Can someone explain this for me ?

[PEDANTICVINDICTIVEMAN]

http://www.jacktroop.co.uk/corgistuff/installer articles/128-Testing and purging.pdf

I am having trouble with what the difference is between the iv 0.035m/3 and iv 0.02m/3.

In example 1 with U6 meter the the volume is less than 0.035 so within scope of the Doc and purged as ige/up/1b

In example 2 with U16 meter the volume is more than 0.035 so purged to
ige/up/1a.

I'm not understanding the Sum up on page 44 and where this "0.02" fits in, can someone explain in blue collar details ? thanks.

 

[Onetap]

Top right of page 2;
The procedure for purging an installation having an IV of less than 0.02 m^3 has not changed (purging through an unlit burner)....

U16 meter has an IV of 0.025 m^3, so that procedure cannot be applied.

 

[PEDANTICVINDICTIVEMAN]

So what is the 0.035m/3 cut off ?

 

[Onetap]

So what is the 0.035m/3 cut off ?

It is the maximum IV for an installation for which the purging procedure described in that document can be used. Above that, you need commercial accreditation and a different purging procedure would be used.

Example 1 is less than 0.035 m^3, so one specified purging procedure is used. Example 2 is more than 0.035 m^3, so a different procedure is used.

The procedure for domestic installations of less than 0.02 m^3 hasn't changed.

 

[PEDANTICVINDICTIVEMAN]

Thanks got that bit now, still a bit confused on the "sum up" where it says "provides Domestic gas installers with a procedure for testing and purging a gas installation that included a meter passing 16m3/h and 35mm pipework" 0.020 - 0.035 =0.01 that only leaves pipework with an iv of 0.01 of pipe volume, it would be a small size and run of pipe, in which case a small appliance in which case I wouldn't need a U16 meter, I don't see the point in the first part of the "sum up" !

 

[Onetap]

"provides Domestic gas installers with a procedure for testing and purging a gas installation that included a meter passing 16m3/h and 35mm pipework" !

That's the point of IGE/UP/1B document, they have had to increase the pipe size and IV of installations that domestic installers can tackle, due to the use of high-output combis.

I need to look up the details of the commercial IGE/UP/1A tests and a duff PC won't let me.

 

[PEDANTICVINDICTIVEMAN]

So which combi on what pipe size can I as a domestic installer fit onto a U16 meter with only 0.01 of pipe volume left to play with ? forgetting the cooker and gas fire for now !

 

[Onetap]

So which combi on what pipe size can I as a domestic installer fit onto a U16 meter with only 0.01 of pipe volume left to play with ? forgetting the cooker and gas fire for now !

I'd think about that when you find one. Have you ever come across a U16 meter before? 0.01 m^3 is equivalent to about 18m of 35mm tube, so it is possible. The meter could supply up to 172kW.

Maybe on a modular boiler installation where a bank of small boilers are used, instead of one or two large boilers. The intention is to split up a large load and also to avoid using more expensive commercial boilers.
(PS Edit to add, read this;
http://www.jacktroop.co.uk/corgistu...1 Modular Boiler Installations (Current).pdf)

The bit of the purging PDF that caught my attention was "In this case the purge process is via an open burner in order that a continuous effort is made to ignite the air/gas mixture whilst purging." (RH column, page 43)

Isn't that a typing error? Surely you'd want to avoid igniting the gas/air mixture since it could be explosive? I thought the whole point of purging was to purge the air out of the gas pipe and fittings.

I need to check up on this.