cold cut and weld procedure in hydrocarbon pipe 1

[urquiam]

Hello,

I have to install a thermal relief in a existing 2.1/2" kerosene line. I would like to know your opinion about the next proposed procedure:

Drain the line
Isolate falnges
Steam purge
Cold cut
Explosiveness measurement
Ballon installation and weld flanges
Install flanged spool


does anyone knows if exists a written procedure or standard (similar to API 2201 for Hot taps) for welding in existing hydrocarbon lines?

thank you in advance

 

[Sam066]

urquiam,

I am not really aware of any detailed code or procedure (that would be public) that deal with this kind of operation (cut-out and tie-in).

Regardless to the length of your spool, and I am sure that you are aware of that, one has to be aware that any hot work, performed on a hotline (or any explosive environment) needs to be performed with an extreme care and by professionals. To my experience, the main challenges remain most of the time the safety (sometimes some tie-ins can be technically extremely challenging though).

Your procedure table of contents seems acceptable and I would just propose a couple of additions/comments:
- Drain the line
- Isolate flanges and make sure that the isolation is effective
- Steam purge
- Bonding for Static Electricity (on 3 points: upstream, downstream and the section to be removed) and then cold cut
- Explosiveness measurement. The Explosiveness will have to be permanently monitored
- Clean the inside of the line as far as you can go (If the steam doesn’t get rid of all the kerosene)
- Balloon installation: Balloons are OK but among all possible vapor plugs, if practical, an aluminum plug with neoprene seal is preferable as some of them offer the advantage of allowing a venting to atmosphere through a fitted hose of the pipe section upstream of your welding location allowing for safer welding.
- Flanges welding: watch out for magnetized pipe as this could makes the welding difficult: experienced welders know how to deal with this issue should it take place.

Sam