of

the method for determining the surface

roughness of a metal resulted in an IR 100

Award to the BFRL research team.

Findings. BFRL's research demonstrated that

image analysis is a powerful and practical tool

for coatings research laboratories to quantify

changes in condition of a painted surface with

time. To quote from a reference to BFRL's

work in a report for EPA, "The critical point is that the definition of failure was clear and

unambiguous.... We found no other example in which the definition of failure was so clearly

stated."

Delivery Method. BFRL's image analysis

techniques were disseminated through: many

technical publications; talks to scientific conferences; and conversations with researchers of

coatings companies, trade associations, and

federal agencies.

Impact. BFRL researchers developed technologies that helped several major paint manufacturers speed up their evaluation of the durability

of new coating formulations. This research

provided paint manufacturers with technology

to understand the mechanisms that affect the

performance of paints and coatings in the

protection of steel against corrosion and helped

manufacturers respond to changing environmental regulations. These technologies provide

coatings research laboratories with knowledge

to change the basis for their observations of

degradation of paint on laboratory test specimens from subjective judgment to quantitative

measurement. These techniques have been

used extensively in developing laboratory data

for demonstrating how to predict the potential

service life of coatings in different environments. BFRL's reliability approach has been

adopted in many coatings laboratories in the

United States and overseas, e.g., the Belgium

Coatings Research Institute. The Atlas Company is now forming a consortium to help the

coatings industry apply the NIST-developed

techniques.

13
Corrosion-Protection for Reinforcing Steel

Problem. The deterioration of concrete bridge

decks in the 1970's was a national problem.

The Federal Highway Administration estimated

$25 billion was needed over the next decade to

repair these failing decks. However, only about

$500 million per year is actually spent in the

United States to replace concrete bridge decks

that failed prematurely because deicing salts corrode the reinforcing steel. The expected life of bridge decks was only 5-10 years in the

northern states where deicing salts are used.

Approach. BFRL developed performance

criteria and test methods for organic coatings

to protect reinforcing bars from corrosion for assuring durability and effective structural

performance and to determine the structural

performance of coated reinforcing bars embedded in concrete. This research was in response

to a Federal Highway Administration (FHWA)

request.

Findings. The research showed that only four

of 48 coatings evaluated performed well in tests of corrosion protection and structural

performance. All four were spray-applied

powdered epoxy resins. The research results

formed the basis for standards for use in selecting effective epoxy coatings for steel

reinforcing bars.

Delivery Method. The results of this work

were adopted in: ASTM Standards; American

Association of State Highway and Transportation Official Standards; and a Concrete Reinforcing Steel Institute (CRSI) Specification for epoxy-coated steel reinforcing bars.

Impact. In 1 990, over 300,000 tons of coated

reinforcing bars were used in the United States,

about 5 1 12 % of the total of all reinforcing

bars. Epoxy-coated reinforcing bars have been

extended from bridge decks to parking garages,

pavements, waste water treatment plants,

marine construction, and other structures. Their use has increased considerably over the

last 1 8 years. Forty-four states use coated

reinforcing bars in bridge deck construction.

A new industry was created to coordinate the

new technologies; it was represented by the

Fusion-Bonded Coaters Association (trade

association of coaters of reinforcing bars).

Findings from FHWA indicate coated reinforcing

bars increase expected life of a bridge deck to

more than 40 years (from 5 to 1 0 without

coating). The cost of coated bars is about 25

percent more than uncoated bars and is insignificant in the total materials and labor cost of a

bridge deck. Considering only the current

annual $500 million expenditure for bridge deck

repairs, an extension of service life from 1 0 to 40 years will, at a discount rate of 7.6 percent

(3.8 percent real interest rates on 30-year trea- sury notes and bonds and a projected inflation rate of 3.7 percent) result in a present-value

savings over 40 years of $745 million. These

savings would be repeated annually for every

$500 million repair expenditure.

14
Prediction of the Service Lives of

Building Materials

Problem. Although building and construction

materials are often expected to have service

lives of several decades, methods have not

been available to reliably predict such long

service lives from short-term tests. The lack of

methods for service life prediction is a technical

barrier to the effective selection, use, and

maintenance of building and construction

materials and has been cited as an important

contributing factor to premature failures. Hence, the need for reliable predictive methods

for assessing the service lives of potentially

beneficial, innovative materials without decades

of testing under actual service conditions led to BFRL's research program to develop reliable methods for service life prediction.

Approach. BFRL developed a systematic

methodology for predicting service lives of

building and other materials. The method

involves identifying the mechanisms of degradation in the service environment, characterizing the influences of environmental pa- rameters, identifying valid accelerated methods

of testing, modeling the degradation process,

and using the model for predicting the service

life in field conditions.

Findings. BFRL demonstrated the application of

reliability theory and life analysis to problems of

building and construction materials durability. It also demonstrated the development of

stochastic models for predicting the synergistic

effects of multiple environmental factors in degrading organic building materials, including

solar energy system components and materials,

plastics, protective coatings and single-ply roofing membranes.

Delivery Method. BFRL's recommendations were accepted by ASTM as the basis for its standard E-632, Standard Practice for Developing Accelerated Tests to Aid Prediction of the

Service Life of Building Components and

Materials, which was issued in 1978. ASTM

E-632 became, in time, the basis for a Technical Recommendation published by RILEM in

1 984 which is now being proposed as a European Standard.

Impact. This research provided the basis upon

which service life prediction problems are being

addressed in the United States by the Steel

Structures Painting Council (SSPC), the National Acid Precipitation Program (NAPAP), and

several ASTM committees. Internationally, the

research stimulated the 1 984 NATO Advanced

Research Workshop on Problems in the Prediction of the Service Life of Building Construction

Materials; led to the establishment by the

International Union of Research and Testing

Laboratories for Materials and Structures

(RILEM) and the International Council for Building Research, Studies and Documentation

(CIB) of a joint working commission on service

life prediction; and provided the technical basis

for research by the Norwegian Institute for Air

Research. In its research on methods for predicting the service life of protective coatings

for steel, BFRL has made significant advances

in methods for quantitatively and nondestructive^ assessing the performance and properties

of coatings. Methods and associated computer

image processing capabilities have been developed which enable the early detection and

quantification of degradation at the

steel/coating interface. As a result of BFRL's

leadership, ASTM has set up a new subcommittee specifically to develop service life prediction standards for all types of materials and

systems.

15
Quality of Construction Materials

Laboratory Testing

Problem. The U.S. is dependent on the quality

of construction materials for rebuilding its infra- structure which is vital to remaining competitive in the global marketplace. An important

component of quality is accuracy in the testing

of materials. Inadequate testing may lead to the rejection of good materials, the acceptance

of poor materials, construction delays due to poor intermediate test results, and structural

failures due to inaccurate predictions of the

performance of materials.

Approach. BFRL through its Construction

Materials Reference Laboratories (CMRL)

operates two Research Associate Programs.

CMEL provides laboratory services to the

construction materials testing community

directed to improve quality of testing. CMRL's

Programs are the Cement and Concrete Refer- ence Laboratory (CCRL) sponsored by ASTM,

and the AASHTO Materials Reference Laboratory (AMRL) sponsored by the American

Association of State Highway and Transportation Officials. Materials covered by these

organizations are soils, bituminous materials,

plastic pipe, metals, Portland cement, blended

cement, masonry cement and portland cement

concrete. Services provided by CMRL are onsite inspection of laboratories and distribution of

proficiency test samples. The inspection

program includes an evaluation of a laboratory's

equipment, procedures and quality system

compared against ASTM and AASHTO standards. Proficiency samples are distributed once

or twice a year with instructions for testing

using the appropriate standards.

Findings. Laboratories participating in the

inspection program receive a written report of

findings shortly after the inspection. CMRL

does not follow-up on correction of deficiencies, but the results of the inspection are often

used by accrediting bodies and other specifying

organizations in their evaluation of laboratory

performance. Laboratories are provided the

overall results of the proficiency sample testing

program from which they may determine their

performance relative to other laboratories in the

program.

Delivery Method. In addition to sending results to the individual laboratories participating in its programs, CMRL provides summary results to ASTM and AASHTO committees for use in standards development such as precision

statement preparation. CMRL also works with

RILEM Committees (International Union of

Testing and Research Laboratories for Materials

and Structures) in addressing common con- cerns about quality tests.

Impact. CMRL programs are provided to over 1000 laboratories in North America and in 15

other countries. CMRL program area used by

the three major accrediters of construction

materials testing laboratories in the United

States AASHTO Accreditation Program (AAP),

American Association for Laboratory Accreditation (A2LA) and NIST's National Voluntary

Laboratory Accreditation Program (NVLAP).

Over $14 billion worth of Federal-aid supported

highways are constructed annually by state transportation agencies who use CMRL pro- grams as part of their quality management

system.

16
Roofing Standards

Problem. About $12 billion is spent each year

in the United States on the installation and

repair of low-slope roofing. Low-slope roofing

continues to lead the list of problems in building

performance.

Approach. BFRL conducted laboratory and field research to develop the technical basis for increasing the performance and durability of

low-slope roofing materials and systems that

lead to test methods and selection criteria suitable for incorporation into building stan- dards.

Findings. BFRL researchers developed test methods for built-up roofing materials which

helped the National Roofing Contractors Association (trade association of over 3000 roofing

contractor and roofing manufacturing organizations) improve the performance of waterproofing membranes used on low sloped

roofing which covers about one-third of the

roof area of U.S. buildings. In parallel research,

BFRL developed data on the performance of

single-ply membranes.

Delivery Method. BFRL research results are described in BFRL published technical reports

and professional journals that are widely

distributed to the industry, and are reprinted in publications such as Professional Roofing, RSI,

and Contractor's Guide. Presentations are made at technical meetings including

NIST/NRCA's National and International Confer- ences on Roofing Technology, and national

seminar programs such as the Midwest Roofing

Contractor Association and the Roof Consultants Institute annual meetings. Results also are provided to standards-writing and related

organizations, such as ASTM Committee D08

on Roofing, Waterproofing, and Bituminous

Materials and the CIB/RILEM Committee on Membrane Roofing Systems.

Impact. The National Roofing Contractors

Association (NRCA) adopted BFRL's technologies on roofing asphalts and built-up roofing

(BUR) membranes. BFRL research results are referenced in the NRCA Roofing and Waterproofing Manual, the most widely used source

in the United States for roofing design and

application procedures. In addition, NRCA cites

BFRL's roofing results in its Roofing Materials

Guide as the reference for characterizing the

properties of BUR membranes. This guide is widely used by architects and engineers for selecting low-slope roofing materials. ASTM

produced several standards under BFRL leadership for single-ply roofing materials, including

standards for polyvinyl chloride), vulcanized

elastomers, and nonvulcanized polymeric

sheets.

17
Simulating Fires with Computers

Problem. Through the 1 980's fire professionals

lacked the ability to predict fire and smoke

transport through a building to understand the

behavior and movement of the building's

occupants and the resulting effect of smoke

and toxic gas on the occupants. Fire professionals needed well-developed methods based on science to make sound judgments about

selecting appropriate materials for fire safety.

Approach. BFRL pioneered efforts to translate

the growing field of fire science into engineering

calculations using computers. Through the

work of staff and grantees at major U.S.

Universities, the first fire models were developed and applied to problems of national and

international interest. As personal computers

brought the hardware to most engineers and

fire professionals, the use of and demand for these analytical tools grew.

Findings. Today, there are more than 50 fire models and related software tools developed in more than a dozen countries, most of which

can trace their origins directly to BFRL models.

For example, BFRL produced the fire hazard

evaluation methodology called HAZARD I. The

PC compatible fire hazard assessment tool

evaluates the fire safety of buildings and determines the number of fatalities and cause of

death for each. These complex fire models address combustion characteristics of the burning

items and building components, the influence

of building geometry and ventilation, and the

physiological and psychological aspects of the

human victims of fire. This software helps

improve design and construction practices, pro- vides fire fighter's training, and quickly provides

product manufacturers with information about

the fire hazard of their products. It is used for

fire reconstruction, building design and code

equivalency analysis, and industrial risk management.

Delivery Method. The methodology was

disseminated to the fire community and pro- fessional societies. In the nearly 2 years since

its introduction, over 400 copies of HAZARD I

have been purchased worldwide (international

sales account for nearly 25% of total sales).

Impact. This software helps improve design

and construction practices, provides fire fighter's training, and quickly provides product

manufacturers with information about the fire hazard of their products. It is used for fire reconstruction, building design and code

equivalency analysis, and industrial risk management. The software predicts the fire induced environment, the reaction time of

building occupants to evacuation, and the

impact of exposure to heat, smoke, and gases

during the evacuation process. A sampling of

the HAZARD I software uses include: a Canadi- an firm evaluated equivalencies to the Canadian

National Building Code; a Swedish government

researcher studied passenger safety on large

ferry boats; an Australian engineer analyzed a

fatal hotel fire and testified at a Coroner's

Inquest; various U.S. forensic firms studied

major fires in conjunction with litigation; a number of U.S. and foreign fire departments

are conducting both post-incident analyses and

pre-planning of tactics for potential incidents;

manufacturers of fire safe products are analyzing the potential benefits of performance

improvements in their products and assisting

marketing efforts by justifying the extra cost,

quantifying the benefits of that performance to

the end user; architects and building designers

have justified requests for variance with building code provisions based on equivalent safety

performance of innovative materials or arrangements.

18
Fire Safety Evaluation System

Problem. The National Fire Protection

Association's Life Safety Code is a model code

designed to provide a reasonable level of safety

by reducing the probability of injury and loss of

life from the effects of fire. It is used in many

jurisdictions in the United States. The code

contains numerous specific provisions for new

and existing buildings under various occupancy

classes such as health care, apartment build- ings, etc. To provide some building design

flexibility in meeting the requirements of the

code, the term "or equivalent" is used. The

problem facing designers and regulators was to decide when a design provides equivalent fire safety.

Approach. For each occupancy, the parameters that affect life safety, e.g., construction,

interior finish, detection and alarm systems,

automatic sprinklers and evacuation routes were identified. Using Delphi panels of experts

in building fire safety, a numerical value was

assigned to various available designs or material

classes for each parameter. A system of

summing the numerical values appropriate to containment safety, fire control, people move- ment safety and general safety was developed

and tested with the Delphi panels. Each Fire Safety Evaluation System was tailored to the

special safety concerns of the occupancy class.

Findings. Fire safety professionals agreed on

using sets of parameter values that provide a measure of equivalent fire safety. The Fire Safety Evaluation Systems are designed for use by building designers and those responsible for approving the fire safety design of constructed

facilities.

Delivery Method. BFRL staff were members of

the NFPA Committee on Safety to Life and the

subcommittees responsible for different occu- pancy classes, and chaired the Subcommittee

on Alternate Approaches to Life Safety.

Prototype fire safety evaluation systems for specific occupancy classes were developed,

tested, presented to the subcommittees, and

refined within the committee's structure. Normal balloting procedures of NFPA were

used to adopt the fire safety evaluation systems.

Impact. Fire safety evaluation systems for health care, detection and correction, board and

care homes, and business occupancies are now

part of the NFPA Life Safety Code as NFPA

101M Alternative Approaches to Life Safety

and are used in many parts of the country to assess the fire safety of existing and newly

designed buildings. At a time when the use of

board and care homes was expanding through

the conversion of older buildings, the application of the system by building code officials and

the Health Care Finance Administration led to dramatic reductions in fire deaths in these

homes. The flexibility that the system provides

avoids unnecessary duplication of requirements

and consequently reduces the cost of providing

adequate life safety protection against fire.

19
Fire Investigations

Problem. Knowledge of the causes and impact

oflarge fires, particularly those that result in death, provide guidance on the need to change

the requirements of fire codes.

Approach. BFRL responds to requests by state

fire marshals and Federal agencies to assist in the technical investigation of high impact fires. Recent fires in which BFRL has played a major

part in the investigation include the Dupont

Plaza Hotel in Puerto Rico, the First Interstate Bank Building in Los .Angeles,, a three bedroom

duplex in Sharon, Pa., the Hillhaven nursing

home fire in Norfolk, Va., the Happyland Social

Club in New York and a board and care facility

in Colorado Springs , Co. In the DuPont Plaza

Hotel fire BFRL engineers worked with the

National Response Team of the Bureau of

Alcohol Tobacco and Firearms, the U. S. Fire Administration, and the National Fire Protection

Association during the on site investigation, and

the exchange of technical information. Based

on BFRL site observations and test samples

obtained at the scene the BFRL team analyzed

the growth and spread of the fire from the

ballroom complex where the fire originated, the

foyer that connected the ballroom complex to the lobby .and casino areas where roost of the

deaths occurred. BFRL's analysis involved the use of fire growth models, engineering formulae

addressing mass burning rate, rate of heat

release, smoke temperature, smoke layer

depth, velocity of smoke/flame front, oxygen

concentration in the smoke layer, sprinkler and

smoke detector response, and fire duration.

Findings. In most cases the analyses show the

most likely path, and extent of the fires's development at different times, sometimes

indicate whether accellerants could have been

involved, and usually point to aspects of the

building design, furnishings or peoples actions

that contributed to the fire development. In the case of the DuPont Plaza Hotel, although there were no sprinklers or smoke detectors present,

the analysis predicted when in the course of

the fire they would have actuated, and the

additional evacuation time that could have been

provided

Delivery Method. An engineering analysis

report is supplied to the local authority or Federal agency and published as an NIST

report. Sometimes depositions are given. In most cases the findings are also presented at technical society meetings such as those of the

Society of Fire Protection Engineers and the

National Fire Protection Association. In the case of the DuPont Plaza fire a member of the

BFRL staff served on a fire code task force in Puerto Rico to recommend changes to the local

fire code,.

Impact. The results of the analysis at the

DuPont Plaza Hotel fire were presented at a Congressional hearing on hotel fire safety, and were used in the writing of the Hotel/Motel Fire Safety Act of 1990, Public Law 101-391. The

fire codes in Puerto Rico have been updated to address most of the findings of the analysis.

This and other analyses have been used by

others in addressing various aspects of fires under litigation and is used as examples in demonstrating the application of analytical methods

to fire investigation. HHS, GSA, the Postal

Service, the Architect of the Capitol, and other

Federal agencies have used the results of our analyses to upgrade facilities and practices.

20
Soot Formation and Evolution

Problem. Unwanted fires cause many thousands of deaths and billions of dollars of

property damages each year in the United

States. Once a fire is larger than about 0.03

m

3

, radiation from soot dominates energy

transfer. Soot formation processes control the

amount of smoke and toxic gases, such as CO,

which are emitted from fires, and visual obscuration from smoke hinders escape from fires.

Approach. BFRL researchers and associated

grantees have performed extensive experimental and modeling efforts which are leading to a comprehensive and integrated description of

soot formation and smoke evolution in diffusion

flames. When this capability is combined with

appropriate descriptions of turbulent flows,

which occur in real fires, then the radiation

properties of fires, the production of toxic

gases, and visibility conditions can be predicted.

Findings. Key contributions were made from

both experimental and modeling approaches.

The basic steps of soot inception, growth, and

oxidation have been delineated. The most

important chemical species involved in each of

these steps have been identified by detailed

measurements in relatively simple, laboratory

size flames. These results have produced

important input and tests of modeling descriptions for soot formation and destruction.

Delivery Method. The experimental and modelling investigations on soot formation processes were authored in numerous papers and archival

journals, i.e., Combustion and Flame and Combustion Science and Technology, presented

through invited talks and at international workshops and conferences.

Impact. BFRL's research findings have advanced the understanding of chemical structure

of hydrocarbon diffusion flames and improved

the characterization of optical properties of soot

particles. BFRL established leadership in making quantitative concentration measure- ments in laminar, hydrocarbon diffusion flames

and in modelling and characterizing smoke agglomerates. BFRL's database of species and

temperature information is the best available for any hydrocarbon diffusion flame and provides a

critical comparison for predictions of flame

species concentrations. Partly as a result of

these contributions, model development on

soot formation processes is now active on a worldwide basis. Most worldwide investigators are incorporating BFRL's data in their descriptions. The quality and impact of this work has

been well recognized by invitations to participate in international workshops and at leading

universities and national laboratories, and election to chair the prestigious Gordon Research

Conference on the Chemistry and Physics of

Laser Diagnostics in Combustion.

21
Cone Calorimeter Development

Problem. Heat release rate (HRR) was identi- fied as the single most important aspect

describing hazard from building fires. Techniques for measuring HRR in a bench-scale test apparatus were under development since the

1 950s. The methods available for use were

troubled by serious errors and were so complex

that they did not lend themselves to standardization and commercial use. Research studies

during the 1 980s identified that some other

material fire properties, especially mass loss

rate, ignitability, and smoke production rate,

needed to be measured on specimens con- comitant with the HRR measurement if proper use of data was to be made.

Approach. BFRL developed several prior

generations of research use apparatuses for HRR measurement. Based on this experience, a development process was started whereby a HRR calorimeter would be designed which

would lend itself to use by commercial testing

laboratories. The engineering principle known

as oxygen consumption calorimetry was

explored and made practical at BFRL during the

late 1 970s and early 1 980s. Use of this

principle allowed a significant simplification to be made in instrument design, which led to the

eventual concept of the Cone Calorimeter. The

name here refers to the truncated-cone shape

of the heating element which impresses a

controlled radiant flux upon the specimen.

Findings. BFRL researchers developed the

Cone Calorimeter; the primary measurement

tool used by industry and testing laboratories to characterize the fire hazards of small samples

(150 mm) of building materials, furniture, and

other products. It proved to be a tool of much

higher accuracy than the previously available

methods. BFRL's work was recognized by an R&D 1 00 Award being granted for its development.

Delivery Method. The Cone Calorimeter was

adopted by ASTM as its E1354 Standard in 1990. ISO has approved it as ISO Standard

5660 in 1991 . Commercial instrument makers

have fabricated over 75 of these units based

on BFRL's construction drawings, and placed

them into service. BFRL published a User's

Guide to the Calorimeter, which constitutes the

most detailed training and operator's guide ever developed for a fire test method.

Impact. The Cone Calorimeter is intended as

the primary measurement tool for characterizing

the fire hazards associated with building materials, furniture, and a wide variety of other

products. A method was developed at NIST

allowing the use of bench-scale Cone Calorimeter data to take the place of testing furniture

items in full-scale. Inexpensive and high quality tests now are available to the design and construction team including the owner for a variety

of building materials. This measurement

method was recognized by the National Fire

Protection Association as having significant

advantages of reduced cost and decreased time

required for testing. The tool is expected to

replace many existing national tests within the

European Community activities. The U.S. Navy

mandated a design procedure for composites

used on submarines whereby Cone Calorimeter

testing is used; it is considered the most

effective way available for characterizing the

fire behavior of these materials. The Cone Calorimeter is being actively explored by the electric

wire and cable industry, for use in characterizing f lammability and corrosivity of their

products. The development and widespread

use of the cone calorimeter has lead to publication of over 300 scientific papers worldwide.

Many of these publications are by authors from

the United States.

22
Smoke Detector Standards

Problem. In the early 1 970's, it was recognized that the widespread use of smoke detectors in residences could reduce life loss in fires by 30 - 50%. However, a barrier to widespread acceptance was the lack of standards

establishing either minimum performance

requirements or installation guidelines.

Approach. BFRL initiated a cooperative project

with Underwriters Laboratories (UL) to develop

performance requirements, including criteria and

measurement apparatus. Tests were per- formed in houses scheduled for demolition by

setting common household fires and recording

the performance of detectors in different

locations to establish the best recommended

numbers and locations. These tests formed the

basis of standards from the National Fire Protection Association (NFPA) and for many

state and local laws requiring detectors in newly constructed homes and apartments.

BFRL worked with NT Research Institute and

UL to develop installation guidelines and effectiveness data.

Findings. During the studies, the BFRL engi- neers uncovered problems with certain detectors which were quickly corrected by their

manufacturers. In a few instances, this result- ed in national recalls monitored by the Con- sumer Product Safety Commission. As a

related technological development BFRL developed the first (and still only) smoke detector

sensitivity tester which can make in-place

quantitative measurements on any type or model of detector.

Delivery Method. The findings were published

in a landmark report known as the Indiana

Dunes Report, which is still the primary refer- ence document on residential detector operation and established the installation requirements contained in the NFPA standard (NFPA

74). The results of this work formed the basis

for the UL standards for residential (UL 21 7)

and commercial (UL 268) detectors. In later years, the UL 217 standard was the basis for an International Standards Organization (ISO)

standard for residential detectors. The technological advances by BFRL received frequent

attention from the popular press including

Parade, Readers Digest, Popular Science, and

Consumer Reports; and were highlighted in a segment on the Today Show which brought

1 7,000 letters to BFRL from viewers.

Impact. All of the model building codes, and

all Federal, state, and local laws requiring

residential detectors in the United States (and

some foreign countries) use the findings from

this study. The publicity given to the results of

this study resulted in increased demand, lower

prices, legislated installations, and spectacular

market developments. Annual sales of residential detectors increased from about 250,000 in 1972 to 14,000,000 in 1978. Today, approximately 80 percent of households in the United

States have smoke detectors. The widespread

use of smoke detectors in the United States

has been a major factor in the dramatic reduction in the fire death rate in the United States,

from over 60 per million population to less than

30. Interest in Europe grew in response to

rapidly expanding U.S. markets. None of the

European manufacturers were positioned to meet these demands; the U.S. manufacturers

captured a large majority of this market, often

representing the first export opportunity for these companies.

23
Standard for the Flammability of

Children's Sleepwear

Problem. Children's sleepwear on the market

during the 1 970s and before, presented an

unreasonable risk of death and injury under the

Flammable Fabrics Act. The majority of chil- dren who were injured or killed from burning

apparel were wearing nightwear. Most of this

nightwear ignited easily and burned rapidly

resulting in up to 300 deaths per year and

thousands of injuries. The majority of burn

injuries were to the face and hands causing

significant disfigurement and loss of much use

of the hands.

Approach. BFRL conducted flammability

studies of full size garments on mannequins,

tested fabric samples according to the then

current ignition and flammability test procedures, surveyed the technology available for providing ignition resistance, studied the eco- nomic impact on garment manufacturers of

various approaches to providing ignition resis- tance, developed an appropriate fire test method, and prepared a draft standard.

Findings. A Standard was approved and

promulgated under the authority given to the

Secretary of Commerce by the Flammable

Fabrics Act as amended. This authority was

later transferred to the Consumer Product

Safety Commission.

Delivery Method. The BFRL procedures developed as the sleep Standard, under the Flammable Fabrics Act, was published in the Federal

Register. BFRL staff regularly gave papers at meetings of trade associations (American

Apparel Manufacturer's Association), standards

bodies (ASTM), and fire related organizations

(NFPA, Information Council on Fabric Flammability).

Impact. There have been no deaths due to the

ignition and burning of children's sleepwear.

Burn injuries have been treatable, usually without hospitalization and without disfigurement.

This work established BFRL as the leading

international authority on apparel flammability.

Smoldering Insulation Fires

Problem. As the cost of energy rose rapidly

after the oil embargo of the early 1 970's, there

was a high demand for thermal insulation in residential buildings. One cost-effective insulation, which became widely used, is cellulosic

insulation which is produced from recycled

newsprint. The extensive use of this poorlycontrolled product led to a rash of home fires across the country.

Approach. BFRL examined the fundamental

and practical aspects of this problem, revealing

that a smoldering fire could be initiated in this

material if it contacted heat sources as re- cessed light fixtures in attic floors. This smoldering could break into flaming in the presence

of light winds through the attic space.

Findings. The smolder initiation process could

be eliminated through proper manufacturing,

which included effective smolder and flaming

retardants, and through careful installation of

the insulation which assured that it did not

come into contact with heat sources. Test

methods were devised which could assure that

the material was properly formulated so as to

minimize its smoldering and flaming tendencies.

Delivery Method. The findings were delivered

to the Consumer Product Safety Commission

who promulgated regulations requiring that all cellulosic insulation pass the BFRL-developed

test methods and that it be installed in a

controlled manner.

Impact. The problem of smoldering insulation

fires in residential buildings largely has been

eliminated.

24
Wood Heating Safety Research

Problem. The energy crisis in the late 1970's

led to a large increase in the use of wood as an

alternate heating source. Along with this in- crease came a dramatic increase in the number

of unwanted fires. The marked increase in the

late 1970's and early 1980's is attributed to a growing number of installations and expanded

use of wood burning stoves in homes

throughout the United States where most

homes are made of combustible construction.

Standards for the safe installation and use of

the appliances were based on information more

than 40 years old and rarely applicable to modern appliances.

Approach. BFRL led concentrated research

efforts to provide new and updated information

to develop appropriate codes and standards for the modern appliances. Programs have been

targeted to raise consumer awareness through

education and to improve the standards and

codes governing the construction, installation,

and testing of appliances. Much of the supporting technical information for the standard

and code changes and for consumer education

has come from BFRL research. Today, much

of the 40-year-old data and folklore originally

used to develop the codes, standards, and

public educational materials is being replaced by

solid technical information.

related to wood heating are based on BFRL

research.

Impact. BFRL's research and others are re- sponsible for improving the safety of these

appliances and reversing an increasing fire incidence rate. After several years of extensive

research on fire safe installation and use of

solid fuel heating appliances have produced

modern data and technical information that

contributed to reversing a dramatically increasing fire problem. The drop in fire incidents is illustrated by the statistics of a high of more

than 200,000 fire incidents per year in 1 980 to

less than 130,000 in 1987.

Findings. Wood heating safety research at BFRL concentrated on several key aspects of

the fire problem: clearances needed between

wood burning appliances and combustible

construction materials, creosote buildup and

burnout, protective barriers to allow reduced

clearances of appliances to combustible walls,

safe methods of joining a chimney connector to a masonry chimney through a combustible

wall, and theoretical prediction of appliance and

wall heat transfer with arbitrary wall protection.

Delivery Method. As the research results

became available in BFRL reports and journal

articles, BFRL staff worked closely with building

and fire code committees to develop a new

generation of code requirements for wood

heating appliances. Most of the current codes

25
SECTION 2

PRELIMINARY IMPACTS
In-Ptace Testing of Concrete

Problem. Knowledge of the strength of concrete during construction is of critical importance for safety and economy. Failure to measure the in-place strength prior to initiating

critical construction procedures have resulted in catastrophic failures and loss of lives. While a

variety of methods have been proposed for estimating in-place strength, they have not

been used extensively by the construction

industry. Reasons for this include the lack of a

clear understanding of the fundamental properties measured by some in-place test methods

and the lack of suitable statistical methods for

arriving at reliable strength estimates.

Approach. BFRL has undertaken research to

establish a basic understanding of some of the

in-place testing techniques. In addition, BFRL

researchers in collaboration with statisticians in the Computing and Applied Mathematics

Laboratory have sought to develop practical

and reliable statistical procedures for evaluating

in-place test results.

Findings. Based on analytical and experimental

studies, BFRL researchers have established the

failure mechanism for the pullout test, which is one of the more reliable techniques for estimating the in-place strength of concrete. In addition, BFRL research has established a rational

procedure to implement the maturity method

for estimating in-place strength of any concrete

mixture. Recent work has also demonstrated

that the method is applicable to "high-performance concrete," which is characterized by its very low ratio of water to cementitious materials. Finally, a relatively simple statistical procedure has been developed to evaluate in-place test results.

Delivery Method. The research results have

been reported extensively in technical journals

and presentations have been made at pro- fessional meetings. In addition, BFRL staff assumed leadership roles to get the research

results incorporated into ASTM standards,

reports of the American Concrete Institute, and

technical recommendations of RILEM.

Preliminary Impact. BFRL research was instrumental in the development of ASTM Standard

Practice C 1 074, the first national standard on

the use of the maturity method. The recom- mended statistical procedure is under consideration as a recommended practice by the

American Concrete Institute. Publication of

these standards promote widespread use of in- place testing and allow U.S. contractors to compete with their international competitors.

27
Communication Protocols for

Building Automation and Control

Systems

Problem. Today's direct digital control (DDC)

systems employ proprietary communication

protocols which prevent systems supplied by

different manufacturers from communicating

with each other. This has resulted in "captive

customers" who, upon buying a control system, are unable to upgrade or expand it without going back to the same manufacturer. This

lack of communication capability between

control systems made by different manufacturers also prevents the building owner from obtaining the most capable building service by not

allowing him to choose, regardless of the

system manufacturer, the best EMCS, the best

digital controllers, the best security system, the

best fire detection system, or the best telecommunications system.

Approach. NIST staff has provided leadership

and technical support for an industry-wide

effort to develop a standard communication

protocol which is capable of meeting the

present and future needs of the building industry. NIST staff has contributed directly to the

standard by writing large portions of the

standard, building laboratory prototype implementations of the protocol, developing a framework for testing conformance to the standard,

and making NIST facilities available to manufacturers who wish to test their own prototypes.

Findings. Under the auspices of the American

Society of Heating, Refrigerating, and Air- Conditioning Engineers (ASHRAE), NIST and its industry partners have developed and published a draft standard titled, BACnet: A Data Communication Protocol for Building Automation

and Control Networks. The standard is usually

referred to as simply "BACnet", an acronym for

Building Automation and Control networks.

The BACnet standard is currently undergoing

public review. A reference implementation of

the protocol has been developed along with a

protocol analyzer which can interpret BACnet

messages and display them for human interpretation. A draft suite of tests for determining

conformance to the protocol has also been

developed.

Delivery Method. The BACnet protocol was

published as a draft standard. The standard

has received wide-spread attention. Several

countries have indicated an interest in adopting

it as an international standard. Detailed technical analysis of portions of the protocol, along

with proposed testing methodologies, have

been published by NIST and presented in industry forums. Articles describing the protocol and its potential impact have been published in building trade magazines. NIST

laboratory facilities have been made available to

industry participants for unofficial testing of

their prototype products for conformance to the

standard. The experience gained from these

tests is expected to be applied to developing an

industry-run program to certify conformance to the BACnet protocol.

Preliminary Impact. Many buildings do not use DDC technology because standards do not yet

exist. In other buildings the technology is used,

but not to its full potential. Adoption of the

BACnet protocol will result in greatly increasing

the use and effectiveness of DDC technology

resulting in significant energy savings, reduced

maintenance costs, improved occupant comfort, and increased productivity. Adoption of

the standard also permits the concept of an

"intelligent building," where HVAC, fire, security, lighting, and other building control systems

are integrated. This allows building owners to optimize the interactions between systems and

streamline management of the systems. The

scale of benefits is broad, potentially affecting

all commercial buildings in the world.

28
Computer Simulation of the Properties of Concrete and Other Porous Materials

Problem. Concrete is a complex, environmentally sensitive, porous material about which it is

difficult to learn from experiment. It would be

desirable to be able to predict the properties of

concrete, particularly those that are difficult to

measure, from the properties and proportions

of its constituents, and the conditions of

mixing, curing, and use. The results would be

valuable for guiding engineers in the design of

concrete for specific purposes and for educating new generations of engineers.

Approach. BFRL is developing computer

models to simulate the microstructure development during the setting and hardening of

cement, and to simulate the transport properties of the hardened porous mass. Models

already developed show the relationship between degree of hydration of a cement and the

pore structure for a given water/cement ratio,

the microstructure of cement paste close to the

surface of an aggregate particle for pastes both

with and without a mineral admixture such as

fly ash or silica fume, and the diffusivity of the

capillary pore system in the structure formed.

Findings. The results of the calculations have

given insights into the diffusivity of cement

pastes that could not have been obtained

without extensive and costly long-term experiments. They also have been used to aid the

interpretation of recent data from Purdue

University on the pore structures of a series of

cement pastes and mortars.

Delivery Method. The results of the BFRL work

are published in journals intended to be read by

potential users on several different levels. The

results also are shared with the research community through seminars, talks at scientific

meetings, and at an annual one-week workshop held at NIST each summer. Since a

portion of the work is supported by the NSF

Center for Advanced Cement-Based Materials,

progress is shared with researchers in the

Center's four participating universities - Northwestern, Illinois, Purdue and Michigan -

through semiannual presentations and research

collaborations; the results are also shared with

the Center's 1 3 Industrial Affiliates. Delivery to the standards community is taking place

through the Research Subcommittee in ASTM

C-1 on Cement, and the Subcommittee on

Mathematical Modeling of Cement Hydration in ACI 225 on Hydraulic Cements

Preliminary Impact. The BFRL work has

received national and international attention. It has been reported in Engineering News Record,

ASTM's Standardization News, Oilfield Review,

and in Cray Channels, the house publication of

the Cray Computer Company. The international impact of the work is recognized by the

award to BFRL's principal investigator, Edward

Garboczi, of the Robert 1 992 L'Hermite Medal

from RILEM, the International Union of Testing

and Research Laboratories for Materials and

Structures.

29
Cigarette-Induced Furniture Fires

Problem. The national fire incidence statistics

continue to reveal that cigarette-initiated fires in upholstered furniture are the leading causes of

fire deaths in the United States. A voluntary

furniture industry program which seeks to limit smolder-prone materials has had a limited

impact on the problem.

Approach. Congress has mandated that an

alternative approach be assessed, that of

modifying cigarettes to lessen or eliminate their

tendency to cause smoldering fires when they

come into contact with soft furnishings. This

has the potential advantage of being able to

impact the problem almost immediately instead

of over a period approaching 2 decades which

would be required to replace existing furniture.

Findings. In the first part of this research, BFRL

established the technical feasibility of cigarettes

which will not ignite soft furnishings, even if the cigarette continues to burn while in contact

with them. BFRL has now developed a stan- dard test method to rate the furniture ignition

propensity of cigarettes. The method is currently in round robin testing among nine laboratories across the country.

Delivery Method. The results of the BFRL

studies are being delivered to the Consumer

Product Safety Commission who convey them

to Congress for possible action.

Preliminary Impact. The potential impact is immense. Should less fire-prone cigarettes

become commercial, up to 1 200 fire deaths

could be avoided annually (1/4 of the current

national total). Additional yearly benefits could

include elimination of over 3000 serious injuries

and $0.5 billion in residential property losses

alone.

Carbon Monoxide Formation in

Enclosure Fires

Problem. Roughly two thirds of all fire deaths

(3000 deaths per year in the United States) are

attributed to smoke inhalation. The component

of smoke which is responsible for the vast

majority of these deaths is carbon monoxide

which is generated at high concentrations by

enclosure fires. Despite the importance of the

problem, very little was known concerning the

generation of CO by fires. An understanding of

the formation of this dangerous gas by fires is necessary so that models of the process can be

formulated and possible means for limiting its formation by fires developed.

Approach. A workshop of fire researchers was

convened in which the understanding of CO

formation in fires was assessed and recommendations were made for a long-range research

plan to address the problem. This led to the

generation of a long-range research plan which

has guided research in this area for the past 4

years. The research plan combines engineering

approaches designed to characterize the

amount of CO formed in enclosure fires and the

parameters which control the amount generated and more fundamental components designed to provide insights based on the physics

and chemistry responsible for fire behavior.

Research is being performed by BFRL researchers as well as by academic workers who re- ceive BFRL grants. The ultimate objective is to provide sufficient understanding to allow

quantitative prediction of CO levels by BFRL

models designed to predict fire hazard.

Findings. Work thus far has demonstrated that

high CO levels are the result of under-ventilated

burning and that vitiation of combustion gases

seems to play a minor role. The results have

confirmed an earlier hypothesis that fires burning within enclosures having two welldefined layers generate CO by quenching the

flame gases in a rich, high-temperature upper

layer. Recent research has shown that CO also can be generated by the direct introduction of

air into the upper layer resulting from underventilated burning. A third mechanism, which

can lead to the generation of very high concen30
trations of CO, has been identified. This

formation mechanism is the result of pyrolysis

of oxygenated organic polymers (such as wood) in a high-temperature, highly vitiated

upper layer. The latter two mechanisms have

been identified for the first time during this

project.

Delivery Method. The results of this work are made available to the fire research community

by a series of NIST reports and journal publications. Additionally, the results are being incorporated into fire models under development

within BFRL to predict fire hazard. These models ultimately will be used to design buildings

with improved fire safety.

Preliminary Impact. The results of this work

are leading to an improved understanding of CO

formation during enclosure fires and are being

incorporated into fire models. Ultimately, the

models will be used to improve fire codes so

enclosure fires will be less likely to generate

and transport the levels of CO responsible for the majority of fire deaths.

Halon Alternative Fire Extinguishing Agents

Problem. The search for chemicals to replace

halon f ire extinguishing agents is proceeding

too slowly for the implementation of alternatives before current supplies of halons become

depleted. None of the alternatives proposed to date have both a low potential for ozone depletion and a high fire suppression efficiency.

Halon 1301 is used in a multitude of aircraft

applications with little understanding of the

phenomena which control the extinguishment

process. Deadlines imposed for ceasing pro- duction of halons have intensified the need for the fire suppression industry and end-users to

identify the best alternatives for maintaining

safe operation of aircraft without further

damage to the ozone layer.

Approach. A comprehensive experimental

program has been established to screen promising chemicals to identify the best candidates for a subsequent full-scale aircraft fire extinguishment evaluation program. The research deals

with the thermal properties and dynamics of

agent dispersion, flame extinction measurements, and flame/agent chemistry. Theoretical

models are being used to interpret the results, to increase our understanding of the suppression process, and to predict behavior over an expanded range of operating conditions. In particular, control of those phenomena which

dominate the actual suppression process is sought, be they the chemical reactivity of the

agent or the properties associated with the

physical mixing of the agent into the fire.

Findings. The effectiveness of a fire suppression agent is related to its thermodynamic

properties, its behavior during two-phase flow,

its interaction with flame chemistry, the timing

of its release and the nature of the fire. The

sudden discharge of low boiling point alternative agents into the atmosphere has been

recorded and numerical models developed to simulate the emptying process and the development of the super-heated spray. Details of the

flow are being measured with high speed photography of the exiting spray. A number of

flame extinction facilities have been devised to

31
experimentally simulate the behavior of the

agent over the operational range of conditions

expected in a full-scale aircraft fire. Chemical

kinetic modeling and the results of diffusion

flame measurements are being used to determine whether the dominant mechanism of

suppression is chemical or physical. Additional

chemicals are being theoretically designed

which appear to have high flame suppression

efficiency and low ozone depletion potential.

Delivery Method. The information gained by

this effort is formally disseminated through

reports to the sponsoring agencies, the Annual

BFRL Fire Conference, and at scientific and

professional meetings. Informal discussions are being held with the fire suppression industry,

chemical suppliers, and other agencies con- cerned with finding satisfactory ozone-friendly

agents.

Preliminary Impact. Research into how halons

suppress a fire or how to increase delivery of

the agent to the fire has lain dormant for decades because Halon 1301 has been such an

effective fire-fighting agent in aircraft applications. By undertaking this research in collaboration with other government agencies, BFRL will be in a position to provide the generic infor- mation to the chemical producers and fire protection industry which is required before a new generation, environmentally benign fire suppression system can be designed. The

impact of this work will be significant because

it will reduce the tradeoffs necessary between

crew safety and aircraft performance.

Turbulent Mixing Research

Problem. Effective models of turbulent combustion are required to allow prediction of the

behavior (especially CO generation) of unwanted fires and to allow the design of practical

combustion devices with improved energy effi- ciency and reduced pollutant emissions.

Approach. BFRL researchers initiated a longterm investigation of isothermal, variable

density turbulent flows. Powerful new optical

diagnostics were developed to characterize

mixing in these complex flow fields. These

diagnostics were applied to both momentumand buoyancy-dominated flows. The findings were used in the generation and validation of

models of turbulent mixing of variable density

fluids-a fundamental requirement for modeling

turbulent combustion.

Findings. Experiments have demonstrated that

the largest eddies (roughly the same length as

the flow) in the flow field are responsible for entrainment into turbulent free shear flows.

The time-averaged mixing is therefore independent of molecular properties. The mixing

behavior is highly dependent on density differ- ences in regions of the flow field where density

gradients are large. Eventually, as the flow

entrains ambient fluid and the jet density

approaches ambient density, the mixing behavior is determined primarily by the flow momentum. Variable-density axisymmetric jets have

been shown to obey simple engineering correlations for large downstream distances where the

flow density is approximately equal to the

ambient density. The results also provided

direct insight into the mechanisms for the

stabilization of lifted turbulent jet diffusion

flames which had been the subject of a great

deal of speculation. The observed eddy struc- ture indicates that stabilization will occur on the

upstream edges of the large eddies where

velocity and concentration gradients are low.

Delivery Method. Results of this research have

appeared as a series of internal reports and

archival journal articles. Findings also have

been presented in numerous invited seminars

32
and national and international scientific meetings.

Preliminary Impact. The results of these

measurements were cited numerous times in the literature and have been used for compari- son with modeling studies. BFRL's approach

for investigating variable density flows was

adopted by the French government which has

funded a National Program in Turbulent Mixing.

Their research Program is an integrated experimental and theoretical effort involving nu- merous government and academic laboratories.

The extent of the Program is evident from a

recent workshop funded by the Centre National

de la Recherche Scientifique in Orleans, France.

William Pitts of BFRL was invited to this workshop as the only foreign participant. Much of

the current French effort is built directly on

BFRL's research. It is anticipated that the

French program will make a significant contribution to the modeling of turbulent combustion.

Materials Fire Research

Problem. Two recent trends which have

started to affect the U.S. plastics and manufacturing industries are polymer recycling and a demand for nonhalogenated flame retardants.

The huge waste volume of plastics is an

important problem for modern society. Landfills

and incinerators are unwelcome on the periphery of cities where they are most needed.

A more popular solution to the problem is recycling. But some of the same social forces

which are encouraging recycling are also having an impact on acceptable retardants.

Brominated flame retardants have gained a major position in the worldwide plastics industry. To meet today's requirements in the

electronics and electrical equipment industries,

for example, virtually every plastic requires

flame retardancy, frequently with brominated

compounds. Due to publicity about dioxin and

furans as possible degradation products, these

retardants have acquired a negative public

image in Europe and soon they may be regulated. Although the overall use of halogenated

flame retardants is still showing an upward

trend, the preceding concerns have started a

definite search for alternatives. As a result of

these trends, it is possible that available selections of polymer materials and of flame retar- dant treatments will be more limited than in the

past. Since the regulations for fire safety will not be eased in the future, this could mean that

improving or even maintaining the current level of flammability performance across the U.S.

plastics and manufacturing industries will become much more of a challenge.

Approach. BFRL performs research on non- halogenated flame retardant treatments which

form char during polymer burning. This treat- ment is ideal because carbon atoms retained in the condensed phase as char lessens the

available fuel for flaming combustion even as

they help insulate the polymer from the heat of

the flame. A molecular dynamic model describing the behavior of polymer chains and fragments from heated polyethylene has been

developed and solved numerically on a super

computer to determine under what conditions

the formation of crosslinks among the polymer

33
chains is enhanced. The model is being ex- tended to apply to other polymers. Experimentally, electron-beam irradiation is applied to various plastics to form crosslinks and the

f lammability properties of the irradiated samples

are being measured. This project is a cooperative study with the Technical Center, Federal

Aviation Administration. In another cooperative

study with GE's Corporate Research and

Develop Center, the effects of silicone on the

f lammability properties of engineering plastics are measured and the effects of varying char

structure on their flammability properties are determined.

Findings. The theoretical calculation demonstrated the possibility of the formation of

crosslinks during the thermal degradation of

polyethylene and determined the conditions

under which this formation is enhanced. The

concept of flame retardancy by the irradiative

crosslinking of a polymer sample was demonstrated by the formation of a small amount of

char from burning the irradiated polyethylene.

The addition of silicone to polycarbonate significantly reduces the peak heat release rate,

although the amount of char formed is about

the same as that without silicone. It appears

that there exist significant effects of the char

structure on flammability properties.

Delivery Method. The results were presented

at various technical meetings and seminars and

published in technical journals.

Preliminary impact. Many inquiries were

received from U.S. companies seeking possible

cooperative studies with BFRL to develop new

type flame retardant treatments. This joint

work will help U.S. industry meet the challenge

described above and to maintain and enhance

its competitiveness.

Furniture Flammability Testing

Problem. The California Bureau of Home Fur- nishings introduced a flammability test for seating furniture for consideration for use in public occupancies (hotels, prisons, nursing

homes, etc.). The ignition source, crumpled

newsprint, resulted in substantial variability in the test results. The variability of the ignition source was particularly critical when applied to

substrates that are marginally ignitable. The

problem was to develop an ignition source of

similar severity but with more consistent

behavior.

Approach. The ignition source of five sheets of

crumpled newspaper was first characterized by

testing it on an inert mock-up. Video observations were made of the flame extension and

the area of impact. An infrared camera was

used to make quantitative measurements of the

two dimensional surface temperature patterns,

and a computer based image analysis system

was used to identify optimum locations for more accurate heat flux measurements. A gas

burner, an inherently more reproducible heat

source, was then designed to replace the

original source. The characteristics of the new

burner were carefully measured.

Findings. By improving the nature of the

ignition source and by making it possible to quantify the rate of heat release from the

furniture item in the test, BFRL brought the test method into the mainstream of modern fire pro- tection technology. The original ignition source proved to be subject to appreciable variability in

its affects on the side arms of the chair, and

the level and duration of heat flux on the seat

back. The gas burner produced a more repro- ducible flame and was preferred as an ignition source.

Delivery Method. BFRL researchers collaborated with staff of the California Bureau of Home

Furnishings (CBHF) during the study. BFRL re- searchers developed source characterization

measurements and CBHF researchers per- formed full scale room burn tests. The results

of the collaborative study were published in NIST research reports and presented at techni34
cal meetings. The new test method is being

introduced to ASTM for adoption as a standard

test.

Preliminary Impact. The new ignition source has been included in the California test and is being used in several private testing and product development laboratories. A number of

other States have pending legislation to adopt

the California test for public occupancy furni- ture. Most public occupancy furniture manufacturers nationwide are making furniture to meet the CBHF test.

Standard for the Cigarette Ignition

Resistance of Mattresses

Problem. Cigarette ignition of mattresses and

upholstered furniture is the leading cause of fire deaths in the United States. Smoldering

combustion is a slow, insidious form of combustion, very difficult to extinguish and may go

unnoticed for up to an hour after the cigarette

is dropped. Smoldering often progresses to open flaming in mattresses and upholstered

furniture. Victims typically die from smoke

inhalation.

Approach. BFRL conducted ignition studies of

full-scale retail mattresses. Methods for improving the ignition resistance were developed

and evaluated. Commercially available ciga- rettes were studied for their ignition performance on mattresses. The potential impact on

the mattress industry of a mattress ignition

standard was studied.

Findings. A cigarette ignition test method for mattresses was developed and a draft standard

was prepared and recommended. The Con- sumer Product Safety Commission published

the final standard after the responsibilities under

the Flammable Fabrics Act were transferred to them.

Delivery Method. The procedures developed

under the Flammable Fabrics Act require three

distinct steps, all published in the Federal

Register. In addition, BFRL staff regularly gave

papers at meetings of trade associations, e.g., National Association of Bedding Manufacturers,

standards bodies, e.g., ASTM, and others. A

major effort was made to provide the mattress

industry with viable means to comply with the

standard through their trade associations and

trade publications.

Preliminary Impact. The effect of the mattress

ignition standard has shown that the incidence

of cigarette ignition of mattresses is reducing

rapidly.

35
Support of Navy Firefighter Trainer Program

Problem. Ships are lost due to fire. It is essential that each seaman receive "Hot Fire"

training to control and extinguish fires that may

occur accidently, or as a result of enemy

action. The Navy is developing and building 33

propane-fired trainers, that will be located at Naval Stations on the continental United

States, Hawaii, and Japan. The trainers must

provide safe and realistic training without

causing unnecessary pollution of the environment.

Approach. Since 1 986, BFRL has served as a

technical resource to this Navy program.

Activities include:

a. measuring the environment within the trainer

for safety and realism - air temperatures, temperatures of equipment that the trainees may

contact, radiant heat flux, gas composition

(breathability), smoke density, and other

characteristics,

b. solving trainer development problems, using

such NIST capabilities as computational fluid mechanics and electron microscopic examination, and

c. helping to satisfy State and Local Air Pollu- tion Control personnel, at the sites where

trainers are built, about trainer emissions.

Findings. Calculations made on prototype

designs showed the need for additional ventilation to avoid hazardous conditions and for in- creased separation of components to avoid

undue thermal exposure to structural elements

of the trainers. Computational fluid mechanics

was used to evaluate various designs of wind

screens to stabilize the fire in the open deck fire simulator. Measurements on samples of simulated smoke from the trainers and technical

information on the toxicity of those products

showed that trainers can be operated within

state air pollution guidelines. Research showed

that the ceramic insulation used in some

trainers to protect the concrete walls was

satisfactory despite the fact that it separated

explosively from the concrete.

Delivery Method. This information is disseminated in official NIST "Reports of Tests" to the

sponsor, presentations to the Fleet Project

Team, discussions with the Navy "Device"

contractors and operating personnel, and

discussions with Navy and State Air Pollution

Regulators.

Preliminary Impact. Two of the Navy Device

Contractors are using Navy technology to

develop and sell trainers for civilian fire fighter

training. Although expensive, trainers with

various scenarios are being purchased by major

civilian fire departments, and consortia of

departments for safe, realistic training of their

personnel. The evaluation of the new wind

screen using new computational techniques

rather than full scale testing saved time and

funding by the Navy in solving flame stabiliza- tion problems.

36
Using Fire to Clean Up Oil Spills

Problem. Subsequent to the major oil spill in Alaska from the grounded tanker Exxon Valdez,

national attention has been focused on the

development of new technology for oil spill

response. As part of a research program

funded by the Minerals Management Service,

the capabilities and impacts of in-situ burning

have been measured to assess the technology

and provide responders with technical information needed for spill response decisions.

Approach. Laboratory and mesoscale experiments have been used by BFRL to measure the

burning rate removal efficiencies, combustion

products, and smoke plume trajectories of oil

spill fires. Measurements have been performed

using standard fire and environmental instrumentation and new exploratory methods of

assessing fire characteristics. Computer

modeling has been used extensively to understand the dynamics of local smoke plume

motion and downwind smoke particulate

deposition.

Findings. Burning has been shown to be a

rapid and cost effective method of removing oil

spills from the surface of the water. In mesoscale experiments, 1 3 m

3 of crude oil was

burned in a 1 5 m square pan in 20 minutes

leaving only 1 percent of the original oil mass

as residue. Measurements have shown that

the surface regression rate of burning crude oil

is 0.055 mm/s. During burning, most of the oil

is converted to the complete combustion

products of carbon dioxide and water vapor.

About 1 0 percent of the oil is converted to smoke particulates. Although a concern in the

immediate area of the burning, the smoke

produced from burning dissipates quickly

downwind of the burn site. In order to predict

the downwind trajectory and deposition of

smoke particulate, a Large Eddy Simulation

(LES Model) has been developed. This model

represents a new technology for assessment of

the local impact of large fire events. Interest has been expressed in using this modeling

technology as the logical successor to an

existing gaussian dispersion model used extensively by U.S. industry and government agencies to assess pollution and hazardous material

exposures.

Delivery Method. Results of this research have

been presented to Regional Oil Spill Response

Teams meeting throughout the United States

and at specialized technical meetings.

Preliminary Impact. In-situ burning of oil spills

offers oil spill response professionals an additional choice to the existing mechanical recovery and dispersant methods. Burning requires a minimum of specialized equipment and has

been shown to be a cost effective response

method. In the arctic area, it is often the old

viable method of oil spill response. BFRL is the

only source of measurements and modeling

applicable to in-situ burning of crude oil spills in the United States.

ti-U.S. Government Printing Office : 1993 - 358-082/37140 37