What to Know About Ammonia Refrigeration Hazards & Controls
Globally, there's a strong movement to use greener products and conserve energy. These efforts include refrigerated environments such as food processors and cold storage facilities. In order to meet these environmental concerns, many companies are swapping out their Freon-based equipment to use ammonia instead. Ammonia refrigeration systems have a significant cost advantage over Freon, however, the hazards are significantly higher, too.
Freon is the brand name for dichlorodifluoromethane, a chlorofluorocarbon (CFC) gas that is being phased out by the Environmental Protection Agency (EPA) as its use causes ozone layer depletion, which contributes to climate change. Ammonia (NH3), a natural substance containing nitrogen and hydrogen, is not an atmospheric threat, but does come with its own dangers and necessary precautions.
Ammonia's Main Hazards
Ammonia is a toxic gas under ambient conditions, meaning that personnel safety is of the utmost importance. It's critical to prevent workers from being exposed to ammonia, as high levels of the gas can burn or irritate the lungs, eyes, skin, throat and mouth and can even be lethal, according to the Centers for Disease Control (CDC).
Is ammonia flammable? While it is not highly flammable, if exposed to high heat, containers of liquid ammonia can explode. Explosions can also happen when releasing ammonia contaminated with lubricating oil. Either way, it can be considered flammable or explosive when mixed with air in a 16 percent to 25 percent concentration of ammonia by air volume.
In gas form, ammonia typically rises since it is lighter than air. Moisture however, including high relative humidity, can cause it to become heavier than air. The vapors can then spread along the ground or into low-lying areas with poor airflow, exposing people to the toxic fumes.
Finally, the dangers of ammonia accumulating tend to happen when there isn't appropriate ventilation, which allows the gas to disperse. This accumulation can occur from rotating seals and pipe leaks. Forklifts or aerial equipment can also hit pipes, valves and evaporators, causing ammonia to leak. Ammonia can also escape as it's delivered, for example, through a leaky hose.
Top Sources for Ammonia Safety
It's important to have a solid risk management program in place if using ammonia refrigeration or ammonia for other purposes. Luckily, there are a number of government and industry protocols that can help manage ammonia risks.
The National Institute for Occupational Safety and Health (NIOSH) recommends using the Hierarchy of Controls to protect workers from hazards like ammonia exposures and to determine which action will best control those exposures, too. The hierarchy includes five steps: elimination, substitution, engineering controls, administrative controls and personal protective equipment (PPE).
The EPA offers risk management guidance for ammonia refrigeration facilities, covering risk mitigation for worst-case ammonia release scenarios. In addition, the Occupational Safety and Health Administration (OSHA) sets limits on how much ammonia and other chemicals a worker can be exposed to during a shift. It also sets standards on employee training for maintenance and safety equipment, as well as emergency action plans and other guidance.
Yet another safety resource comes from the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), which publishes an industry consensus best-practice standard that professional heating, ventilation and air conditioning (HVAC) practitioners adhere to: The 15-2022 Safety Standard for Refrigeration Systems.
Safety measures for ammonia refrigeration
There are a number of safety measures businesses should use for ammonia refrigeration. The New Jersey Department of Health (NJDOH) has a good example of what some of these measures include.
- Train employees about ammonia hazards
- Provide emergency showers and eye wash fountains in case of exposure
- Monitor airborne ammonia levels
- Follow guidance by using available controls if ammonia concentrations exceed recommended exposure levels
- Refrain from smoking, eating and drinking anywhere that chemicals are stored, handled or processed
- Wash hands not only when exposed to chemicals, but before eating, drinking, smoking, using the bathroom or applying make-up (e.g. touching the face)
- Wash or shower if the skin comes in contact with ammonia
- Wash hands at the conclusion of every shift
- Change into clean clothing if work clothes are contaminated
- Leave contaminated clothing at the workplace and obtain training to wash contaminated clothes
Physical Safety Measures for Ammonia Refrigeration
When setting up ammonia refrigeration, companies will need to keep regulations and safety in mind. While there are specific rules to follow, it's helpful to understand the big picture with these four safety measures.
- Detached building: Ammonia refrigeration machinery should be kept in a detached building, or at least the machinery room should have one or more walls with doors leading directly outside. Since people often ask, “is ammonia flammable?" know that, yes, it can be.
- Separate ventilation: Companies should use separate ventilation intake louvers and exhaust devices, with all exhausts venting directly outdoors.
- Sensors: It's also important to install sensors in areas subject to ammonia contamination, testing them at least annually. The alarm should be audible in a constantly attended area, with automatic equipment shut-down capabilities that accompany any alerts of improper ammonia levels.
- Emergency response team: Finally, any company that uses ammonia should have a regularly trained emergency response team. Those individuals should understand the ventilation equipment/systems, the dispersion/diluting procedures, the refrigerant equipment and the preventative maintenance safety equipment required. They should also know how to contain a leak. Business owners should keep updated diagrams available to their workers showing all component locations, with copies in multiple places, including some that are off-site. They should also involve the fire department in planning.
Ammonia refrigeration is better for the environment, but it does need careful monitoring. Following proper protocols will keep employees and the physical plant safe. Learn more about how to mitigate risks in your business and get in touch with an agent today.