I'll ask the unthinkable question, is the BoR demand on the placard worthwhile?
Hydraulic calculations are done back to the effective point of the flow test.
The underground losses, hose demand and sometimes backflow preventer losses are
taken before the BoR. Consequently you cannot compare the BoR demand to a new
public water test and make a valid conclusion without a full set of original
plans and calculations. Wouldn't it make more sense to put the demand at the
water source on the placard?
Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT
860-535-2080 (ofc) 860-608-4559 (cell)
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On Fri, Jul 8, 2016 at 10:21 AM, Ed Kramer <e...@bamfordfire.com> wrote:
I’ve asked this question in the past and the answers have been all over the
board.
I tend to think the BOR location needs to be consistent from project to
project, whether it’s a single system riser or multiple system risers. In our
part of the universe, most (but not all) backflow preventers are located inside
the building immediately downstream of the underground flange. I locate the BOR
at the underground flange on all systems. By placing data from that location on
the Hydraulic Design Placard, it makes it easier for someone else to compare
the sprinkler system demand to water supply data.
I believe the intent is to include the combined hose allowance, but got nothing
from the standard to back that up. With a strong water supply (lots of volume),
available pressure while flowing the sprinkler plus hose demand is going to be
virtually the same as pressure available while flowing only sprinkler demand.
But many of the water supplies we work with are marginal. Removing 100, 250 or
500 gpm combined hose allowance from the water supply can make a very
significant difference in available pressure. So when comparing sprinkler
demand to water supply data, knowing the combined hose allowance is very
helpful.
Respectfully,
Ed Kramer
Bamford Fire Sprinkler
From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] On
Behalf Of Ben Young
Sent: Thursday, July 07, 2016 3:06 PM
To: sprinklerforum@lists.firesprinkler.org
Subject: Base of riser on placards
What's the general consensus on the location of the 'base of riser' for
hydraulic placards that everyone uses? See Figure A 24.5 in the 2010 Edition of
13 and/or 24.5.2
I feel its supposed to be at the base of each sprinkler riser (where you have
multiple systems) where it ties into a common header.
Others in my office think its where the incoming flange comes into the riser
room.
If you have a vertical riser with a vertical backflow, then these two points
would be the same with either method in my line of thinking.
Also, is the hose indicated on the placards supposed to be inside hose only, or
combined in and out? I just realized after reading this today that it could
only be referring to inside hose, but I've always put the combined hose there...
Thanks,
Benjamin Young
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