Tech Talk:  SIPs & Multistory Fire Safety

Multistory buildings have very unique considerations to be understood when it comes to designing for fire safety.  As the name implies, Multistory buildings have vertically stacked floors and often have medium to high people occupancy.  Office buildings, hotels, college dormitories, multi-family residences as examples, all meet this Multistory building profile.  Over the years, many fire incidents have originated in the lower floors of Multistory buildings, where the fire has penetrated an exterior window opening and thus, tragically caused an upward-moving fire involving the upper floors.  As you can imagine, upward-moving building fires become very difficult to contain and subsequently extinguish.  Also, upward-moving building fires make evacuation of the building extremely challenging for occupants, first responders and firefighters.

With the experiences and knowledge of how Multistory building fires behave, the National Fire Protection Association (NFPA) in 1998, created a Multistory fire test standard – the NFPA 285: Standard Fire Test for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components.  The NFPA 285 is also known as the Multi-Story Fire Test.  The NFPA 285 fire test reveals which building components, making up an exterior wall assembly, when exposed to an interior fire moving out through a window open, will not cause an upward moving fire.  The test fixture consists of a first-floor frame,  with a furnace that applies a constant flame front onto the interior face of the wall assembly.  The frame has a ceiling/floor structure separating the first floor from the second floor.  The test wall assembly, with dimensions of 14’ wide, by 18’ high is in then attached to the test frame.  The test wall assembly has a window opening in the first-floor wall.  In addition to the interior room furnace, an additional  burner is placed horizontally along the window's exterior, with its flame being directly positioned along the length of the window header. 

The Test – The interior furnace is ignited.  Shortly thereafter, the burner positioned on the window header is ignited.  The interior first floor room fire temperatures will reach over 1,400 degrees F during the 30-minute fire exposure required of the test.  Similar temperatures will be reached at the exterior header location.  As the fires impinge on the wall assembly visual and video observations are recorded.  Thermocouples arrayed over the wall assembly, both interior and exterior are also monitored.  In order for the test wall assembly to pass the requirements of the test, no flames may propagate higher then 10’ up from the window header, no flames may reach a lateral distance of 5’ from the vertical center line, no visible flames in the second story room, no temperatures exceeding the testing limits can occur at the second story, the exterior wall above the window, or in the insulation core. 

Premier SIPS are being increasingly specified for Multi-story applications.  Therefore, PBS elected to conduct an NFPA 285 Fire Test on its  “SIP Assembly Base Wall”, using 5/8” Type X on the interior face and 5/8” exterior grade gypsum on the exterior.  The Premier SIPS Base Wall was subjected to the 30-minute fire exposure and passed every requirement of the NFPA 285 standard.  In addition, the Premier SIPS NFPA 285 Base Wall Assembly, will allow for a variety of non-combustible exterior claddings to be applied, i.e., metal, cement board, brick, stone and similar materials. In addition to non-combustible wall claddings, Exterior Insulated Finish Systems (EIFS), that have tested under the NFPA 285 Fire Standard, may also be applied over the Premier SIPS NFPA 285 SIPs Base Wall.  Premier SIPS provide both fire safety and a wide range of exterior wall cladding choices. 

Premier SIPS with their faster, stronger, greener capabilities are a great choice for building multistory buildings.  And now, with recognition of passing the NFPA 285 Fire Test, Premier SIPS brings assurance of high-level fire safety.

Learn more:  SIPS & Fire Performance FAQ - Understanding the Safety of Structural Insulated Panels