Mike: The old Model B deluge valve cannot hold air pressure without a riser check valve installed above it. The alarm line trim is directly connected to the inside of the deluge valve without the use of any intermediate type chamber in the seat. Therefore, air pressure introduced into the valve will leak directly out the automatic ball drip valve on the alarm line. This design permits visual inspection at the ball drip for any leaks at the seat, as well as enabling draining of any water due to condensation or drainback. By installing a valve on this line, you lose visually a way to detect a leak at the seat, as well as prevent a waterflow alarm occurring from the eventual buildup of pressure from such leak. .
Salvatore J. Izzo, P.E. SFPE, Manager - Technical Services The Reliable Automatic Sprinkler Company, Inc. 103 Fairview Park Dr. Elmsford, NY 10523 Tel: (864) 843-5252 Fax: (864) 843-3073 E-mail: [email protected] ________________________________________ From: [email protected] [[email protected]] On Behalf Of Morey, Mike [[email protected]] Sent: Thursday, December 01, 2011 1:40 PM To: [email protected] Subject: Reliable Model B Deluge Valve - Air Supervision We have what amounts to a closed head electronically actuated deluge system, or maybe a non interlock electronically actuated preaction system? I'm not even sure how to make the distinction. It utilizes a reliable model B 6" deluge valve that appears to have more or less standard trim and an alarm pressure switch. We're attempting to convert the system to low pressure nitrogen supervision only to monitor the integrity of the pipe. The issue we're running into is that when we attempt to pressurize the system the ball drip/velocity check in the alarm pressure switch trim leaks air at a high rate. The proposal was to add a check valve above the deluge valve to allow an intermediate chamber without air pressure to be monitored for alarms, but this adds another drain, pressure gauge etc that will all have to be piped into 2 large and unwieldy systems that are already installed. Is there anything that would prohibit us from just replacing the ball drip valve with a standard d rain valve, or adding a shutoff in front of the ball drip? These systems are pretty meticulously maintained so draining off the alarm line wouldn't be a major issue. Code wise I can't see anything that mandates the presence of the valve, it seems to be more to allow condensate to drain and allow the alarm line to be drained quickly after a trip. Mike Morey, SET, CFPS Sprinkler Designer BMW Constructors, Inc. O: 317.651.0596 | C: 317.586.8111 www.bmwc.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20111201/cac144ef/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
