Control Valves leak check.

Anonymous Coward writes:
Hi everybody, I'm Hairudin and I perform leak testing and hydrostatis testing for valves. Recently a client requested that I test their valves for leakage. The problems is:

1). The process line doesn't have any isolation valves to by-pass the process medium.

2). There's no flow indicator or transmitters to detect the process variables of the process medium.

3). The process line doesn't have a common drain valves that can be opened while the process is running.

4). Packing at the by-pass valves are passing.

My client requested that I check the leak rate - whether it is within the specification criteria. What is the best method for me to check the leak??

Thank you and best regards:

Hairudin