In the aviation industry, the safety of aircraft hangars is of utmost importance. Fixed foam systems were added to medium and large-sized hangars in the 1980s to suppress large-scale liquid fuel pool fires, despite little evidence of these types of fires occurring in hangars. This resulted in numerous false foam activations over the years, leading to equipment damage, business interruption, environmental damage, and personal injury. However, recent studies have confirmed that almost all foam activations were false, leading to a shift towards PFAS foam removal and the adoption of new fire protection options.
False Foam Activations: Understanding the Causes
Power outages, lightning strikes, regular system maintenance, a child activating a pull station, and even barbecue grills are causes we’ve heard from dozens of stories of accidental foam system discharge in operational aircraft hangars that we have visited. Almost always, these foam system releases have resulted in equipment damage, business interruption, and in the more severe cases, extensive environmental damage and personal injury. What we do not hear as the cause of a fixed foam system discharge in an aircraft hangar is the type of large-scale hazard these systems are designed to suppress; a fire.
In an industry where the saying “The codes are written in blood” typically holds true due to the reactive nature of safety regulation development. The requirement for fixed foam systems in aircraft hangars added in the 1980’s to NFPA 409 is a glaring exception. There is little or no evidence of large fuel spill fires occurring in hangars, and yet the addition of fixed foam systems to medium and large size hangars has resulted in numerous false foam activations in the decades since. What was observed anecdotally by operations personnel for years was analyzed and quantified in recent studies by the University of Maryland and the National Air Transportation Authority, which confirmed that almost all foam activations studied over a 16-year period were false activations or occurred in response to small normal combustible fires. With this evidence, the most recent 2022 edition of NFPA 409, which is the standard that regulates fire protection in aircraft hangars, now allows hangar fire protection options without foam.
The Shift Away from Foam in Hangar Fire Protection
This paradigm shift regarding the use of foam in hangars coupled with the emerging awareness of PFAS environmental risk from legacy low-expansion foams has resulted in owners and operators throughout the aviation industry transitioning rapidly to build new hangars without foam and removing foam from existing hangars. The new NFPA 409 allows multiple options for fire protection without fixed foam systems including performance-based design, risk analysis, outright prescriptive exemption from foam, and alternate technologies like ignitable liquid drainage floor assemblies.
In each case where a hangar owner/operator wants to remove foam, replace foam with non-fluorinated foam, or even harden existing foam systems to minimize risk of accidental discharge, the first step should be consulting with design professionals familiar with the field and their local authorities having jurisdiction to select the best option to both maintain safe fire protection and reduce risk of accidental foam discharge.
Choosing the Best Fire Protection Option for Your Hangar
As the aviation industry transitions towards PFAS foam removal and new fire protection options, hangar owners and operators should consult with design professionals and local authorities to select the best option that maintains safe fire protection while reducing the risk of accidental foam discharge. By embracing new technology and shifting away from outdated methods, the industry can ensure the safety and well-being of everyone involved.
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