Fire only, manufacturing/warehouse occupancies. :) next to two 2,000 GPM pumps, I thought 2.5" WAS small ! I want to make sure it doesn't get clogged, but DUH, pilot lines aren't 2.5" or ", are they. Will look at 2", smallest without switching styles down to a 3/4".
glc -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Thom McMahon Sent: Wednesday, September 19, 2007 8:13 PM To: [email protected] Subject: Re: PLD and PRV Since your only using it to restore the lower operation pressure in the mains why use a 2.5" device? The smaller a device the lower the impact if it fails open. Also if the only usage on this system is for fire, you'll have a small spike at start up, but a very low volume to deal with to return it to 155 / 160 Psi. If the system feeds domestic / industrial uses wouldn't that relieve the excess? Thom McMahon Firetech, Inc. 2560 Copper Ridge Dr Steamboat Springs, CO 80488-2136 Tel: 970-879-7952 Fax: 970-879-7926 ----- Original Message ----- From: "George Church" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, September 19, 2007 6:05 PM Subject: PLD and PRV > > We've noticed the PLD's we've installed allow brief surge of > overpressurization while the diesel starts up, builds pressure, and for > the > time it takes the PLD to react, there's an inrush of some of the churn > pressure until the governor kicks in and backs it down. Guy at Clarke > confirmed this. > > We have a project with what is possibly fragile UG in many sections of the > facility. We're trying to keep it, and the related interior systems, from > creeping up to high pressure (isn't that why we have the PLD?). This > particular site is getting twin 2,000 @ 150 diesel vertical turbines, > which > feed a large looped yard system, in turn feeding -oh, couple dozen risers > scattered around. > > We're thinking a small (2.5"?) Relief valve located past the pump > discharge > valve, just before it drops into the yard system, PRV discharge piped back > to the reservoir, set point 5 PSI above the PLD, set adjustment on > reaction > time to ASAP setting, so it will bleed off the excess pressure as soon as > possible. We think the size of the yard loop- complete with sectionals, > hydrants, etc.- will absorb the shock with only a small amount of it > getting > into the interior systems. If some does, 1/2" relief valves on the grid > will > take care of anything > 175. But we want to be able to have the UG drop > back > to the 155~160 range as soon as possible. > > Since the twin pumps go into one yard system, the small PRV only has to be > installed on one of these. Since its relatively small, even if it failed > OPEN the loss wouldn't de-rail the train, we have 150 @ 4,000 when > combined, > and demand is about 150 @3,000. Assuming the 2.5" PRV stuck open wouldn't > flow more than 1,000 GPM, it could drop the water back in the hole to be > re-pumped all day long. > > Both pumps will start remotely from elec detection systems on these large > demand systems, and on pressure drop for the conventional wets. > > Yes, the owner has authorized high pressure testing of the UG, still > doesn't > mean we can slam the heck out of it or let it sit at 175+ and not see a > main > break in a couple yrs. > > Any other thoughts from those with some PLD experience? > > glc > > _______________________________________________ > 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)
