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0 0 <br /> 3) Prior to any work commencing in the tank,oxygen contents and flammable vapor <br /> concentration must be at safe levels.Tank entry restrictions are based on measured <br /> oxygen and/or explosion limits*: <br /> NO ENTRY is allowed if the oxygen levels are below 16%and/or explosion levels are <br /> above 20%LFL. <br /> RESTRICTED ENTRY is allowed if oxygen levels in the tank are between 16.1% and <br /> 19.4%,and explosion levels are less than 10%LFL. Personnel may enter the tank only <br /> with proper breathing and safety equipment. <br /> GENERAL ENTRY is allowed if oxygen levels are between 19.5% and 21.4%, and <br /> explosion levels are below 3% LEL. Breathing apparatus is not required, however a <br /> safety harness and line must be worn by all personnel entering the tank, and <br /> continuous venting must be maintained to ensure safe oxygen and explosion levels. <br /> *See Appendix 1 for more detail. <br /> 4) Certain specific equipment must be available for rescue operations or other <br /> emergencies: <br /> Positive pressure air-supplied respirator with full-face enclosure <br /> Safety harness and line attached to an OSHA approved tripod hoist <br /> Self-contained breathing apparatus <br /> Fire extinguisher <br /> A safety attendant must be stationed immediately outside the tank anytime <br /> personnel are inside the tank (see 29 CFR, Part 1910.134). <br /> 5) Positive pressure air-supply sources must be monitored continually for carbon <br /> monoxide. <br /> 6) Personnel entering the tank during the cleaning process must wear a positive <br /> pressure air-supplied respirator with full-face enclosure and safety harness connected <br /> to a safety line suspended from a tripod-like or equivalent lift mechanism. Oil and <br /> water-resistant rubber or neoprene boots must also be worn. Protective clothing, <br /> resistant to the types of products stored in the tank, must be worn to protect arms, <br /> legs, torso and head of employees entering the tank. <br /> 7) Clothing saturated with the stored product must be removed immediately. <br /> 2.2 Preparation of Tank Interior <br /> 2.2.1 Tank Cleaning <br /> a) Upon initial entry into the tank, accumulated liquid sludge or residue must be removed. <br /> Material capable of absorbing liquid residues must be spread throughout the tank bottom <br /> to collect any remaining liquids.When absorbent becomes saturated,add new absorbent <br /> to suppress vapors and dry area. Monitor vapor readings throughout the entire cleaning <br /> process. If lighting is necessary during initial cleaning operation, use Class 1, Division 1, <br /> Group D, explosion-proof lighting. <br /> b) Remove solid sludge or saturated absorbent material from tank bottom using a non-ferrous <br /> or spark proof shovel,and place it in tightly sealed containers or drums.Dispose containers <br /> 2/99 <br /> Page 7 of 30 <br />