In defense of Paul, he was not disagreeing with the original thread but very
accurately pointing out a fire marshal cannot legally require any more than
the code (law). He (and I last week) are talking about the resignation many
seem to have the AHJ is always right or at least you follow their direction.
Now George points out he has some fire marshals that have legally modified
the standard thus making something more restrictive the new minimum in at
least that jurisdiction. No one is complaining about these legal
modifications. It's the non-legal ones sometimes called policies.
I'll also defend Paul's other comments about built in safeties. He never
said 0.913 is OK. Nor did he suggest the building would get built to plan.
He was just pointing out what Ron summed up another way:
"> Yet another case of calculate with a computer, measure with a
> micrometer, mark with a piece of chalk and chop off with an axe.
> Ron Fletcher"
Oh, and I don't know Paul, have never received and compensation from him for
any reason.
Fully .913 is OK with NFPA 13 IF the flow test is accurate and accounts for
reasonable fluctuations AND the system isn't modified AND a few other
caveats.
But none of this means we should design for 0.000 "safety". And I say
"safety" because this is on top of all the other safeties and is only a part
of the real safety. We should (but don't have to by law) consider what
could change or go wrong and pad the issue to protect in order of importance
the life of occupants (including FF), the valuable of occupant's possessions
and your corporate assets.
It's fully reasonable for the AHJ after installation to reject a system with
a .913 safety because a line was shifted or whatever.
Does anyone want to reasonable argue on the day of a fire if the supply
pressure is a few PSI under the calculated PSI it's going to make a
difference in the outcome of the fire. If so I suggest you get a copy of
NFPA's report on sprinkler operations that basically says if the valve is
open things will be OK. That may be simplifying it a bit but that's what I
come away with. Systems fail because there is no supply, or high piled
storage with a light hazard design or other gross problems. A few PSI here
or there will not make a difference in 99.9999% of the cases. And the
.0001%, well we have bigger issues to resolve.
You may not believe it but I had someone ask if a sprinkler company could be
held liable for over designing because of too much water damage. I think
they were trying for if 15 gpm would put out the fire then they were liable
for the extra 30 gpm that actually came out. But I wouldn't entertain the
conversation long enough for such IMHO foolish ideas, lawyers!
Chris Cahill, P.E.
Fire Protection Engineer
Sentry Fire Protection, Inc.
763-658-4483
763-658-4921 fax
Email: [EMAIL PROTECTED]
Mail: P.O. Box 69
Waverly, MN 55390
Location: 4439 Hwy 12 SW
Waverly, MN 55390
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Kathryn Tyler
Sent: Friday, March 16, 2007 9:42 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
Paul and Chief Life Safety Engineer,
Maybe you have not designed jobs to actually be installed in the field, but
chances are the building will not get built exactly as the plans indicate,
the HVAC will not get installed exactly as the plans indicate and so on...
AND THE FIRE PROTECTION MAY NOT GET INSTALLED EXACTLY AS IT IS DRAWN, which
means the fitters may have to add a few 90's, etc. and that is way a safety
margin of 10% is not only a good practice, but possibly to make sure of
changes in the field will still allow the system to function properly and
put out a fire if needed.
Kathryn
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Paul Pinigis
Sent: Friday, March 16, 2007 7:14 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
We have an AHJ who has developed a "god complex" from years of having
contractors, engineers, and building owners bow down to kiss his feet and
satisfy his every whim. It is now at the point that he believes that it is
his prerogative to choose the construction type of the building, the type of
smoke detection system that is used, the manufacturer of the fire alarm
system, etc.!
The AHJ is there to enforce the code, not to reinvent it.
Paul J. Pinigis, P.E.
Chief Life Safety Engineer
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Friday, March 16, 2007 10:05 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
I know the municipal AHJ issue has been discussed before. When the AHJ asks
for something and denies a C.O. based on your refusal to provide what was
asked, it's often easier to comply if it's not a liability or cost issue.
Most owners don't appreciate a delay in occupying their facilities based on
the legality of what the AHJ can or cant legally ask
for. Sure we would like to push back and fight it, but the reality is
sometimes that's not practical or feasible. The owner may never see you
again after your job is done but he'll probably see that fire marshal every
year.
Also the term AHJ can also apply to a corporate life safety manager or other
corporate entity for companies who are self-insured and self sufficient,
i.e. no interface with local municipalities, they have their own private
water supplies, private fire brigades, etc.
Craig L. Prahl, CET
Fire Protection Group
Mechanical Department
CH2MHILL
Lockwood Greene
1500 International Drive
PO Box 491, Spartanburg, SC 29304-0491
Direct - 864.599.4102
Fax - 864.599.8439
[EMAIL PROTECTED]
http://www.lg.com
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Paul Pinigis
Sent: Friday, March 16, 2007 9:54 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
Yes, the insurance underwriters can add their requirements, but the AHJ
cannot. The AHJ is tasked with enforcing the adopted codes, not inventing
new ones or adding his/her personal preferences. The code does not demand a
pressure cushion, neither can the AHJ.
Paul J. Pinigis, P.E.
Chief Life Safety Engineer
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Friday, March 16, 2007 9:41 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
Also, some insurance underwriters and AHJ's have requirements relating to
particular required safety factors in the calcs. Don't forget to
check with them as well.
Craig L. Prahl, CET
Fire Protection Group
Mechanical Department
CH2MHILL
Lockwood Greene
1500 International Drive
PO Box 491, Spartanburg, SC 29304-0491
Direct - 864.599.4102
Fax - 864.599.8439
[EMAIL PROTECTED]
http://www.lg.com
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Paul Pinigis
Sent: Friday, March 16, 2007 9:31 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
If you can achieve 10% without spending your client's money (or your
own) great, but it is not necessary.
Paul J. Pinigis, P.E.
Chief Life Safety Engineer
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Brian Harris
Sent: Friday, March 16, 2007 9:29 AM
To: [email protected]
Subject: RE: Minimum Supply Pressure
10% is what we go by, based on your numbers your only at around 2% :(
Regards,
Brian Harris
First Defense Fire Protection
Design Engineer
[EMAIL PROTECTED]
704.948.3506 phone
704.948.3507 fax
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Charles
Thurston
Sent: Friday, March 16, 2007 10:19 AM
To: [email protected]
Subject: Mininum Supply Pressure
Hello All,
Let me be the one to start things today.
What is the minimum safety pressure allowed ? I have looked in 13 and did
not find it.... I have a situation where the safety pressure is
0.913 psi.
Basis is:
Hose 250
Static 67.00
Residual 38.00 @ 920.00
Available 40.128 @ demand of 882.87
Requires 39.215 psi
Leaving a safety of 0.913 psi
--
Best regards,
Charles mailto:[EMAIL PROTECTED]
Coastal Fire Protection
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