A ‘confined space’ is a space which is substantially (though not always entirely) enclosed, and presents one or more ‘specified risks’.
Dangers can arise in confined spaces because of the following issues.
- A lack of oxygen;
- Poisonous gas, fume or vapour;
- Liquids and solids which can suddenly fill the space, or release gases into it, when disturbed;
- Fire and explosions (e.g., from flammable vapours, excess oxygen etc).
- Residues left in tanks, vessels etc, or remaining on internal surfaces, which can give off gas, fume or vapour;
- Dust present in high concentrations, e.g., in flour silos;
- Hot conditions leading to a dangerous increase in body temperature.
Some of the above conditions may already be present in the confined space.
However, some may arise from the work being carried out, or because of ineffective
isolation of plant nearby, e.g., leakage from a pipe connected to the confined space.
Examples of confined spaces include:
- Ducts, culverts, tunnels, boreholes, bored piles, manholes, shafts, excavations and trenches, sumps, inspection and under-machine pits;
- Freight containers, ballast tanks, ships’ engine rooms and cargo holds;
- Buildings, building voids and some enclosed rooms (particularly plant rooms) and compartments within them; and
- Interiors of machines, plant or vehicles.
As for all work activities, a suitable and sufficient risk assessment must be made of all works to be undertaken within a confined space. If the risk assessment identifies any risks of serious injury from work in confined spaces, such as those highlighted above, the following key steps must be taken:
- avoid entry to confined spaces, e.g., by doing the work from outside;
- if entry to a confined space is unavoidable, follow a safe system of work; and
- put in place adequate emergency arrangements before the work starts.
