Normal air is a mixture of oxygen and nitrogen, together with small quantities of carbon dioxide and other gases. When the oxygen content is lower than normal air, e.g. when it is intentionally lowered for special applications, the resulting gas is called hypoxic air or low oxygen air.
Oxygen is critical for both life and combustion and the industrial applications of these environments include fire prevention systems which prevent ignition, particularly of papers and books in archives or libraries. They are also used to reduce oxidisation or oxidative degradation of fresh produce and other materials such as food, paintings, metals), for physical training and rehabilitation of athletes and in medical research.
Such systems require an enclosed area which is airtight; this and the specific risk of a reduced oxygen atmosphere created within this area, means these spaces meet the definition of a confined space and are subject to the Confined Spaces Regulations 1997.
Therefore, when a hypoxic air system is to be installed, or has already been installed, it has to undergo a suitably detailed risk assessment to meet the requirements of both these Regulations and the Management of Health and Safety at Work Regulations 1999, including consideration of the suitability of such a system for the specific application at its location, such as:
The risk assessment should also consider any protective measures that may be required to ensure the health and safety of all persons having access to the protected space. The concentration of oxygen will decide the type of precautions you should take. Reduced oxygen levels have an impact on people working in the confined space and the lower the concentration the more likely that staff will be affected. You may need to:
For more advice on your specific system speak to the manufacturer or supplier.
For more information on risk assessments read Controlling the risks in the workplace.