I suspect there isn't a regulation as such, just if it meets whatever the maker's design authority  felt  was reasonable at design time
Do the makers. specify anything at all about cross-coupling , or ventilation of the rear of the two units ? Quite often units are boxed in 'tighter' than they should have been according to the installation instructions.
Mike.

Sadly they only state it meets a specification and all ovens do it.

Our previous ovens have not had this problem.

In this regulated Health and Safety  risk adverse society I cannot believe a regulation does not exist somewhere.

Interesting question Iain. I've always assumed that there is a layer or two of robust of insulation between the top and bottom ovens to prevent too much heat transfer but if yours is getting to over 100C then that's an awful lot of heat there! I sometimes use my top oven to warm the dinner plates when I have the bottom one on but it gets nowhere near 100C! 

As Mike says I'm not sure there is a specific regulation to determine what is an appropriate level of transfer across ovens but maybe a quick call to either the manufacturer or perhaps BSI themselves will help? Or maybe pick another manufacturer of ovens and ask their technical team for advice? 

Unfortunately I don't think I've come across any IET members working in that particular industry so I'm not able to put you in direct contact on here with anyone specifically.  

If anyone does have any contacts or knows anyone in this field though please bring their attention to Iain's question here!

do they not say which specification There are recommendations about how hot external surfaces and controls can get - not aware of any about inside a second chamber

Ovens & Cookers

Electric ovens are measured in accordance with standards EN60335-2-6.

Test conditions

For a central oven temperature test.
Pre heat the oven to a temperature of 200°C
Depending on the height of the oven different temperatures apply.

For Freestanding cookers and ovens built-in below 850mm from the floor

Temperature limits are as follows

• Metal and painted metal 45°C plus ambient temperature
• Vitreous - enamel metal 50°C plus ambient temperature
• Glass 7 ceramic 60°C plus ambient temperature
• Plastic 80°C plus ambient temperature

For Freestanding cookers and ovens built-in above 850mm from the floor

Temperature limits are as follows

• Control knobs and handles are tested in the following manner:
• Fan ovens; heat to a temperature of 220°C
• Conventional heat ovens; heat to a temperature of 240°C
• Grills are run for 30 minutes, however if the power input can be adjusted then it is run for 15minutes on full and 15 minutes at 50%.

Temperature limits for control knobs and handles

• Metal and painted metal 35°C plus ambient temperature
• Plastic knobs with a metallic coating of at least 0.1mm thick are classed as metal,
• Vitreous - enamel metal 45°C plus ambient temperature
• Plastic 60°C plus ambient temperature
• Metal and painted metal 60°C plus ambient temperature
• Vitreous - enamel metal 65°C plus ambient temperature
• Glass 7 ceramic 80°C plus ambient temperature
• Plastic 100°C plus ambient temperature

  Gas Ovens & Cookers

Gas ovens are measured in accordance with  Standard EN30-1-1

Front and side Accidental touch.

Test conditions

Ovens are operated at 200°C Centre Oven Temperature
The cooker is run for 60 minutes.
Grills are not tested if the user instructions state open door grilling.
If the instructions state closed door grilling, then the grill is operated for the last 30 minutes with the control set according to the maximum in the user instructions.& then turned down to 50% for the last 15min.

Temperatures are not measured for surfaces that are:

• Not accessible to 75mm diameter probe.
• Surfaces that are 25mm below the level of the hob.
• Surfaces that are within 10mm of the edges of the door.

Temperature limits for gas ovens

• Control knobs & handles are measured with:
• Ovens to be heat to a temperature of 200°C (Gas mark 5 or 6 depending on model)
• Grills are run for last 15minutes on full

The permitted temperature limits are as follows

• Metal and painted metal 60°C plus ambient temperature
• Vitreous - enamel metal 65°C plus ambient temperature
• Glass 7 ceramic 80°C plus ambient temperature
• Plastic 100°C plus ambient temperature
• Metal and painted metal 35°C plus ambient temperature
• Vitreous - enamel metal 45°C plus ambient temperature Plastic 60°C plus ambient temperature

I wonder if the heat loss from the lower oven (into the upper one) might cause difficulty for the energy efficiency regulations. Or on the other hand, it might be the case that the heat loss from one oven to another is much like it used to be, but better thermal insulation around the pair of ovens means that the same amount of heat finds it much more difficult to escape from the second oven, so produces a far greater temperature rise.

    - Andy.

Makes sense to me.

In the days of freestanding cookers, the grill cavity was ideal for warming plates when the oven was on.

On the basis that nobody is going to want an oven at less than 100 deg C, I don't really see a problem, but the heat conservation is poor.

Are they made by the same manufacturer? Does the manufacturer(s) allow both ovens to be stacked?

Are the ventilation requirements met for both ovens individually? Usually there is a gap behind and a gap or grill at the front above an oven, if fitted under a worktop.

Make and model of each oven please, or link to the installation instructions might be helpful.

Hi Andy

Energy Efficiency regulations sound like a good route to go down - but do you know what they are?

Chris the big issue is that any unsuspecting person can get burnt at much lower temperatures, but at 100C the from door to the oven is above 40C and that is an issue for a child.

Hello

As both ovens are in the same shell and sold as a double oven, you can assume the are made by the same manufacturer.

In this case both ovens are both convection ovens, here is a link to an example of a double oven. Built in double oven Hotpoint DU2 540 IX, other double ovens are available.