Background
NFPA 285 is a fire test method that determines the fire propagation attributes of exterior wall assemblies with combustible materials and components. Apart from some exceptions and conditions set forth in the International Building Code (IBC), NFPA 285 testing is triggered when the wall assembly contains certain combustible components and the building is Type I, II, III, or IV construction. The NFPA 285 test is typical of multi-story construction since the apparatus includes first and second floor rooms, a window opening, plus floor and roof slabs. The test specimen is comprised of all exterior wall components (interior finish material, framing, exterior sheathing, water resistive barrier, thermal insulation, cladding, etc.) and is attached to the front face of the test structure. The methods, components, and details are stipulated to be representative of typical field installations. Typically, a construction product manufacturer initiates the testing, determines the construction methods/components and uses the results to support product applications. The results apply to the assembly and components as tested although engineering judgements are sometimes used to qualify alternatives that are deemed to perform equivalently.
NFPA 285 tested assemblies
Photo credit: BASF Corp. – Wall Systems
Combustible exterior wall system components often include air/water resistive barriers along with certain types of insulation and exterior claddings. NFPA 285 tested assemblies frequently include more than one combustible material and oftentimes these components will be supplied by more than one manufacturer. It is also common to have the same type of components available from multiple manufacturers. Given the many component and manufacturer options, it can be time consuming to research and locate a specific assembly. Below are some suggestions that may help you find tested assemblies more quickly.
Third party databases
Similar to databases that exist for fire resistive assemblies, some third-party test and quality control agencies now publish NFPA 285 results in databases that are searchable by key words, components, manufacturer. etc. While such databases cannot be expected to include every available manufacturer and assembly, they can be a quick and easy search option.
Product manufacturers test data
Cladding manufacturers can be a good starting resource for NFPA 285 data since building design typically prioritizes cladding selection over other components in the wall assembly. Once an assembly with the cladding is located, there will often be many options for the other assembly components. Additionally, some product manufacturers publish results in tables or databases that contain a menu of product options for each wall assembly component. This gives the user a range of product options to choose and achieve a NFPA 285 compliant wall assembly.
About the author
Bill Egan has more than 35 years of construction experience that includes product and system design, standards development, testing, building code compliance as well as claim investigation and resolution. Prior to starting the Bill Egan Group, a provider of consulting services related to building enclosures and products, Bill held key technical roles with construction product companies that manufactured Exterior Insulation and Finish Systems (EIFS), stucco, air and water resistive barriers, non-metallic lath and architectural coating systems. Egan graduated from Roger Williams University with a BS in Civil Engineering, holds numerous patents, and participates in various industry associations. He serves on ASTM committees related to stucco, lath, air/water resistive barriers and is the E6.58 subcommittee chairman for the Performance of EIFS. http://www.billegangroup.com/ [email protected]
