This is one of three forms that supersede HTM 2022 (1999, ISBN 011322141X). Separate forms are available for Low hazard (ISBN 0113227388) and Bacteria filter (ISBN 011322740X) permits to work. Guidance on use of the forms is contained in HTM 02-01 Part B Operational management (ISBN 0113227434), and further information on the new system is available in HTM 02-01 Part A Design, installation, validation and verification (ISBN 0113227426). On cover: Medical gases