Potential impacts from major accident hazards associated with COMAH establishments can extend beyond the boundary of the site. Three risk based land use planning zones exist in relation to COMAH establishments, namely the inner zone, middle zone and outer zone. The Health and Safety Authority (HSA) provides land use planning guidelines to planning authorities that restrict the nature and size of developments that can occur within these land use planning zones (PADHI methodology – Planning Advice for Developments near Hazardous Installations). The HSA also provides advice to planning authorities regarding the siting of new COMAH establishments and modifications to existing establishments on the basis of the consequences and risk of major accident scenarios and also on the basis of societal risk.

AWN provide the following services in relation to land use planning in the vicinity of COMAH establishments and societal risk assessment:

• Assessment of the suitability of development proposals near COMAH establishments taking into account their location in relation to land use planning zones, and individual and societal risk posed to the proposed development;
• Modelling the consequences and risk of major accident scenarios for new COMAH establishments, determination of land use planning zones for the facility and assessment of the impacts on land use planning outside the facility boundary. We have also carried out this work in respect of proposed modifications to existing COMAH establishments;
• Quantification of societal risk at developments with the consultation distance surrounding COMAH establishments using techniques such as FN-Curves, Scaled Risk Integral, Expectation Value and COMAH Risk Integral;
• Provision of expert technical advice to Planning Authorities in respect of proposed COMAH establishments.