Todd,
A fair amount of experience with two-inlet FDCs with a single clapper and a
bypass around the check valve. I don't recommend it as the clapper can be
unstable and slam shut...talk about water hammer! I like Tom Worley's
suggestion.
Dwight HavensFire Code Official - retired.
On Thursday, March 28, 2024 at 10:55:32 AM EDT, Fpdcdesign
<[email protected]> wrote:
To a certain extent, this is a rhetorical question. We can use the 1st floor
hose valve on the standpipe as a flow outlet. I assume with the available
water, flowing 250 gpm through a single 2-1/2” hose and Hose Monster is not
going to be a problem.
But the real problem is that there is not a good way that I know of to predict
this. I won’t know until the job is done if there is enough water from the hose
outlet to meet the requirement. Then if the system has to be retrofitted, it
becomes a big deal and a big expense. How is everyone else handling this?
Todd G Williams, PEFire Protection Design/ConsultingStonington, CT860-535-2080
(ofc)860-554-7054 (fax)860-608-4559 (cell)
On Mar 28, 2024 at 9:54 AM, <Jackie Ward> wrote:
Or mech-tee the riser and add a hose valve.
Thank you,
Jackie “JW” Ward
1-405-240-7076
From: Worley, Tom <[email protected]>
Sent: Thursday, March 28, 2024 8:46 AM
To: Discussion list on issues relating to automatic fire sprinklers
<[email protected]>
Subject: [Sprinklerforum] Re: BFP Forward flow test design
Just make the main drain 2½. A 2” may even suffice depending on how the water
supply is.
Thomas R. Worley
Estimator/Design Manager
Fire Foe Corp.
999 Trumbull Ave.
Girard, OH 44420
P: 330-759-9834 x112
F: 330-759-8949
E:[email protected]
From: Fpdcdesign <[email protected]>
Sent: Thursday, March 28, 2024 9:38 AM
To: Sprinklerforum <[email protected]>
Subject: [Sprinklerforum] BFP Forward flow test design
I am working on a re-design of a system where I need to include a provision for
doing a forward flow test for the backflow preventer (4”). Due to space issues,
I would like to do a by-pass around the check valve to the FDC. Is there a
problem with this due to the clappers in the FDC?
Also, the building is Residential or Light Hazard and the maximum demand flow
is around 250 gpm. If I have to add another outlet for the test, would a single
2-1/2” FDC be acceptable? Unfortunately, I am not aware of any way to predict
what would be required. Is there any rule of thumb for the design of these
things?
Todd G Williams, PE
Fire Protection Design/Consulting
Stonington, CT
860-535-2080 (ofc)
860-554-7054 (fax)
860-608-4559 (cell)
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