Before going inside confined or enclosed spaces, proper ventilation is applied and appropriate and continues atmospheric testing follows to obtain 21% oxygen by volume, 1% LEL of hydrocarbons, max. 30 ppm carbon monoxide, max. 10 ppm sulfate oxide and max. 5 ppm benzene. Personnel entering the space are required to be equipped with a portable gas meter for continuous monitoring of the atmosphere and this requirement will suffice for ongoing gas testing.
Of course entry permit is necessary before going into action. This permit is issued by a responsible person (Chief Mate or the Master) permitting entry to a space or compartment during a specific time interval. No person should open or enter an enclosed space unless authorized by the Master or designated officer and unless the appropriate safety measures were laid down. Communication is also important to maintain a high level of safety and security during enclosed space work.
Exposure or vulnerability to harm is part of entering confined or enclosed spaces. Asphyxia caused by toxic vapors is the common cause of casualty among seafarers. Enclosed spaces are left with different types of vapors produced by clingage (i.e. oil remaining on the walls or surface of the tank interior), sludge and other materials forming inside spaces.
Shown on the picture is C/M Alejandro Bersaluna, a cadet, an AB and the author ventilating a ballast tank located at the Bosun’s store.
