The burning of woodfuel invokes a number of pieces of legislation, mostly surrounding the emission of certain pollutants that can negatively affect air quality. We have provided here a summary of the most common items of legislation encountered during biomass woodfuel projects:

Clean Air Act – Emission of Dark Smoke

Emission of “dark smoke” (appearing as dark or darker than shade 2 on the Ringlemann Smoke Chart) is prohibited under the Clean Air Act 1993. A correctly installed woodfuel boiler or stove should never emit dark smoke.

Clean Air Act – Chimney Height Approval

It is an offence to cause or permit a furnace to burn solid fuel at a rate of 45.4kg/hr or more unless the height of the chimney has been approved by the Local Authority.

Note: As the moisture content of biomass fuels affects their net calorific value, it is not possible to convert the 45.4kg/hr fuel feed rate directly into a kW or BTU boiler rating. To provide some practical guidance, however, it is safe to say that up to a boiler rating of about 120kW, even wet woodfuels are unlikely to exceed the maximum fuel feed rate. Above around 200kW, boilers will almost certainly need to apply for chimney height approval. Between 120kW and 200kW, whether the fuel feed rate exceeds 45.4kg/hr will depend upon the moisture of the fuel burnt. This rule of thumb only applies to woodfuels.

Clean Air Act – Smoke Control Areas and Exempt Appliances

Under the Clean Air Act, Local Authorities are able to define “Smoke Control Areas” within which it is an offence to burn any solid fuel (including biomass) unless:
1. The fuel is a smokeless fuel which has been classified as an ‘exempt fuel’
2. The solid fuel is burned within an exempt appliance which has been tested and approved for that fuel

Most boroughs within London and other major cities have been designated as Smoke Control Areas. Many suburban boroughs have designated some of their wards as smoke control areas. The UK Smoke Control Areas website (www.uksmokecontrolareas.co.uk) holds information on every borough in the country but if you require information on a ward level, you will need to contact the Environmental Health Officer of that borough.

No type of wood (logs, woodchip, pellet or briquette) has been classified as an exempt or ‘smokeless’ fuel. Therefore, if your project does fall within a smoke control area, you will need to install an exempt appliance that has been approved to burn the particular type of biomass or woodfuel that you wish to burn. A list of exempt appliances can also be found at www.uksmokecontrolareas.co.uk

Local Air Quality Management Areas (LAQM)

As part of the Government’s Air Quality Strategy, local authorities have a responsibility to review and assess air quality within their areas and work towards achieving the government's health-based national air quality objectives. Some authorities have subsequently declared air quality management areas (AQMAs) with associated action plans for reducing the levels of certain pollutants. If an AQMA has a specific objective to reduce levels of NOx, the installation of biomass boilers (which normally have higher NOx emissions than gas boilers) could be considered as contrary to the aims of the Air Quality Regulations. Essentially, although many biomass appliances may have achieved an exemption allowing them to be used in smoke control areas under the Clean Air Act, they may still emit pollutants which local authorities have a statutory duty to reduce.

When first considering installing wood fuel technology, it is recommended to contact the environmental health department of the local authority to discuss the proposed installation and what, if any, additional requirements there may be. The presence of AQMAs does not necessarily mean that biomass technology cannot be installed. Most pollutants giving rise to AQMAs are road transport based and accordingly, action plans are usually tailored to deal with emissions from that sector rather than from small boilers.

Building Regulations

Part J of the Building Regulations concerns combustion appliances and fuel storage systems. All combustion appliances must be installed in compliance with Part J. Specifically, Section 2 of Approved Document J relates to solid fuel installations of up to 50kW output in terms of air supply, flueing and hearth requirements. To view Approved Document J in full, click here.

Part B of the Building Regulations concerns appropriate levels of fire resistance for walls, floors, ceilings and doors within buildings, including, for example, the enclosure of spaces of special fire hazard such as plant rooms and fuel stores. To view Approved Document B in full, click here.

Waste Incineration Directive

The Waste Incineration Directive (WID) is a European law which aims to prevent or limit, as far as practicable, negative effects on the environment and the resulting risk to human health, from the incineration and co-incineration of waste. DEFRA have produced a guidance document on the implementation of the WID, which is located here.

The important question is therefore, “Is wood waste?” The Environment Agency has provided clear guidance on this question within their “Regulatory Position Statement on the Environmental Regulation of Wood” Essentially, the EA does not consider virgin timber (e.g. material from forestry or virgin wood processing such as sawdust) to be waste, but does consider non-virgin timber to be waste (even if it is clean). Therefore, the WID and EP Regulations do not apply to virgin timber.

Additionally, the WID does not apply to non-virgin wood which is free from halogenated organic compounds or heavy metals.

Note: For those installations which are subject to both the WID and the EP Regulations, described above, compliance with the WID is not necessarily sufficient. EP Regulations may involve more stringent emission limit values and conditions. The converse may also be true.

Environmental Permitting Regulations

• Part A(1) activities are covered by Integrated Pollution Prevention and Control (IPPC) and are regulated by the Environment Agency
• Part A(2) activities are covered by the Local Authority Integration Pollution Prevent and Control (LA-IPPC) and are regulated by Local Authorities
• Part B activities are covered by the Local Air Pollution Prevention and Control regime (LAPPC) and are regulated by Local Authorities

The description of activities falling under Parts A(1), A(2) and B, can be found within Part 2 of Schedule 2 of “The Environmental Permitting (England and Wales) Regulations 2007” including the Energy Activities of combustion, gasification, liquefaction and refining.

Essentially, the only time when EP Regulations will apply to the use of clean, uncontaminated woodfuel from a non-waste stream is if the appliance input (or aggregate site input) is 50MWth or above. Woodfuel projects below this scale (if the wood is from a non-waste stream) do not fall within EP Regulations.

If the wood, or other biomass fuel, is from a waste stream or has been contaminated in any way, the project is likely to fall within one of the three EP Regulation categories outlined above and further guidance should be sought regarding permits.

Note: For those installations which are subject to both the WID and the EP Regulations, described above, compliance with the WID is not necessarily sufficient. EP Regulations may involve more stringent emission limit values and conditions. The converse may also be true.

Process Guidance Notes

DEFRA has produced a number of ‘Process Guidance Notes’ to help regulators and operators achieve best practice within the various combustion and incineration sectors. A number of these guidance notes may be relevant to certain activities within the bioenergy sector:

• PG1/1 (04) - Waste Oil and Recovered Oil Burners less than 0.4MW
• PG1/02 (05) - Waste Oil or Recovered Oil Burners, 0.4 3 MW Net Rated Thermal Input
• PG 1/3 (95) - Boilers and Furnaces, 20 50 MW Net Rated Thermal Input (non-consolidated unofficial version with additional guidance AQ23 (04))
• PG1/05 (95) - Compression Ignition Engines, 20 50 MW Net Rated Thermal Input (unofficial version)
• PG1/12 (04) - Combustion of Fuel Manufactured from or Comprised of Solid Waste in Appliances Between 0.4 and 3MW Net Rated Thermal Input

Appliance Standards

There are various standards which biomass systems should adhere to, some of which are noted below. Customers may like to confirm if their system adheres to a specific British Standard – these can be found on www.bsi-global.com.