Are There Any Listed "Cheater" Extension Fitting?

5/9/2025

NFPA 13, 2016 Section 6.4.8 permits using extension fittings ("cheaters") for sprinklers K8 or smaller.

Does anyone actually make a listed cheater?

There are multiple manufacturers/suppliers that sell them, but none of them appear to be listed.

I see the benefit of using small extension fittings that don't impact hydraulic calculations (per Section 6.4.8.5.1) when ceilings are installed at the wrong elevation, but I don't see how you can use them if they aren't listed per NFPA 13, 2016 Section 6.1.1.

Thanks in advance.

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8 Comments

Pete H

5/9/2025 06:38:21 am

The Viking Residential sprinkler extensions are UL listed for residential sprinklers with a K factor of 5.5 or less.

The United Brass Works 101L extensions are not UL/FM Listed, but are UKAS/nqa ISO 9001 registered.

Anthony

5/9/2025 06:51:09 am

Isn't this the point of flex drops? Any issue with fit can be alleviated with a minor adjustment.

Michael

5/9/2025 08:22:42 am

These are usually used and seen in the cpvc projects.

Jesse

5/9/2025 08:33:23 am

Yeah flex-drops are an option but they have a pretty serious impact on the hydraulic calcs. Though there are new 1.25" flex drops that calc 1-0 per 1-0 from Viking and Vic, they're pretty pricey

Colin

5/9/2025 10:37:16 am

I just priced them out and in my market, the price difference was something like $25 vs $30.....not too bad considering.

Jack G

5/9/2025 09:42:27 am

Years ago I had a meeting with victaulic to produce a 1.25 flex drop that was 1.25 x 1.25 and 1.25 x1 , the purpose being that retrofit on existing system could be done without requiring hydraulic calcs and save the time and money to map the existing system for a calc. They supplied me with drops I tested commercially, and I used them / bought for that purpose.
Extenders have to be ul approved for an important reason. They are tested.
A few years back a fire marshal called me in because a contractor used 3/4 male to 1 inch female to change heads on a BJ s to go with a 25.2 tyco/ central sprinkler.
At the time tyco still had a test lab in providence Rhode Island.
Since the head and fittings were their products ( they told the contractor it was ok— and even did a calc on the system)— hydraulic software has built in eq. lengths) ( the reference was a NFPA section that showed the extension fitting)
I told them it was not ( sizes involved and configuration would alter the K) and to measure the new flow and k . ( I cheated and set up a test rig in my shop);
What they found was the fitting altered the k factor of the 1 inch sprinkler and the flow to 9.97 k from 25.2, and drastically reduced the flow.
We informed the fire marshal. The issue was resolved by drilling 1 inch mech tees, and plugging the 3/4 inch outlets.
From that day I am careful where I use cheaters.

Jack G

5/9/2025 09:54:52 am

NFPA 13. 16.8.6 now limits the use to 8.0 k s or smaller and also limits the length to just 2 inches ( which in my book limits the use of multiple extensions— like what you find in an old system where they used multiples for drop length with ceilings )
Tricky . I try to stay away.

Jose R Figueroa

5/9/2025 10:42:53 am

Have you visited the FM Approval Guide?

https://www.approvalguide.com/

How long would the fitting extension be? The friction loss could not be negligible

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Are There Any Listed "Cheater" Extension Fitting?

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