Craig,
That's consistent with an awful fire here in Escondido a few years
ago. A multi-family multiple building site under construction caught
fire around 1:00 pm, and every fire department in the northern region of
San Diego county responded to that event. Six of the seven buildings on
the site were completely destroyed despite the presence of the fire
departments with all the equipment you could imagine. After five hours
their operations changed from fire fighting to mop up and hot spot
attacks. In the aftermath it was learned that the two local water
purveyors in Escondido had delivered more than one million gallons to
the activities, and the discussion was put forth late in their effort
that the demand had reached a point where no more water could be sent
without drawing the reservoirs below the minimum levels.
If you do the quick math that's more or less 3,333 gallons a
minute. And they still were unable to stop the fire. For that project,
based on the same section you're referencing in the California Fire Code
(amended IFC), was around 6,000 gpm reduced to 3,000 as the buildings
were provided with sprinklers. The sprinklers didn't have any affect on
this fire, however, as their installation hadn't been completed.
*Ken Wagoner, SET
*Parsley Consulting***
*350 West 9th Avenue, Suite 206
*Escondido, California 92025
*****Phone 760-745-6181*
Visit our website <http://www.parsleyconsulting.com/> ***
On 8/28/2014 6:21 AM, [email protected] wrote:
The Fire Flow value is not about sprinklers. It is about hydrant flow.
Remember the majority of sprinklers are designed to control, (suppression mode
aside) not necessarily extinguish the fire. So in a significant fire, the fire
department is tasked with the extinguishing effort via hydrants and manual hose
lines.
Depending on the conditions of the fire, the manual fire fight could take
hours. Recent warehouse fire was a 13 hour fire fight due to the commodity.
So if you flow 1000-1500 from a deck gun then add 3-4 hose lines at 250 -500
gpm each and you can see where a lot of water can be used rather quickly.
Remember that for the most part sprinkler flow is 1 hour or 2 hours, not 4
hours.
I think as fire protection engineers/designers we primarily focus on the
sprinklers and often forget that when the sprinklers go off, that's only the
beginning of the suppression effort. There is much more tied into this work we
do.
Craig L. Prahl
Fire Protection Group Lead
CH2MHILL
Lockwood Greene
1500 International Drive
Spartanburg, SC 29303
Direct - 864.599.4102
Fax - 864.599.8439
CH2MHILL Extension 74102
[email protected]
-----Original Message-----
From: Sprinklerforum [mailto:[email protected]] On
Behalf Of Brad Casterline
Sent: Thursday, August 28, 2014 9:09 AM
To: [email protected]
Subject: RE: 1, 2 & 3 hour stored water duration requirements
That is mind-bending Craig, thanks. I do not doubt the procedure for coming up with 2
million. I guess what's bothering me is along these lines: "If a couple three
thousand GPM flowing for 30 minutes doesn't do the trick, how is 10 times that going to
help"?
Brad
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Thursday, August 28, 2014 7:11 AM
To: [email protected]
Subject: RE: 1, 2 & 3 hour stored water duration requirements
Fire Flow from Section 507 of the IFC is typically the driver when it comes to
large aboveground tanks. This is one issue often forgotten or overlooked in
fire protection design.
When determining the adequacy of water supplies, both the sprinkler flow and
Fire Flow must be considered.
I had a project last year with 8000 gpm for 4 hour duration for fire flow.
Yes it was a big honking tank, 2 million gallons. Deluge system flows were
at the 7500 gpm mark.
Got one right now that's a bit smaller with only 6000 gpm for 4 hours for fire
flow.
Rule of thumb for estimating tank cost is between .60 cents and $1.00 a gallon
depending on location and installation issues.
Craig L. Prahl
Fire Protection Group Lead
CH2MHILL
Lockwood Greene
1500 International Drive
Spartanburg, SC 29303
Direct - 864.599.4102
Fax - 864.599.8439
CH2MHILL Extension 74102
[email protected]
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