NEW DECOMPRESSION procedures have been announced this week by the Health & Safety Executive (HSE) to reduce the number of tunnellers affected by the sickness known as the bends.
The HSE has pushed through the changes in the 1996 Work in Compressed Air Regulations ahead of an expected boom in tunnelling work over the next few years.
In future it will be compulsory for contractors to use oxygen in decompression chambers on projects where people are working at pressures greater than one bar.
Air pressure is often kept artificially high during tunnel construction to prevent collapses in unstable ground. After working in compressed air, operatives must immediately go through a decompression process.
Inadequate decompression can lead to the sometimes fatal decompression sickness known as the bends. This causes sharp pains in the limbs and breathing difficulties and is the result of a build up of nitrogen in the blood.
Compulsory use of oxygen during decompression replaces the existing practice of using a conventional air supply. The change follows a five year £750,000 investigation that included extensive medical advice.
The study concluded that breathing pure oxygen during decompression would help eliminate nitrogen from the body, reducing the risk of the bends.
Changes in the regulations also mean that contractors must appoint a competent attendant to ensure compliance with safety procedures.