BS -- Respiratory protective devices for use against chemical, biological, radiological and nuclear (CBRN) agents Positive pressure, self-contained, open-circuit breathing apparatus. Specification,2020

This British Standard specifies requirements for positive pressure, self-contained, open-circuit breathing apparatus (SCBA) intended to be used during fire-fighting, rescue, evacuation, escape, hazard containment and decontamination, and similar activities by emergency first responders (e.g. fire, ambulance, police, and associated civilian agencies and workers) in areas containing and contaminated by chemical, biological, radiological and nuclear (CBRN) agents.