Your employer should identify if the work activity, hazards and area of work is, or should be, classed as a confined space. Anyone working in a confined space must be properly trained.Work in a confined space needs safety documentation to produce a safe system of work.
- A suitable and sufficient task and site specific risk assessment.
- A method statement, including a rescue plan.
- A permit to work (to manage and control entry).
The safe system of work will identify important issues, such as those listed below.
- Who the supervisor will be. (The supervisor should make sure the task has been properly planned and check safety at each stage. They will need to be present while work is underway.)
- Safe access and egress (how to get in and out safely).
- What tools and materials to use, and how they should be used.
- The type of air and gas monitoring equipment and alarm system.
- Who can enter and for how long (time limits).
- What PPE and respiratory protective equipment (RPE) to use.
- The emergency arrangements.
- The rescue equipment and trained rescue team.
The air within the space must be tested before entry, and constantly monitored while the space is occupied using a meter with an audible and visual alarm. If the alarm sounds, the area must be evacuated as quickly and safely as possible. There should be one person (known as the attendant), at the entrance to the confined space, whose job is to raise the alarm and start the rescue plan if things go wrong.
There must always be a clear means of communication between workers inside the space and those outside.
In some cases, it may be necessary for site management to provide information about the confined space work to the emergency services, in case they may need to be called or involved in the event of an emergency.
At Carsington Reservoir in Derbyshire, four young, physically fit men, aged between 20 and 30, died at the bottom of an open-topped inspection shaft. Naturally evolved carbon dioxide had displaced the oxygen, but no tests were made before the first man entered. He collapsed and the three other men in turn climbed down, trying to rescue their colleagues. They were overcome by the lack of oxygen and later died.