I've wondered for a long time if Section 126.96.36.199.5.1 of NFPA 13 (2019 edition) in a way allows for unsprinklered combustible concealed spaces, like a large wood canopy, if the remote operating adjacent to the area is increased to 3000 sf and there's a fire barrier between the two areas?
Is this an acceptable approach?
I'm assuming the barrier's rated must be equivalent to the required water supply duration, if so.
Thanks in advance.
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8/10/2022 08:08:47 am
Concealed spaces operate with protection below/adjacent to achieve an acceptable balance to cover Life & Property, compensating for the delay of not have protection in all concealed spaces. Completely removing protection and assuming a larger remote area adjacent to a location will not provide adequate protection (this more akin to an exposure protection system) is not a applicable method in my mind for this scenario just based on 13 rules.
8/10/2022 08:19:48 am
Large wood canopies would not be considered CONCEALED combustible spaces.
8/10/2022 08:29:11 am
The NFPA 13 handbook is a wonderful tool! There is commentary in section 188.8.131.52.5 that states (in part): "The intention of 184.108.40.206.5.1 is not to permit the omission of sprinklers from combustible concealed spaces . . ." When other sections of 13 (9.2) specifically allow the omission of sprinklers in specific areas, section 220.127.116.11.5 may require the design area be increased to 3,000 sf.
8/10/2022 08:42:13 am
Ed nailed it. I think I've only had a couple times that I've had to use the 3000 sqft modifier due to an unprotected concealed space. It's a nice compromise in an existing building in a retrofit situation where there "might" be a combustible concealed space, but the existing hard ceiling is remaining. Especially when the system is voluntary or "encouraged" to be installed in old row type buildings.
8/10/2022 09:05:46 am
A canopy would not be considered a concealed space. The omission ability presumes adequate protection under and adjacent to the area where the combustible concealed space hazard is.
8/10/2022 09:42:36 am
Agreed with comments above that state the canopy would not be considered a concealed space.
8/10/2022 10:49:28 am
Ed beat me to it. Even though the handbook commentary is not official, it does help clarify the intent of many things. So, agreed - The 3,000 modifier may not be utilized "backwards" to avoid sprinklering an adjacent concealed space. However many canopies DO have a concealed space within (if that was the intent of the question), in which case 18.104.22.168.18 (2016) 22.214.171.124 (2019) would apply. (The handbook shows a photo of an example, they changed the photo betwen the 2016 and 2019 editions.) and sprinkler protection could be eliminaded from within IF the four sentences that follow in the standard are met. I remind trainees one does have to hop between sections of the standard depending on whether you are investigating the space beneath a canopy or projection, a concealed space within, or merely an archtectural design element.
8/10/2022 11:04:48 am
Sprinklers can be omitted from several exterior spaces. Canopies, balconies, decks, roofs, and Porte cocheres that are constructed of noncombustible materials, limited combustible materials, or fire-retardant-treated wood need not have sprinkler protection.
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