A
ALEC1
shoild we take this into the combustion chamber?
Help needed for gas pipe size
- Thread starter 10Pints
- Start date
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The previous idiotic suggestion that an unregisted householder should ************ was totally inappropriate advice and should have been deleted by a Mad Mod!
But the calculation method is "theory" and I dont see why it should not be mentioned here. Particularly as demo calcs have already been given.
I know GW is usually right ( ish ) but perhaps I have forgotten something and its important that we always get this right.
The OP's installer was being VERY silly as he will have been recently trained and should have done the calcs properly.
The OP has also been very reasonable asking him to come and correct the gas pipe size and agrees to pay for the extra cost of 35 mm tube and fittings where required.
Tony
But the calculation method is "theory" and I dont see why it should not be mentioned here. Particularly as demo calcs have already been given.
I know GW is usually right ( ish ) but perhaps I have forgotten something and its important that we always get this right.
The OP's installer was being VERY silly as he will have been recently trained and should have done the calcs properly.
The OP has also been very reasonable asking him to come and correct the gas pipe size and agrees to pay for the extra cost of 35 mm tube and fittings where required.
Tony
A
ALEC1
That assumes that the boiler wasnt upgraded after the pipe installed, and the range cooker also a later addition...
I dont think we know all the facts, and I dont think RGE's shoud be jumping to conclusions...still britains blue collar workers are adept at keeping themselves in their perceived place!!!!
Happy to stay learning here..I just thought that was the idea of the CC
I dont think we know all the facts, and I dont think RGE's shoud be jumping to conclusions...still britains blue collar workers are adept at keeping themselves in their perceived place!!!!
Happy to stay learning here..I just thought that was the idea of the CC
G
gaswizzard
If we were to take the OP's example then we have 2 sections , ie:.....
A to B (meter to first tee)
B to C (first Tee to boiler) or B to D (first tee to range)
1 mb /2 = .5mb...each section should have a pressure drop not exceeding .5mb , in the OP's case 28mm to first tee would have a loss of...
22.44/40m= 0.56mb........not a problem for 2 sections as long as first tee to boiler/range is below 0.44mb to which it isn't (2mb).
If the OP had 4 appliances then each section would be sized on a pressure drop of 1/4=.25mb per section.
The 22.44 metres from meter to first tee would be sized for...22.44 x 2 (sections) = 44.88 m equiv length , so 50m @ 33.77 m3/hr would suggest a pipe size of 35mm , some may do it different than above although it doesn't leave much scope.
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very good explanation gaswizzard, can see why kim described you as mathematician of our time.
G
gaswizzard
A
ALEC1
Yeah that is true, but not what was expressed, or intepreted...
Going back to the OP If the 15mm was accesable then this could be up graded too...what do you think GW?
Going back to the OP If the 15mm was accesable then this could be up graded too...what do you think GW?
G
gaswizzard
At what point was the confusion?
A
ALEC1
22.44 x 2 branches = 44.88 metres.
That is what was throwing me ...
Th books express that in a different way...
That is what was throwing me ...
Th books express that in a different way...
G
gaswizzard
G
gaswizzard
0.75mb loss between meter/1st tee?
I may be mistaken, but I always thought that the 1mb allowable drop was from the meter to the device, i.e meter to boiler, or meter to range.
Thats right David.
But GW had chosen to give 0.5 mB to each section of the gas supply.
Actually that is not the only/best way to apportion the permissible pressure drop.
It can be apportioned any way but thats usually best done according to the easiest/cheapest way to size pipework.
One way I do that is to make the pipework close to the meter larger as there are usually many elbows there and each elbow is cheaper to upsize than a metre of pipework.
Tony
But GW had chosen to give 0.5 mB to each section of the gas supply.
Actually that is not the only/best way to apportion the permissible pressure drop.
It can be apportioned any way but thats usually best done according to the easiest/cheapest way to size pipework.
One way I do that is to make the pipework close to the meter larger as there are usually many elbows there and each elbow is cheaper to upsize than a metre of pipework.
Tony
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