Potable water diver

A potable water diver works in a potable water tank performing inspection and cleaning tasks.

Inspection of the interior of a municipal water tower requires specialized training and safety equipment.

Certified commercial divers can inspect water storage tanks, towers and clearwells without draining them or taking them out of service. SCUBA certification alone is insufficient, and additional training is required. The American Water Works Association publishes a technical standard, C652, that outlines recommendations for divers in potable water facilities.[1] The diver is totally encapsulated (no part of the divers body touches the water) in a sealed drysuit and then washed down with a 200ppm chlorine solution prior to entry into the tank. All diving dress is to be used exclusively in drinking water. This meets American Water Works Association (AWWA) standards for entering a public water system. The diver is then able to move about the tank to perform inspections or clean the tank. AWWA recommends removing sediment accumulations over 1/2" deep from the floor of a drinking water tank because it can harbor bacteria and/or other contaminants which could adversely affect water quality. Using a specially equipped pump or airlift system the diver is able to remove the loose sediment without damaging painted surfaces. This allows the chlorine in the system to more effectively do its job. Divers are an effective means to clean and inspect potable water storage tanks because all of the maintenance can be done while the tank remains in-service and full of water, and most of the interior surfaces of the tank can be easily accessed.

Diving in a tank presents hazards, particularly in all water towers (EST) and ground tanks (GST) above 100,000 Gallons. Divers require confined-space training and working at heights certification. In the USA commercial diving operations require at least one trained tender, a diver, and a supervisor. Surface-supplied air with two-way radio communications to the diver and a safety rope are preferred. The Occupational Safety & Health Administration regulation 29 CFR Part 1910, Subpart T allows scuba with a rope for basic communications.[2] The diver should be wearing a harness, strapped to a safety rope, so that in case of an emergency the dive tender can pull the diver up. Divers always need to check the safety legislation appropriate to their local jurisdiction.[3]

References

  1. ↑ American Water Works Association, Disinfection of Water-Storage Facilities, ANSI/AWWA C652-11, section 4.4.5
  2. ↑ "CPL 02-00-151 - 29 CFR Part 1910, Subpart T – Commercial Diving Operations". US Department of Labor. 13 June 2011. Retrieved 6 February 2016.
  3. ↑ Australian Tank Maintenance, Field Technician


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