Here in taxachusetts, we can omit the pump if sprinkler will work off street
pressure and the inside hose allowances can be flowed at whatever the street
provides per our Building Code ('93 Boca w/amendments). But (sorry Sister),
a performance test must be done with a pumper truck to meet the 100 PSI
flowing at 500+250+250... for acceptance. One worthwhile note is our
Building Code requires the non-pumped standpipes be hydraulically sized
based upon 150 PSI at the FDC. I sometimes have to take pressures to 175
PSI on the FDC gauge to make them work. So much for shop drawings, huh?
No manual standpipes here unless granted relief by the ZBA.
Tom Duross
Yes I agree this is correct Paul but some jurisdictions such as here in
Rapid City do not allow the manual standpipes per local ordinance. I am sure
there are other jurisdictions that have their own reasons but our fire
department pumper trucks cover a very large geographical area and are many
times servicing the latest rural fire in ten buck two or assisting with
forest fires. We have the only full time fire department in this half of the
state. (Only 2 full time departments in the whole state).They simply have
made the decision that they don't want to have to limit how many of their
trucks that they can lend out to ensure that they have enough to cover
whatever may come up in town so they require the fire pump. I understand
that in most areas that are more populated this is not the case but just an
FYI..
Rod DiBona
Rapid Fire Protection
OK...
I have to say that I have learned a thing or two in this thread...but for
most of it I keep thinking like a code consultant......somebody tell me I am
wrong but....
IBC requires a Class III standpipe for buildings over 30 ft above the lowest
level of FD access. Since the building is sprinklered, the Class III
requirement is now a Class I requirement due to the IBC exception #1.
Now, at 6 stories, the walking surface (floor level) of the 6th floor is
almost always less than 75 ft above the lowest level of FD access....a non
high rise.
Now you go to NFPA 14 5.4 permits manual standpipes for this type of
installation...even if in combination with a sprinkler system (See NFPA
14 7.7.3). The only "automatic" requirement in the building code is for
Group A occupancies and NFPA 14 only requires it for high rises
Bottom line, you can rely on the FD pumper to provide adequate pressure to
the top floor....not your fire sprinkler system fire pump. This usually
reduces the size of the fire pump considerably and eliminates the issue of
having a pump capable of providing min 100 psi at 750-1000 gpm some 65 ft.
up while still maintaining system pressure below 175 at the lowest levels at
churn.
Am I missing something here? I will not say that this logic always works as
site conditions can make this a closer call. But an FD pumper pumping at
175 psi should have no trouble overcoming the 65 ft (30 psi) elevation loss
and any friction losses with some room to spare.
Paul Sincaglia, P.E.
_______________________________________________
Sprinklerforum mailing list
[email protected]
http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
