VESDA is a huge increase in reliability. You should see the barrels of bad or discarded smokes around some of the preaction systems we do not to mention tripping the valve 12-14 times just so every detector is tested annually.
-----Original Message----- From: Sprinklerforum [mailto:[email protected]] On Behalf Of å... .... Sent: Friday, November 13, 2015 1:16 PM To: [email protected] Subject: Cross zoned preaction detection . It would be interesting to hear someone else's experiences, but for the majority of these systems, we are parsing " bad" reliability from "quite bad" reliabiliity. From what I find, parsing these systems is a fine line that I would rather decline--than devine-and-design. Many of these "multi-dimensional, layered" systems offer attractive engineering-approaches that pencil out on paper and make for good rhetorical bling on a power-point presentation. But after 15, often 10, sometimes even 5 years from commissioning, an unacceptably large fraction of these systems are impaired. Unless the client has a knowledgable, dedicated and motivated in-house maintenance staff, keeping these systems in service becomes a cash-cow, usually for the fire alarm contractor, but the sprinkler contractor too. My first choice would be wet-pipe, zero-interlock and try to maximize the use of sidewalls. If the facility has 24/7 staffing I would recommend VESDA with staff trained on occupant-use extinguishers (CAF). If the assets are uber-sensitive to water--and can skirt the OSHA regs-- consider a hypoxic air system. After approximately 12 years, many of the fire alarm components will no longer be supported, so figure into the cost, a new fire alarm system is likely every 15/20 years. Scot Deal Excelsior Fire/Risk Engineering _______________________________________________ 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
