Trust the professionals
 

This is a snippet from a post of mine from last Tuesday:


Secondly she is having a new cooker and hob, changing from gas to electric,
consequently I will need to cap the old gas feed as it's in the way.

I am a competent wet plumber but was wondering if there was any advice for a
job like this (i.e. don't do it). It seems straight forward, Turn off gas at
meter, cut pipe, make end good, then solder on new end cap, turn gas back
on, and check for leaks with gas aerosol stuff. ( what about any gas left in
the pipe when I'm soldering, will air have got into the system during the
process, etc)


The general consensus was to get a Corgi registered person to do the job.
Reluctantly I did this.

Now this work was taking place behind a washing machine, so access was sort
of available. Anyway I always thought it was best practice to use soldered
joint on gas, but it was acceptable to use compressions where there was
access to the fitting. But if compression was used the yellow tape should be
used. The Corgi plumber has used a compression with no tape, is this
acceptable? Should I redo the job myself using a soldered joint, or should I
just loosen the compression and wrap some yellow tape, or has he done an
acceptable job?

TIA

Jon

Trust the professionals
 

In article , jon
writes

The Corgi plumber has used a compression with no tape, is this
acceptable? Should I redo the job myself using a soldered joint, or should I
just loosen the compression and wrap some yellow tape, or has he done an
acceptable job?

Compression joints do not require tape or any other sealant to make a
good joint, this is true for both water and gas.
--
fred
Plusnet - I hope you like vanilla

Trust the professionals
 

fred wrote:

Compression joints do not require tape or any other sealant to make a
good joint, this is true for both water and gas.

Agreed - but what I'm wondering is this - when you create a dead-end in
a gas pipe system like this, is there any requirement to purge it (to
get rid of the trapped air) or do you just allow time and the natural
diffusion of gases to do the job.

--
Andy

Trust the professionals
 

Andy Wade wrote:
fred wrote:

Compression joints do not require tape or any other sealant to make a
good joint, this is true for both water and gas.

Agreed - but what I'm wondering is this - when you create a dead-end
in a gas pipe system like this, is there any requirement to purge it
(to get rid of the trapped air) or do you just allow time and the
natural diffusion of gases to do the job.

There is no requirement to purge it and it would be pointless anyway as it's
still connected to the main supply.
There is a requirement to isolate a dead leg with water pipes because the
water inside could stagnate and then find it's way back into the main.

Trust the professionals
 

jon wrote:
This is a snippet from a post of mine from last Tuesday:


Secondly she is having a new cooker and hob, changing from gas to
electric, consequently I will need to cap the old gas feed as it's in
the way.
I am a competent wet plumber but was wondering if there was any
advice for a job like this (i.e. don't do it). It seems straight
forward, Turn off gas at meter, cut pipe, make end good, then solder
on new end cap, turn gas back on, and check for leaks with gas
aerosol stuff. ( what about any gas left in the pipe when I'm
soldering, will air have got into the system during the process, etc)


The general consensus was to get a Corgi registered person to do the
job. Reluctantly I did this.

Now this work was taking place behind a washing machine, so access
was sort of available. Anyway I always thought it was best practice
to use soldered joint on gas, but it was acceptable to use
compressions where there was access to the fitting. But if
compression was used the yellow tape should be used. The Corgi
plumber has used a compression with no tape, is this acceptable?
Should I redo the job myself using a soldered joint, or should I just
loosen the compression and wrap some yellow tape, or has he done an
acceptable job?
TIA

Jon

You should have just done it yourself, and no, there is no need for tape,
gas isn't under much pressure anyway - you can stop it with one finger

Trust the professionals
 

jon wrote:

The general consensus was to get a Corgi registered person to do the job.
Reluctantly I did this.

IIRC there were two parts to the question, the first was with regard to
a cast iron gas pipe that sounded like a disused feed? If so then
dealing with *that* pipe would be better left to the gas suppliers.

Dealing with blanking a copper connection however is much simpler.

Now this work was taking place behind a washing machine, so access was sort
of available. Anyway I always thought it was best practice to use soldered
joint on gas, but it was acceptable to use compressions where there was
access to the fitting. But if compression was used the yellow tape should be
used. The Corgi plumber has used a compression with no tape, is this
acceptable? Should I redo the job myself using a soldered joint, or should I
just loosen the compression and wrap some yellow tape, or has he done an
acceptable job?

The gas (yellow) PTFE tape is for use on threaded connections that seal
on the threads. A compression connection does not seal like this, and
hence does not require tape.

(sometimes tape is used on the thread of a compression fitting as an aid
to lubrication - it makes doing them up slightly easier but does not
change their ability to seal.

--
Cheers,

John.

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