Formulas

[Barry98]

I know we have different ways of working things out , depending on age , location and how we were taught but at the weekend I had a barney with a so called gsr guy (who'd left a leak on a lpg cooker luckily I was close to home so came and got van) Any way he was asking me about purging etc cos we all do the calculations now I use on a u6 5 times its badges capacity approx 1/3 of a revolution and he starts going into you times this by that didide by this etc like I would to get btu's so just wondered what you all use

 

[Rickster123]

I use the 1/3 method but I'm sure at my acs assessment there was something said about it. Where's kirk when you need him?

 

[Billy Bob Bob]

dont do lpg but if its NG 5 times the badged capacity 4 for the meter one for the pipework volume

 

[Reg Man]

Correct with the U6 meter. General rule is 1.5 times the installation volume including pipe work. So an E6 meter it would be the 1.5 times the pipe volume.

 

[Barry98]

Yeah this was ng mark I just drifted of

 

[mikegas]

The calculation is to determine the purge method, iv below 0.02 can be purged to atmosphere, above this needs to be continually ignited

 

[tamz]

You shoulda just hooked him :smile:

 

[Billy Bob Bob]

You shoulda just hooked him :smile:

4 in the head and one in the nads for the volume:lol:

 

[kirkgas]

I only do domestic, which is 0.35 ft3 for U6, and 0.01m3 for E6 if both no more than 28mm pipe on both
Purge for larger meters or pipes is 1.5 x IV of installation

 

[Dotty]

I only do domestic, which is 0.35 ft3 for U6, and 0.01m3 for E6 if both no more than 28mm pipe on both
Purge for larger meters or pipes is 1.5 x IV of installation

I hate doing this Kirk but you're wrong.

On larger meters it's 5 x the cyclic volume + 1.5 x the pipe volume + 1.5 x purge stack volume.

 

[Barry98]

fight fight fight

 

[Leo21]

Fight!

 

[mikegas]

I hate doing this Kirk but you're wrong.

On larger meters it's 5 x the cyclic volume + 1.5 x the pipe volume + 1.5 x purge stack volume.

Does this only come into play if the iv is above 0.035 or the meter has a greater capacity than 16m3/hr?

 

[Reg Man]

E6 G4 U6 pipework <28mm PV= 0.01m3, G4 pipework >28mm PV= 0.01m3 + 1.5 IV of pipework, E6 pipework >28mm PV= 0.0036m3 + 1.5 IV of pipework, G10 U16 pipework up to 35mm PV= 0.3m3 + 1.5 IV of pipework.

 

[kirkgas]

Not at all, as I said at the start of the post, I only do domestic so that's all I can quote on

 

[kirkgas]

Does this only come into play if the iv is above 0.035 or the meter has a greater capacity than 16m3/hr?

Yes because what I quoted was for domestic and under the values you quote here

 

[kirkgas]

E6 G4 U6 pipework <28mm PV= 0.01m3, G4 pipework >28mm PV= 0.01m3 + 1.5 IV of pipework, E6 pipework >28mm PV= 0.0036m3 + 1.5 IV of pipework, G10 U16 pipework up to 35mm PV= 0.3m3 + 1.5 IV of pipework.

The figures you quote are 100% correct but the new IGE/UP/1B quotes them differently now, they quote UV calculation as meter IV + PIPEWORK IV +10% for fittings THEN x 1.5, which gives the same answer

 

[Leo21]

It's all very clear now. Thankyou.

 

[Reg Man]

The figures you quote are 100% correct but the new IGE/UP/1B quotes them differently now, they quote UV calculation as meter IV + PIPEWORK IV +10% for fittings THEN x 1.5, which gives the same answer

Thanks for that update. Its interesting why IGE and BSI want to change the formula's in lots of different standards. They call them amendments or revised standards, but there never seems to be much wrong with the original formula's. Is it just keeping some technical committee in a job, and trying to confuse the engineers that have to keep up to date and buy lots of expensive technical documents. It's is good business for the training and assessment centre's too. No offence met