We did a couple of rehab houses where the piping was in the unheated attic. In one case we had a wet system serving the occupied space with 6" of batt insulation laid over the piping, stapled to the bottom chord of the trusses with roofing felt laid over the insulation to protect it and prevent it from being disturbed. That is one problem. While you can lay insulation over the pipe, you can't guarantee it won't stay put if people are moving around in the attic at some point in time. Once exposed you have a potential problem.
The other scenario was dry system for the attic and the occupied space based on the fact that both systems were located in the unheated attic. Insulation over the pipes was not considered a reliable means of protecting against freezing by the AHJ. NFPA 13, 8.16.4.1 (2007) gives some options for protection of piping against freezing. There is no restriction in using the dry system in an occupied area per NFPA 13 that I can find but not saying that some other code or applicable standard might be more restrictive than NFPA. (one of our jobs was with the State Dept. of Health, which had some additional restrictions) As far as the time delay, there are specific time parameters we must meet as listed in NFPA 13, (2007)Table 7.23.6.1. Note it lists from Residential to Extra Hazard occupancies, leading one to believe that a dry system is acceptable for any of these occupancies. Not to be argumentative but I would definitely ask the AHJ where the restriction for use of dry systems is located in NFPA 13. Craig L. Prahl, CET Fire Protection Group Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive PO Box 491, Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 [EMAIL PROTECTED] http://www.lg.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fletcher, Ron Sent: Monday, July 30, 2007 10:08 AM To: [email protected] Subject: RE: Dry System with Pendents The only thing I have ever been able to find is in the handbook 9-125 18th edition. "Dry-pipe systems should only be used in areas subject to freezing temperatures." I have had an AHJ use this as justification for a slightly different application. Isn't there something about insulation not being a suitable separation between hazards? I would hate to rely on the insulation being undisturbed throughout the life of the system to prevent freezing. Ron Fletcher Aero Automatic Phoenix, AZ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Greg McGahan Sent: Friday, July 27, 2007 2:59 PM To: [email protected] Subject: Dry System with Pendents We have an AHJ telling us that we can not use a dry system to feed an unheated attic and the heated space below the ceiling. He is insisting that we use a wet system for the lower area with insulation on top of the piping. We have done this many times in the past but on this project it is very difficult to accomplish this due to the construction. I am having a hard time refuting him with concrete proof that there is nothing wrong with using the dry system with dry pendents. Thanks for any input from the forum. Greg Living Water Fire Protection, LLC 1160 McKenzie Road Cantonment, FL 32533 850-937-1850 Fax: 850-937-1852 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
