Page Last Updated: 16/10/2017

The FAQ pages are currently undergoing consolidation into new documents. From time to time this page will be updated to indicate where relevant information contained within the FAQs has been moved to.

Bookmarked links to individual FAQ pages should be updated to follow the new guidance locations.

FAQSort by TitleKeywordsPublished Date (sort)
15 None of the screening tools available for stacks (e.g. the HMIP D1 method or the LAQM Emissions Screening Tools) are applicable to my installation due to a low exit velocity, or buildings taller than the stack. How do I assess its air quality impact?Modelling Industrial exit velocity stack building taller D1Height screen 13/10/2017
16 How do I calculate an appropriate chimney height to ensure emissions of NO2 from small gas boilers controlled by the Clean Air Act do not lead to an exceedence of the Air Quality Strategy's objective for nitrogen dioxide (NO2) prescribed in the Air Quality Regulations 2000, SI No 928?Modelling Industrial chimney D1 clean air act Stack Height CHM 01/03/2010
18 Can I use the Chimney Heights Memorandum to determine the stack height for room-sealed boiler flue systems?Modelling Industrial chimney height memorandum room-sealed boiler 01/03/2010
46 How should emissions from gas boilers, not subject to LAPC/PPC controls, be considered for the purposes of LAQM reviews and assessments?Industrial Modelling boiler gas small chimney height approvalfurnace 01/03/2010
89 The Process Guidance Note states that a stack height calculation is required following the HMIP D1 Method. Where can I find this?Industrial Modelling D1 Stack Chimney Height clean air act 01/03/2010
100How do I calculate an appropriate chimney height for furnaces/boilers not subject to controls under the Clean Air Act?Modelling Industrial chimney height stack boiler gas CHMlow Nox burner Memorandum condensing 01/03/2010
101How do I calculate chimney height for multiple gas boilers/furnaces which are individually below the Clean Air Act threshold of 366.4 kilowatts and are not served by one single chimney but several separate ones?Modelling Industrial chimney multiple clean air act Stack Height 01/03/2010
105What impact do trees have on air pollutant concentrations?AQAP Planning Modelling Road Mitigation Tree 01/03/2010
111What is the Supplementary Assistance: Chimney Height Calculation Spreadsheet?Modelling Industrial Pollutant SO2 Stack Chimney Height 01/03/2010

Show all FAQs