The Clean Air Act 1993 requires the heights of certain chimneys to be approved.

Installations in 'normal' domestic premises would not normally need approval. Those requiring approval are those serving furnaces, boilers of similar appliances that:

• burn pulverized fuel
• burn, at a rate of 45.4 kg or more per hour, any other solid matter, or
• burn at a rate equivalent to 366.4 kW or more, any liquid or gaseous matter

Due to the size of these furnaces, this is only likely to apply to industrial or commercial premises.

This is in addition to any other permissions (such as planning permission for example) that may also be required, and also applies to replacements as well as to new installations.

Application form for the approval of the height of chimney(s) serving furnaces (PDF).

For help and guidance with determining the correct height for your chimney, refer to Chimney Heights, the 3rd edition of the 1956 Clean Air Act Memorandum (ISBN 0-11-751556-6) or contact Bexley's Air Quality team, email airquality@bexley.gov.uk