Hydrotesting of Shell & Tube Heat Exchanger

Dear Mr.uday_pr

Pl. refer the reative code.

Normally Testing Pressure is 1.5 times Working Pressure.

Even if the Test Pressure is equal to Working Pressure, there should be no leakage

DHAYANANDHAN.S

Dear Sir,

Thanks. I want to know, how much time, pressure to be kept? During boiler testing, I have seen that boiler inspector normally ask immediately to release the pressure after his visual inspection - say max 30 min.Is the same rule apply for Shell and Tube Heat Exchanger also/or applicable for any hydrotest?

It is more complex than you think and give very little information. (Type of exchanger, pressures, material, temperatures .....). You will need two independent tests: 1. tube side, 2 shell side.

Very generally you can use the following formula:

Ptest = 1.5 P desingX (Sta / Std)

Sta: Material stress at ambient temperature

Std: materials Stress Desing temperature .

More than this, you have to analyze the pressures and temperature differentials between the tube bundle and casing.

If the exchanger is going to be stored, you should dry well after the test. For that you must know the required Dew point.

If the test was performed at shop, you can evaluate a new pressure test after installation (To prevent possibles damages during transport)

I recommend you to consult your engineering department.

Other recommendations:

Prepare a hydrostatic test means that you should take all precautions inherent to the process; It's like setting the stage for a great event. This is arisk operation. According to the above should consider the following:

Ensure the site to make easy access for inspection.

Make a reasonable analysis of all process steps for testing, to ensure that the equipment or bundle pipe that is under test does not suffer an "accidental impact."

It is not allowed for any reason to hit the pipe or equipment, nor try to correct leaks between flanges with keys, while the system is pressurized.

Ensure all pressure relief devices, such as orifice plates, expansion joints, valves and similar accessories instrumentation, among others, are excluded from the test so they should be replaced by temporary or isolated parts discs using blind.

Have adequate feed and discharge connections of the test fluid, so that the system can be filled and drained within a reasonable time; likewise, provide for adequate and effective isolation such connections pads at high points to ensure complete displacement of the entrapped air.

Having a suitable pump for testing, with two (2) gauge least

calibrated and placed where they can be easily seen by the staff responsible for monitoring the test.

Ensure that any post-weld heat treatment that was required in the welding procedure is completed well in advance of the test.

Ensure that any welding, which should be covered with external insulation for process reasons or lined with paintings on grounds of protection remain free or uncovered until the test is completed.

Ensure that the pressure does not exceed the set value during the test (1 to 6 hours, depending).
WP

Ask your insurance company.

1.3 times not 1.5 times as per ASME sec VIII-1 and TEMA

A1) It depends upon the requirements of the Engineer/Surveyor from the company that is supplying burst/collapse indemnity insurance cover on the equipment. This can then be written into the <...procedure...> so that it is available in future for others at the facility to follow. If in doubt, pick up the phone and ask.

A2) In theory, indefinitely, though this takes place after item 1 has been completed.