I'm dealing with a situation now where we are completely renovating an old mixed-occupancy property and the plans were drawn and approved with a 2-inch incoming service for both the residential domestic water and the fire suppression system.
Now that the fire sprinkler contractor is ready to install, and the fire chief reviewed plans for the 2-inch pipe, the fire chief says he won't approve it unless we install a minimum of 4-inch incoming pipe from the main.
The architect says the city already approved the pipe size. Fire Marshal says no.
Anyone have code/insight to support either way?
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10/31/2022 08:07:12 am
First question is - Were the calculations performed with both the domestic supply and the fire sprinkler supply combined? (13-22 * 22.214.171.124).
Todd E Wyatt
10/31/2022 08:25:35 am
2022 NFPA 13 states :
10/31/2022 08:27:53 am
Agree with Dan, should be OK per code as long as you include the domestic demand in your calculations. You'd need good water pressure to be able to calculate NFPA 13 demand and domestic through a single 2" supply line though.
10/31/2022 08:42:51 am
Tyco dies make a RAPID RESPONSE Model RSV-1 Residential
10/31/2022 08:34:26 am
10/31/2022 09:39:08 am
I'm doubtful that a true demand calc was done.
10/31/2022 01:09:41 pm
Regardless of the pipe size approved by the city, the AHJ is the Fire Chief/Fire Marshal and they have the last say, not the city/architect. Good luck!
10/31/2022 03:46:29 pm
Arguing with an AHJ is like wrestling with a pig in the mud. Pretty soon you learn the pig enjoys it. Why argue? Change it to 4", get a CO and move on. This is not the first time this has happened and won't be the last.
11/1/2022 02:27:05 pm
I agree, as long as the demand of the domestic is added at the point that the water supply splits; one side to fire and one side to domestic you are ok. But if the AHJ says that is a no-go then try to get a CO and press forward. Personally I don't like the water supply to be smaller than 4" since it gives you more flexibility in the future whether its use change or the city supply degrades.
11/8/2022 07:22:11 am
early MEP plans probably did not include any calcualations. I can we why they are throwing a red flag unless there are sprinkler hydraulic calcs to back it up
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