The United States Occupational Safety and Health Administration (OSHA) defines, in its general industry rule, a confined space as having three attributes:
- Large enough to enter and perform work;
- Limited access and egress; and
- Not designed for continuous occupancy.
Australian Standard (AS2865-2001) defines a confined space as:
“An enclosed or partially enclosed space that is at atmospheric pressure during occupancy and is not intended or designed primarily as a place of work; and
a) Is liable at any time to:
i. Have an atmosphere which contains potentially harmful levels of contaminant;
ii. Have an oxygen deficiency or excess; or
iii. Cause engulfment; and
b) Could have restricted means for entry and exit.
The United Kingdom Health and Safety Executive (UK HSE) says:
“It can be any space of an enclosed nature where there is a risk of death or serious injury from hazardous substances or dangerous conditions (e.g., lack of oxygen)”.
Obvious confined spaces include:
» Tanks;
» Stacks;
» Tunnels; and
» Trenches.
Some less obvious confined spaces include:
» Rooms which are inadequately ventilated;
» Shrouded columns or vessels which render them ‘air tight’;
» The roof of floating roof tanks; and
» Rooms and areas that become confined spaces by virtue of the activities being undertaken.
In all cases, confined spaces are particularly dangerous because they may frequently:
» Contain or have the potential to contain an hazardous atmosphere;
» Contain a material that has the potential for engulfing the work party;
» Have an internal configuration that might cause an entrant to be trapped; or
» Contain other recognized serious safety or health hazards.
Because confined space work can be so dangerous, there are a number of safety-critical controls that need to be applied to all confined space entry activities. The safety-critical controls are highlighted below:
- Identify the hazards using the Think 6, Look 6 process;
- Once hazards are identified, search for ways of eliminating or isolating them;
- In addition, always consider eliminating the confined space entry activity;
- If there are no alternatives to confined space entry, always test for presence of gas;
- Remember to continuously gas monitor atmospheric conditions;
- Always ensure that confined space entry is controlled by an authorized “Permit to Work”;
- Ensure workers performing confined space entry work are suitable trained;
- Ensure that a stand-by person acts as a sentry;
- Provide adequate Supervision, especially where contractors are involved; and
- Prevent unauthorized entry.
For a useful toolbox presentation on the management of confined space entry work, click the link to our “process safety tools”.
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