My first impulse is to say it isn't actually a true ceiling if it isn't continuous from wall to wall to trap the heat and there is a ceiling above it that does so like you indicate. What you describe below the true ceiling is an obstruction to sprinkler discharge over 4 ft wide that lay people might call a ceiling.
It isn't a term actually defined (by itself) in NFPA 13. (2010) NFPA 13 3.1 refers you to Merriam-Webster's Collegiate Dictionary, 11th edition for terms not defined. My Merriam-Webster College Dictionary isn't the 11th edition [I did just email my request to order the 11th edition to my boss...]; however, it defines a "ceiling" (in its number 1 definition) as "the overhead inside lining of a room." [So if it isn't continuous from wall to wall it is not the true ceiling...] I recommend you carefully study the definitions in (2010) NFPA 13 Sections 3.3.3 (Ceiling Height) THROUGH 3.3.7 (Drop-Out Ceiling). Note in the definition of compartment in 3.3.6 it states "A space COMPLETELY enclosed by walls and a ceiling." I also recommend you read the last three paragraphs of the handbook commentary to (2010) NFPA 13 8.5.5. On a related note, it is interesting that (2010) NFPA 72, the fire alarm & signaling code, does define "ceiling" by itself; and, it is also a standard that covers ceiling mountable devices that are activated by heat. (2010) NFPA 72 3.3.1 defines ceiling as "The upper part of a space, regardless of height. Areas with a suspended ceiling have two ceilings, one visible from the floor and one above the suspended ceiling." If I've forgotten something else to say on the subject or misspoken, I hope someone on the will post a reply. David W. S. Blackwell, II, PE, CFI-I, CFPE Engineering ---------------------------------------------------------------- Office of State Fire Marshal 141 Monticello Trail Columbia, SC 29203 Phone: 803.896.9833 Fax: 803.896.9806 Email: [email protected] OSFM Website: http://www.llr.state.sc.us/firemarshal.asp ---------------------------------------------------------------- -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jimmy Waite Sent: Tuesday, December 14, 2010 8:52 AM To: [email protected] Subject: Ceiling "Clouds I know this has been talked about before, but I am having trouble getting onto the archives. I have a situation in an auditorium/lecture hall that has a ceiling that steps down as you get closer to the front of the room. However, there is about a 2'-0 perimeter around the room that is open to the non-combustible space above the ceiling. In this case I'd be willing to sprinkle around the opening (sort of like 8.15.1.5 in the '07), but it seems pointless to provide coverage over this entire lowered ceiling. Is there any code that backs this up? I thought I've heard some, but I don't know where it is. Thanks, Jimmy Waite Design Engineer [email protected] mobile: 919.622.7030 _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
