1. Respiratory protective devices for use against chemical, biological, radiological and nuclear (CBRN) agents. Self-contained open-circuit compressed air breathing apparatus incorporating a hood for escape. Specification Part 3.1, (24th August 2020) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (12 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗