I have been following this thread since it started, and shaking my head all
the while.
Steve, your points are spot on.
Jeff Hewitt, PE, SET, SFPE (Prof. Member)
Corporate Engineer
Bi-State Fire Protection Corporation
636-946-0011
636-946-5172 (FAX)
----- Original Message -----
From: "Steve Leyton" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, January 15, 2007 4:03 PM
Subject: RE: max velocity
I love this. So now it's your responsibility to manage what the client
might do or what might happen to this occupancy in 3, 5, 10 or 20 years?
With all due respect, that's not your responsibility and beyond that,
where does it end? I had a fire official try to require a .45/3000
s.f. design in a 3-story office one time because she pointed out that if
a future owner or occupant cut out part of the second and/or third
floors they could theoretically use the building for high-piled storage
some day - do you agree with that?
I hope not, but if you squint and look at it in just the right light
it's the same thing as saying that there's some value to future owners
or tenants if you make the installer hold velocity to some arbitrary
level or not allow the efficiencies associated with the hydraulic design
of QR sprinklers. For the past 5 days including the weekend, a
stream of extremely articulate rebuttal has been running through the
forum that casts aspersions on the validity of velocity limits, yet at
least two of us cling to this notion that there's a benevolent value to
society (?) if we dig in and obstinately insist that there is a basis
for an archaic requirement such as this. It has even been pointed out
that the original basis for your opinion, that it was once in NFPA 13,
isn't accurate yet some would cling to the notion that it was ever
codified to begin with.
Mario, I believe your opening line is a misstatement - "Usually the
customer changes the occupancy or the use of the building or certain
areas of the building or increase the size of the building." That is
not true; SOMETIMES a building gets enlarged and sometimes its use
and/or occupancy changes, but I'll bet that it's 1% of the time, maybe
2% (I would value the opinions of others on this point.) A tilt-up
shell is a warehouse is a warehouse is a leased light industrial or
heavy industrial use, is a warehouse. And an office shell may have a
small deli or mini-mart, but for the life of that building it's an
office shell. Same for retail (admittedly there is more to that type
of project in terms of design criteria, but it's still going to be a
mercantile project for it's entire life span). Same for a courthouse.
Same for a high-rise condo or a mid-rise condo. Or a hotel. Or, or,
or ...
It is NOT the responsibility of the AHJ to read the tea leaves and
ordain the a project should be designed in accordance with any code or
standard except those that apply to what it is or is proposed to be as
submitted. You need peace of mind to sleep well at night? You can
have it. Make it the safest hotel we can reasonably make it according
to what's in writing the day they submit for permit. But protecting a
hotel with arbitrarily oversized piping or a pump that it doesn't need
or three times the amount of water in the system than it requires only
costs our community money and there is not tangible benefit no matter
what weird science you throw at the issue.
Steve Leyton
Protection Design & Consulting
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Monday, January 15, 2007 1:36 PM
To: [email protected]
Subject: Re: max velocity
Mr. Rahe Loftin,P.E.:
I agree with you. Usually the customer changes the occupancy or the use
of the building or certain areas of the building or increase the size of
the building. If the piping is at the beginning small then the customer
is penalized because he has to revamp the system. There are some
agencies that specify 20 fps to allow them to expand the building; to
have a margin of safety if the city drops the pressure;to be sure to
have 7 psi at the last sprinklers; to be sure that the highest branch
has 15 psi.
The water pressure will compensate if high velocities are used if the
city would provide more pressure.
The Hazen Williams formula was developed at 3 fps for open channels.
Keep up the good work.
Thank you.
Mario Berrios, P.E.
-----Original Message-----
From: [EMAIL PROTECTED]
To: [email protected]
Sent: Mon, 15 Jan 2007 4:03 PM
Subject: RE: max velocity
I suggest that Schedules 10 and 40 domestic pipe and (with a few quality
imports excepted) domestic fittings as well, are the best way to assure
the proverbial 50-year building. But the rest of it is just a waste
of taxpayer money, as far as I'm concerned - especially velocity limits
or any other unsubstantiated provision that only adds cost to the
construction without tangible benefit. Our firm does a measurable
percentage of work in the Federal jurisdiction (NAVFAC and ACOE,
primarily) as well as State of California projects for schools and
licensed healthcare. Although this work contributes to our bottom line
and puts food on the table, I always marvel at how public money seems to
be "cheaper" than private money - at least to the folks who spend it.
Steve Leyton
Protection Design & Consulting
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Monday, January 15, 2007 10:55 AM
To: [email protected]
Subject: RE: max velocity
Folks,
Here is some more food for thought. I provide the sprinkler
specification for all of my federal projects. I use 20 fps velocity as
a limit and a maximum C of 100 to insure that I have a system that has a
chance to last for the life of the building (approximately 50+ years).
Our buildings are always being changed with the sprinkler system being
drained and modified many many times by all sorts of contractors, from
the best to the worst.
Once the building is constructed and occupied, the local GSA service
center does all of the work in the building, usually with the lowest
bidder.
Therefore, we need some sort of hedge against all of this. Once the
building is built, it is out of my control. I see no problem specifying
these limits as long as everyone is bidding the same job.
Any suggestions?
Thank You
Rahe Loftin, P.E.
Region 7 - GSA
Office - 817-978-7299
Fax - 817-978-8644
Cell - 817-371-3102
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