Hot tapping - bad experiences?
Hot tapping - bad experiences?
(OP)
I've got a project coming up involving a size-on-size tie in to a high pressure (ANSI 900# line class) natural gas pipeline. I'm looking at three or four ways of doing it, probably one of the cleanest would be hot-tapping - assuming I figure out a way to bring the operating pressure in the pipeline down during the actual tapping procedure. The biggest problem I have with hot tapping right now is the size-on-size (8" into 8") factor, and the fact a number of people who wouldn't have a problem tapping, say, a 4" leg into an 8" run, don't trust size-on-size. Just wondering if anyone out there has ever had a real problem doing this (assuming it's properly engineered in the first place) or if it's one of those "I know a guy who knew a guy" stories originating from an improperly engineered application.





RE: Hot tapping - bad experiences?
RE: Hot tapping - bad experiences?
By all means, make sure that you contract with a "hot tapping" firm with HP natural gas experience!!!! Size-on-size is rhe most difficult tap
There is an API Standard that governs hot tapping of systems.....API-2201
TD Williams (and others) have websites to gain more information.
MJC
RE: Hot tapping - bad experiences?
RE: Hot tapping - bad experiences?
As far as experienece, I have done two SOS taps like the one you wish to do. Both were done with a split tee, flange top and a completion plug. One was 8" the other 10", C.S. natural gas line. The reduced size taps you may have done before may have used a weldolet and a weld by flange ball valve. This will be different.
I have never had a "bad" experirnce with a hot tap, if I ever do you will see it on the evening news.
Basic warnings include pre heat and trying to reduce the pressure and the flow durng the proceedure. While reduced pressure is easy to understand, the reduced flow will aid in reducing the amount of heat that is carried away by the gas during the fillet welding processes used to secure the split tee to the carrier pipe.
RE: Hot tapping - bad experiences?
RE: Hot tapping - bad experiences?
RE: Hot tapping - bad experiences?
Reducing the line pressure simply reduces hoop stress, it has little to do with burn through. As with most pipeline technologies, it's OK if the crews do the right things for the wrong reasons, as long as they do the right things.
RE: Hot tapping - bad experiences?
RE: Hot tapping - bad experiences?
RE: Hot tapping - bad experiences?