You would want a main drain where it is installed so the system can be drained 
for maintenance, hence the word drain. Do you need another drain on the suction 
side of a pump for a test to verify condition? There is some merit to that 
idea. 

Todd G Williams, PE
Fire Protection Design/Consulting
Stonington, CT
www.fpdc.com
860-535-2080 (ofc)

> On Dec 12, 2013, at 3:49 PM, "Tom Duross" <[email protected]> wrote:
> 
> 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?
> 
> TD
> 
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