I'm looking for opinions on this. A new building I just took over ITM on has a fire pump feeding combination standpipes, fully sprinklered high-rise circa 1974. Existing 2" main drain is toast, handle broken, stem all chewed up from wrenching. I proposed we change it, use a 300# ball valve, galvy pipe; do it right. BUT, it's on the system riser off the pump discharge and I say wrong location. Even the standard still says do a main drain test when you have a fire pump (imho silly), so I do. A main drain test is to verify supply condition. I say with it where it is, we either have to drop the building to street pressure OR do a main drain with the pump running. In a case like this I always do the latter but I see others dropping the building and I think it's unnecessary and an impairment. The problem I have with doing 150-200# main drain tests is they do dump a ton of water, even with a fire hose off the 2" el and a hose monster. I feel it's overkill and unnecessary on top of a waste of time but whatever. My issue (finally) is where to properly place a main drain when you have a pump. I say on the street side bypass supply, just flow supply pressure and be done with it. Facilities guy says others dumped building and just do that. Sprinklers are tested with the pump running, last few companies shut it off and went on jockey, that's why they're gone. Looking for opinions and even second opinions (ok you're ugly too). What's the proper location?
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