What is meant by 'minimum distance to combustible materials'?

When you install any stove it is important that you adhere to the manufacturer's declaration regarding minimum safe distances to combustible materials as this will be fundamental to you and your family's safety.

The importance of a genuine CE tested stove

Any stove which has been CE tested in a UK or EU notified laboratory will clearly state these safe distances within their instructions. The problem is that there are still a lot of stoves on the market which purport to be CE tested and which are clearly not (rest assured these are not sold by The Stove Yard) and therefore any declared minimum distances stated by these unscrupulous manufacturers or importers are likely to be pure guesswork on their part and must be assumed to be potentially unsafe.

The CE test is the only way to accurately determine these minimum safe distances and that's why you see such a wide variation from model to model. There is no rule of thumb either which can be adopted to replace this critical laboratory test – and remember, these distances are 'minimums'. To calculate these safe distances the EN13240 standard for freestanding stoves takes accurate worst case scenario heat readings from the sides and the rear, and for inset stoves, the EN13229 standard, the heat readings are taken from the sides and the top (referred to as the 'shelf'). As yet there is no shelf (or top) distance test for free-standing stoves, hence a number of stove manufacturers recommending the use of non-combustible mantels (see our FAQ on this subject) or in some cases undertaking their own tests to provide this information. Current EN13240 testing in some notified laboratories (reflecting the forthcoming EN16510 tests) are also testing the temperatures on the hearth and floor up to 1 metre in front of the stove. Some of these temperatures can be surprisingly higher than you might imagine.

Choosing a radiant or convector stove can make a difference

Traditional radiant stoves, because they are designed to get extremely hot to enable them to radiate sufficient heat, will require much greater combustible distances than convector stoves with the same heat output. Convector stoves use vertical channels behind the outer bodywork (most often at the sides) to draw cooler air in at the bottom of the channel, warm it as it passes upwards and then disperse it around the living space from the top of the channels. This means that the bodywork of a convector stove can be significantly cooler than that of a radiant stove and this will often provide a significant reduction to the safe distances to combustible materials.

Generally, the greater the heat output from the stove then the greater the safe minimum distances that are required – but not always. So if your minimum combustible distances are very tight then you may need to choose your stove based mainly on how easily it will make it to comply to these requirements. This would normally mean choosing a convector stove, or alternatively in free-standing installations using some form of heat shielding to protect the combustible areas. The revised British Standard BS8303 (2019) now provides improved guidance on heat shielding for stoves which is not covered in any current Building Regulations. A number of stoves which have been designed specifically for the off-grid market, where buildings are generally constructed in timber, provide optional heat shielding enclosures – see 'off grid installations' below.

What exactly is a combustible material?

A combustible material is anything that is flammable. Sometimes this is not always obvious – the biggest offender being plasterboard with its cardboard outer which invariably uses a wooden frame for support (stud partitioned walls). It never ceases to amaze us at The Stove Yard just how many stove installations we come across where the plasterboard's flammability or structural stud work have not been taken into consideration when applying safe combustible distance requirements. Wooden fire surrounds and wooden mantles are others.

Minimum distances in non-domestic or off-grid installations

When the issue of combustible materials and minimum distances are considered and fully understood then installing a free-standing stove (not forgetting its flue) in garden sheds, shepherds huts and any manner of off-grid structures where virtually everything is combustible becomes a complete minefield. Just because there are, as yet, no specific regulations for non-domestic structures doesn't mean that you can just ignore the basic best practice developed over many years in the domestic sector. 

Despite this some people carry on regardless. Fortunately reputable manufacturers, like Chilli Penguin and most recently Ekol ApplePie which specialise in stoves for the off-grid market are all too aware of such issues. They will supply optional purpose-made and safety tested heat shields for their stoves, so really there's no excuse to put yourself at risk when you're going off grid. Charnwood also offer some great decorative heat shield solutions with their range of Vlaze vitreous enamel panelling.

Off-gridders should check out this information...

As previously stated, currently there is no standard for installing stoves in off-grid or non-domestic temporary structures, although Hetas, with the input of the stove industry, is currently working on new comprehensive guidance which it aims to publish in late 2020. In the meantime however, we can thoroughly recommend the Soliftec Canal Boat Guide for installing stoves in boats. Many of its safety considerations could equally be applied to the confined spaces and combustible structures of shepherds huts, garden offices and yurts etc. Finally if safety is in doubt always revert to the guidance in England and Wales Document J and BS8303.