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Work in compressed air regulations 1996

OC 420/6

This OC gives details of the administrative arrangements associated with the Work in Compressed Air Regulations 1996.


1 The Work in Compressed Air Regulations 1996 (WCA Regulations) replace The Work in Compressed Air Special Regulations 1958 and associated amendments and orders. They became law on 16 September 1996.

2 The WCA Regulations apply where tunnelling, pipe-jacking and shaft and caisson-sinking are carried out in compressed air. In the main this work will be covered by inspectors dealing with the construction industry. The Regulations do not apply to hyperbaric oxygen treatment of patients in hospitals.

3 The WCA Regulations are accompanied by comprehensive guidance A guide to the Work in Compressed Air Regulations(file 420). This OC does not provide such guidance but outlines the administrative procedures associated with the Regulations.

4 Reference to "the contractor" in this OC is to "the compressed air contractor".


5 The WCA Regulations requirement for notification is in addition to the notification required under the CDM Regulations. The contractor should notify HSE at least 14 days before the work in compressed air is due to start. Schedule 1 to the Regulations contains the particulars that the contractors have to notify.

6 On receipt of the notification the band 2 for the FMU which covers the area where the compressed air work is to take place should contact:

(1) the contractor to request a copy of the health and safety plan for the compressed air work;

(2) the local RSG Construction Engineering PSI; and

(3) DST E2 to request advice and assistance.

7 DST E2 keep a central register of compressed air contracts and can be contacted on:

0151-951 4877 (general office).

8 Experience has shown that a pre-start meeting involving the contractor, the client, the local construction FMU, RSG and DST E2 is invaluable in ensuring that the work is set up properly as regards health and safety. Inspectors are strongly advised to continue the practice of arranging and attending pre-start meetings with DST E2 and the local RSG.


9 Regulation 11(1) requires the contractor to use compression and decompression procedures approved by HSE. When the WCA Regulations were made the only compression and decompression procedures and tables which HSE approved were reproduced in Appendix 9 of the guidance. Essentially that appendix contains the compression and decompression procedures approved by HSE including the 'Blackpool Tables', which are only part of the approved decompression procedure.

10 If clients or contractors wish to use decompression tables or procedures other than those which are approved, they will need HSE's formal approval before putting them into use.

11 Any inspector who receives a request for approval of new tables or procedures (either in relation to a particular project or for a range of projects) should forward it to SPD B4 copying it to DST E2, HD D2 and the Construction Sector. SPD B4 will process the request taking into account medical and scientific advice, and other factors from HD D2, DST E2, and the Construction Sector.


12 FOD offices may also be approached to approve particulars contained in the health record (reg.10(3)(a)) or particulars to be recorded on the badge, label or other device reg.19(1). Paragraphs 150(a)-(d) and 254 of the guidance outline the particulars which have been approved. If the application received excludes the particulars outlined in the guidance, forward the request to SPD B4.


13 Copies of the approvals for regs.10(3)(a), 11(1) and 19(1) can be obtained from SPD B4.

Cancellation of instructions

14 Fic OC 420/5 -cancel and destroy.

(amended by OM 1997/27)

4 July 1997


Disc: J:\Editors\CA1\OCFiles\420_6.sam\gk

ASI headings

Construction: Work in Compressed Air Regulations 1996: tunnelling.

Updated 2008-05-13