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Discuss Gas pipe oversizing. 22mm vs 32mm in the Gas Engineers Forum area at PlumbersForums.net

Messages
18
Just to be really clear I will not be doing any of the work mentioned below. This will all be carried out by Gas Safe Engineers.

I'm looking to get a Gas Safe engineer to move a boiler from the main house to the garage. As part of this process I will also be getting the main gas supply and meter moved from inside the house to outside.

I've been through the gas sizing calculators online and for my very short run (~2m), 2x90 degree bends and the boilers size (24kw) a 22mm pipe would be absolutely fine with a pressure drop of 0.1212 mb.

Aside from the cost, is there any downside to oversizing the pipe to 32mm? Same calculator shows a pressure drop of 0.0194 mb.

I ask because I've seen a number of TracPipe offcuts and fittings on eBay which would be massively cheaper than a TracPipe Pipe Replacement Kit DN22 x 5m. Clearly it would be up to the plumber to decide if comfortable using this but at the prices I've seen it would be well worth a punt.

This is in a house I am in the process of buying so do not have the luxury of getting a plumber round to take a look just yet
 

Last Plumber

Esteemed
Plumber
Gas Engineer
Messages
4,314
No real reason other than cost of pipe, fittings and the unnecessary over-sizing.

I would leave it to your Gas Safe registered installer if I were you. I know if I turned up somewhere and the customer asked me to install over sized trac pipe my answer would be no.

It is an advertisement that you don't know what you're doing to the engineers that follow and I personally wouldn't put my name to it.
 

Ric2013

Plumber
Messages
3,315
No real reason other than cost of pipe, fittings and the unnecessary over-sizing.

I would leave it to your Gas Safe registered installer if I were you. I know if I turned up somewhere and the customer asked me to install over sized trac pipe my answer would be no.

It is an advertisement that you don't know what you're doing to the engineers that follow and I personally wouldn't put my name to it.
Interesting that you wouldn't put your name to it. Would you refuse to install the over-sized pipe even if the customer were not supplying it, say the customer just wanted it oversized for future-proofing reasons? Or is the issue the fact that the customer is supplying and so you'd lack product traceability? Just wondering what the main issue would be for you.
 

Last Plumber

Esteemed
Plumber
Gas Engineer
Messages
4,314
Interesting that you wouldn't put your name to it. Would you refuse to install the over-sized pipe even if the customer were not supplying it, say the customer just wanted it oversized for future-proofing reasons? Or is the issue the fact that the customer is supplying and so you'd lack product traceability? Just wondering what the main issue would be for you.
It's not the future proofing element. We often install gas pipework with that in mind. So for example, a factory might want to allow for additional plant/process equipment in the future or even additional heating so we would size accordingly and leave it finished with that intention, valve, tee with test point, plugged.

With this there were other reasons.

One was that I don't like trac pipe. I think it looks messy and temporary (my opinion). We have never used it and never needed to.

Two was that we only supply and install our own equipment and materials. We provide a full warranty for parts and labour and that avoids any disputes if there is an issue. If there is a fault within the warranty period, we will deal with it and the customer is not involved in any way.

Three was that this read to me like the OP was buying it over sized because it was a good deal? It is only supplying the boiler from the meter over a short distance. There is no requirement for anything additional following on, unless there is something we don't know about.

Whatever work we are carrying out, we always have the thought in mind that another engineer will follow on. They should not be able to criticize, pass negative comments, fault or condemn your work.
They should if nothing else, be impressed!

By installing something unnecessarily over sized, you are in my opinion, advertising that you don't know what you're doing to the engineers that follow. There will not be a label on the installation explaining to them that the customer insisted on doing it this way. It isn't just over sized gas pipes, it goes for any aspect of your work. e.g. I see boilers that are way over sized for the pipe work and pump they are attached to. That demonstrates that the installer didn't understand what he/she was doing.

This is by no means intended to 'have a go' at the OP. As I said in the beginning I think that the provision of materials is best left to the installer. Anything incorrectly installed is then purely down to them.

Others might not give a damn about what others think about their work. We are not all the same. It would be boring if we were!
 
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Messages
18
It's not the future proofing element. We often install gas pipework with that in mind. So for example, a factory might want to allow for additional plant/process equipment in the future or even additional heating so we would size accordingly and leave it finished with that intention, valve, tee with test point, plugged.

With this there were other reasons.

One was that I don't like trac pipe. I think it looks messy and temporary (my opinion). We have never used it and never needed to.

Two was that we only supply and install our own equipment and materials. We provide a full warranty for parts and labour and that avoids any disputes if there is an issue. If there is a fault within the warranty period, we will deal with it and the customer is not involved in any way.

Three was that this read to me like the OP was buying it over sized because it was a good deal? It is only supplying the boiler from the meter over a short distance. There is no requirement for anything additional following on, unless there is something we don't know about.

Whatever work we are carrying out, we always have the thought in mind that another engineer will follow on. They should not be able to criticize, pass negative comments, fault or condemn your work.
They should if nothing else, be impressed!

By installing something unnecessarily over sized, you are in my opinion, advertising that you don't know what you're doing to the engineers that follow. There will not be a label on the installation explaining to them that the customer insisted on doing it this way. It isn't just over sized gas pipes, it goes for any aspect of your work. e.g. I see boilers that are way over sized for the pipe work and pump they are attached to. That demonstrates that the installer didn't understand what he/she was doing.

This is by no means intended to 'have a go' at the OP. As I said in the beginning the provision of materials is best left to the installer. Anything incorrectly installed is then purely down to them.

Definitely not taken as having a go and I actually found this to be a really good read. Thanks so much for replying so comprehensively.

My motivation was definitely a good deal, but having read this I actually really like the idea of future proofing. I am doing the same with my electrics (installing 25mm2 cables to allow for an EV charger) and also my networking (adding fibre from garage to house).

I do totally get the point around supply and warranty etc. The only comeback on this is that the expectation is that this will be fully tested for leaks and drops etc and at that point should a problem occur, my trench would still be open and we can have another go with copper instead.

Not a plumber but I am a fan of TracPipe as it saved my bacon in the past. Gas leak under my newly laid flooring. TracPipe fed through meant not having to rip that up which would have been awful as I have insulation and underfloor heating packed between the joists. But having said that, I'm not the one who would have to work with the damn stuff....
 
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