(87c) Propane Cylinder BLEVE: Investigation Findings and Lessons Learned in the 2014 Philadelphia Food Truck Explosion

On July 1, 2014, a propane cylinder catastrophically failed and exploded on the back of a food truck parked at the intersection of Wyoming Avenue and 3rd Street in Philadelphia, PA. The explosion led to a sudden release of pressurized propane vapor and superheated propane liquid, which rapidly evaporated resulting in a large white cloud that entered and engulfed the rear of the food truck. This cloud ultimately found an ignition source within the food truck and resulted in a significant fireball burning both inside and outside of the food truck. The explosion and ensuing fire fatally injured the food truck owner and her daughter, and also caused injuries to 11 other individuals. This paper will first present the results of our investigation into the cause and origin of the catastrophic failure and explosion event, which included: (1) video footage of the explosion and ensuing fire; (2) advanced propane phase diagrams to determine the expansion and resulting pressures within the cylinder prior to failure; and (3) applying advanced blast techniques to determine the post catastrophic blast and ignition during the event. These techniques included advanced computational fluid dynamic modeling.

The paper will also discuss safety critical design features and processes in the propane industry that must be in place to ensure the safe use and filling of propane cylinders, which include: requalification of the cylinder; having a fixed maximum liquid level gauge; scales; and pressure relief valves.