HSE banner
A compression pump

Work in Compressed Air

General

There are various types of health problem (decompression illness) which can be caused by working in compressed air. The most common are:

  • decompression sickness, an acute condition which occurs most commonly in compressed air work as pains around the joints (often referred to as Type 1 Decompression Sickness or known colloquially as “The Bends” or “Niggles” if less severe). It also occurs more rarely as a serious and potentially life-threatening condition which affects the central nervous system (often referred to as Type 2 Decompression Sickness),
  • barotrauma, where a change in surrounding pressure causes direct damage to those air-containing cavities in the body which are connected with the surrounding atmosphere, principally the ears and sinuses; and,
  • dysbaric osteonecrosis, which is a long-term, chronic condition damaging the long bone (hip or shoulder) joints.

Legislation

Under domestic law (the Health and Safety at Work etc Act 1974) employers are responsible for ensuring the safety of their employees and others. This responsibility is reinforced by regulations.

The Work in Compressed Air Regulations 1996 provide a framework for the management of health and safety risks by those undertaking tunnelling and other construction work in compressed air. They address such issues as:

  • notification of the work to HSE
  • safe systems of work;
  • competent persons to undertake various defined roles;
  • provision of plant and equipment;
  • health surveillance;
  • compression and decompression procedures (including HSE approval of procedures);
  • medical treatment;
  • emergency procedures;
  • fire precautions;
  • provision of information, instruction and training; and,
  • maintenance of health and exposure records.

Many of the duties are placed on compressed air contractors. This reflects the practical operation of the industry and recognises the fact that the contractor in charge of the compressed air operations is best placed to manage and control the health and safety risks of such work. The regulations require the appointment of a Contract Medical Adviser to provide occupational health advice on all aspects of the work in compressed air. A requirement for oxygen breathing during decompression was introduced in 2001.

Because of the number of people required to carry out and manage the work the Construction (Design and Management) Regulations 2007 apply to compressed air projects. For most, but not necessarily all, projects the compressed air contractor will be the principal contractor under these Regulations. Additional requirements relating to emergencies, fire precautions and welfare are set out in the Work in Compressed Air Regulations because of the particular risks and conditions involved.

Published Items

Guidance on Regulations 'A guide to the Work in Compressed Air Regulations 1996' ISBN 0 7176 1120 5

An addendum to "A guide to the Work in Compressed Air Regulations 1996" giving “Guidance on OXYGEN DECOMPRESSION and the use of Breathing Mixtures other than Compressed Natural Air in the Working Chamber” is available from HSE’s Construction Division Technology Unit, Redgrave Court, Bootle.

A training video on fire precautions in compressed air work “The heat within” is available.

Details of articles, publications and videos can be found in HSE's Publications and Videos.

Contact details

Notification of work in compressed air, requests for information or advice on a specific job you are involved with should be directed to your local HSE office. For further information on Work In Compressed Air please contact HSE's InfoLine.