Mines safety alert no. 367 | 07 August 2019 | Version 1
Worker receives flash burns while repairing fuel tank on loader
The crack being repaired was on the top of the left hand tank. Nitrogen was introduced into the top of the right hand tank.
In order to speed up the process, the crack was being prepared for welding using an air arc gouging torch, in preference to a grinder. This caused a flash fire in which the worker sustained injuries to their neck and right arm.
How did it happen?
The fuel in the left hand tank rose up to be level with the crack due to the uncontrolled introduction of nitrogen in the right hand tank. The fuel, together with the oxygen from the air arc gouging torch created a flammable atmosphere which ignited.
- Ensuring the fuel is at ambient temperature and then isolating the tank that is not under repair.
- Draining the fuel out of the tank that is under repair and using water to flush out any residual fuel. This eliminates the risk of a fire resulting from the tank splitting during the repair work.
- Introducing carbon dioxide (CO2) into the top of the tank at an appropriate rate. CO2 is an inert gas and is heavier than air and will displace any pockets of air. Using CO2 may require a heated regulator.
- Monitoring the oxygen level inside the tank using a calibrated instrument and when it is less than 3% and stable, grinding or air arc gouging can start.
- Ensuring a second person monitors the oxygen level throughout the repair. Work should stop if the oxygen level rises above 3%.
- Continuing to purge the tank and monitoring the oxygen level after the repair is completed until the tank cools to below the flash point of the fuel before refilling the tank.
Investigations are ongoing and further information may be published as it becomes available. The information in this publication is what is known at the time of writing.
We issue Safety Notices to draw attention to the occurrence of a serious incident, raise awareness of risks, and prompt assessment of your existing controls.
The hazards associated with welding on fuel tanks are well known but vary from one situation to another. Relying on a generic procedure is not an acceptable practice.
Contact: Richard Horsburgh, Authorised Officer , +61 7 40285623 email@example.com
Issued by Queensland Department of Natural Resources, Mines and Energy
Placement: Place this announcement on noticeboards and ensure all relevant people in your organisation receive a copy.
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