If these beams are not structural in nature, move them to meet the requirements of TFP 490 pages 16 thru 18. If they are structural and the building is not built yet, have the structural engineer Move them to meet the above.
To change from a 13D to a 13 is really not advantageous. Changes from 0.05 Gpm/Sf to 0.10 Gpm/Sf (Doubles water demand, Change from 2 head to 4 head design. (Doubles water demand again) If you can't meet the beam spacing rules I'll bet you don't meet the requirements for room design either. If this room is so small that you wouldn't design to 4 heads as a room design what about HSW LFII up to 12" down from ceiling? This house have a mech. room? If so your room design may be the OH mech.room, garage or storage @ 0.15 or 0.20 per AHJ. You could even run into a 3000Sf design area if it has concealed combustible TJI type construction. Find a way to stay in 13D even if that involves a head in every pocket. You won't have increased flow or demand or pipe size, just more heads. Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of George Medina Jr Sent: Thursday, July 16, 2009 9:26 PM To: [email protected] Cc: [email protected] Subject: Room design method - Technical information ?I am trying to help a contractor friend with a residential fire sprinkler system originally designed per NFPA-13D using Tyco 'LF-II' 4.9K. His client has areas where the beams are spaced less than 3'-6" and are 8" in Depth . He can not ( or does not) want to change the beam depth or spacing if possible so I inquired with the local AHJ about changing it to a regular NFPA-13 system and using the room design method (so as to use quick response heads near the bottom of the beams). I got the ok for that part, but the room configuration doesn't quite fit the code configuration. The most remote and demanding area is a third floor room (loft?) which has two compartments one being opened to the 2nd floor below. By reading the section on 'Room Design Method' it appears the main concern is keeping the heat in 1 room long enough to activate all the heads in it and possibly 1 or 2 heads near the unprotected opening. It appears that it would meet all other aspects of the code but the only difference being that the high room area has a 12' wide opening on the 2nd floor to an adjoin room (10' below the high ceiling). Is there a ny research data on the 'Room Design Method' where the mathematics and science required the 8" lintel and/or 8' maximum width of unprotected opening? Any suggestions? (besides walking away from it). George Medina Jr. Sr. Fire Sprinkler Designer 95-1015 Ka'apeha Pl. Mililani, HI 96819 _______________________________________________ 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)
