Headlines containing the phrase “shipping container” and words such as “fire” and “fatality” are becoming way too common.
In the last issue of Industrial Fire World we covered a hazardous materials incident that shut down Canada’s Port Metro Vancouver, North America’s third largest port facility. Heat generated by chemical decomposition destroyed more than 22 tons of a caustic bleaching agent sealed in a shipping container that was blocked at both ends.
Then there are the astounding photographs from the Port of Tianjin, China (see Page 10), showing crushed shipping containers piled into five- and six-story mounds after multiple explosions in August 2015. More than 140 people died in the disaster. Many others reported missing have yet to be found.
Intermodial shipping containers range from 20 feet to more than 50 feet long. However, the basic design has changed very little since the 1950s. Heavy steel corner posts allow the containers to be stacked up to six containers high. Hinges are recessed to further facilitate stacking. Otherwise, shipping containers are little more than big steel boxes with almost no ventilation.
Just as railroad cars are often adapted for use as culverts or bridges, other uses are being found for shipping containers. In a fatal December 2011 explosion in Canada, the 40-foot shipping container in question had been converted into storage for power tools, including gasoline-powered chainsaws.
Three buildings or structures were directly affected by the initial fire – a post-and-beam production building, a modular trailer used as a break room and the metal shipping container. The eight-foot-wide, eight-foottall container had only four small vents, one at each top corner.
According to the Workers’ Compensation Board of British Columbia, when the main fire was brought under control, firefighters shifted from initial attack to a mop-up procedure. Inside the container, the plastic components of the chainsaws melted at a temperature of 200 degrees Celsius, allowing the gasoline to vaporize and escape.
When the fuel ignited, the explosion blew off the container’s two padlocked 250-pound doors, one of them striking and killing volunteer firefighter Daniel Botkin before landing 140 feet away. The other door went through the production facility before landing 200 feet away.
The manner in which the shipping container was being used conformed to the British Columbia Fire Code. There had been no telltale indicators such as venting smoke, peeling paint or noise from inside. In fact, firefighters had been standing atop the container while attacking the blaze at the main facility.
Fire requires only three elements – fuel, oxygen and an ignition source. A fourth is needed for an explosion – containment. The shipping container provided that. The report states that because shipping containers allow very limited ventilation, heat builds quickly. Either the vaporized fuel ignited from contact with the flames outside or the gasoline autoignited from the heat alone.
I have never thought of shipping containers having much potential to go boom – until now. The rash of shipping container emergencies being reported deserves serious pre-planning attention.