Wrapped Insulation OK for Steel Sprinkler Pipe?

2/17/2023

We are working on freeze protection for an enclosed canopy which is also attached to the main building. There is no exposed metal pipe to the elements.

Per the AHJ, the only approved insulating process for metal sprinkler pipe is a thermal paint insulation.

I found the section for wrapped insulation that is allowed on non-metallic pipe by NFPA 13, but is there a section where wrapped insulation can be used on metal pipe?

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11 Comments

Dan Wilder

2/17/2023 07:32:34 am

From a non-freezing part of the country....and unless the AHJ has specifically written into their adopted codes/standards this requirement, I would argue it.

Thermal paint (I've not heard of this before for fire sprinkler use) reflects heat or creates a situation where the pipe is insulated from ambient heat...this works while the piping is warm, but as it inevitably cools off and the needed heat to keep the pipe or to reheat the pipe above 40°F is also slowed. This is the same with wrapped insulation, it just slows the process without circulating water or passive/active heating methods. It will create a longer time period before freezing so not sure what area of the country you are in. I've argued that even with a day or two where the low temp dips below freezing, the average or mean temp over that time period is above freezing (we just default to the use of minimum 2" pipe for exterior use).

Tented piping works well because the exposed side is facing a warmer zone (i.e. the room below) thus trapping the warmer air around the piping and preventing heat loss to the air space above. Unfortunately, with your description, this is not available.

To answer your question 13-22 Ed - 16.4.1.3 but does not specify pipe material.

Where aboveground water-filled supply pipes, risers, system risers, or feed mains pass through open areas, cold rooms, passageways, or other areas exposed to temperatures below 40°F (4°C), the pipe shall be permitted to be protected against freezing by insulating coverings, frost proof casings, or other means of maintaining a minimum temperature between 40°F and 120°F (4°C and 49°C).

ENHANCED CONTENT
Other means of freeze protection referred to in 16.4.1.3 include steam coils, heat tracing, and circulating hot water tubing that has been specifically investigated and listed for use with sprinkler systems. With any of these alternative approaches, caution must be used to verify that temperatures do not exceed the maximum ambient temperature allowed for the sprinkler’s temperature rating. Excessive temperatures can be conducted through the piping and can lead to unwanted sprinkler operation. In addition, the need for insulation in conjunction with an alternative approach system must be evaluated.

Anthony

2/17/2023 07:42:41 am

Insulating pipe won't do anything to prevent pipe from freezing if there is no heat source. Insulation just slows the travel of heat it doesn't create heat.

NFPA 13-16:
Any insulation is allowable per: 8.16.4.1.3
Heat trace is permitted per: 8.16.4.1.4

On non-metal pipe (CPVC) the listing and manufactures allowable contact mediums are the direction,

If the AHJ is saying that you can't do something request the code reference. When they say "because I said so" remind them, politely, that they can enforce code, they can approve alternatives for code, but they cannot make up and supplant code.

2/17/2023 08:13:32 am

Because I said so always works with my kids.

Dan Wilder

2/17/2023 08:34:35 am

Because they don't know any better only lasts for so long...
and I'm pretty sure my local AHJ's aren't grounding me or not giving me dessert but I like and have used the approach!

Jesse

2/17/2023 08:04:59 am

Agree with both above comments. I would take a good look at the AHJ's local amendments. If it doesn't specifically exclude the type of insulation you want, I'd appeal it.

Glenn Berger

2/17/2023 08:11:02 am

You did not say where in the world this project is located.

Like others have said, do not just provide insulation as a means for maintaining temperature above 40F for sprinkler piping. Insulation works in systems that have continuous flow in them.

Recommend using a heat tape for this application.

Jim Derifield

2/17/2023 08:37:29 am

From my experiences in the field, when you wrap steel pipe in insulation you will also have accelerated corrosion issues over time.
And as others have stated, without providing heat tape the insulation wouldn't be useful in preventing freeze damage.

Franck

2/17/2023 09:56:08 am

As indicated above, I would be very cautious with pipes exposed to freezing conditions, as water is not moving and the temperature will drop down anyway.

But if it is a limited portion of pipe (a few in. / ft) with large section (3-4 in.), then I would be less afraid than an entire sprinkler system with sprinklers and branch lines (it takes longer to freeze a large pipe section and burst it).

I had some freeze up of sprinkler systems (wet systems) provided in attics above cold rooms during a cold winter. Lots of pipe burst and resulting water damages. They then moved to a dry sprinkler system.

I personnaly recommend the use of antifreeze systems (don't know if it is still allowed in the US) for small canopies or dry pipe system to limit future problems.

And note that wrapping can create obstruction to sprinklers if you apply it on branch lines (if the resulting pipe diameter is greater than 2-1/2", it becomes an obstruction to upright sprinklers - and I would not install pendent sprinklers in an area where freezing conditions may be found).

Schulman

2/17/2023 10:30:43 am

Heat Trace tape. Don't forget the monitoring module and the connection to the fire alarm or other monitoring/notification system which notifies maintenance that the tape has failed if it does.

Fernando

2/19/2023 12:25:20 am

And this approach is very expensive
Stay with an antifreeze or dry system

Rob B

2/21/2023 08:06:19 am

I always love on the forums when guys are like check local amendments. This most of the times has little with solving the issue, especially in the OPS case.

Wrapped Insulation OK for Steel Sprinkler Pipe?

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