Purging long gas supply

[tamz]

Technically if its a g4/U6 and pipework 28mm or under you don't need to bother working out the IV. The PV is 5 x cyclic volume (0.002) = 0.01

 

[Masood]

Every app you use will prob give different answer.
If you want accuracy you need go old school and work out using your fingers and toes with standardised formula.
I got 0.02934 volume for a G4 meter.

You've added 10% to the pipework before adding meter volume, right?

 

[Masood]

Technically if its a g4/U6 and pipework 28mm or under you don't need to bother working out the IV. The PV is 5 x cyclic volume (0.002) = 0.01

True, as that is minimum purge vol but I want to check whether I was taught wrong about the multiplying by 1.5?

 

[GrahamM]

You've added 10% to the pipework before adding meter volume, right?

yip.

 

[REDSAW]

Where are you getting 35m of 22mm? I thought we were looking at 30m x 28mm + 10m of 22mm??

that size is the iv of your result/size over 35m of 22mm

 

[Masood]

Almost right. :yes:
Went wrong by adding the meter before adding your 10%.

Now that's a funny thing. When I first did ACS, I was taught to do your method. Subsequently I was taught to add meter volume first and then add 10%.

 

[Masood]

that size is the iv of your result/size over 35m of 22mm

Sorry Martin, I don't follow?

 

[tamz]

True, as that is minimum purge vol but I want to check whether I was taught wrong about the multiplying by 1.5?

No its right enough.
You would only bother working out the IV for a purge if there was > 28mm or a G10/U16 on it so it is irrelevant in this case anyway.

 

[tamz]

Now that's a funny thing. When I first did ACS, I was taught to do your method. Subsequently I was taught to add meter volume first and then add 10%.

Some acs centres have their heads up their rses.
Gimme a minute and i'll post a pic from UP1B.

 

[Masood]

Some acs centres have their heads up their rses.
Gimme a minute and i'll post a pic from UP1B.

Just checked the Construction Skills textbook. 10% added to pipework and then meter volume added. So yeah, the worksheet the assessment centre gave us was wrong!

Although, I noticed something else in the book - we've all been adding 0.008m3 as meter volume, but that is meter internal volume. Meter purge volume is given as 0.01m3 for U6/G4.

God, I'm sad...

 

[REDSAW]

according to this app (uk gas app) with a g4 meter with straight run of 35mx22mm pipe with no fittings comes to 0.0305m3 so a 30m run of 28mm and 10m of 22mm with 6 fittings cant equate to the same?

looking at same volume

 

[tamz]

 

[REDSAW]

Just checked the Construction Skills textbook. 10% added to pipework and then meter volume added. So yeah, the worksheet the assessment centre gave us was wrong!

Although, I noticed something else in the book - we've all been adding 0.008m3 as meter volume, but that is meter internal volume. Meter purge volume is given as 0.01m3 for U6/G4.

God, I'm sad...

the inspectors will be busy next week.lol

i rely on my app's or last resorse get the book out of van.
did my resits last week and they said 'right get your prefered app ready for purging/pipes & vents.lol

 

[GrahamM]

Just checked the Construction Skills textbook. 10% added to pipework and then meter volume added. So yeah, the worksheet the assessment centre gave us was wrong!

Although, I noticed something else in the book - we've all been adding 0.008m3 as meter volume, but that is meter internal volume. Meter purge volume is given as 0.01m3 for U6/G4.

God, I'm sad...

Yip. For standard G4/E6 upto 28mm pipe the standard purge is 0.01.
Bigger meter and or greater than 28mm pipe then you need to calculate.

 

[REDSAW]

View attachment 25827

feck! cant see your bank details on there!

 

[tamz]

Meter purge volume is given as 0.01m3 for U6/G4.

Only if pipe is no bigger than 28mm (5 times cyclic volume which used to be called badged capacity)

 

[REDSAW]

Yip. For standard G4/E6 upto 28mm pipe the standard purge is 0.01.
Bigger meter and or greater than 28mm pipe then you need to calculate.

depends!

 

[mutley racers]

Wow.a lot of info in there guys. Thank you. So basically, all I need to do is purge 0.01 and all is well as no 35mm pipe or u16 meter.

So I am within scope.

I know some boilers have a purge setting on them so think I shall do it this way


Thanks for all the help guys. I appreciate it.

 

[mutley racers]

Just one more thing to clarify, it is the installation volume that makes it commercial and not the purge volume correct? Which is what tamz's diagrams explains

 

[REDSAW]

Wow.a lot of info in there guys. Thank you. So basically, all I need to do is purge 0.01 and all is well as no 35mm pipe or u16 meter.

So I am within scope.

I know some boilers have a purge setting on them so think I shall do it this way


Thanks for all the help guys. I appreciate it.

no!
the installation volume is>0.035 and by the book..its out of scope!
whether it matters could be debateable but you wouldnt do it near an inspector
perhaps were all on a learning curve here, one for the acs reassesment center when tickets are due.haha

however, based on this there in scope and simular to what tam said, so 'grey area'?
http://shop.igem.org.uk/download/document/Pages from IGE-UP-1B Edition 2.pdf
http://shop.igem.org.uk/download/do...UP-1A Edition 2 (Reprint with amendments).pdf

 

[Dotty]

no!
the installation volume is>0.035 and by the book..its out of scope!
whether it matters could be debateable but you wouldnt do it near an inspector
perhaps were all on a learning curve here, one for the acs reassesment center when tickets are due.haha

however, based on this there in scope and simular to what tam said, so 'grey area'?
http://shop.igem.org.uk/download/document/Pages from IGE-UP-1B Edition 2.pdf
http://shop.igem.org.uk/download/do...UP-1A Edition 2 (Reprint with amendments).pdf

He's well within scope!

Scope refers to the installation volume, not the purge volume. Installation volume in this case is, as several have worked out, 0.030M3

The purge volume is 0.085m3 which, if you crack a joint under the boiler, will take 180 seconds to purge.

You'll have gas long before that but the 120 will definitely prevent any air pockets being left.

 

[tamz]

The volume is 0.2934 so its fine

I should reload again after going to the shop

 

[Dotty]

The volume is 0.2934 so its fine

I should reload again after going to the shop

And divide by 10. And round up to 3 dp.

Personally I've always rounded up, never down.

 

[mutley racers]

He's well within scope!

Scope refers to the installation volume, not the purge volume. Installation volume in this case is, as several have worked out, 0.030M3

The purge volume is 0.085m3 which, if you crack a joint under the boiler, will take 180 seconds to purge.

You'll have gas long before that but the 120 will definitely prevent any air pockets being left.

Just wondering how you worked out the purge time. Is there a calculation you do to figure this rather than having to go to the meter to make sure you purge the correct amount?

 

[Dotty]

Just wondering how you worked out the purge time. Is there a calculation you do to figure this rather than having to go to the meter to make sure you purge the correct amount?

Download IGEM/UP/1 from my Dropbox, think it's section 6 off hand.

https://www.dropbox.com/sh/yrr0bvvr2tcp0ik/AABD_O6cBb9OY6Jg7r28GWdHa?dl=0