Folks, you are missing the picture here...no one said it was an AHJ who asked
the question! Lets not make that jump, cause I have volumes of pictures from
contractor installations that would make you change your name. The point here
is that NFPA 13 does not say when to stop looking. 13 does not tell you after
so many feet in the air you don't have to put them in even though it wasn't
until the early to mid 90's that we were actively pursuing full scale testing
above 45 feet and that was all storage testing at that. Why 45ft you say?
cause that was the height of the roof deck at the testing lab! and on top of
that we have no clue if heads in a mall with a ceiling height of 60ft is going
to work...sure we can model it and make some safe assumptions and put a seal on
it...but without burning it, we are guessing. Just like we were guessing with
attic designs until we found out what was in the book for attics from the
beginning actually burned down....three times. That doesn
't automatically mean we should stop putting them in...but we have to be
realistic about how effective sprinklers will be at those heights given light
hazards. Conversely, no where in 13 does it say when to stop looking below the
deflector...in other words, after the golden zone of 18" at what point can we
say...the pattern is developed. Take a look in chapter 8 at the minimum
distances a sprinkler must perform for a listing at 7psi, I am traveling right
now so don't have the reference but its the picture of a spray pattern that you
have passed by hundreds of times while looking for something else.. somewhere
around 8.5 I think. Digest that a minute. The point I am making is that this
4ft rule, which ole Joe Hankins shared with me years ago, had nothing to do
with duct work or conference tables. Look at the diameter of the spray pattern
at 18" down and then 4ft down. The fact is you can give James G at Tyco or any
of his counterparts a storage configuration and he will
be one of the few that has a chance at getting close to what will happen.
But then ask him how many full scale tests have we run simulating light hazard
scenarios. You will think your phone lost its signal. Do we really need to
put sprinklers under a duct that is 49" wide and 24" off the ground? This is
my point. We cannot claim ignorance at one group or another...it is the
condition of prescriptive codes and standards that is at fault here. My first
cycle I was on the committee we went to dinner one night and I got sat down
next to Chet. As we talked he said something to me that stuck like pipe dope
to my door handle...and that was in the world of prescriptive codes, once
something makes it into the book, good luck ever taking it out (hence the
difference in size from 1970 to now) because the measuring stick after it gets
in their is that if people are not dying and buildings are not burning
down...then the rules must work! That's the only reason the 4ft rule is ha
s survived over 100 years. Just look at the difference between the storage
chapters and the rest of the book. If theres one thing we are getting our
hands around..it is storage. But light and ordinary are left guessing, hoping,
modeling, wondering......the answer to the original question is still put a
head under the door and omit it from the calcs....but ya gotta love how we get
there!Whew...almost missed the plane! Ciao,Scan
> From: [email protected]
> Date: Wed, 9 Oct 2013 11:48:36 -0500
> Subject: RE: Sprinklers Below Overhead Doors
> To: [email protected]
>
> Too many times, bottom line for owner's................Low bidder......
>
>
> David Autry
>
> Meininger Fire Protection Inc.
> 2521 W L St. Suite No.4
> Lincoln, Ne 68522
> Voice (402) 466-2616
> Fax (402) 466-2617
> [email protected]
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Todd
> - Work
> Sent: Wednesday, October 09, 2013 11:23 AM
> To: [email protected]
> Subject: Re: Sprinklers Below Overhead Doors
>
> Unfortunately, "experienced" and "responsible" are vague terms and open to
> too much interpretation. It is incumbent on the property owners not to
> hire bozos, unfortunately, that does not always happen
>
> Todd G Williams, PE
> Fire Protection Design/Consulting
> Stonington, CT
> www.fpdc.com
>
> On Oct 9, 2013, at 11:59 AM, David Autry <[email protected]> wrote:
>
> > From my 1961 Edition:
> >
> > (in bold print no less)
> >
> > 1421. Sprinkler system layout and installation should be entrusted to
> > none but fully experienced and responsible parties. Sprinkler system
> > installation is a trade in itself. Inspectors cannot be expected to
> > act as working superintendents or correct errors.
> >
> >
> > David Autry
> >
> > Meininger Fire Protection Inc.
> > 2521 W L St. Suite No.4
> > Lincoln, Ne 68522
> > Voice (402) 466-2616
> > Fax (402) 466-2617
> > [email protected]
> >
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]] On Behalf Of
> > Cahill, Christopher
> > Sent: Wednesday, October 09, 2013 10:37 AM
> > To: [email protected]
> > Subject: RE: Sprinklers Below Overhead Doors
> >
> > I wish I could find my 1936 copy. That was in there. Well it went
> > more like this...sprinklers are their own trade and shall be installed
> > by only those trained and experienced. AHJ is not a field
> > superintendent and is not expected to supervise the work. OK maybe
> > yours improves with bringing AHJ into the knowledgeable.
> >
> > Chris Cahill, PE*
> > Senior Fire Protection Engineer
> > Burns & McDonnell
> > 8201 Norman Center Drive
> > Bloomington, MN 55437
> > Phone: 952.656.3652
> > Fax: 952.229.2923
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