Protect Sprinkler Main in Non-Sprinklered Space?

1/26/2021

We are working on a project where a feed main is running through an unsprinklered space to get to a sprinklered area. I've heard that sprinkler pipe needs to be protected by sprinklers so we are trying to figure out if this is an actual requirement or not.

We are talking about putting uprights on the feed main in the unsprinklered area to protect the pipe but I can't find anything in NFPA 13 that actually requires the pipe to be protected.

Does anyone know if this is a requirement or not?

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7 Comments

Franck

1/26/2021 09:13:44 am

You will find the answer here in NFPA 13 (2019).

16.4.3 * Protection of Piping in Hazardous Areas.
16.4.3.1
Private service main aboveground piping shall not pass through hazardous areas and shall be located so that it is protected from mechanical and fire damage.

16.4.3.2
Private service main aboveground piping shall be permitted to be located in hazardous areas protected by an automatic sprinkler system.

Franck

1/26/2021 09:20:01 am

In other words, if you're pipe is running in an unsprinklered area where there is (and will never be) no fire exposure hazard, then it might be acceptablme by the AHJ not to provide a sprinkler protection.

Be careful if you put upright sprinklers directly on the pipe, then you may have an obstruction issue and you have to provide a riser nipple depending on the pipe size (3 x the pipe diameter up to a maximum of 600 mm - 24 in.). This applies to pipes which are 3 in. wide in diameter or more.

You will find this info here:

10.2.7.2.1.3 * Minimum Distance from Obstructions.
Unless the requirements of 10.2.7.2.1.4 through 10.2.7.2.1.9 are met, sprinklers shall be positioned away from obstructions a minimum distance of three times the maximum dimension of the obstruction (e.g., structural members, pipe, columns, and fixtures) in accordance with Figure 10.2.7.2.1.3(a) and Figure ⁠10.2.7.2.1.3(b).

10.2.7.2.1.8
The requirements of 10.2.7.2.1.3 shall not apply to sprinkler system piping less than 3 in. (80 mm) in diameter.

10.2.7.2.1.9
The requirements of 10.2.7.2.1.3 shall not apply to sprinklers positioned with respect to obstructions in accordance with 10.2.7.1.2.

Casey Milhorn

1/26/2021 09:29:27 am

Oldie but a goodie. Haven't looked that one up in awhile so was curious what the newer standard says. This is what I found in the appendix A8.1.
"Where buildings or portions of buildings are of combustible construction or contain combustible material, standard fire barriers should be provided to separate the areas that are
sprinkler protected from adjoining unsprinklered areas. All
openings should be protected in accordance with applicable
standards, and no sprinkler piping should be placed in an
unsprinklered area unless the area is permitted to be unsprinklered by this standard."
The issue is the sprinkler protection of the existing space probably wasn't determined by "this standard" and was something per applicable building code. Also, as Franck stated, if the area you are passing through is deemed hazardous, then protection should be required. Hazardous would be something that is above and beyond what is normal for the occupancy you are protecting, or for the building. Like a paint storage room in the middle of a light hazard building. BUT, I would say it's well worth the investment of a few extra sprinkler heads sprigging up off the main on your way through. I'd get the EOR to make that call though, if you have one. Don't want someone to knock a head off in that area, flood the building, and then you are on the hook for the damages possibly.

CJ Bonczyk

1/26/2021 09:31:31 am

As mentioned by Frank previously, NFPA 13 2019 16.4.3 addresses this issue. I would advise to consult with the AHJ as to what will be deemed an acceptable means of protection based on the adjacent occupancy classification. Ensure sure the pipe is protected based on the existing occupancy hazards, and try to get something in writing in the event it changes at some point in time. We have done this many times in warehouses and we have received various answers from all AHJ's. We have even had to insulate and heat trace because the adjacent tenant space owner was not providing enough heat in the facility.

Keith A Heckler

1/26/2021 09:46:30 am

To add to the conversation, the 2019 NFPA 13 provides a statement "If automatic sprinkler protection designed for the hazard involved is provided, the potential for main damage is minimized".

Keith A Heckler

1/26/2021 09:47:23 am

Forgot to say Handbook

Willie Nel

1/26/2021 12:38:17 pm

Lines conveying liquid being above 4 inches should not be damaged by a fire scenario as the liquid will dissipate the temperature. Obviously should the liquid be flowing in the line, the line would not fail either. Even over pressure scenarios should have a very limited (bending) effect on lines but pressurized flame impingement is a different ball game. I would, in any case, investigate the use of fire proofing, maximum 1 hour, instead of sprinklers to protect such a line.

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