Once emptied of their original cargo, some shipping containers are finding second lives as offices, storage sheds, or work or living spaces. At first glance, this looks like a great idea — they’re relatively inexpensive, weather-resistant, and sturdy.
But Andy Lim, supervisor, prevention field services instructor with WorkSafeBC, points out these new uses include “many things they weren’t designed for” and bring serious risks with them.
Designed to protect cargo in transit across oceans, the containers are water- and weather-resistant, with limited ventilation. The first two qualities make them appealing for storage, but the last quality is what can make them dangerous.
Lack of ventilation
What do you know about the cargo it once carried, or chemicals used to protect that cargo, such as pesticides or fumigants? Any residue from the contents, including spills that soaked into the wooden floorboards, can create a buildup of harmful fumes and overcome workers who enter the container, unsuspecting and unprotected. Before you use the container on your worksite, clean it thoroughly and consider replacing the floor. Take precautions against contamination during this process.
Lack of ventilation also affects what should be stored in them later, and what activities should be conducted inside or around the containers.
“They have the potential to become a pressurized bomb if they contain enough of the three elements of the ‘fire triangle’ — oxygen, fuel, and a heat source,” warns Lim.
Equipment commonly stored on worksites, such as paint, fuel and gas-powered tools release flammable vapours which can build up to dangerous levels in a tightly closed, poorly ventilated storage facility.
Two serious explosions
There have been at least two serious incidents in B.C. highlighting these dangers. In 2011, firefighters were called to a fire at a construction business in Enderby. Gas-powered chain saws were being stored in a shipping container located near the fire. The heat from the fire ignited the gas vapours inside the container, resulting in an explosion that blew the doors off the container, striking and killing one of the firefighters. In 2013, a container exploded on a Saanich construction site when the thermostat relay in the cooling system of a drink-vending machine sparked the fumes from the propane barbecue tank stored beside it. No one was injured in the explosion, but there was considerable property damage from flying debris and the fire.
Reducing the risk
When using shipping containers, there are a number of precautions you can take to reduce the risks to workers and company property.
Improve the ventilation system. Many harmful vapours are heavier than air and will sink to the floor of the container.
Locate the shipping container away from potential heat sources and where, in the event of a fire or an explosion, damage to the surrounding area and to anyone working there, will be limited.
Limit the amount of time workers spend inside and around the container.
Remove anything that may provide a potential spark or ignition source.
Ask your local fire department for advice about the safe use of shipping containers, and include information about their contents in your fire safety plan.
Regulation and Code requirements
There are also sections of the Occupational Health and Safety Regulation that may apply to the reuse of shipping containers. For example, if hazardous materials are stored inside, there are requirements for warning signs, permitted quantities, and storage conditions such as lighting, ventilation and worker access.
To employers who are using or thinking of using shipping containers for storage or work spaces, Lim has this important reminder: treat the container as a building.
“Review the BC Building Code,” he advises. “And check with your local government. Your municipality may require the BC Fire Code to be applied for shipping containers…You can also ask our prevention officers for assistance.”
Reusing a shipping container might seem like a low-cost, ready-made solution for storage or temporary office space, but you need to educate yourself on the hazards and how to minimize them.
For resources on minimizing the hazards when reusing shipping containers, search “shipping containers” on worksafebc.com.
Roberta Sheng-Taylor is a manager of industry and labour services – construction at WorkSafeBC.
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