Jim,
I completely agree with what Travis has noted. You didn't mention which
edition of NFPA-13 was in force in your area, however here's some
relevant sections from the '19 edition:
Table 27.2.4.8.1 advises that the C-factor should be 100 when using
steel pipe in a "dry systems including preaction."
The same modification applies to the use of galvanized steel.
Section 19.3.3.2.5 requires that dry pipe and double interlock preaction
systems require an increase in the remote area by 30% without revising
the density. The annex to that section deals with the use of extended
coverage sprinklers, and the release system activating prior to the
sprinkler system. The text is unchanged from 11.2.3.2.5 in the '13 and
'16 editions.
There is some explanatory text in the handbook, explaining the reason
for the requirement of area increase has to do with the delivery of
water taking longer in such systems, and to compensate for this the
remote area is increased.
I am not suggesting that you become confrontational with whoever told
you that the increase was not necessary. However I would advise them
that you're increase of the most remote area is specifically required by
that section of NFPA 13. I don't get all that upset when an AHJ takes
this position. However, an FPE taking that stance is specifically
telling you to design a fire sprinkler system which does not conform to
NFPA 13. That sort of position entails all sorts of liability issues.
When ever I am confronted with a mandate of that nature, I ask for that
requirement in writing, and make sure that both my attorney, and
insurance underwriter has a copy on file.
And no, I don't believe you've been doing it wrong for the last 15
years. If you are, then I've been doing it wrong for 40 years.
sincerely,
*Ken Wagoner, SET*
*Parsley Consulting
500 West Mechanic Street
Harrisonville, Missouri 64701-2235*
*Phone: (760) 745-6181 *
*Visit the website
<https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.parsleyconsulting.com%2f&c=E,1,Y5zKJKPEh1mBEBqSR-VE9cUKl5y-eyP8BpvmE_5j9ZqW2eJbNphYzrCMBZ-2YuX6d-RRkHI4gQ1FV-cvOeCfRC58uZS9NiToZv2mx7909oCqLvCW_n5hDHeK&typo=1>*
_______________________________________________
Sprinklerforum mailing list
[email protected]
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
