Buildings are currently not designed specifically to offer protection against chemical, biological and radiological (CBR) releases. However, should a CBR event occur, it has the potential for a high adverse impact on buildings, their occupants’ health and wellbeing, and also on business operations and services. Since buildings have a long lifespan, consideration of protection measures is particularly important at the early stages of design. Once built, retrofitting to mitigate CBR impact will be time-consuming, disruptive and expensive. It is therefore important to consider and incorporate means of reducing the impact of CBR releases as an integral part of the initial building design, planning and construction process.

This Information Paper considers ventilation and infiltration as prime routes for the ingress of external contaminants into buildings. It provides an overview of some existing design standards, methods and practices that may be further reviewed and implemented at the design stage without adding significantly to costs.