Fishbone diagram

Barrier Analysis

Part 1: Barrier Analysis Worksheet

Barrier	Intended function	performance
leaking pressure relief valve	This was a barrier for transferring liquid propane by three propane service technicians from one tank to another.	The transfer of propane from one tank to another did not happen as intended, as propane vapour was released and caused a flash of fire.
damage to the filter valve	After the leakage, the technicians moved the tank from its installed place and replaced it with a new tank. After that, they wanted to use a filter valve to evacuate the old tank.	The evacuation of the old tank was not performed as intended. This was because the damage to the filter valve made the propane stick and release vapor. The propane vapor reached a truck parked near the location and ignited, which caused a fire in the kitchen house.
Attempt to close the valve	A group of firefighters came to assist in putting out the fire and attempted to close the valve. They also tried to move the three service technicians from the fire and rush them to the hospital.	The attempt by the firefighters to put off and attempt to close the valve before it caused more damage did not work as planned. This was because the valve had been sheared off. The chicken house was entirely damaged. They managed to rush the three injured service technicians to the hospital. However, the three were severely injured and died in the hospital.

Part 2: potential causal factors

Firefighters should let propane technicians work on propane tanks in case of emergencies. In this case, when the firefighters were called, they tried to cool the tank using water and attempted to close the valve instead of containing the fire from reaching the truck. By doing this, the fire spread got the car and burned the chicken house.

Placing a tank containing a thousand gallons of propane behind the chicken house is risky. The owner should have put it far away from the chicken house. Another causal factor that led to ignition was a tank-to-tank transfer using a filter valve instead of a pressure relief valve (Ferrara et al.,2008).

Unidentified causal factors

The report does not indicate whether the propane tank service technicians had the required qualifications and experience to service a leaking tank and transfer propane from one tank to another. The report does not indicate the time taken to rush the burned service technicians to the hospital. Evacuation of casualties during an emergency is crucial and saves lives.

On the report, the service technicians were working without supervision. To avoid such incidences, junior technicians are supposed to work under supervision.

The report does not indicate the ignition source after the propane's leakage. After the valves failed, the propane leaked, and fire ignited, which burned a truck, the service technicians and the chicken house. However, there is nowhere in the report the source of the fire was indicated. In addition to that, the cause of death of the service technicians is not shown. More analysis should be undertaken to tell whether it was the severity of burns, infection of the burn wounds, inhalational burns or other causes.

References

Ferrara, G., Willacy, S. K., Phylaktou, H. N., Andrews, G. E., Di Benedetto, A., Salzano, E., & Russo, G. (2008). Venting of gas explosion through relief ducts: Interaction between internal and external explosions.  Journal of hazardous materials,  155(1-2), 358-368.