Do No Harm: Canada’s Position on
Welding Power Source No-Load Voltage In 2019, the CSA Group published the Canadian National Standard CSA W117.2:19 Safety in welding, cutting, and allied processes. For environments in which there is an increased risk of electric shock, the Standard includes a requirement that a voltage reduction device—that limits the open circuit voltage of MMAW, GTAW and Air Arc Gouging power sources to 12 volts—is used. Dave Hisey, Chair of the Canadian Safety in Welding Cutting and Allied Processes Committee, provides an overview of the Standard. Background: Case Studies On 25 June 2014, a 29-year-old male welder died when the welding electrode penetrated his neck. He was seated on the building structure to which his return lead was connected. This was the case which caused the reduction in acceptable no-load voltage (open circuit voltage or OCV) under specified conditions to 12 volts within Canada. From Engineering Report, Electrocution Incident Carmuse Lime, Dundas Operations, Dundas, Ontario, Canada (Cement Plant Kiln): • The kiln was in operation and extremely hot humid (50°C and 85% humidity) and noisy at the time of the accident. • The welding spot was tight, awkward, and the lighting was poor. • There was no insulating material to isolate the welder from the work piece (coal bin) or other metallic parts inherently connected to the work piece. • There was no safe place to place or store the live electrode holder • The return lead was connected to structural members more than 30m from the area where the victim was welding creating stray welding currents throughout the structure. Does any of the above sound familiar to repair and maintenance welders? Electrical Contact Points The coroner detected only one massive entry wound, where the electrode penetrated the victims neck. The electrode had embedded in the victim’s neck at a downward angle, exit burns were found in the vicinity of his knee. In the follow-up court review of the death, there was discussion that the victim may have committed suicide as the investigators had
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Australian Welding
no experience with electrode shock fatalities, and for part of the actual investigation could not believe that a welding machine could kill anyone. For the family, I reviewed and created a report on 18 welding electrode fatalities I had on file. In a review of 18 individual cases of electrode shock death, I found that: • 8 had electrode contact points of face or neck • 2 cases rescuers were unable to remove the electrode from the victim’s mouth due to locked condition • 11 were found in lying position in contact with metal or ground • 1 sitting position on base metal • 1 foaming at the mouth • 1 had high enzymes (muscle damage or excessive use) • 1 had lung and kidneys congested with fluids. Additionally, one of the serious injury cases had direct forehead contact with a new electrode, welder lying in prone position - knocked unconscious for an undetermined time period. Face and neck contact is a normal finding in fatal or serious injury welding electrode shock occurrences. From a welding electrode fatality perspective, the 25 June 2014 investigation provides a disorganised report; concentrating more on the primary power circuit than the welding circuit which was the cause of the fatality. This is not unusual; I have looked at many welding electrode fatalities where the investigation team is not familiar with this cause of death. They eventually get to the cause.
