The Confined Spaces Regulations 1997 apply where risk assessments, carried out under the requirements of the Management of Health and Safety at Work Regulations 1999, identify risks of serious injury from work in confined spaces. These regulations contain the following key duties:
Any enclosed space where there is a risk of death or injury from hazardous substances or dangerous conditions is defined as a ‘confined space’. Examples include spaces where there are limited openings, such as enclosed drains, sewers, silos and storage tanks. Less obvious ones include ductwork, excavated trenches, ceiling voids, open-topped chambers, vats and unventilated or poorly ventilated rooms.
Many people are killed or seriously injured each year in the UK as a result of working in confined spaces. Confined spaces can create dangerous environments such as lack of oxygen, and as a result, those who enter them are rapidly deprived of oxygen, causing suffocation, which could potentially lead to death. This situation can happen across a wide range of industries; from those involving complex plant to industries using simple storage vessels. There are many incidents annually; some resulting in the death of the worker, and also to those who try to rescue them.
Risks and consequences of confined spaces include the following:
| Risk | Consequence |
| A lack of oxygen / air flow | Asphyxiation |
| Poisonous gas, fumes or vapour | Asphyxiation, chemical burns, fire and explosion |
| Liquids and solids which can suddenly fill the space, or release gases into it, when disturbed | Drowning, asphyxiation, fire and explosion |
| Conducting hot work such as welding | Fire, explosion and asphyxiation |
| Residues left in storage tanks which can give off gas, fumes or vapour | Fire, explosion, chemical burns and asphyxiation |
| Dust present in high concentrations, e.g. conducting hot work or use of non-intrinsically safe electrical equipment in flour silos | Dust explosion |
| Hot conditions leading to a dangerous increase in body temperature | Collapse and heart failure |
Some of these conditions may already be present in the confined space, although some may arise from work being carried out in them. Machinery used in confined spaces may need special precautions, such as dust extraction provision for portable grinders, or special precautions against electric shock. If access to a space is through a restricted entrance, such as a manhole, escape or rescue in an emergency will be more difficult.
