Sean,
You might want to take a closer look at 17.2.4.1.2(4), as it tells
you quite clearly that the approach you're considering using the 14.0 or
16.8 K-ESFR's is fine if the slatted shelves do not exist above the
12'-0" level, and clause (8) which identifies the maximum roof height as
27' where ESFR's are used, and clause (9) which identifies the maximum
storage height as 20'.
As 17.2.4.1.2 requires that _*all*_ of those 10 conditions have to
be met I don't believe you should start down the path of using the
slatted shelf rules, since what you described does not conform to at
least two of the ten items.
sorry,
*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 11/12/2015 8:27 AM, [email protected] wrote:
Hi Forum,
The following is based on NFPA 13 (2013). We have a roof height of 30ft, owner
wants to store exposed unexpanded plastics in double row open racks up to 25ft.
No solid shelves or open top containers. Looking at Table 17.2.3.1 my options
are 14k@50psi OR 16.8k@35psi. We have low water pressure and the owner doesn't
want a fire pump, he also wants ESFR, so we want to use K25@15psi. K25 doesn't
come into play until storage is 25ft with a 40ft roof, but it requires 50psi.
This pressure wouldn't work for what we are being asked to do. Using our
K-factor formula equation the K14 and K17 heads require roughly 100gpm based on
this table. If I run the K25 at 15.7psi I get 100gpm. Does anyone see this as
being a problem? Is there an issue with the water not being able to penetrate
the fire if the pressure is so low on a K25 while also being located so close
to the top of the storage?
To make this extra confusing If we read through section 17.2.4, it appears it
will allow me to use the K25@15psi so long as I meet the 10 requirements. But
this section is for when you want to use slatted shelves. Which would seem to
delay heat travel and water travel compared to open racks. I'm sure I can
convince the owner to follow these line an verse if he wants to do this storage
arrangement, but it doesn't make sense to me that adding slatted shelves and
wire mesh should be necessary. Since it specifically doesn't state that open
racks are also allowed with this design, I might run into a reviewer that is
checking boxes rather than trying to think it through.
Thoughts? Thank you for your time an help.
Thanks,
Sean VG
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