Over the course of my career we have penetrated duct work with sprinkler piping countless times. The key to avoiding the issues of condensation and noise as Tom and Mark alluded to is to sleeve the duct. Drop a 1.25" or 1.5" piece of round duct (can be hard to find it that small), or conduit, or the flex ducting that is referred to as "rubber hose" in the HVAC biz, and then pipe through that. Seal the penetration of the sleeve and you get a better fit and finish as far as noise-proofing.
I can't recall ever dropping through a duct vertically, but horizontally is almost always viable. The MEOR should do a quick look-see calc' to assure that there isn't excessive friction loss from the sleeve(s) in the stream. Steve Leyton -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, June 12, 2013 9:48 AM To: [email protected] Subject: routing sprinkler pipe through a duct Yeah you read that right. I had a query regarding running a 1" sprinkler drop through a duct to provide sprinklers below. The client is afraid that running the line beside the duct will look ugly and doesn't want to do that. The area does have a finished ceiling and the duct is exposed and extends to about 2ft below the ceiling. Essentially the duct is similar to a soffit as far as obstruction rules are concerned. The duct is just over 48" in width. I suggested just spacing the sprinklers beside the run of duct as if you were dealing with a soffit but for some reason the idea of punching through the duct is more attractive. I couldn't find any prohibitive language in NFPA 13 that would prevent this. Anyone know of anything or any text that expressly prohibits this? Craig L. Prahl, CET Fire Protection CH2MHILL Lockwood Greene 1500 International Drive Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 CH2MHILL Extension 74102 [email protected] _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
