SprinklerDesigner2
Mechanical
- Nov 30, 2006
- 1,251
Two cotton warehouses, each measuring 180'x400', protected with two manifolded dry pipe systems with 6" riser, 4" looped mains and 2" branch lines.
Water supply is 1,500 gpm @ 120 psi vertical turbine pump supplied from a 1 million gallon pond.
Air capcity of each system is 1,140 gallons. I've done enough of these in the past I am not concerned with getting water to the the inspector's test connection in 60 seconds as long as I have a QOD which is required anyway. If I did run into trouble I left an out where I could easily add a third riser to the manifold, split the systems in to an equal three with the largest not exceeding 750 gallons. I doubt I'll have trouble with trip times but I've been around long enough I've learned to play a lot of "what if" games.
I've been looking at NFPA #13 Section 11.2.3.9 Dry System Water Delivery which is an alternative to inspector's tests. I've looked at the program that does this, it's a bit pricey and one of it's downfalls is that it does not calculate trip time through loops so even if I had the program I couldn't use it here.
But what if I installed an inspector's test with a maifold of 4 17/32" outlets fed with 2" pipe (same size as the end of my branch line) with a 2" angle valve instead of a globe valve?
If I demonstrated we would have water in 40 seconds (per the table for high piled storage) would it be an acceptable alternative to the single outlet/60 second inspector's test?
I got a feeling it wouldn't be, that the table is meant only to outline the criteria for the listed programs, but would like to hear what others think.
Thanks
Water supply is 1,500 gpm @ 120 psi vertical turbine pump supplied from a 1 million gallon pond.
Air capcity of each system is 1,140 gallons. I've done enough of these in the past I am not concerned with getting water to the the inspector's test connection in 60 seconds as long as I have a QOD which is required anyway. If I did run into trouble I left an out where I could easily add a third riser to the manifold, split the systems in to an equal three with the largest not exceeding 750 gallons. I doubt I'll have trouble with trip times but I've been around long enough I've learned to play a lot of "what if" games.
I've been looking at NFPA #13 Section 11.2.3.9 Dry System Water Delivery which is an alternative to inspector's tests. I've looked at the program that does this, it's a bit pricey and one of it's downfalls is that it does not calculate trip time through loops so even if I had the program I couldn't use it here.
But what if I installed an inspector's test with a maifold of 4 17/32" outlets fed with 2" pipe (same size as the end of my branch line) with a 2" angle valve instead of a globe valve?
If I demonstrated we would have water in 40 seconds (per the table for high piled storage) would it be an acceptable alternative to the single outlet/60 second inspector's test?
I got a feeling it wouldn't be, that the table is meant only to outline the criteria for the listed programs, but would like to hear what others think.
Thanks