To develop and apply advances in fire and structure-fire measurement capabilities and behavior predictive computational tools, standardized fire testing tools and methodologies, advanced fire detection technologies, and advanced fire resistant materials to enable innovative, cost-effective fire protection technologies that increase the safety of building occupants, and the fire resistance of building structures and contents.
What is the problem?
According to the National Fire Protection Association (NFPA), the annual cost of structure fires in the United States is $185 B or about 1% of the U.S. gross domestic product. An analysis of the fire cost in buildings in the U.S. was documented in the Strategic Roadmap for Fire Risk Reduction in Buildings and Communities. Based on this analysis this program was tasked with reducing the cost of the two largest components of the U.S. fire burden: commercial building fire protection costs and residential building fire losses.
Fire protection costs ($63 B) are the single largest component of the structure fire problem. These costs are estimated at 2% of the overall construction costs in developed countries and 12% of construction costs for non-residential buildings in the USA. Switching from the current prescriptive-based to performance-based design (PBD) codes and standards (specifying construction requirements according to performance criteria rather than to specific building materials, products, or methods of construction) will provide architectural freedom that can drastically reduce the cost of fire protection without a loss in fire safety. The research in this program (e.g., computational tools and structure-fire metrology) will provide the technical basis and guidance needed to enable the development of PBD commercial building codes and standards.
Residential building fire losses ($35 B) are the second largest component of the structure fire problem. These losses account for 85% of all civilian fire deaths, 77% of all civilian fire injuries, and 72% of all structure fire property losses. To decrease these loses requires lower flammability building contents that will delay fire growth and spread, and more fire and less nuisance sensitive detectors that will advance occupant escape and fire fighter response. The research in this program will enable the development of environment, health, and fire safe materials and products (e.g., residential upholstered furniture), and fire detectors with new algorithms that will allow more sensitive detection of fire signature and discrimination of the non-fire (nuisance) signatures (e.g., cooking).
What is the new technical idea?
There are several new ideas for PBD. First, use of predictive fire models for performance-based design depends on demonstrated accuracy and robustness of the models combined with targeted development based on user needs. Recent progress in verification and validation (V&V) standards has enabled V&V for both FDS and CFAST to be conducted in a consistent manner. Additionally, new algorithms are improving the accuracy of the predictions.
The ability to predict fire growth and spread, the combustion products and their effect on occupants, and the movement / behavior of the occupants is critical to realizing the potential of PBD. The development of a unified PBD methodology to evaluate the fire behavior of structures by incorporating knowledge concerning fire load, material response, and overall structural response to fire will, for the first time, consider fire as a design condition in the building design process. The building layout (compartmentation and geometry), windows (ventilation), materials of construction, passive and active fire protection systems, and amount and location of combustibles will be included in the proposed approach. Validated predictive models of structural system performance under fire will require the development of experimental database on the performance of large-scale structural connections, components, sub-assemblies, and systems under realistic fire loads. The National Fire Research Laboratory (NFRL) at NIST is the only research facility in the world that allows scientists and engineers to conduct research on the response of real-scale structural systems to realistic fire and mechanical loading under controlled laboratory conditions. This research will enable the development of the technical basis for PBD methodologies for structures exposed to fire. As a result, new measurement capabilities for predicting the response of multi-story structural systems to fire and other imposed loads is being developed in the NFRL, which will enable safer and more cost-effective building design.
The strategy to reduce residential fire losses through improved material flammability is pursuing several new technical ideas. This research is developing, deploying, and evaluating new material based technologies that comply with Environment, Health and Fire Safe (EHFS) requirements. The technologies are fire resistant coating applied to the surface of components in residential furniture to enable compliance with furniture flammability regulations. Closely aligned, the furniture flammability project is developing a technically sound furniture design tool based on characterized physical and combustion properties of the furniture components that will be used by furniture manufacturers to produce residential upholstered furniture (RUF) with improved flammability behavior. Both projects are working together with regulatory agencies and manufacturers to develop furniture flammability regulations and compliant furniture. The smoke alarm project is characterizing early combustion signatures using multi-angle scattering methods (which can be orders of magnitude more sensitive than traditional sensing methods) combined with new knowledge about particle characteristics of various sources and on-board sensor analytics. This is enabling the design of smoke alarms with detectors that are more sensitive to fire signatures and algorithms that can discriminate these signatures from non-fire (nuisance) signatures. This understanding is being used to develop new codes and standards for commercial smoke detectors and placement of these detectors in residential homes.
What is the research plan?
The two research thrusts are (1) to reduce the cost of fire protection (while maintaining the same level of fire safety) in buildings by enabling PBD and (2) to reduce residential fire losses through early and reliable warning and reduced flammability of key building contents. Within the PBD thrust, the research plan is to enable the next generation of PBD through accurate simulation of the hazard of a fire to the performance of the structure. The predictive fire modeling will simulate the growth and spread of fire in structures. Critical tasks include extending the FDS V&V parameter space, implementing novel algorithms,15 enabling direct CAD import for building geometry, and improving the computational efficiency of SmokeView. This research is coupled with a series of NFRL projects on performance-based design methodologies for structures in fire to develop performance-based methods to predict and evaluate fire behavior of structures and to deliver validated and improved tools, guidance, and standards for the fire resistance design and assessment of structures. These projects deal with the (1) NFRL large-scale testing of the performance of composite floor systems in a steel structure, (2) NFRL operations and metrology to develop the capabilities to measure the structural deformation in a fire defined in the large-scale testing project, (3) NFRL computational tools that will couple the fire model (FDS) and structure model (LSDyna) to design the parameter space of the large-scale tests that will result in the desired output (e.g., failure criteria) and to extend the results of the large-scale fire tests to include parameters that are both an interpolation and extrapolation of the planned testing matrix.
The research plan for the reducing the residential fire losses thrust will primarily provide the measurement science that enables a reduction of residential soft furnishings and enables early warning of unwanted fires. Two projects will enable cost-effective mitigation of the largest fuel source in homes (residential upholstered furniture, RUF): (1) eliminating RUF as a fire hazard by evaluating a novel FR coating technologies for foam and fabric , and developing/using tools to measure the FR durability of the technology over the life time of the product, and (2) conducting small- and meso-scale measurements of RUF to establish the technical basis for a RUF design tool, which will enable design of RUF with substantially reduced fire hazard. The other project in this thrust will enable the development of more fire sensitive and less nuisance sensitive smoke alarms by evaluating novel detection technologies (e.g., multi-angle multi-wavelength light scattering).