A change in the operation of an industrial installation is defined as being substantial where it may have significant negative effects on the environment. For a site due to be regulated under IPPC, a substantial change would require early entry into the regime. Sites already under IPPC may be required to fit additional abatement to reduce the impact of the change.
The guidance has been revised to take account of the EU Directives on large combustion plant, solvent emissions and waste incineration.
On large combustion plant, an increase in capacity of 50MW or more would be treated as a substantial change. For incineration, any change to incinerate or co-incinerate hazardous waste is regarded as substantial.
Any small solvent-using site caught by the regulations implementing the solvents Directive which is considering an increase in its VOC emissions of more than 25% is also deemed to be making a substantial change. At other solvent-using sites the threshold is 10%.