Gas pipe sizing

Discussion in 'Engineers' Talk' started by jimoz, Mar 10, 2019.

  1. jimoz

    jimoz Screwfix Select

    Refurbing a property and I need a new gas feed from meter as moving boiler location. Plumber seems to think we need a 25mm pipe but I think he's being over cautious. The boiler will likely be the only gas appliance in the house. The meter is wall mounted outside around 9m away horizontally with a 2m drop to the meter and 2m drop to the boiler say.

    I imagine it will be around a 30kw boiler. I've got a table up on the internet but its hard for me to interpret with it not being my trade.
     
  2. Mike83

    Mike83 Screwfix Select

    I think 22mm will be borderline for pressure loss. Anything over 5 bends will probably need 28mm.
    Probably best doing it on 28mm the full run or at least partially.
     
  3. jimoz

    jimoz Screwfix Select

    Thanks glad to get second opinion
     
  4. Mike83

    Mike83 Screwfix Select

    Pressure loss between gas meter and gas valve inlet shouldn’t exceed 1mb.
    A quick calculation with 9m 22mm copper and 5 bends would be 0.922 mb.
    So if only 5 bends between meter and boiler then that’s fine. But it will probably be a few more than 5.
    A 28mm pipe also give the option of increasing the size of the boiler in the future without increasing the pipe size
     
    KIAB likes this.
  5. gas monkey

    gas monkey Well-Known Member

    wickes £24/lenght of 28mm robery
    use 28 as you,ve futerised it if thats a word
     
  6. Bob Rathbone

    Bob Rathbone Screwfix Select

    Use bends formed with a bending machine rather than elbows, they will present less of a frictional loss as turbulence will be reduced. I would do it in 22mm, but then again I am an Electrician.
     
  7. gas monkey

    gas monkey Well-Known Member

    turbulence is really only relavent in large pipes
    always use bends rather than fittings if poss thes the way
    28 as you may have a fire cooker later on
     
  8. Mike83

    Mike83 Screwfix Select

    Using bends rather than fittings is best but sometimes can’t be avoided.
    Coming off a meter fitting inside a gas meter box usually involves 2 bends straight away.
    Also sometimes the final connection at the boiler will require a fitting (bend) as space is tight.
     
  9. Honestly

    Honestly Member

    Are you gas safe registered? If your not and anyone else answering this post shouldn’t be advising on things that 1 they most likely don’t understand and 2 should not be telling you or encouraging you to install.

    Given what you said 28mm copper pipe would be advised with a 30kw boiler
    Bends add to friction if gas flowing through pipes - get a gas safe registered engineer in to advise correctly

    The boiler has to be signed of in Benchmark for building regs compliance. ANY GAS SAFE REGISTERD ENGINEER SHOUKD NOT SIGN OFF UNLESS THE GAS SUPPLY HAS SUFFIECIENT GAS!!
    It makes me laugh when people ask for advise because they don’t have a bloody clue then knock down the people who are qualified and registered to know what’s needed
    - Honestly!!!
     
  10. gas monkey

    gas monkey Well-Known Member

    i ve got them and lots of others and a lifetime of knowlege sun shine fret not
     
  11. Honestly

    Honestly Member

    Obviously you are a unable to control your ego on this chat room by the way in which you behave - like a child who’s lost his toys

    You are either stupid or an idiot but I cannot decide - boilers require correct size gas pipe it is important so appliance runs as the manufacturer intended and as gas safe regulations make clear - a maximum of 1 mb drop from gas meter to appliance with all other gas appliances running
    A undersized gas supply causes incomplete combustion that can lead to higher carbon monoxide levels - but I suppose an idiot who behaves like a baby knows such stuff
    Idiot! I can’t remember Goerge foreman ever being disrespectful to his peers with knowledge?
     
  12. gas monkey

    gas monkey Well-Known Member

     
  13. gas monkey

    gas monkey Well-Known Member

    hes a troll son have a chill pill
     
  14. Honestly

    Honestly Member

    Just to educate you further because you appear to be an idiot with no knowledge attall other than critisize others
    Carbon monoxide kills and I’m
    Sure JIMOZ would be grateful to
    Understand why a gas supply must be correct - idiot
     
  15. gas monkey

    gas monkey Well-Known Member

    honestly do not bite son hes enjoying it
     

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