Maximum velocity natural gas pipeline tap

[Iga2016]

What is the maximum velocity that should be used to determine the diameter of a tap on a natural gas pipeline. We use 60 ft/sec as maximum velocity for the pipeline itself, Is there a diffrentet condition for the tap itself?

Thank you

 

[MortenA]

i would say that for dry natural gas is mostly about noise and dP (erosion should not be an issue). So in reality its very site dependent - although most companies have a "mas value" this could be wavered if e.g. noise and/or is not a problem.

 

[LittleInch]

At that velocity you may need to look at vibration and associated issues.

If you can then its better to have a larger tee and then reduce down for the valve and main run.

Its stronger and you have less velocity related issues.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MortenA]

OK, i didnt mention vibrations, and i agree with Littleinch

 

[Iga2016]

Thank you for your response, I have found very valuable information in this site and it is the first time I ask for advice
My case is as following
I have an existing 2" tap where the gas consumption will increase in the near future
Minimum main pipeline operating pressure: 476 psig
Excepted Natural Gas pick consumption: 395 MCFH
Tap diameter: 1.437"
Pipe diameter after de tap 2” Sch 80
Length of the pipe: 18 meters
Velocity: 293 ft/sec (doesn't consider compressibility factor)
After the 18 meters the pipe changes to 3”

What methods can I use to predict the pressure drop through the tap itself? (I haver the one for the 2" pipe already)
How can I predict noise and vibration and evaluate if it can harm the pipeline?

Because of excessive regulation, my firm wants to avoid the change, I believe this can be a problem but I have no evidence to show. The transmission company hasn’t said anything about it.
Any additional information will be appreciated

 

[rconner]

fyi

http://www.eng-tips.com/viewthread.cfm?qid=147153