nfpa 13 d water requirements

[inspectortx2]

went to a house to inspect the fire sprinklers for insurance reasons system had no calc tag and 52psi at the base of the riser and flowed forty psi at the main drain. No room had more then 1 head in it and system was looped from city supply. does system have enough water and is a loop system legal in 13d cant find any thing in 13d 2007

 

[TravisMack]

looped is fine. You just have to follow calc procedures in NFPA 13.

No way to know if there is enough flow/pressure without a lot more information.
elevation
k-factor of sprinkler
water meter size
lead-in size
backflow preventer?
diameter / lengths of piping
etc....

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[inspectortx2]

I got all that info if you can give me an answer 9ft ceilings 4.2k heads backflow is 1" watts 007 meter is 1" pipe is all 1" cpvc most remote head is 54ft from riser feed from street is 1".

 

[TravisMack]

You need to have a schematic of the piping system in order to calculate it and see if it will work.

Is there a remote insp test connection? If so, do a bucket test. That will give you a good idea of what is available and if the system works or not.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[inspectortx2]

what is the bucket test never seen one of those. and how do you preform it. Wish i could draw it out on here for you

 

[TravisMack]

A bucket test is where you flow through an orifice and time how long it takes to fill a 5 gallon bucket. Then, you can figure your gpm through that orifice. If it matches the sprinkler criteria, then you are good.

If you can draw it out, you can calc it

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[inspectortx2]

dont know if i can calc it im just an inspector though i did pass level one for wated based lay out for nicet but i can hand draw it but thanks for the info it help how many heads do you have to calc on a 13d system?

 

[TravisMack]

Calc all of the heads in a compartment to a maximum of 2. If each room only has 1 head, then you are only going to calculate 1 head.

With current programs, it is not really all that hard. Even doing a loop calc by hand is not overly difficult, especially when it is only 1 head flowing.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[stookeyfpe]

Another option is one can now perform hand calculations using Section P2904 in the 2009 International Residential Code. It is completely prescriptive.

 

[TravisMack]

Stookey: Is that for tree systems only, or is it also for a looped/gridded system? There is a simple layout in 13D for tree calcs. But, if you loop or grid, then you have to follow NFPA 13 procedures.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[stookeyfpe]

It's designed for tree systems. But the calculation prove you can make it work for a circuit (loop) with a simple loop design. The calculations consider the pressure drop on both sides of the circulating loop.

I hope that was helpful.

 

[cdafd]

So you are an inspector

And the owner or insurance company wants you to say system is good to go

Sounds like I would put it back on the owner / insurance co to hire someone to prove ip the system

I would not put my name on it, being an inspector also

 

[inspectortx2]

Thats why im here every thing is in working order but i dont know if there is enough water to run the system im not a designer and there is no calc tag . so i told the owner he would need a design evaluation done and have it calc by one of our designers before i hang a tag. the owner needs and inspection done so he can get an insurance credit but i wont put my name on it unless i know its good

 

[cdafd]

Do you work for a private company or public agency???

 

[inspectortx2]

private company what about you

 

[cdafd]

City inspector

So sounds like one of your designers needs to do some work

 

[inspectortx2]

Yep and i know just the designer to give it to. We did not put it in but we will make it right if any thing is wrong.