Gas pipe sizing

[bster]

Is there an actual calculation I can use to find out the correct pipe size for a 40meter run. I’ve tried the charts\wizards but they only give flow rates upto a max of 30meters. and you cant guess by deducting the flow for a 10meter run because it is not a constant difference (you know what i mean).

 

[doitall]

Got a chart up to 50m if you want to email me.

 

[chrishutt]

The flow rate that gives a 1.0 mb drop over 40 metres will be the same as the flow rate that gives a 0.5 mb drop over 20 metres, or a 0.25 mb drop over 10 metres, for any given pipe size.

 

[doitall]

But if 40m of 22mm pipe had a discharge of 2m³/hr, how would you apply that to say 50m.

 

[croydoncorgi]

Easy....
calculate the pressure drop over the max length given in your table, then re-calculate for the rest of the actual length using the 'dropped' value. OK - it probably won't be 100% accurate but it will be within 5%, I believe.

 

[doitall]

Easy....
calculate the pressure drop over the max length given in your table, then re-calculate for the rest of the actual length using the 'dropped' value. OK - it probably won't be 100% accurate but it will be within 5%, I believe.

Using that method would give you a pressure drop of 1.25m/bar which is correct, but can you estimate the discharge using the same method or is there a sneaky way of multiplying length x pipe size x pressure.

for example, 50 m of 22mm will discharge 1.78m³/hr whereas 40m will discharge 2m³/hr.

There must be a formular I think.

 

[bster]

thats it a fomula would be nice.

i've worked it out know by seperating the runs into sections (there are 3 appliance), so the 40meters became 10m,10m and 20m sections (done properly using a gas sizing example and breaking the sections as appliance are being teed off).

28mm pipe for the 40m run to a 3.8m\hr appliance and a .2m/hr heater (21m run) and 1m/hr hob (7m run).

= 28mm pipe from meter for 40 meters to 3.8m/hr appliance and 15mm pipe at the 10meter tee for .2m/hr appliance and 15mm pipe for the hob teed at 30meters off the 28mm pipe.

 

[doitall]

But the 28mm wouldn't be large enough with those rates.

 

[bster]

i,ve worked it out and it was well under

I'll post the breakdowns if u want to check (and probably show me up!).

 

[doitall]

i,ve worked it out and it was well under

I'll post the breakdowns if u want to check (and probably show me up!).

Ok, if you email it I can return the chart.

 

[bster]

just read your post and i'd already copied some figures from word so i may as well paste them on now i'm here.

here goes

a-b = 4.9m\hr@10m = 28mm(meter - first tee)
b-c = 0.2m/hr@22m = 15mm(first tee - 1st appliance)
b-d = 4.7m/hr@20m = 28mm(first tee - second tee)
d-e = 1.0m/ht@6m = 15mm(second tee - second appliance)
d-f = 3.7m/hr@15m = 28mm(second tee - third appliance)

note: all lengths are the total equivelent (inc bends,tees,elbows) lengths. I have taken the pipe sizes from the BS chart, but i have not calculated the allowable pressure drop, in this case .33mb per appliance.

 

[kevplumb]

just read your post and i'd already copied some figures from word so i may as well paste them on now i'm here.

here goes

a-b = 4.9m\hr@10m = 28mm(meter - first tee)
b-c = 0.2m/hr@22m = 15mm(first tee - 1st appliance)
b-d = 4.7m/hr@20m = 28mm(first tee - second tee)
d-e = 1.0m/ht@6m = 15mm(second tee - second appliance)
d-f = 3.7m/hr@15m = 28mm(second tee - third appliance)

ohh bonny lad are you ever digging your sen a hole

 

[bster]

i love diggin holes - i used to be a gardener and then an archaeologist (i'm not joking) .

dew you speel rongely on porpus

 

[kevplumb]

i divvent spell rongly bonny lad that's ow i speek ask DIA

marra

 

[bster]

marra

eh?