Hydrostatic Test Req'd for Adding Few Sprinklers?

12/2/2024

Is a hydrostatic test required for adding two new sprinklers to an existing system?

For this, assume it can be isolated, and the local jurisdiction refers to NFPA 13 - 2016 Edition.

This is the most referenced code outside of the obstruction rule, and is the most common I've seen interpreted differently amongst professionals.

Reference Chapter 25, Section 25.2. What is your "threshold" for triggering a hydrostatic test?

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14 Comments

Dan Wilder

12/2/2024 07:25:50 am

Technically, yes on all systems per 25.2.1.4 (working pressure) and again 25.2.1.4.1 (200 PSI for modifications >20 sprinklers) or when isolation is not possible, test to working pressure per 25.2.1.4.2. So, no matter what, there is a test. I think the issue is everyone jumps to 200# (up to 225#) when they hear "Hydrostatic", not just a given pressure for a set amount of time as defined in 3.8.1.14.3.

The 2019 Edition moved this into its own Chapter 29 for "Existing System Modifications" (specifically 29.7) and does not fall into Chapter 28 for System Acceptance.

However, many AHJ's have modified this to their liking. Some of my AHJ's do not require testing when the work is 20 sprinklers or less (or they just want the system locked in at working pressure so technically a "working pressure" test), some like to see 50 PSI over working (kind of picking and choosing), another one used to state 20 sprinklers/40 fittings/40 feet of pipe (exceed any of those 3 and a 200# hydrostatic test needs to be performed), and others that have hardlines hydrostatic testing on all modifications that need to go to 200 PSI (we will typically isolate the area of work or get a letter signed from the owner about areas outside our scope becoming issues).

12/2/2024 07:10:22 pm

Thanks for the response. I take a very similar stance as you. Also, thank you for pointing to a seemingly simple but very helpful reference to the definition.

Anthony

12/2/2024 07:37:28 am

Yo can always get the base of riser pressures and flow, At least the start of a curve. You'll have a static pressure at the riser and a residual pressure when you flow through the test port on the system. Use the test port and K factor and calculate the flow given the pressure on the riser. Note this should only be done where the test port is on the riser not a remote test port.

I'd think that would suffice for a 2 head addition and not need calcs all the way back out to the street.

Glenn Berger

12/2/2024 08:13:11 am

I have never had a project that a hydro test was not mandated. Normally just at system pressure for any type of system modifications regardless of the number of sprinklers added or subtracted.

12/2/2024 07:13:10 pm

Thanks for your response. I believe, like Dan noted really well above, is that people tend to jump to a definition of hydrostatic testing automatically triggering a 200 lb. test and not other methods i.e. system pressure, 50 psi above operating pressure, etc.

Anthony P

12/2/2024 08:17:36 am

As Dan said, confirm with the AHJ. New York has a few different scenarios for this. Whether its Port Authority or DOB. I have seen it where the AHJ just wanted an Air Test and for it to not lose pressure.

I have also seen some scenarios where it was stated once you touch the system you own it so be very specific on the matter.

Jerry Clark link

12/2/2024 09:50:10 am

And to back up what Dan said at the beginning of the thread, the 2016 commentary recognizes that systems may not require a full hydrostatic test for minor modifications:

"Paragraphs 25.2.1.4 and 25.2.1.5 address additions and modifications and specify when new piping installations are to be isolated and tested. In many cases, segregating new work from existing work is difficult. To require the entire system to undergo another hydrostatic test when only relatively minor changes are made is unreasonable and not required by NFPA 13.

Where system modifications are made and the piping cannot be isolated, such as relocated drops, NFPA 13 provides some flexibility and permits hydrostatic tests to be conducted at the system’s normal static pressure. In general, existing portions of the system do not need to be subjected to a new hydrostatic test."

Anonymous

12/2/2024 07:21:04 pm

would you consider two new sprinkler heads to an existing system, a "modification"?

Jack G

12/2/2024 10:17:09 am

I agree with Jerry.
I usually ,in my proposals , do not include a hydro of the entire system at 200 psi. Just the 50 psi over the static as stated in nfpa 13.
I also state in acceptance of proposal that if the 200 psi hydro is required, ( and the hydro of 50 psi over the system pressure) my company is not responsible for fixing the leaks or water damage and will be addressed as a T&M change order.
This is usually the practice in the 3 states I work in and is generally an accepted clause to contract.

Ryan

12/2/2024 11:55:24 am

Where are you getting the additional 50psi over system pressure?

12/2/2024 07:16:54 pm

NFPA 13 - 2016
25.2.1.2

Ryan

12/3/2024 12:07:07 pm

The 50 psi is only when the system pressure is always at or higher than 150. So if static on system is 160, it has to be tested at 210. No other time do you have to add 50 pounds.

sean

12/2/2024 10:18:48 pm

all new heads need it. modifications can can be at system pressure.

I think the isolated is abused. being isolated does not need to be easy just possible.

Mark Harris

12/8/2024 11:43:21 am

Agree that sometimes the requirements seem excessive. I always thought the 20 sprinklers was reasonable compromise. If there is a workmanship or defective fitting most times system pressure will show it. As far as two isolated heads what about the connection when you are done with the hydro test on two heads? Or hydrotest done at rough in and then cutting drops after ceiling install. Just saying think the test requirement could easily be abused and additional cost may be excessive. We are a code driven industry but still want our end users to consider they are getting value. First step of that value is providing quality workmanship and materials. Sprinkler systems have an enviable track record so we never want to compromise system integrity. If those two sprinklers are over a multi-million dollar clean room tool verses two sprinklers for a couple bathrooms in a Great Clips lease space I may look at it differently. Glad NFPA 13 has tried to clarify but ultimately it is up to the AHJ.

Hydrostatic Test Req'd for Adding Few Sprinklers?

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