Merchant coupling usage..........

singh

Early in my career I once worked on a job that we ran over 300' of 4" overhead gas pipe and we used those couplings,boss thought he was saving a few bucks, every single one leaked under test.

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Seattle Nick

Merchant coupling usage..........

....what good are they anyway? I did find this quote on Eng-Tips:

"Merchant couplings are thread protectors, and nothing more. They're installed on one end of mill threaded pipe to protect the threads from damage during shipping. I don't know of any pressure piping code that permits them to be used in service. They are to be removed and discarded."

I tend to agree with that statement, but am I missing
something? Would a professional use a merchant on a 2" galvanized water line between the main and the meter?
No big deal? What do you think? Should I trust the other forty feet of pipe we can't see?

EBEBRATT-Ed

Many may not agree with me but I have done the research. 2" and down throw them out they are only thread protectors.

2 1/2" and up you can use them they are perfectly good. The reason is 2" and under do not have tapered threads they have straight threads. 2 1/2" and up come with tapered threads.

I convinced a tough gas inspector on this and showed him and he acepted this.

ED

Seattle Nick

Bill Hobbie_2

NICE JOB ED.
Bill Hobbie

Tony Conner_2

Thread Protectors

People need to look at the code requirements for their particluar installation. Depending upon what you're doing, the installation could fall under:

1/ plumbing

2/ sprinker/fire protection

3/ fuel utilization

4/ ASME pressure piping codes (there are several of these)

People need to know the codes for what it is they're working on. Lots of different grades of fittings: 125/250 cast iron, 150/300 malleable, 2,000/3,000/6,000 forged steel, etc.

Toss the mechant coupling/thread protectors in the scrap bin unless you know for a fact that they're ASME registered fittings.

bob young

banded couplings

believe it or not ,we used those couplings all the time until fairly recently and with minimum problems. water piping we always used wick & compound so no problem there ,gas another story but always used permatex &it usually held the mewrcury test. we didn't know any better although the code stated " banded fittings" we never even gave it a thought. sometimes ignorance is bliss !over thirty years 'till we figured it out ! what a ride !