Hot zone vertical separation

Nov 11, 2009
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Our kitchen rip out starts on Monday, following four week kitchen update at our daughter's house. We are scrapping the cooking range and going to a more normal sized gas four burner cooker. The plan is to install an angled extractor above the hob. But like most things its not a simple "just do it". Our installer says that the extractor must be 800mm above the level of the hob burner. Nothing I have seen has equalled 800mmfor the vertical height of the hot zone for gas installations. Many seem to quote 750cm on various websites. and appliance suppliers but without reference to a source reference. The AEG cooker installation instructions say 650mm, and the Franke hood say 650mm too. On that basis both are okay for a 650mm minimum height separation. So I looked at the Gas Safe website, but it doesn't give a lot of insight as I am not registered for it. However, I found Technical Bulletin 005(A) dated July 2015 which deals with ventilation requirements for gas cookers in internal kitchens.The only information that was relevant was:

"If the extraction is via a cooker hood, it should be installed paying due regard to both the hood and cooker manufacturers installation instructions" There is reference to a Gas Safe TB 095 dealing with extract fans and open fluid appliances, but I can't find anywhere to view it.

I then went to the Health and Safety Executive website, but their gas safety helpline wasn't available. However, reading the most recent guidance "HSE Safety in the installation and use of gas systems and appliances, Gas Safety (Installation and Use) Regulations 1998 as amended July 2018 L56." the advice guidance was in Part E Gas Appliances Regulations 26 and 27. It stated:

"261 Minimum clearance distances for operation, inspection and maintenance purposes are normally specified in manufacturers’ instructions for the installation of appliances."

And that's it in a nutshell. I am none the wiser as to where the "trade" get their 750mm vertical height separation between gas hob and hood. Per se it's not gas safety installation issue, more one of fire safety. But does anyone know why the 'trade" use 750 mm, or more when two authoritative bodies advise to align with alliance makers recommendations?

I will not be working on anything to do with gas or electrics although I have in the past done both for two separate kitchen installations, and had them checked out afterwards. Not nowadays, it's a minefield when you cannot readily source the "trades" base data for hot zone vertical separation distances.

Now about caravan cooker installations........ HSE have advice on that too. :unsure:
 
Last edited:
Mar 17, 2020
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I'm astonished you have gone to all the trouble researching. Well done that man! You obviously must feel it's an important decision. :unsure:

Have you considered changing your Installer to one who is more flexible if the current one pays no attention to your research?

You can bet that whatever height it ends up at the results for efficiency will be the same won't they?

Intrigued to hear what height is eventually used.
 
Nov 11, 2009
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Thanks, I've not yet given him the benefit of my research. But angled hoods are more sensitive than traditional ones which are just mounted horizontally. Once the electrician has cut and channeled the cables and power outlet laid I could even put it up myself. But that wasn't the aim of Mrs OC's dream project, as she would like it all working for Christmas ...but with 16 weeks lead time for flooring contractors that could be a dream too far.

Looking at caravans and how my last one had cupboards above the hob with an internal electric 13 amp socket for a microwave, and adjacent was the wardrobe with only some sheet metal for heat protection from the side of the ho,. I suspect the 750mm plus was probably derived by a caravan maker :), as its source is just as nebulous as some of the guidance given for caravans.

PS changing installers isn't that easy when rip out begins in two days, and the plasterer and electrician, and gas are all lined up. The last thing I want is a garage load of units, worktops and appliances in the garage waiting for a new man. This guy is absolutely meticulous and made super job of our daughters kitchen, so at the end of the day its down to my powers of persuasion or DIY.
 
Sep 7, 2020
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Just checked the installation manual for the one I put in and it states....

For best performance install at a distance between 65cm to 75cm from the hotplate surface......never lower than 65cm.

No mention of any difference for gas vs electric.
 
Nov 11, 2009
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Just checked the installation manual for the one I put in and it states....

For best performance install at a distance between 65cm to 75cm from the hotplate surface......never lower than 65cm.

No mention of any difference for gas vs electric.
That’s interesting as most seem to say hot zone vertical distance can be 450 mm for electric hobs. Could this be another industry based on guidelines derived from when our ancestors roasted a joint of mammoth over an open fire pit?
 
Sep 7, 2020
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That must be for short order cooks because that low I'd have trouble seeing under it.

I just measured mine and I went for 700mm.
 
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Nov 11, 2009
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That must be for short order cooks because that low I'd have trouble seeing under it.

I just measured mine and I went for 700mm.
At 5 ft 2 inch the principal user would never bang her head or be unable to touch the controls even at 450 mm. Me I’m heavily into microwaves on a standard height work surface.
 
Sep 7, 2020
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You might want to consider any splashback you're going to install. So for instance if tiling, position it as best as possible to avoid cutting tiles.
 
Nov 11, 2009
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2,396
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You might want to consider any splashback you're going to install. So for instance if tiling, position it as best as possible to avoid cutting tiles.
Probably going to have a custom made toughened glass splashback once everythings position is sorted. There are some where you can have a favourite picture printed on them. Our daughters friend has one with a picture of a Scottish loch. But we will stick to a plain colour.
 

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