Guidance for Industrial and Commercial Users

The following questions and answers provide information and guidance.

  • Can I burn medium density fibreboard (MDF) in a smoke control area?

    MDF is a manufactured wood board product essentially made of wood chip and urea-formaldehyde resin. In the UK it is largely made from recycled wood but manufacturers include measures to reduce the likelihood of treated/coated wood being used. Combustion of MDF can fall under a number of legal instruments:

    Combustion of MDF could fall within the scope of the Waste Incineration Directive (2000/76/EC) or "WID" but, Defra guidance (under the environmental permitting regulations for England & Wales) is that the MDF manufacturing process does not use chemicals containing halogens or heavy metals so, provided clean waste wood was used to manufacture the MDF, WID does not apply to MDF combustion. See the section on waste wood in the guidance at this link for details:

    Note that combustion of faced MDF could be a WID activity because, although the resin used in such facings is very similar to the urea-formaldehyde resin used in the board, the facings often contain other materials (paper, plastics).

    The combustion of non-WID solid fuel derived from waste materials is covered by the Environmental Permitting Regulations (EPR) or PPC regime if the combustion device is larger than 400 kW (thermal input). So if an appliance is burning MDF and is larger than 400 kW (thermal input) regulation of the appliance would be under the EPR (in England & Wales) "LA-PPC" regime.

    Combustion in appliances larger than 3 MWth is also covered by a higher tier of EPR.

    Where an activity is regulated under the EPR/PPC regulatory framework the Clean Air Act does not apply.

    For appliances burning MDF below 400kW the Clean Air Act (CAA) applies and an appliance can be exempted for use in smoke control areas. The Defra exclusion of MDF from WID means that some appliances can be exempt for burning MDF. Under the CAA, emission of smoke is not permitted in a smoke control area unless an appliance has been exempted for use in a smoke control. Note that exemption does not mean that an appliance cannot emit any smoke; the nature of solid fuel means that there is always scope for a particulate (dust/smoke) emission however provided the appliance is demonstrated to be capable of operating within an emission limit (defined by the appliance output) then it can be exempted. Emission of dark smoke however is not permitted in a smoke control area (or indeed outside a smoke control area).

  • Is there any additional guidance relating to PPC and the Clean Air Act or relating to Environmental Permitting Regulations?

Further information on Smoke Control Areas is available in the background information section.

The answers to the most commonly asked questions are provided above. This is the fastest way to find the information you are after. However, if the questions and answers on this page do not fully answer your specific query, then you can contact Defra for information at or visit the Contact Us page.

If your query is of a technical nature for instance concerning aspects of the exemption or authorisation process then please contact Ricardo-AEA at

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