L ET’ S TA LK S A FE TY This column addresses safety issues of interest to water and wastewater personnel, and will appear monthly in the magazine. The Journal is also interested in receiving any articles on the subject of safety that it can share with readers in the “Spotlight on Safety” column.
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Climb Into Confined-Space Safety
confined space is any area with limited entry and exit that contains known or potential hazards and is not intended for continuous human occupancy. In the water industry, these spaces include manholes, trenches, storage tanks, wells, vaults, and tunnels. Hazards within a confined space include: S Oxygen deficiency by displacement with other gases and the introduction of nitrogen from cable pressurization S Toxic gases from decomposing soil, chemical spills, and engine combustion exhaust (from vehicles and equipment) S Combustible or flammable vapors and gases from underground storage or piping facilities S Moving equipment parts, structural hazards, entanglement, slips, and falls
S T emperature extremes, including atmospheric and surface S Shifting or collapse of bulk material S Barrier failure resulting in a flood or release of free-flowing solids S Uncontrolled energy, including electrical shock or water pressure S Visibility S Biological hazards The buildup of gases, including carbon monoxide and radon, poses one of the mostcommon and lethal dangers in confined spaces. If an oxygen deficiency or hazardous atmosphere may exist in the work area, the air must be tested before employees enter and also while the work is being conducted. If necessary, ventilation must be provided and continued as long as the manhole or vault is open. If the confined space is vacated for any
period of time, such as a lunch break, the atmosphere should be retested before re-entry is allowed.
Safety Equipment Several pieces of equipment are required for safe entry into a confined space: S Work-area protection devices, such as traffic (reflective) vests, traffic cones, manhole guards, work-area protection signs S Manhole cover lifter and manhole hook S Atmospheric tester for combustible gas, oxygen deficiency, and other toxics S Power ventilator (blower) S Pump to remove water S First aid kit S Portable fire extinguisher (dry chemical)
The 2020 Let’s Talk Safety is available from AWWA; visit www.awwa.org or call 800.926.7337. Get 40 percent off the list price or 10 percent off the member price by using promo code SAFETY20. The code is good for the 2020 Let’s Talk Safety book, dual disc set, and book + CD set.
26 October 2021 • Florida Water Resources Journal
