​In the event that entry into a confined space cannot be avoided, a suitable and sufficient risk assessment must be carried out and a written safe system of work developed including the provision of emergency procedures.

2.1 Assessing the risks from entry

When assessing the risks, use must be made of all the information available about the confined space. All foreseeable hazards and risks must be considered in advance and the following issues may need consideration:-

Confined Spaces can include:

• some places which may only become confined spaces occasionally, such as rooms during fumigation;
• areas which may have open tops such as water tanks

The Assessment should include consideration of:

• The task;
• The environment;
• Communications;
• Mechanical and electrical isolation of equipment;
• Ventilation and purging;
• Materials, tools and lighting to be used;
• Competency of staff involved;
• Arrangements for rescue.

Associated Hazards may include:

• Previous contents, residues and contamination;
• Flammable substances or oxygen enrichment;
• Toxic gases, fumes or vapour;
• Oxygen deficiency;
• Physical dimensions;
• Ingress or presence of liquids;
• Solid materials which can flow;
• Presence of excessive heat;
• Electricity or static electricity;
• Cleaning chemicals;
• Work out of hours.

In gathering information for an assessment, managers may need expert advice. Information on confined spaces is available from the HSE website at  http://www.hse.gov.uk/confinedspace/ (link opens in a new window)or from the SHE Group.

2.2 Developing a Safe System of Work

In the development of a written safe system of work, the information gathered during the risk assessment will be used to construct a document that will give information and instruction to the employees who are to carry out the work including safe means of access and egress.

This will include all of the risk control measures and the reasons for their application. e.g. the need for forced air ventilation to ensure oxygen levels are maintained and a comfortable working temperature.

It will also detail the means for preventing unauthorised access when there is no need for anybody to access the confined space, and the means of emergency evacuation will also be documented.

2.3 References and further reading