You can use a loop and no check valve as long as the loop drops 5' and rises to no higher than 12" below the supply line (13-2007 figure 7.6.3.1 note 1). Most AHJ's will require that there be an RPZ somewhere in the system if any contaminant is introduced to the potable water supply (antifreeze)
Matt Grisé PE*, LEED AP Sales Engineer Alliance Fire Protection *Licensed in KS & MO 913.888.0647 ph 913.888.0618 f 913.927.0222 cell www. AFPsprink.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jay Jay Blocker Sent: Tuesday, January 19, 2010 8:23 PM To: [email protected] Subject: Antifreeze Backflow Prevention Using NFPA 13 (2007 thus the reason for my question) I cannot find anything saying that using a swing check valve at the end of a wet system and transitioning to a glycol system is allowed. Basically 1 section of a parking garage is exposed to cold temps when the garage door opens. Door failed to shut and several freeze breaks happened. The question has been asked if adding a separate control valve before a single check valve at the end of the wet system and turning it into antifreeze (without a rpz or a loop) was an option. I don't see where this is an option by 7.6 anywhere. I feel like I'm missing something here. Are any of the older editions of 13 saying this is allowed or am I looking in the wrong spot? J. Blocker EFPS (303) 353-9712 _______________________________________________ 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)
