How to Calculate Bullhead Tee on Riser Nipple?

5/16/2022

I'm hoping someone might be able to provide a little direction on the requirements of NFPA 13 2016 Section 23.4.4.8.1 (4) for hydraulic calculations.

We typically use 2"x2"x2 1/2" Vic IR Bullhead Tee directly on the welded grooved outlet. Per NFPA we should be including these fittings on the branch line, but we have always included the tee fitting on the 2 1/2" riser nipple because inside diameters are not typical to a 2" tee.

We have been doing this for the longest time and recently received corrections from the local AHJ. Victaulic does not specify the frictional resistance - equivalent length of the NO. 104 Bullhead Tee fitting on the branch line.

Have you come across this before, or any suggestions?

I tried to create a new fitting type in HydraCalc, but was having trouble. Also, might be pointless since there is no data for this on Victaulic's cut sheets. Thanks in advance.

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9 Comments

Glenn Berger

5/16/2022 08:24:28 am

Treat the bullhead tee as a standard 2-1/2 tee, with reducer to the 2 inch pipe.

Joshua Mann

5/16/2022 11:15:59 am

I thought that could potentially be an option, but to include the fitting on the branch and not riser nipple, I would need to add another node at the reducing coupling? Is that the same way you would calculate it?

Dan Wilder

5/16/2022 08:39:21 am

Section 5.0 - Friction Flow Data for the No.104 (I'm assuming that is the fitting type you are referencing)

https://www.victaulic.com/assets/uploads/literature/10.06.pdf

5/16/2022 11:18:55 am

Yes, that's the one. Not sure why they don't include an equivalent length for the 2" bullhead tee on the branch. They only provide the data on the run.

David Kendrick

5/16/2022 11:38:08 am

Victaulic 10.06
Page 6 Friction Flow Data Table.
Far right column shows data for the bull head tee equivalent to schedule 40 pipe.
If it were me I'd use the 2" pipe size and move on.

Mike

5/16/2022 09:57:54 am

For a reducing tee I'd be using the smaller diameter.

Brian Gerdwagen

5/16/2022 01:26:17 pm

2" tee on the line. Ignore the reducing part. If it was a 2 1/2" line to a 2" Riser Nipple, then use a 2" tee in the riser nipple. Smallest diameter governs.

Jack G

5/16/2022 03:33:27 pm

I think you might be trying to eliminate a node, for input reasons ?
So if it’s 10 ft of 2 inch to this 2 x 2 x 2.5 tee, the input would be 2 inch, 10 ft, schd 10, c 120 , fitting tee.
To top of rn tee.
Then , if t.o. Is 3 inches to main, you would have a node on main.
So it would be: 2.5 inch, schd 40, c-120, .25 ft of pipe and a tee.
This more than compensates for any friction loss.
You could also hook it up to a test header, pitot at flow rate, record friction loss.
Easy Peasy.
That’s how we did it 50 years ago when data wasn’t as available.

Tracey D Bellamy

3/22/2023 03:06:24 pm

NFPA 13 requires the equivalent length for the loss associated with the tee is to be included in each side for the branch lines fed from the tee. This is based on the loss being associated with amount of water being turned which would be represented by the flow in the branch line on each side.

How to Calculate Bullhead Tee on Riser Nipple?

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