CTI logo no writing


BSI reg
BSI reg 2


D1 Stack Height Calculations

Services Provided

Appropriate chimney heights for pollutant dispersion can be calculated in accordance with HMIP’s Technical Guidance Note D1 “Guidelines on Discharge Stack Heights for Polluting Emissions” . The methodology takes into account a number of factors, including stack diameter, pollutant emission rates, emission temperature, efflux velocity and the effect of nearby buildings. This simple, low cost method dates from 1993 but is still widely used and accepted by regulators and site operators and can be applied to single chimneys or groups of chimneys.

Alternatively, detailed dispersion modelling can be used generate a more accurate stack height. Although dispersion modelling is more expensive, it can be cost effective in cases where the D1 calculation results in excessively high stack heights that would be expensive to install.

Please get in touch if you wish to discuss this service.


Cti can also perform simple chimney height calculations in accordance with HMIP Technical Guidance Note D1 (Dispersion): Guidelines on Discharge Stack Heights for Polluting Emissions, or the Environment Agency's IPPC HI Guidence Note: Environmental Assessment and Approval of BAT.

Cti Environmental, 7 East Bank Road, Sheffield, S2 3PT, Tel: +44 (0)114 2728647, Fax: +44 (0)114 2730852, UKAS Testing Lab No. 0144