Dark smoke
Dark smoke can be produced if you burn:
- tyres and other rubber-based products
- plastics such as polystyrene
- cable to remove the plastic insulation
- oils and paints.
You must prevent the emission of dark smoke from:
- chimneys serving furnaces, fixed boilers or industrial plant, whether they are attached to buildings or not
- any industrial or trade premises.
Industrial or trade premises include:
- the site where you are working, such as a building or demolition site
- any site that you own or lease
- land used for commercial agriculture or horticulture.
Your local council does not need to see the emissions of dark smoke to take action against you. Evidence of burnt materials that could cause dark smoke, such as steel reinforcement from tyres, or plastic residues, is sufficient. You cannot use a defence of lack of visual evidence, for example, if you burn materials at night.
A Ringelmann chart is used to define dark smoke. The chart has five shades of grey with 0 being clear and 5 being black. Smoke is considered ‘dark’ if it has a shade of 2 or darker. You can find the Ringelmann chart in British Standard BS2742C.
Exemptions
There are certain exemptions from the dark smoke emission restrictions when burning certain waste materials in the open. These include:
- timber and some other waste materials from building demolition or site clearance
- waste explosives
- materials burned as part of fire fighting research or training activities
- road and other paving surfacing materials
- diseased animal carcasses.
However, you must still comply with the requirements of any other legislation that may cover these activities.
There is no longer an exemption for burning agricultural or veterinary containers that are contaminated with pesticides or other toxic substances in England and Wales.
Any exemption will have one or more of the following conditions:
- there is no other reasonable, safe and practicable method of disposing of the matter
- burning must be under the direct and continuous supervision of the occupier of the premises or someone authorised to act on their behalf
- care must be taken to minimise dark smoke.
Installing furnaces
Your local council must approve your plans and specifications before you can use a furnace (except a domestic furnace) in a building, fixed boiler or industrial plant.
If you are installing a new non-domestic furnace in a building, it must be fitted with approved dust and grit arrestment equipment if it is going to be used to burn:
- pulverised fuel
- any other solid matter at a rate of 45.4kg or more an hour
- liquid or gaseous matter at a rate equivalent to 366.4 kW or more.
If you install a new furnace, it must be able to operate continuously without emitting smoke when burning the type of fuel it has been designed to use. Obtaining planning permission or a building warrant from your local council for the construction of the chimney or plant is not sufficient.
Chimney height
In England, Scotland and Wales, your local council must approve the height of any chimney associated with a furnace (except a domestic furnace) or boiler if you burn:
- pulverised fuel
- any other solid matter at a rate of 45.4kg or more an hour
- liquid or gaseous matter at a rate equivalent to 366.4 kW or more.
In Northern Ireland you must obtain approval from your council for a chimney, by satisfying them that your chimney will be tall enough to prevent its emissions becoming a nuisance.
Your application must contain details of:
- the purpose of the chimney
- the position and type of local buildings
- local ground levels
- any other issues that must be taken into account
Your local council may apply certain conditions to their approval such as the rate and quality of emissions from your chimney.
A chimney may be exempt if it is used as part of:
- a temporary replacement, for example if the boiler or furnace is being repaired
- a temporary source of heat or power for building works
- auxiliary plant to bring main plant up to operating temperatures
- a mobile source of heat or power for agricultural purposes.
Smoke, grit and dust emission limits
Your local council can apply limits on emissions of smoke, grit and dust you produce. If you exceed these limits you may be committing an offence and could be prosecuted. Your local council is likely to set limits for sites with a history of complaints or sites that use fuel or procedures that they were not designed to use.
You should use the best practicable means to minimise emissions, for example:
- fitting grit and dust arrestment filters
- inspecting boilers, furnaces and filter equipment regularly for correct operation
- installing filter performance monitors.
Fuel oils
You must not use
gas oils with a sulphur content higher than 0.1% by weight.
You must not use heavy fuel oils with a sulphur content higher than 1% by weight. This does not apply if your plant came into operation after 1 July 1987 and you hold a PPC permit that contains conditions limiting sulphur dioxide emissions.
If you operate a pre-1987 combustion plant, and you do not require a PPC permit, you may choose to comply with the 1% limit or you can apply for a sulphur content of liquid fuels permit from:
- your local council in England and Wales
- SEPA in Scotland
- the Industrial Pollution and Radiochemical Inspectorate (IPRI), which is part of the Northern Ireland Environment Agency (NIEA), in Northern Ireland.
