Natural Resources Wales
A medium combustion plant (MCP) includes all the following:
- a combustion unit, such as an engine, boiler or turbine
- any abatement
- the attached stack or flue
- air cooling where its part of the combustion unit
A MCP does not include:
- fuel handling or storage
- waste handling equipment
- external water or air cooling
Use this guidance to work out if your MCP:
- is excluded from MCPD controls
- generates electricity, whether both the MCPD and specified generator regulations apply
- capacity is covered by the regulations
- is classed as new or existing
MCPD controls do not apply to all MCPs. Check if they apply to your type of MCP.
MCPs that are also under the Industrial Emissions Directive (IED)
MCPD controls do not apply to IED:
- chapter 3 large combustion plant
- chapter 4 incinerators or co-incinerators
MCPD controls may apply to IED chapter 2 installations. Read how to meet MCPD requirements for IED chapter 2 installations.
MCPs that are also an environmental permitting Part B activity
Read the guidance on requirements for MCPs that are also a Part B activity.
Mobile MCPs and mobile boilers
MCPD controls do apply to mobile MCP placed on the market (for distribution or use) before 1 January 2017 and with an engine above 560 kilowatt (kW) drive output.
MCP placed on the market before 1 January 2017 but not operated for the first time until after 20 December 2018, is classed as a new MCP rather than an existing MCP.
MCPD controls do not apply to mobile MCP placed on the market after 1 January 2017. They are covered by the revised Non Road Mobile Machinery Regulations (NRMM). These regulations extended the scope of the previous NRMM Directive (engines up to 560kW drive) to include engines with no upper size threshold.
MCPD controls do apply to a mobile boiler on a trailer for transporting it from site to site.
MCPD controls do not apply to an on-farm combustion MCP if both of these apply, it:
- has a rated thermal input of 5 megawatts thermal (MWth) or less
- only uses unprocessed poultry manure as fuel
Animal by-product regulations control these MCPs.
If you use other types of manure (mixed or unmixed), the MCP is classed as using other solid fuel and MCPD controls apply.
Direct heating and drying
MCPD controls do not apply to MCP using the gaseous products of combustion for direct heating, drying or other treatment of materials.
Examples of this include:
- annealing of metals
- brick manufacture
- vehicle spray booths which use combustion to condition the air
- asphalt plants which heat and dry aggregates before adding them to asphalt
- concrete block and precast concrete product manufacture which use heat to speed up the curing process
- mortar plants which heat and dry sand before adding it to the mortar
- chemical reactors which use a direct flame
- direct gas fired ovens which have the burner located within the oven chamber so that the hot combustion gases come into direct contact with the product
MCPD controls do apply to autoclaves that use steam because the steam is not a gaseous product of combustion. For example, aircrete block manufacture which use hot steam to speed up the curing process.
Direct gas-fired heating
MCPD controls do not apply to a MCP that uses the gaseous products of combustion for direct gas-fired heating to improve indoor workplace conditions. This is where the flame itself provides the heat, rather than where the flame heats a fluid that is then used to transfer heat to the surrounding work space.
MCPD controls do not apply to flares for disposal of waste gases.
Post combustion plant designed to purify waste gases
MCPD controls may apply to a MCP used to destroy odour or abate volatile organic compounds which do not run as an independent combustion plant. It will depend if the primary purpose of the combustion unit is to provide:
- heat MCPD controls do apply
- abatement MCPD controls do not apply
For example if:
- odorous gases are used as part of the boiler feed air, MCPD controls apply to the boiler
- the combustion plant has a post combustion supplementary fired thermal oxidiser to destroy odour MCPD controls do not apply to the supplementary fired thermal oxidiser
However, this type of abatement, if the combustion plant is part of a Part A or B installation will need to meet best available techniques.
Vehicle, ship or aircraft
MCPD controls do not apply to any technical apparatus used to propel a vehicle, ship or aircraft, including auxiliary engines in ships.
MCPD controls do not apply to gas and diesel engines and gas turbines installed on offshore platforms. See Schedule 25A to check the location requirements.
MCPD controls do not apply to a MCP in a gas or oil refinery installation firing:
- refinery fuel gas (RFG) alone
- refinery fuel oil (RFO) alone
- RFG or RFO combined with commercial fuels
MCPD controls do apply to a MCP firing these fuels adjacent to but independent from the refinery.
MCPD controls do not apply to these refinery activities:
- fluid catalytic cracking units including carbon monoxide heat recovery boilers
- sulphur recovery units t