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Group 4 hangar protection

Question asked by etanrivermis on Dec 13, 2018
Latest reply on Dec 21, 2018 by lozmun


I'm working on a hangar project which is a Membrane-Covered Rigid-Steel-Frame-Structure Hangar.

The hangar has a 6800 m2 fire area. With regard to fire protection system design as per NFPA 409-Chapter 9, I'll proceed with high-expansion foam system as specified in states the following "The application total discharge rate shall include the sprinkler breakdown factor specified in of NFPA 11." 

As per this statement, shall we install a sprinkler system in addition to high expansion foam system? I mean, is it mandatory by the standard? If yes, shall we follow Chapter 6/6.2.4 for sprinkler system design? 


If it is not mandatory, is the sprinkler system recommended? or not necessary? 


By the way, there's a requirement for the sprinkler system per 9.14.3 but it only relates to hangars having a hangar fire area less than 1115 m2, correct?