As urbanization and multi-story buildings continue to be a component of modern construction trends, fire safety tests that consider the fire-resistance of complete wall assemblies, like NFPA 285, are crucial to ensuring that structures are safe for building occupants. NFPA 285 is a test method used to evaluate combustible components in exterior building wall assemblies and to help limit the likelihood that flames will spread to different stories of a building through an exterior wall. In our recent webinar, we discussed NFPA 285 and what makes it unique. Here are 5 key take-aways from the webinar.
1. Products don’t pass NFPA 285, assemblies do: What makes NFPA 285 unique is that it tests the performance of a complete assembly, including the insulation. While there are many other test methods out there that explore the combustible properties of a single product, NFPA explores how the entire system may react in a fire. In real-world applications, materials will rarely be used as a single component, but rather as components of wall assemblies. This is why NFPA 285 testing is so relevant - because it explores how the assembly will act as a whole, rather than its individual components.
2. Thermally efficient exterior plastic foams can be part of an assembly that passes NFPA 285 test requirements: Since NFPA 285 tests the complete wall assembly, building designers can get a better picture of how the installed materials would perform in the real world in the event of a fire. This allows specifiers more options to use highly thermally efficient exterior plastic foam insulations, like rigid polyisocyanurate foam or spray polyurethane foam (spray foam). Both of these insulations have been tested in specific wall assemblies that pass the NFPA 285 test requirements.
3. The ultimate goal of NFPA 285 is not to create a completely non-combustible building: It may be tempting to think of NFPA 285 as a test method to evaluate whether a building is non-combustible, but this isn’t what it’s designed to do. Instead, it is intended to test whether the wall assembly can control the spread of the fire long enough to allow building occupants sufficient time to escape. The test is designed to support this objective, and the necessity for the test is determined by the building construction type and the materials specified for the wall system.
4. There are specific requirements for how the flames can spread in an NFPA 285 test: For the test, a two-story wall assembly is constructed around two gas burners. After the burners have ignited, the temperature increases every 5 minutes to replicate increasing flame temperatures during a fire. In order to pass the test, the flames must not extend more than 10 feet up the wall and they must not extend more than 5 feet from the center of the source flames for the entirety of the test (30 minutes). Additionally, flames cannot occur in the interior of the second story or adjacent rooms during testing. These specifications are designed to ensure that the wall assembly does, in fact, limit the spread of flames over time.
5. There is an increased demand in codes adopting NFPA 285 tests: Across the U.S., states are incorporating building code requirements that reference NFPA 285 testing, such as ASHRAE or the 2015 IBC. Understanding how to design, specify, and build NFPA 285-compliant wall assemblies is a crucial component to the future of commercial building design.
For more information about NFPA 285 and for details on how to build an NFPA 285-compliant wall assembly, watch our recent Insulation Intel® webinar, Cracking the Code: NFPA 285 for Wall Assemblies by clicking the play button below, or watch this webinar and others on demand on the Source.