Hydrotest pressure hloding time

VIII. Pressure Vessels - Division 1

===========================================================

if this is what you are referring to

install a pressure gauge into system if there is none

pressure the system at the design pressure

the design pressure if done right should have safety margin

I would not go over that PSI with out special precautions

check the reading if it drops after 24hrs

you have a leak in the system

Basically, from my experience and understanding, the ASME considers two types of hydro static tests:

Strength and Tightness;

Strength test is a 150% of design pressure test which is conducted once in a lifetime.

Thus

Every test after the once in a lifetime is a Tightness test of 110% of design.

Duration of testing: Suffient to verify the objective of the test.

Thus, if you are doing a strength or tightness test the time required for satisfactory results is the time required to do an adequate inspection to certify that the testing. Therefore, the criteria for a vessel is the time required to do the inspection. Vessel pressure must be held test pressure sufficiently long for the inspector to inspect the vessel. Same for a tightness test . . . how long it takes to inspect for leaks.

Note: A written test procedure should define the inspection requirements and may define a hold time.

It is my understanding that the test pressure in the current ASME code is 130% of the vessel design pressure (ASME Section VIII, Design of Unfired Pressure Vessels), having been changed in one of the more recent editions.

This is "off subject," however.

Re 4. What do other international codes say?

Australian Standard AS 4037-1999 says:

AS 4037—1999

17.3.2 Application of test

The test pressure shall not be applied until the fabrication

and its test fluid are at about the same temperature.

The full test pressure shall be maintained for 30 minutes minimum unless otherwise

specified in the application Standard and preferably for one minute per millimetre of

thickness.

Prior to close examination of the vessel or component, the test pressure shall be reduced

to 85–95% of the test pressure and held for sufficient time to perform the examination.

hello,

As per ASME 31.1

For NBEP(Non Boiler External Piping) hydrostatic test pressure (gauge) at any point in the piping system shall not be less than 1.5 times Design Pressure(gauge),but shall not exceed mamximum allowable test pressure for any non-isolated compoent in the system such as valve etc.This should be maintain for minimum 10 minutes.Then reduce Test Pressure to Design Pressure and held it for examination of leakage in the system.

Thanks Malcom...that's a piece of useful information.

If ASME B31.3 is applied, what is the minimum holding time? And which pressure should be reduced to perform leak-test?

It's 10 minutes (minimum).

Go through this article. It may help you. http://www.thepetrostreet.com/article_0001.html

Regards,

Ashfaq

5. What does the Engineer/Surveyor for the company that is to supply burst/collapse indemnity insurance cover on this artefact have to say?