Results 1 to 10 of 10
  1. #1
    Join Date
    Nov 2011
    Location
    Kent
    Posts
    4
    Rep Power
    0

    Pressure testing with ofn



    Hi all
    I may be dumb but I have been having this argument at work dose it state in f gas regulation how long you have to leave a system on pressure test.

    I have been told it needs to be on test overnight ie 12 to 24 hours, but one of the guys at work said it only needs a hour or 2.

    Please help



  2. #2
    Join Date
    Feb 2009
    Location
    telford
    Posts
    1,892
    Rep Power
    24

    Re: Pressure testing with ofn

    I guess you could leave it for infinity but and a big but clearly label it for safety sake,yes you should be able to find your leak within two hours,some new equipment comes charged with nitrogen I think to stop moisture ingress.

  3. #3
    Join Date
    Sep 2007
    Location
    Split Croatia
    Age
    51
    Posts
    6,094
    Blog Entries
    6
    Rep Power
    30

    Re: Pressure testing with ofn

    Depending on what pressure test you are conducting.
    Leak test=> at least 12 hours, normally 24hours. You are establishing leak rate here. Longer is better.

    Pipe work strength test (1.1 to 1.43 times PS) => reasonable long (15 min). You are determining strength of joints, and by doing so, you are also stressing them. Shorter is better.

    https://www.coolconcerns.co.uk/image...re_testing.pdf
    Last edited by nike123; 14-11-2017 at 12:09 AM.
    Now, when I am officialy citizen off EU, I am looking for decent job! For any job offer please check my profile!

  4. #4
    Join Date
    Jan 2006
    Location
    Norway
    Age
    39
    Posts
    780
    Blog Entries
    4
    Rep Power
    21

    Re: Pressure testing with ofn

    I can't really tell you what the rules are,

    usually, we do 1.5X max working pressure for 5-10-20 minutes and the surveyor is happy, he says "Nothing exploded, very good" and then we can continue to vacuum the system.

    What is the point of keeping the pressure for 24 hours? if it wasn't leaking in 5 minutes, it's not going to leak after 10 hours.

    And then there is the other surveyor who wants 1.5X pressure for 24 hours.
    I will put the pressure up, with an external manometer for the surveyor to monitor.
    Then I will give him my small note book and say "if you want the pressure to hold for 24 hours, here is a note book, please note any decrease in the pressure every 30 minutes, I am going home now"
    -Cheers-

    Tycho

  5. #5
    Join Date
    Sep 2007
    Location
    Split Croatia
    Age
    51
    Posts
    6,094
    Blog Entries
    6
    Rep Power
    30

    Re: Pressure testing with ofn

    Quote Originally Posted by Tycho View Post

    And then there is the other surveyor who wants 1.5X pressure for 24 hours.
    Yet another surveyor who is confused with strength and leak test!
    Now, when I am officialy citizen off EU, I am looking for decent job! For any job offer please check my profile!

  6. #6
    Brian_UK's Avatar
    Brian_UK is online now Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    69
    Posts
    10,419
    Rep Power
    50

    Re: Pressure testing with ofn

    Some say 6 hours minimum and others state 30 minutes. To date I can't find an f-gas document that gives time limit.

    If you do long time periods don't forget to record the ambient temperature at the start and end of your test.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015
    Please support http://the100project.net/Home

  7. #7
    Join Date
    Sep 2007
    Location
    Split Croatia
    Age
    51
    Posts
    6,094
    Blog Entries
    6
    Rep Power
    30

    Re: Pressure testing with ofn

    And what type of test you are referring now Brian?

    What is the point of leak test if time is insufficient to show leakage which has small leak rate but still big enough to consider it unacceptable!

    Also, what is the point in long time stressing joints with overpressure of 1.5 times max working pressure if it is enough only short time to establish that joints are strong enough to whithstand max working pressure and 50% more for short period needed for protective devices to function and stop pressure to rise more than max working pressure.


    Obviously, it is confusion of these two separate tests (which can be conducted in one combined procedure) which is giving us this theme for discussion.

    Since you are doing strength test, and if it is successful it is most economical to perform leak test right after that strength test by lovering pressure and leaving equipment 12-24 hours pressurized to its maximum working pressures.

    And there is source for confusion about times for each test.

    Correct times are 10-15 minutes strength test immediately followed by at least 12 hours leak test (assuming that there are no weak joints and big leaks).
    Last edited by nike123; 14-11-2017 at 06:39 PM.
    Now, when I am officialy citizen off EU, I am looking for decent job! For any job offer please check my profile!

  8. #8
    Join Date
    May 2012
    Location
    England
    Age
    53
    Posts
    1,228
    Rep Power
    28

    Re: Pressure testing with ofn

    .

    There are 2 tests one after the other.
    The first is a strength test to prove integrity of joints and fittings.
    The second is the tightness test to prove the system is gas tight.

    Strength test is done at x1.1 to x1.43 of the working pressure (Ps)
    at 32degC for the low side and 55degC for the high side (air cooled
    condensers only), manufacturers instructions used to find max
    pressures of individual components and test is completed to the
    lowest component pressure. This test is done for the shortest
    possible time required to visually check the entire system. This
    test should never be done for more than 1hour so if it requires
    2 or more other engineers to ensure this test is done in as short
    a time as possible then that should be done. Out of hours working
    is also a consideration?

    The gas tightness pressure is the working pressure 32degC or
    55degC (Ps) on air cooled condensers only. The tightness pressure
    is held for as long as possible 2 hour minimum, 4 hours is better
    and 12 to 24 hours is ideal, remember returning the following
    morning may mean the ambient temperature has changed and
    that will affect the final pressure.

    Some tests may have to be done in front of an independent witness
    who will sign it off as complete for insurance purposes and these
    test might be completed over days or even a week.

    All this information is contained within the BS EN 378 part 2, 2016.

    Rob

    .
    Last edited by Rob White; 14-11-2017 at 10:17 PM.
    .. ... -. .----. - / -- --- .-. ... . / -.-. --- -.. . / --. --- --- -..

  9. #9
    Brian_UK's Avatar
    Brian_UK is online now Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    69
    Posts
    10,419
    Rep Power
    50

    Re: Pressure testing with ofn

    Thank you Rob.

    Usual problem nowadays I suppose, employer should have these documents to hand for employees to check against, but I'm no longer employed so don't have access anymore.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015
    Please support http://the100project.net/Home

  10. #10
    Join Date
    Oct 2001
    Location
    Nottingham UK
    Posts
    5,063
    Rep Power
    42

    Re: Pressure testing with ofn

    And all assuming that no inline components will not be damaged by the test, i.e. EPR's
    I'm back on the Pale

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •