Pipe sizing calculation

[jh75]

I just moved into a old house and wanted to just put pen to paper to see if the pipe sizes in the house satisfy the gas appliances adequately, does anyone have the formulas to work this out?

 

[gigz]

Yeah, think of a number, double it, add 5 then subtract your age (10). This is called dix formula.

 

[slippyr4]

DIY gas alert.

 

[muggles]

I thought you were converting to oil, as you couldn't find any small herding dogs to do your work for free?

 

[slippyr4]

I thought you were converting to oil?

He can't even be bothered to lie consistently.

 

[jh75]

lol... just stick to topic please rather than making jokes

 

[Dan Robinson]

Why don't you purchase the relevant british standard and read up on it like the rest of us?

 

[jh75]

Why don't you purchase the relevant british standard and read up on it like the rest of us?

I'm not a professional... so dont want the corgi books etc, just wanted to check if my appliances are adequately supplied because its a old house

 

[HERTS P&D]

This one?

https://www.google.co.uk/search?q=c...hULDcAKHbynDagQ_AUIBygC#imgrc=Jl0Cpci0ywUmSM:

Andy

 

[Dan Robinson]

I'm not a professional... so dont want the corgi books etc, just wanted to check if my appliances are adequately supplied because its a old house

Pay someone to do the correct tests.

 

[Newboy]

There's no harm in letting the OP try the calculations!

(Diameter of pipe in mm x Total pipe run in mm) + (λ value of any couplings) + (λ x 5 x no. of elbows) (assuming end feed rather than compression, if there are pulled bends rather than soldered fittings then factor is x 1.9) = total flow resistance (TFR) of the pipe run (Δβ).

If you contact your supplier and ask them for the 'local supply pressure' (usually know as LSP) in mm/Hg this will give you the working head (assuming that the regulator fitted at your meter is providing the necessary boost).

Once you've got this figure you can work out the pressure drop to the appliance by subtracting the the result of your flow resistance calculation (LSP-Δβ).

If you contact the appliance manufacturer (or check the installer's manual) and ask them for the gas consumption rate (GCR) - usually in watts/min. The supplier should also be able to provide the calorific value of the supply to your property - once you have this then you can work out the calorific value of the gas needed to run the appliance at it's optimal rate (if it's a combi then you'll need to take into account the modulation rate - but assume a factor of 1.62 usually does the trick). As long as the ∑ value from the LSP/TFR calculation is at least 1.3 then the rate to the appliance will be satisfactory.

For help with multiple appliances post back.

 

[jh75]

Also found this great resource which is exactly what I need


https://www.google.co.uk/url?sa=t&s...iQg2E9X1fxR248K1A&sig2=IAxEu0W0nZ8E5Qgrds6XLg

 

[muggles]

lol... just stick to topic please rather than making jokes

It wasn't a joke. You told us you weren't having gas any more, you were having oil, so gas pipe sizing won't help you. 10mm will do for most domestic oil supply pipes

 

[jh75]

Pay someone to do the correct tests.

I'm skint!

 

[slippyr4]

This thread might help you:
//www.diynot.com/diy/threads/diy-gas.8090/

To be honest though, if you're too stupid to figure out the answers to these basic questions on your own, then god help your neighbours when you fire up your death trap contraption. Or your family, at risk of CO poisoning.