Module 9 : Confined Space Hazards A confined space is any area with limited means of entry and exit that is large enough for a person for a person to lift into but is not designed for occupancy. Examples include vaults, silos, ship compartments, train compartments, sewers, and tunnels. To ensure that a confined space is safe, the following questions should be asked and answered in the affirmative before allowing entry. A negative response to even one of those questions means that entry into confined space in question is not yet safe. • • • • • • •
Are accesses and exit equipment such as ladders and steps are in good working condition? Has the confined space been properly purged of the toxic vapours and other toxic substances? Are all lines that transport potentially hazardous substances into or through the confined space turned off and properly capped? Are all moving equipment and moving parts of equipment in the confined space shut down and locked out? Has proper ventilation been provided? Has the atmosphere in the confined space been checked by appropriate sensitive detection devices? Have provisions been made to monitor continually the atmosphere inside the confined space during work?
In addition to the toxic and explosive hazards associated with the confined spaces, there are often physical hazards. For example, tunnels often contain pipes that can trip a worker or that can leak and cause a fall. Empty liquid or gas storage vessels may contain mechanical equipment or pipes that must be carefully maneuvered around, often in the dark.