Dear Parsley, What could I say? You are absolutely right. I agree that customer will have mixed commodities - Class I -IV.
I was afraid that going beyond the 16.70% pitch could affect my design approach, this is: no sprinklers in racks, ordinary temperature sprinklers, ESFR K=25. I appreciate your time for sharing your thoughts. Kind regards, Cesar Villavicencio ________________________________ From: Parsley Consulting <[email protected]> To: [email protected] Sent: Sun, May 30, 2010 4:26:30 PM Subject: Re: WAREHOUSE SLOPED CEILINGS Cesar, There are a couple of thoughts on your last e-mail. First, be careful how you use the term "miscellaneous storage", as the term is defined by NFPA-13 in somewhat narrow terms. A building with 40' high ceilings could - of course - be used for miscellaneous storage, but it would seem unlikely to me. A quick look at the definition in 3.9.1.14 ('07 edition) would suggest that it is storage that does not exceed 12'-0" in height, along with some other criteria. I certainly don't know the parameters of the storage, but from what you described, it might well be described as "mixed commodities" in Classes I-IV, rather than "miscellaneous." There is some flexibility in design when using the criteria from FM Global, as section 2.2.1.6 of their data sheet 2-0 (2010 edition), indicates that if you can use standard response storage sprinklers in ceilings with a slope not exceeding 20 degrees, provided that in-rack sprinklers are installed. FM Global is more restrictive when no in-racks are provided, limiting the use of QR or SR storage sprinklers to ceilings where the pitch is does not exceed 10 degrees. (Table 14, data sheet 2-0). FM Global also provides some alternatives and some requirements when the pitch is in excess of 10 degrees, such as a sprinkler being required within 3'-0" horizontally of the peak (measured along the slope) when the pitch exceeds 5 degrees. It does sound like you're limited in what you can do, to either requiring a false ceiling, at a flatter pitch, or seeing if the architects might flatten the roof itself. One thing to be aware of is that if the roof structure is combustible, and you install a ceiling below it, you may end up with a combustible concealed space which might require sprinkler protection as well. Sorry if that's not what you're looking for. PARSLEY CONSULTING Ken Wagoner, SET 760.745.6181 voice 760.745.0537 fax [email protected] <mailto:[email protected]> e-mail www.ParsleyConsulting.com <http://www.ParsleyConsulting.com> website César Villavicencio wrote: > Dear Ron, Todd and Tom: > > Appreciate so much your entries. > > Yes, the warehouses (in planning stage) will be 40 feet high and they will > store miscellaneous storage, Commodities I - IV. > > If the 18% ceiling slope is a little bit above of the 16.7% established by > NFPA13, a 30% design area increase will be necessary? If not, what else could > I do? Ceiling false will go further of the client's budget. > > Look forward to hearing from you. > > > Cesar Villavicencio > > > > > ________________________________ > From: Ron Greenman <[email protected]> > To: [email protected] > Sent: Sun, May 30, 2010 11:08:43 AM > Subject: Re: WAREHOUSE SLOPED CEILINGS > > 2 in 12 is considered flat. Over 2 in 12 is sloped, though, as Todd > points out, in Cesar's case it is minimal. I wish I could easily point > you to a head that has design data for sloped ceilings in warehouses > but you need to define your storage requirement and design approach a > bit more. If you're 12 feet or under with nothing outside the types > and classes of commodities (i.e.: nothing too out of the ordinary) a > head is probably available. If the building is still in the planning > stage perhaps you can get the architect to lower the slope (anything > between 2:12, minimum roof slope, and 3.5:12 will be a membrane of > some sort). There are directions for using standard spray sprinklers > in factories and warehouses with sawtooth roofs-anybody else here > remember the fifties-many of the buildings are still around. I cannot > believe there is no other solution than a costly and unnecessary > ceiling, I just don't work with storage enough to have a handy > solution in my pocket. > > On Sun, May 30, 2010 at 7:58 AM, Todd Williams <[email protected]> wrote: > >> A 16.7% slope is 2.0:12. and 18% slope is >> 2.16:12. The slope difference is 2" in 12 ft. >> That is pretty minimal. Could you get a Code mod >> for that? I would be tempted to go that route and >> over-design the system a little. I have no idea >> if the 2:12 was determined by testing and experience or was made up. >> >> >> >> At 10:38 AM 5/30/2010, you wrote: >> >>> Dear Forum Members, >>> >>> >>> NFPA 13 1999 chapter 7-3.1.3. says that >>> sprinkler system criteria is intended to apply >>> to buildings with ceiling slopes not exceeding 16.7 percent. >>> >>> What if we have warehouses with slopes of 18%, >>> what should I do? Should I ask a false ceiling >>> to the client? It is a lot of area, the client will not be happy with this. >>> >>> Warehouses Class IV Commodities >>> >>> Could I make any adjustment in order to avoid >>> the construction of false ceiling? >>> >>> Please advise. >>> >>> Thanks so much. >>> >>> >>> >>> César Villavicencio >>> >>> >>> >>> _______________________________________________ >>> 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) >>> >> Todd G. Williams, PE >> Fire Protection Design/Consulting >> Stonington, CT >> 860.535.2080 >> www.fpdc.com >> >> _______________________________________________ >> 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) >> >> > > > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.437 / Virus Database: 271.1.1/2906 - Release Date: 05/30/10 > 09:21:00 > > _______________________________________________ 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)
