Steve and Todd,
The sentence that you quote continues with "...except where sprinklers are not required to be installed by 8.15.1.2.1 through 8.15.1.2.1 through 8.15.1.2.18...". Then, in article 8.15.1.2.1, we have "Concealed spaces of noncombustible and limited-combustible construction with minimal combustible loading having no access shall not require sprinkler protection." The concealed space in this project meets all of these conditions, but only if the roof deck qualifies as "limited-combustible construction". So, it appears to me that we do have to split hairs and determine if this assembly meets the definition of limited-combustible construction. Please note also that 8.15.1.2.12 permits "exposed combustible insulation where the heat content...does not exceed 1000 Btu/ft2.", so the fact that we have a continuous flat surface does not by itself force us to install sprinklers. The main criteria appears to be the heat content of the material, which is not always easy to determine. I probably will wind up requiring sprinklers in this space, but I wanted to have a specific article to back up that decision. Thanks for your responses. David Bitton From: Sprinklerforum [mailto:[email protected]] On Behalf Of Steve Leyton Sent: Friday, March 10, 2017 9:07 PM To: [email protected] Subject: RE: RE: Built-up roof deck as a limited-combustible construction I agree with Todd. The standard says, “Concealed spaces of exposed combustible construction shall be protected …” This trumps the subjective hair splitting with regard to what constitutes limited combustible construction and to what extent combustible material might be allowed in limited amounts. You have one entire and continuous surface that encapsulates the concealed space(s) in question; that’s not limited, IMHO. Steve L. From: Sprinklerforum [mailto:[email protected]] On Behalf Of [email protected] Sent: Friday, March 10, 2017 4:07 PM To: Sprinklerforum Subject: Re: RE: Built-up roof deck as a limited-combustible construction I think the term Limited Combustible is purposely vague. Personally, I would think this is not limited since it covers the entire flat space and there is continuity. If a fire did get into that space, it could run over the entire structure with no good way for the fire department to fight it. What a local authority or insurance company would say is something else. You probably should consult with them. Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT 860-535-2080 (ofc) 860-553-3553 (fax) 860-608-4559 (cell) On Mar 10, 2017 at 5:47 PM, <David Bitton <mailto:[email protected]> > wrote: Yes, it is a flat roof, built in 1973. I have no doubt that it will burn, and I am classifying it as a combustible roof. (I know about the fire at the GM plant in Livonia.) My question is more along the line of: Can a noncombustible structure built on top of a typical built-up roof deck with combustible insulation meet NFPA 13's definition of "Limited-combustible construction"? From: Sprinklerforum [mailto:[email protected]] On Behalf Of Art Tiroly Sent: Friday, March 10, 2017 5:14 PM To: [email protected] Subject: RE: Built-up roof deck as a limited-combustible construction Is it a flat roof? Is it covered with gravel or stone? If it is built of felt paper and asphalt/tar it will burn. Art Tiroly ATCO Fire Protection/Tiroly 24400 Highland Rd CLE 44143 216-621-8899 216-570-7030 cell From: Sprinklerforum [mailto:[email protected]] On Behalf Of David Bitton Sent: Friday, March 10, 2017 4:57 PM To: [email protected] Subject: Built-up roof deck as a limited-combustible construction Hello, I have a 35 ft high building being built adjacent to a 22 ft high building which has a built-up, insulated metal deck roof. The structural engineer has devised a sloped "snow shed" between the addition and the lower building in order to distribute the increased snow load at this juncture. This will create an inaccessible concealed space on the roof which will be of noncombustible construction, with the exception of its base, which will be the built-up metal deck roof of the existing building. Would you consider this as meeting the definition of "limited combustible construction", meaning that the space would not require sprinkler protection? David Bitton, ing./Eng. Quest Loss Control Services Inc. 5100, rue de la Savane, bureau 200 Montréal, Québec H4P 1T8 T: (514) 341-4545 C: (514) 996-7483 www.questlosscontrol.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon>
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