In general Thom is correct but you specifically mentioned spray booth. Note 8.3.4.1 seems to limit less than 5.6 for all but light hazards. Even at 36 sq.ft. * 0.4 it's still a little less than 7 psi on a 5.6. 4.2 might not be OK. 5.6 relative to a k11 (or 8) is smaller orifice and probably fine if that's what you meant. But it's not what I would consider a small orifice (4.2 or less, my definition). In this situation an 11 probably balances better with a 4.2 than a 5.6. I think we had this discussion about 6 month ago on the forum. Don't remember if there was more to the story.
Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Randy Knutson Sent: Monday, June 15, 2009 1:06 PM To: [email protected] Subject: RE: Mixing k-factors in paintspray booths Thanks Thom. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Thom McMahon Sent: Monday, June 15, 2009 11:56 AM To: [email protected] Subject: RE: Mixing k-factors in paintspray booths NFPA 13, 2007 A.22.4.4.8 The use of sprinklers with differing orifice sizes in situations where different protection areas are needed is not considered balancing. An example would be a room that could be protected with sprinklers having different orifice size in closet, foyer, and room areas. However, this procedure introduces difficulties when restoring a system to service after operation since it is not always clear which sprinklers go where. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Randy Knutson Sent: Monday, June 15, 2009 11:42 AM To: [email protected] Subject: Mixing k-factors in paintspray booths Forum Members, Can I use a smaller k-factor sprinkler in the pit and exhaust plenum of a paint spray booth? Due to the geometry of the pit and exhaust plenum. The sprinklers in there are covering about 36 square feet per sprinkler. Any insight would be appreciated. Randy Knutson Shilo Automatic Sprinkler, Inc. _______________________________________________ Sprinklerforum mailing list http://lists.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 http://lists.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 http://lists.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 http://lists.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)
