2 replies to this topic

[PME]

Pl. tell me if there is a requirement of hydrotest vent in Plant air & water piping ?

Pl. tell the mandatory conditions for which PWHT treatment is required ?

Regards
Sachin Rastogi
Refinery

[ankur2061]

Sachin,

Plant air lines or even for that matter instrument air lines are generally not hydrotested but are pneumatic tested. You pressurize the air piping network with compressed air and then perform a pressure hold test. To check for leaks you do a soap suds test. The reason for this is that the economics for hydro test for air lines are not justified. Also there is the issue of complete removal of water from air lines after hydrotest is complete.

However, some operating companies have guidelines about hydrotest which include air lines. It is a matter of individual choice but personally I would not recommend hydrotest of air lines.

Water lines whether process cooling water or service water are generally hydrotested because the service is related to water.

During mechanical completion of the plant, what I have seen is that the piping contractor hydrotests the sections of pipe which are site shop welded. After installation on the pipe rack, many operating companies prefer to do a pneumatic test which includes large network of the piping for the given service.

Hope this explanation helps.

Regards,
Ankur.

[PME]

Sachin,

Plant air lines or even for that matter instrument air lines are generally not hydrotested but are pneumatic tested. You pressurize the air piping network with compressed air and then perform a pressure hold test. To check for leaks you do a soap suds test. The reason for this is that the economics for hydro test for air lines are not justified. Also there is the issue of complete removal of water from air lines after hydrotest is complete.

However, some operating companies have guidelines about hydrotest which include air lines. It is a matter of individual choice but personally I would not recommend hydrotest of air lines.

Water lines whether process cooling water or service water are generally hydrotested because the service is related to water.

During mechanical completion of the plant, what I have seen is that the piping contractor hydrotests the sections of pipe which are site shop welded. After installation on the pipe rack, many operating companies prefer to do a pneumatic test which includes large network of the piping for the given service.

Hope this explanation helps.

Regards,
Ankur.

Thanks for your first answer.

Regards
sachin