An Assessment of the National Institute of Standards and Technology Building and Fire Research Laboratory: Fiscal Year 2010 (2010)

The goal of BFRL’s Fire Research Division is to reduce the impact of fire on communities, structures, building occupants, emergency responders, and the economy by providing the measurement science needed to reduce preventable fire losses. The areas of expertise within the division include all areas of fire science and fire protection engineering. More specifically, fire science includes flammability, computational fluid dynamics, heat transfer, fire growth modeling, and combustion chemistry and toxicity—whereas fire protection engineering includes hazard assessment; fire detection, suppression, and smoke control; building egress design (involving stairway and elevator technology and occupant behavior); fire service technologies; and codes and standards.

The NIST Fire Research Division ably serves the national needs and is clearly superior worldwide to other fire research centers for its breadth and excellence in fire research serving national needs. Other fire research centers target different areas of specialization. The modeling of the physics and chemistry of fire is the fundamental strength of the division. Its Fire Dynamics Simulator (FDS) model is used worldwide to evaluate the hazards of a specified fire. Maintaining and improving on this strength to predict fire growth is essential to the division’s longer-term mission. The division is notable for its success in performing key research leading directly to the adoption of numerous standards and codes.

The FRD has four groups: Fire Fighting Technology, Fire Measurements, Engineered Fire Safety, and Materials Flammability.

The programs and their primary responsibilities supporting the fire protection goals are the following:

• Reduced Risk of Fire Spread in the Wildland-Urban Interface (WUI) Program: To improve the fire performance of structures and communities in the wildland-urban interface through the development of standard test methods for building materials and risk-assessment and risk-mitigation tools for use by community decision makers, homeowners, and fire officials.

• Advanced Fire Service Technologies Program: To increase the effectiveness and safety of emergency responders by enabling the development of improved protective equipment, situational awareness, and science-based tactics and training tools for the fire service.

• Reduced Risk of Fire Hazard in Buildings Program: To increase the safety of building occupants and the fire performance of structures and their contents by enabling the implementation of innovative, cost-effective fire protection technologies. This program includes the further development of NIST’s wellknown Fire Dynamics Simulator.

• The Fire Grants Program: To conduct measurement science that enables innovative fire protection and reduced flammability of materials through grants and contracts to appropriate institutions.

• Reduced Flammability of Materials Program (reviewed by the Sustainable Infrastructure Materials review team; see Chapter 4 in this report): To develop measurement science tools to aid the materials industry in producing sustainable, cost-effective, fire-safe products through the development of validated bench-scale flammability measurement methods, models, guidelines, and databases.

The BRFL presented to the panel a sample of projects in each of the major research programs as described below.

Fire spread in the wildland-urban interface is an increasing problem caused by (1) more people living on the wildland-urban interface (second homes, etc.), (2) the increased buildup of vegetative and construction fuels that occurs at the interface, and (3) climate change—especially droughts in the southwestern United States. Wildland fires are spread by firebrands, radiative heat transfer, and direct flame contact. The WUI research program is very responsive and well thought out. The program has three parts aimed at technical progress:

1. To develop validated computer models for fire spread through WUI fuel (structures and vegetation), with model development including laboratory and field measurements of wind, vegetation, terrain, heat fluxes, and firebrands’ generation and transport;

2. To develop a database characterizing the vulnerability of different structural materials and assemblies to ignition from firebrands, including roofing materials and firebrand penetration through openings and protective screens and vents; and

3. To perform on-site post-fire forensic studies of buildings in consultation with local firefighters to validate NIST’s experience and expertise.

CFD modeling of fire spread is particularly challenging, as it involves the bridging of scales over eight orders of magnitude, ranging from millimeters for structural ignition and firebrand production, to hundreds of kilometers for regional-scale smoke transport. Three near-term standards are expected from this research. They are as follows:

1. Measurement of the vulnerability of building elements, including roofing, decking, siding, and vents, to ignition and/or penetration by firebrands;

2. Guidance for both homeowners and professionals regarding the vegetation and general landscaping surrounding homes at the WUI; and

3. Standard methods for reporting fire losses at the WUI that might eventually improve the defenses against wildfires by guiding building codes and standards improvements.

The Advanced Fire Service Technologies Program provides great help to firefighters by performing research ensuring their safety and effectiveness. A good example of the research is the study on the effective functioning of respirators for firefighters. The research represents a particularly good use of NIST’s technical capabilities. It is customer-driven and requires a multidisciplinary team (involving CFD, toxicology, materials, etc.). Another example is the recently issued performance-based standard for thermal imaging cameras used by first responders to find victims in smoky conditions or fires hidden behind walls or ceilings. Performance-based testing of thermal imagers ensures that cameras work under actual-use conditions. In addition, science-based standards enable U.S. manufacturers to develop innovative and more effective technologies for both domestic and international customers.

Another problem in firefighting is the degradation of protective clothing by exposure to smoke and toxic products of combustion. A standard is being developed to ensure the performance of existing gear and to provide a method for retiring gear that has reached the end of its useful life. The problem becomes acute for firefighters and their protective clothing exposed repeatedly to contaminants during training exercises. Again, it is a complex multidisciplinary problem.

Finally, there is the concept of having a device called an Emergency Fire Fighter and Occupant Locator to locate people having transponders in a burning building. After careful evaluation, the concept appears solvable for residential occupancies but more challenging for larger commercial buildings, whose exterior walls are more opaque to electromagnetic waves.

Recent data from New York State show a notable reduction in the loss of life following New York’s adoption in 2005 of the new cigarette ignition propensity standard (i.e., “fire-safe cigarettes”). Apparently there has been a reduction in the unwanted ignition of fires by cigarettes in New York State. Smoking has long been the single largest cause of deaths from fires in the United States. However, the adoption of fire-safe cigarettes now causes a problem. The widely used ignition-resistance tests for mattresses and upholstered furniture (16 CFR 1633 [took effect in 2007] and pending 16 CFR 1634, respectively) have used a particular “pre-standard” cigarette, which is no longer manufactured. NIST is completing the development of a standard reference material, a uniform cigarette with the same ignition propensity as that of the former test cigarette.

Smoke inhalation kills more people than the number who die of burn injuries, and smoke obscuration is a principal factor in the escape time from a fire. There is need for a standard laboratory test method for estimating the toxic potency of smoke from burning buildings and furnishing. NIST has available considerable well-documented data for smoke and toxic products produced in full-scale residential fires. A project is underway to subject specimens from complex products (chairs, electrical cables, bookcases, etc.) to several different laboratory-scale test methods to determine the extent to which accurate toxic-potency data for smoke can be obtained, compared with data from room burns of the full objects.

Egress modeling is receiving considerable attention. A thorough technical foundation for egress modeling has three elements: building details, human behavior, and the movement of people. Research on these elements should lead to models as well as codes and standards.

The well-known Fire Dynamics Simulator has provided the foundation for much of NIST’s fire research over the past decade. Its development by NIST took 30 years of patient research. Fire protection engineers now use it worldwide. The engineer typically specifies the geometry and heat-release rate of the fire, and the code then predicts the subsequent movement of the smoke and hot products of combustion. It provides excellent visualization, is easy to use, and is surprisingly fast on a typical personal computer. There have been several recent improvements in the numerics in the code of interest to CFD specialists. These include employing the dynamic Smagorinsky closure, optimizing scalar transport, and implementing the Werner-Wengle wall-stress model.

FDS is limited in its ability to predict the fire spread or growth rates of hazardous-scale fires. This limitation prevents the use of FDS to predict whether a small fire will grow and transition into a big fire. It is a serious limitation. The difficulty arises from the fact that thermal radiation dominates the heat transfer in hazardous-scale fires, and FDS lacks a validated treatment for thermal radiation. As a result, engineers using FDS must specify the fire heat-release rate rather than letting the model calculate the heat-release rate. To move forward the division needs to reach out to other organizations for the expertise in measuring and modeling thermal radiation in fires. Other institutions, including the commercial insurance company FM Global and the Sandia National Laboratories (SNL), are currently moving the state of the art forward. Both FM Global and SNL have decades of experience in both measuring and modeling the heat transfer taking place in large fires.

NIST has recently upgraded its Large Fire Laboratory (LFL), used by the division. Soon to be attached to the LFL will be the new National Structural Fire Resistance Laboratory. The expanded facilities will have a major impact on the entire BFRL program—both technical and managerial. There is a need for added staff. It will also require considerable managerial resources and a business plan for the operation of the facility over the next several years.

Measurements taking place inside large fires can be technically demanding. Instruments must be extraordinarily rugged to survive large-fire environments. The division was pleased to report its reduction in the uncertainty in the measurement of the rate of heat release from fires in the LFL. This reduced uncertainty increases the quality of the facility and its potential for national use. The BRFL should consider having a biannual workshop among the three leading U.S. large-fire research laboratories (NIST, FM Global, and SNL) dedicated to advancing measurement techniques specific to large fires.

The Fire Grants Program, even though shrunk by a factor of eight in inflation-adjusted terms since the 1980s, has proven to be a vital resource in stimulating research in areas critical to the BFRL’s needs and in developing future fire researchers in universities. The grants program, together with workshops and Cooperative Research and Development Agreements, are vital tools for focusing the rest of the nation in important research in fire science and engineering.

The panel did not learn anything suggesting that the facilities in this priority area need improvement. The division is appropriately using ARRA funding for the new buildings. The staff has also devoted much time and effort to improving the general awareness of safety. For this they are to be commended. Even though the technical work reviewed is of high quality, there are significant areas not being addressed—specifically, measurements and modeling of flame heat transfer including thermal radiation.

Important technical staff members have been lost through promotion and retirement. Staff with leadership potential need to be added in these areas.

The dissemination of the results of this work to the research and customer communities is excellent.

The panel’s overall conclusions are as follows:

• The innovative BFRL Fire Research Division ably serves the national needs and is clearly superior to other research centers worldwide for excellence in fire research serving the national needs. Other fire research centers target different areas of specialization.

• The modeling of the physics and chemistry of fire is the fundamental strength of the division. Maintaining this strength will require adding staff with leadership potential and expertise in the modeling of flame heat transfer within fires.

• The division does an excellent job of interacting with customers, but it does not always take advantage of leading work taking place around the world (China, FM Global, and the Sandia National Laboratories).

The recommendations of the panel based on its assessment of the Strategic Priority Area of Measurement Science for Innovative Fire Protection are as follows:

• The BFRL should add staff with leadership potential and expertise in the modeling of flame heat transfer within fires.

• For the Large Fire Laboratory, additional staff are needed. Considerable managerial resources and a business plan for the operation of the facility over the next several years are also needed. The BRFL should consider holding a biennial workshop among the three leading U.S. large-fire research laboratories (NIST, FM Global, and the Sandia National Laboratories) dedicated to advancing measurement techniques specific to large fires.