This document establishes the requirements, recommendations and methodology for microbiological contamination control in clean controlled environments. It also sets out the requirements for establishing and demonstrating microbiological control in clean controlled environments. This document is limited to viable microbiological contamination and excludes any considerations of endotoxin, prion and viral contamination. There is specific guidance given on common applications, including Pharma/BioPharma, Medical Devices, Hospitals and Food.