15mm or 22mm gas supply to 5-burner hob?

[guymark]

Hi.

Before any tells me that if I don't know I shouldn't be messing with Gas - I agree.

Please let me explain what I want to do.

I have been told by several folks that if I lay the piping out, make holes in walls ready and use sleeving in such holes - so all a gas fellow has to do is to check the integrity of the pipes (new), make the joints and then connect to the meter and the hob, it will be cheaper than if he has to bang holes in walls, and fit pipe clips everywhere and provide the pipe cut to size etc etc.

I can get the pipe clipped in place, routed through walls (in sleeves) and in short, reduce the amount of time a Gas Safe fellow has to spend doing things even I can do - I will just leave joints for him to do.

I have measured today and (give or take about 2M meters, the hob (far end of the house) is about 20 Metres from the gas meter. There are no other appliances (or won't be after he removes it) running on gas - it is hob alone.
There needs to be 7 x 90 degree bends in the pipe run and it is a HOB only - no oven (elec)

The hob is a "Smeg Piano P75" which has a total output of 9.55 Kw if all five burners are on full tilt.

As a very distinct preference I would like to use 15mm because I have almost enough to do the job - and because 22mm is goppingly expensive.

The hob itself only has a 15mm sort of size connector - but I realise it might still need a 22mm pipe for most of the way if the distance is too far.

Can someone please tell me if I need to buy / layout the system for 15mm or for 22mm. It doesn't matter if 15mm would do if the gas fellow then says it HAS to be 22mm to comply with some sort of code - so the official answer please; not a "will do at a push" - tempting though it is.

Also, please can someone tell me if I should provide compression fittings, solder ring or just plain (cheapest) copper which he uses solder instead. I am guessing soldering is the preferred option - which suits me as it is cheaper than compression. If I am wrong, please tell me.

Many thanks

Kind Regards

Mark

Oh, and if there is a Gas Safe fellow around Wellingborough who would like to actually do the work once I have laid out the piping, please get in touch and give me a ball park figure please - will be 7 right-angle fittings and 2 straight ones (plus possibly one at the meter).

 

[jj4091]

You really are better off leaving it to the expert to advise on site as there are other issues to consider like possible future additions, also every joint you make is a potential leak & a proffesional will be able to do it without so many. In my experience you may be looking for a false economy.

 

[guymark]

i.

Sorry, I thought I had made it clear in my posting that the house has been "de-gas-applianced" - my apology - now using heat pumps, have no intnetion to ever add any further gas appliances - it was only due to the concern over "heavy gas falling to the cellar" that I haven't just had the propane jets fitted to the hob and dump natural gas altogether. I DO have a healthy concern of gas - and would much rather not have it. Just ghastly using electricity for a hob.

Have no wish for any further gas appliances - let alone at the far end of the house in the kitchen. No gas expansion wanted. If my inheritors end up wanting more, then they can pay a plumber to do extra work - it will no longer be a concern for me one way or another

I have already taken into account bends where a pipe bender can be used - and all stra ight couplings are in 3M pipes. Because of the infrastructure, some bends really ought to be joints as getting a "3M pre-bent pipe in" is going to be a VERY difficult job. I accept possibly two of the seven could be bent and not joined - but if it is THAT much of a deal breaker for 15mm, then perhaps I need 22mm anyway just to give SOME margin.

I think the idea that it is false economy to avoid the need of a gas guy knocking through walls and providing pipe clips ready to be used over about 70' is curious. Let alone to have everything on-site, prepared ready so he needs to couple, test and go. I am not sure where the false economy is.

I just wanted an answer, based on the tables / charts of what diameter pipe is needed over some 20 odd metres when there are seven right angles in the pipes. If I faiuled to provide enough info, I am happy to provide more.

I thought that rating of appliance, distance, number of right angle bends and confirmation that nothing else would be supplied from the pipe was possibly enough for an answer. I am only a DIY fellow - if I have missed out an important bit of data, let me know what and I will gladly provide.

Kind Regards

 

[jj4091]

I am not an expert in this field so cannot give realistic advice but perhaps this may help http://www.ukcopperboard.co.uk/lite...ion-Tips/Domestic-gas-planning-and-sizing.pdf