Bushing issues 3

[PSP113]

My pipefitter has issues with using bushings. I've heard of others not liking the practice of using bushings, but no one can explain why. The only thing I've been able to find is that the lack of "meat" in a bushing doesn't lend much confidence to it's pressure rating. My feeling is if a reputable company is willing to stamp it with a pressure rating, there should be no issues. Any thoughts?

 

[Bribyk]

Bushing are allowed by Gas Code around here, as long as they are not nested (i.e. using two bushings together to get down to the desired size). Good bushings will have the same pressure rating as your piping but you're adding one more potential leak point (threads) by using a bushing. It depends on your fluid and process conditions though...

 

[JLSeagull]

For B31.3 applications, threaded fittings are not permitted on the piping side of the piping isolation valve. Things are more flexible after the first block valve.

When I worked in a plant in the early 1970's we used bushings when necessary for small bore connection issues. Since then I have heard that bushings were not acceptable. I used a bushing last year on a UK device with straight threads to match nominal pipe threads in a nearly atmospheric application. My suggestion would be to avoid bushings when possible.

 

[LUDPEKA1]

I don’t know the technical reasons for it, but at the refinery that I work at, we as a general rule of thumb do not use bushings. They are not included in any of our piping specifications.

Now, if you go out in the field you will run across them. Most of the time in a utility service, but not always….. The maintance people like to work by their own rules.