Carol-Ann D. Fletcher Member Name
Senior Environmental Health and Safety (EHS) Consultant, P.Eng., EP(EMSLA)
Artificial ice-skating and curling facilities are the heart of many communities’ sports, recreation, and social lives. Beverage and food-processing plants and refrigerated warehouses provide jobs, and in some cases a market for farmers in the area. What all these facilities have in common is the potentially hazardous coolant used to keep many of these facilities working – anhydrous ammonia – which if breathed in, can damage health and in some cases, can even be fatal.
Ammonia is a gas at atmospheric temperature and pressure, and because refrigerant systems keep it contained under pressure, a leak can cause a release to the surrounding air. This means that an ammonia leak can be a hazard to people inside the building, and if ammonia is vented to the outside, it can threaten the surrounding community as well.
There are many regulations(e.g. Environmental Emergency Regulations, SOR 2019-51), guidelines and standards that direct the safe operation and maintenance of ammonia systems. But accidental releases can and do happen, sometimes with fatal consequences as seen in Fernie, British Columbia in October 2017. In our experience, the identification of potential process failure and release scenarios, and the determination of emergency planning zones and response procedures can be improved. Golder uses a range of expertise and tools to understand and assess the human health and ecological risks to then develop plans to manage those risks with facility owners, managers, and operations and maintenance staff.
We start by evaluating the potential for a release from the physical plant, as a result of a failure of pipes, pumps, compressors, chillers, valves, tanks, and other components of the refrigeration system. We evaluate the way that people can interact with different components of the system. We evaluate alarms, interlocks, sirens and other emergency notification systems. As well as the physical plant, we use education as a mitigation factor by verifying that risks are understood and safe work procedures are in place for anyone working in the facility and interacting with the system.
We also evaluate the appropriateness of the processes and procedures that alert building staff and other building users if there is a release of ammonia. We check that the procedures are in place for fast response in case of a leak.
In a fire, common practice is to clear the building, but in an ammonia leak it may be safer for people in the building to stay inside. This is because emergency procedures may involve releasing the ammonia in the system’s pipes and equipment to the outside atmosphere.
Because a release of ammonia can be a hazard to anyone who is exposed to it above a certain dose (based on duration of exposure and concentration of the chemical), the impacts of a release of ammonia must also be evaluated. Such an evaluation will help define the size and complexity of the emergency planning zone – that is, the area around the facility that has the potential to be impacted by a release.
To understand the fate of a hazardous gas release, Golder uses complex computer-based dispersion models, together with information on local wind speeds, direction and other factors, to develop projections of how different ammonia releases will behave. This helps with emergency planning – indicating how long emergency services have for notifying nearby residents, and informing the municipality and facility about the size and complexity of the potential impact zone.
Our goal is to help municipalities and businesses in those communities understand and better manage the significant risks associated with these hazardous chemicals. Good understanding of the risks and how to manage them helps to make that possible.