Examples of metal components that have a potential to accumulate hazardous levels of electrostatic charge are end couplings and metal wire helixes that run through the structure of the hose. If components like these become isolated they can accumulate static electricity and rapidly build up to a voltage capable of discharging a static spark into the potentially combustible atmosphere in which the driver and truck is operating. Periodic resistance testing of hoses with multi-meters provides some level of comfort in terms of ensuring faulty hoses are taken out of service at the time of testing. However, there are plenty of operating environments that place a tremendous strain on the durability of hoses. For example, a metal wire helix that detaches from a coupling could go unnoticed by drivers and be used continuously in the field until a scheduled test identifies the isolated components, or worse still, when the isolated components discharge a spark during operations.
The OhmGuard hose continuity tester not only ensures the hoses are functioning correctly prior to every product transfer operation, it also ensures that the assembled hose sections have a low resistance electrical bond connection to the grounded truck. This ensures that any static electricity generated by the product transfer process is transferred by the hoses to ground, via the truck’s verified ground connection and ensures that the metal components of the hoses will not be a spark ignition risk during operations.
Unlike standard multi-meters, the OhmGuard does not require specialist training. The driver simply connects the hoses to the truck and then connects the OhmGuard to the coupling or nozzle of the last hose. If the hoses have good electrical continuity with the grounded truck, the green LED mounted in the OhmGuard will pulse continuously. If the hoses have a break in continuity the green LED will NOT pulse. If this situation arises the driver can then test each hose individually to help identify the faulty hose(s).
The possible ramifications of a lack of training in static risk prevention in tanker truck operations, is detailed in one of Newson Gale’s case studies. Here, a company supplying aluminium powder had an order cancelled when the bulk truck transporter carrying the powder was en route to a railcar hopper loading station. The truck driver was instructed to return the aluminium to the plant from where it was manufactured. As this scenario had never occurred before there was no standard operating procedure in place to offload the aluminium from the truck back into the production facility. Shortly after the operators had worked out how to overcome some practical challenges for moving the powder back into the plant, an explosion occurred which propagated throughout the plant.Click here to download the case study on how an isolated hose ignited and caused an explosion
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