Tom, your real world experiences are priceless. Keep them coming! Ed Kramer Littleton, CO
The 150 PSI supply requirement comes from our Building Code section on standpipes. Ours is a modified BOCA '93 currently. I've done some where the client's designer has been present and they've come out so close to calc, it's scary. A few of the times we've had tested calc'd standpipes and they've failed have been very few, mostly due to field changes where they had to use 6 elbows between the FDC check off the riser and the connection, another time where they used about 10 feet of 2 1/2" to relocate the FDV from the stairshaft to the smoke vestibule (field change). A common problem we had about a year ago with a couple of clients were their designer would just calc a hole in the standpipe where the FDV was and then when he started calc-ing 1/2 a foot of 2 1/2" from a tee to the FDV, he was using 14's equivalent for the valve and I urged him to goose it up another 10 feet. Boston has 2 decommissioned or spare pieces they use for all standpipe tests, 1250 GPM diesel hales rated at 150 psi. Most of Boston has 2 services in the street (plus a pumped HS controlled by BFD in most of the "downtown" area for their use only and special black 4-eared hydrants with no steamer), the high which is supposed to be used for fire protection averages between 90 and 130 psi, the low can be anywhere between 40 and 80 psi, depending on the location and elevation. The hydrants are split between services where we have two so it's a coin flip if we get a HS hydrant or a LS but either way we never have a problem supplying the constant 150 at the FDC. I always put a 200# gauge on the draft hydrant and another 300# on a tapped swivel on one of the FDC inlets, I instruct the pump operator to keep the needle of the gauge at 12 o'clock (150 psi) for the duration so I know what I have there. I always have to remember to ask them to charge the building "slowly" and to raise the throttle "slowly". I record hydrant, pumper suction and discharge (spare pieces so they're hardly ever accurate), FDC and FDV static and residual and flow. Works well. Half an hour of laying hose and setup for a 10 minute test. I can send you the form I use, it's just a word template file. Tom Duross Go Pats!!! _______________________________________________ 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)
