Upgrading from a u16 to a u25

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Charlie BH

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Hi There,

We need some help..please. We have been told SO many different things about this - its impossible to know who to believe. For the record - I'm a chef - not a gas engineer.

We have been happily working from 2 commercial kitchens on the ground floor in our commercial catering premises for 10 years.

Covid etc means are in the midst of creating 6 smaller kitchens here. We will rent out 4 and use 2 ourselves.

This has been expensive! New, bigger grown-up extraction system for a start. ANYWAY.

We have a u16 meter. We understand this can cope with 66 – 173 kW.

In each kitchen we plan to have a 6 grid gas combi (13kw max) and a gas 4 ring burner with normal oven underneath (23kw max) plus we have a 28kw combination boiler....

36kw x 6 + 28kw = 244kw (if they are all on full blast at the same time).

So we need a u25 (174 - 271 kW) to be safe.

A selection of opinions I have gathered are recounted for you below:

1) We had one gas engineer saying: keep each kitchen under 78kw and we can get each one installed and signed off in the domestic category - there will be more than enough gas from the u16
2) We had another say "this is a light industrial estate - more than enough gas here - get a private firm to drop in a u25 meter - ta-daaaaa"
3) We had an energy supplier come and test the pressure in the pipe by the meter. He says that the service pipe energy value is 133kWh (that means we need to upgrade the meter (£250) and the supply (£19,000 for bespoke gas pipework)

We can't do anything illegal. Equally we cant spend £20,000 on the upgrade. Truth is that we are never going to be running all the gas a appliances together.

Do we restrict each kitchen to 24kw max for gas (24kw x 6 = 144kw + 28kw for boiler = 172kw (1kw below u16 threshold).

Or do we go for it - and in the event that everyone is on full gas power together - surely the pressure drops a bit (No big deal? Or does this blow up the building/postcode)?

We want to get open for business first - if we HAVE to upgrade the gas - we'd rather do that later on when we have some money in the bank.

If we have to upgrade the entire supply - we dont want to ALSO have to upgrade the pipework in the building as well.

My mind is boggling. Any thoughts?

Thanks

Charlie
 
OK, I'll say from the off that I'm qualified for domestic gas only, but I'm not sure if anyone here is commercial so I'll stick my head above the parapet for you...

1) 70kW is the domestic limit, not 78kW, but in any case a commercial kitchen is a commercial kitchen regardless of the total load.

2) A finger in the wind approach is never going to work

3) If your energy supplier says the maximum you can draw is 133kwh, then the maximum you can draw is 133kwh and the maximum load you can connect is 133kwh. 133 - 28kW boiler = 105kW. 105 / 6 kitchens = 17.5kW maximum per kitchen.

I'm not aware of anything in the regs that says you can apply a diversity factor to allow a greater load to be connected on the basis that not everything will be turned on at the same time, but that might be where the holes in my commercial knowledge start to show through. That being said, I'd very much doubt it would permit you to have all the appliances you want even if a diversity factor were possible. Unless someone can tell you different, I'd plan on no more than 17.5kW per kitchen until you can get the supply upgraded.

Either way, your internal gas pipe size needs to be able to cope with the maximum possible load, so if that's 244kW then your internal gas pipework needs to be sized for 244kW. There's no diversity for gas pipe sizing, of that I am certain. And no, you can't just connect everything and overload the incoming supply.
 
Thanks Andrew. Very helpful. If we have to upgrade the supply - I'm sure there are cheaper ways to do it than £20K British Gas quoted us.
 
If the service pipe is not big enough then you have no choice but to pay for an upgrade .
 
Service pipe is huge. According to the plumber (and domestic gas/heating engineer we happen to have on site today). Not sure if this picture helps!
 

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The service pipe is the one at the left of that picture its 1" at best.

A lot will depend where the distribution pipe enters the estate compared to where you are.

This is the reason lots of estates are being fitted with medium pressure supplies round here but that doesn't help you.

Even the shut off valve looks sad about the situation....


Screenshot_20210203-213357_Samsung Internet.jpg
 
service is definitely too small and will need upgrading and they will be working from maps detailing sizes of pipes already in the road .
1 , He is talking shyte
2 Is also talking shyte
3 have the information to hand and know what is underground and should be working from that ,their price is their price
 
that is the service pipe and way too small for your requirements
 

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I did say inch at best lol

Yes I agree the 133kW available sounds about right. I presume it was a GT1 survey?
 
They measured it with a micrometer screw gauge - 31mm apparently...

Yes it was a GT1 survey. The commercial upgrade dude I spoke to said they would another GT1 (and that they are allowed to do them and submit them to cadent...)
 
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