Confined Spaces - Workplace Safety and Health Council

Before carrying out any cleaning work, it is important to conduct a risk assessment to identifyand evaluate any possible hazards. It is necessary to put in place any reasonably practicablecontrol measures that will help to reduce the risk to an acceptable level.Before the inspection, it is necessary to ventilate the ISO tank thoroughly. It is critical to conductgas testing to ensure that the atmosphere in the tank is safe for the worker to carry out theinspection.It is also important to appoint a safety attendant to keep watch and continuously monitor theatmosphere so that it is maintained at acceptable/safe levels.It is essential to establish safe work procedures and implement them to ensure that the inspectionof ISO tank can be carried out safely without endangering the safety of the worker and otherworkers in the vicinity.It is important for workers who carry out the ISO tank inspection to be properly trained and fullyinstructed on the potential hazards in connection with the work. It is also necessary for them toput on appropriate protective equipment during the inspection.It is critical to provide adequate and suitable lighting with illumination of not less than 50 lux forthe workers to do their inspection in the ISO tanks. It is also important to note that all portablehand-held lightings provided in confined space shall be operated at a voltage not exceedingalternative current (AC) 55 volts between the conductor and earth or direct current (DC) 110volts.12. AcknowledgementsThis TA was developed with inputs from members of the working committee. Workplace Safetyand Health Council (WSHC) would like to thank them for their valuable contributions to this TA.WSHC IndustryCommitteesSCICSISOSLPEquipment SafetyMembers of the Working CommitteeMr Lee Yeok Hoon (Jurong Shipyard Pte Ltd) ChairmanMr P K Raveendran (Sembawang Shipyard Pte Ltd)Mr Soh Hong Kuan Bernard (Rotary Engineering Ltd)Mr Yeo Tiong Joo (OCWS Logistics Pte Ltd)Mr Tay Cheng Pheng (Chevron Phillips Chemicals Asia Pte Ltd)Mr Wendell Harms (Pfizer Asia Pacific Pte Ltd)Mr Soh Cheng Seng Jacob (Singapore Refining Company Pte Ltd)Ms Ang Siew Lan Veronica (Dräeger Safety Asia Pte Ltd)MOMWSHCMs Colleen LowEr Tan Kee ChongThe two confined space warning signs (Figure 4) are taken from ISO 7010 : 2003 (P004 & W001)and reproduced with permission from the International Organisation for Standardisation, ISO.Copyright remains with ISO.The pictures used for illustration purposes (Figure 5, 6, 7, 8, 11, 12 and 13) in this TA are reproducedwith courtesy of Dräger Safety Asia Pte Ltd.The pictures used for illustration purposes (Figure 17, 18, 19 and 20) in this TA are reproducedwith courtesy of Air Systems International, Inc.The pictures used for illustration purposes (Figure 14 and 15) in this TA are reproduced withcourtesy of Land Transport Authority.84 85