A tragic event on Dec. 29, 2011, mobilized the British Columbia fire service to find out more about the dangers of shipping containers. Now, after two investigations and a lot of research, the province’s fire chiefs want to make the fire service aware of the possible hazards of containers and work to ensure that Ottawa and the provinces regulate their use.
The line-of-duty death of Capt. Daniel Botkin, a volunteer firefighter in Enderby, B.C., was a wake-up call. Until members of the Fire Chiefs Association of BC (FCABC) started digging for more information about shipping containers, the general perception was that because the boxes are structurally strong – built like tanks – they posed no fire risk.
But the investigations into Botkin’s death concluded that the exposure fire at the log cabin manufacturing site caused small volumes of flammable liquids inside the container to pyrolize, forming explosive vapour mixtures that detonated with sufficient force to cause the container to rupture or explode. The lack of any significant venting and the general conditions of the outside of the unexposed sides of the shipping container gave the firefighters no sign that there were hazardous conditions within the shipping container, until it failed.
|Capt. Daniel Botkin’s widow Miranda Hansma (left), and his father, Doug, accept a helmet in his name at the Canadian Fallen Fire Fighters memorial service in Ottawa in June 2012. Photo by Laura King|
The detonation tore the steel container roof along most of the 12 metre length of the container facing the exposure fire, sheared the eight steel door hinges, and folded the two 113-kilogram doors in the centre and ejected them from the door assembly.
One of the doors struck Botkin and landed 41 metres southwest of the container. The other door was found 54 metres northwest of the container.
The WorkSafeBC report and the FCABC position paper (available at FCABC.ca) provides more detail on the specifics of the incident; the WorkSafeBC site (WorkSafeBC.com) has a copy of the detailed investigation and an excellent slideshow/animation of the incident.
On April 23, 2013, in Saanich, there was another shipping-container incident at a construction site. A leaking propane barbecue stored in a secure shipping container exploded at the start of the workday when the electrical supplies for the containers were connected. Parts of the container roof landed about 200 metres away, the walls were flattened and the adjacent containers were heavily damaged. Luckily no one was seriously injured in this incident.
After these incidents, a fire chief in one of British Columbia’s smaller communities had his staff try to determine the shipping-container risk in his area. Staff found seven properties on which there were shipping containers used for storage; four contained significant volumes of flammable liquids or flammable compressed gases.
There seems to be a perception that shipping containers are a good place in which to store equipment and fuels because they are strong and secure. The research found that besides conventional storage, containers are being used:
- to store fireworks
- to store flammable gases and liquids at construction sites
- as first-aid buildings at construction sites (with supplies of antiseptic alcohol or oxygen bottles inside)
- as construction offices
- by hobbyists to recharge hunting ammunition
- as electrical rooms or electrical vaults at construction sites (with the accompanying arc blast risk)
Surplus shipping containers – or intermodal shipping containers (which means the containers can be moved from one mode of transportation) – are readily available for rent or purchase and are affordable for use for storage; they are available in a range of sizes from sizes from 1.5 metres to 16 metres in length.
Containers are designed to be strong; they can be stacked up to nine high on ships and can carry up to 32,200 kilograms of cargo. The side walls are designed to withstand shifting loads up to 60 per cent of the permitted load and the doors are designed to withstand loads up to 40 per cent of the permitted load. The containers are designed to withstand drop tests and are secure from theft and weather due to a tight structure and gasketed doors.
The only venting in shipping containers are groups of nine small holes – of between three millimetres and six millimetres – in the corners that act as air-equalization vents so that the container does not bulge or cave in during changes in ambient temperatures (plus or minus 20 C to 30 C). The holes are protected by external covers that prevent the entry of water. The small size of the holes and the external cover make them a poor indicator of the internal conditions of the containers.
The FCABC’s research and analysis of the fire hazards of shipping containers looked at available fire testing, the impacts of typical fuels commonly found in containers, the impact of ignition sources and the current governance for shipping containers.
A 1977 United States Coast Guard report on the Fire Performance of Intermodal Shipping Containers indicated that the small venting area of the air-compensating vents of a closed container caused internal slow growth fires to vitrify or smother themselves.
The report also found that an exposure fire could increase the internal temperature of a container to 230 C in four to nine minutes, and the ignition or charring of Class-A fuels within five minutes. These tests showed that an exposure fire could raise the internal temperatures quickly and could easily reach the auto-ignition temperature of gasoline.
The fuel analysis of the Enderby incident showed that methanol had a vapour density at normal conditions of 1.1 compared to the 1.0 for air. With the higher air temperature at the top of the container where the methanol was stored, the methanol vapour could have been buoyant. Methanol has a flammable range of between six per cent and 36.5 per cent compared to 1.4 per cent to 7.6 per cent for gasoline. The analysis showed the conditions for the ignition and detonation of the gasoline and methanol were plausible. Some rough calculations of the maximum unvented pressure in the container were done during the analysis and the half litre of methanol and the one litre of gasoline could have created internal pressure of greater than 700 kilopascals or 100 pounds per square inch.
The research also indicated that some jurisdictions in Canada, the United States, New Zealand and Australia had recognized these fire-safety issues associated with shipping containers and had put in place bylaws or other regulations for use of containers.
In most of the jurisdictions reviewed, the key governance measure was to define and declare shipping containers as buildings; therefore, when they are used for purposes other than the transport of goods, they can be regulated.
Once containers are regulated, then their location, use and contents can be dealt with to help ensure fire safety for the public and firefighters.
In Canada there is no national standard that controls or defines shipping containers as buildings when they are not being used to transport of goods, but Saskatchewan and Ontario have their own regulations.
In Saskatchewan, under Bulletin A19 Saskatchewan Building Standards Advisory, a shipping container is considered a building when it: is no longer used for the shipping of freight, is placed on a property either temporarily or permanently, and is used for any shelter or occupancy.
In 2002, an Ontario court determined that a shipping container used for the storage of goods on a private property in Mississauga was a building based on the Ontario Building Code. Subsequent Building Code Commission hearings have ruled similarly.
In British Columbia, a shipping container is defined as a building only if it is on a foundation and has been modified with, for example, conventional doors, windows or an electrical supply.
The FCABC has concluded that in order to improve the fire safety of shipping containers, the fire service must work to change legislation to
- Regulate the use of containers – The FCABC believes that amendments are required to national and provincial codes that will allow local governments and fire services to regulate the uses of shipping containers when they are not being used to transport goods. Code changes must include the way the containers are used, where they can be used and what can safely be stored inside. The FCABC has included a sample bylaw template in its position paper for local government to use as a tool to regulate the use of containers. In June, the FCABC passed a motion to ask the Canadian Association of Fire Chiefs to work on an initiative to improve awareness of the fire-safety hazards of shipping containers and to have changes made to the National Building Code and fire codes to recognize the possible hazards that shipping container can create for the public and firefighters when they are used as buildings. In September, the CAFC passed the resolution recommended by the FCABC.
- Weaken the structure to allow for earlier structural failure – One of the major concerns with shipping containers is that they are so internally strong that pressure builds to a high level before the containers rupture. These higher pressures can then cause components such as doors and roof sections to become dangerous projectiles. The presence of small volumes of flammable liquids that are below the regulated volumes in the fire codes can cause a container to rupture and expose the public or firefighters to harm. The solution is to install secure openings (i.e. roll-up doors) that weaken the containers to allow them to vent any internal pressure before rupturing.
- Ensure containers are properly vented – In the Enderby incident, it was difficult during the nighttime fire attack to see indications of smoke pushing out of the container’s small air-compensating vents; therefore, the firefighters were not aware of the conditions within the container. Provision of larger high- and low-level vents will provide cross ventilation of a container and will allow responders to see indications of smoke pushing from a container that is exposed to a fire.
- Educate departments about incident safety – Fire departments should consider the formulation of standard operating procedures to ensure that the lessons learned from the Enderby LODD become part of the their tactics. The incident size-up should consider the impact that an exposure fire can have on a shipping container, what exclusion and hot zones should be used, and the best fire-attack strategies.
Shipping containers are very useful as structures or buildings, but the tragic loss of Capt. Botkin showed that when a series of unforeseen conditions occur, containers can be a hazard. In order to prevent similar incidents, the fire service must work to communicate to our own members the potential fire hazards of shipping containers and change the way that containers are regulated.
Don Delcourt is the industrial director for the Fire Chiefs Association of BC and the BC Hydro and Power Authority Fire Marshal. The 33-year veteran of the industrial fire service is also chair of the IEEE Substation Fire Protection working group and the chair of the ASTTBC Certification Board for Fire Protection Technicians in BC. Contact Don at email@example.com