What is a confined space?
A confined space is a space in which, or from which, access or egress is restricted and in which, because of its construction, location, contents or the work activity therein, a hazardous gas, vapour, dust, fume or oxygen-deficient atmosphere may occur.
As a rule of thumb any area which was not designed for regular human occupancy should be considered a confined space. Examples include tanks, silos, hoppers, bins, dust collectors, vats, pipes, sewers, pumping stations, digesters, liquid manure spreaders, chemical storage tanks, and wells.
How should you enter a confined space?
Prior to entering a confined space, all safety equipment must be inspected for defects, and setup appropriately to allow fast response in case of emergency.
The atmosphere must be tested prior to entry and all electrical or mechanical devices locked out, or completely disabled. A safety person is required to watch the entrant at all times, in case of emergency. Often times during tank clean outs, for example, the gas levels in the tank will change drastically as the material is stirred up. Continuous gas monitoring is essential.