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Number of sprinklers on a branch line? 1
- Thread starter carlosgw
- Start date
skdesigner
Mechanical
No. You can have as many heads on a line as can be proven with hydraulic calculations.
Sdpaddler50
Mechanical
I am not a sprinkler designer, and only periodically fire up my hydraulic software, but yes, there is definitely a limit to the number of heads allowed on a branchline.
Use the skew formula to determine this. I have not checked for many years, but it should be in NFPA 13. Its 1.4 x square root of the remote area. Note: I believe NFPA is 1.4, and FM notes 1.2, but i will let you confirm that. For example if you have a 2,000 sq ft remote area, using this formula gives you 54 ft. If you are using 10 ft line spacing, you therefore can have a max of 5 heads per line.
For ESFR, you are limited to 4 heads per line. For the typical 12 head ESFR design area, it is therefore 4 heads on 3 lines.
This is important. Fires dont grow in one dimension. These rules make sure designers are applying remote areas that most closely resemble a someshat cirucular fire growth pattern.
Use the skew formula to determine this. I have not checked for many years, but it should be in NFPA 13. Its 1.4 x square root of the remote area. Note: I believe NFPA is 1.4, and FM notes 1.2, but i will let you confirm that. For example if you have a 2,000 sq ft remote area, using this formula gives you 54 ft. If you are using 10 ft line spacing, you therefore can have a max of 5 heads per line.
For ESFR, you are limited to 4 heads per line. For the typical 12 head ESFR design area, it is therefore 4 heads on 3 lines.
This is important. Fires dont grow in one dimension. These rules make sure designers are applying remote areas that most closely resemble a someshat cirucular fire growth pattern.
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TravisMack
Mechanical
Sorry, but the above statement by Sdpaddler50 is incorrect. NFPA 13 does not put a limit on the number of sprinklers on a branch line. You can have as many as you can calculate. If I have a gridded system with branch lines 200' long between mains and 10' on center, I am going to have 20 heads on that line. That is not a problem. I can have a tree system as well with any number of heads on the branch line.
There is a practical limit just due to the size of pipe that may be involved. But, NFPA 13 does not have a limit anywhere in the standard on the number of sprinklers per line.
Travis Mack
MFP Design, LLC
There is a practical limit just due to the size of pipe that may be involved. But, NFPA 13 does not have a limit anywhere in the standard on the number of sprinklers per line.
Travis Mack
MFP Design, LLC
Sdpaddler50
Mechanical
Yes, my bad. I was referring to the number of heads than can be calculated per branchline. When the OP said 8 heads, i thought he was referring to remote areas for hydraulic calculations. My mistake.
TravisMack
Mechanical
No problem. I just wanted to make sure that no one was confused.
Travis Mack
MFP Design, LLC
Travis Mack
MFP Design, LLC
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