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Ammonia is a gas that occurs naturally in the environment and is also manmade. Liquid ammonia is found in many household cleaners. Ammonia is considered a high health hazard because it is corrosive to the skin, eyes, and lungs. Exposure to 300 parts per million (ppm) is immediately dangerous to life and health. Ammonia is also flammable at concentrations of approximately 15 percent to 28 percent by volume in air. When mixed with lubricating oils, its flammable concentration range is increased. It can explode if released in an enclosed space with a source of ignition present, or if a vessel containing anhydrous ammonia is exposed to fire. Ammonia has a low odor threshold (20 ppm), so most people will seek relief at much lower concentrations.
Accidental releases of ammonia from refrigeration facilities have resulted in both injuries and deaths to employees. These injuries and deaths are caused from contact with both liquid and vapor forms of ammonia. Because refrigeration systems operate at elevated pressures, additional care must be taken to maintain and operate these systems so as to prevent releases with potentially catastrophic consequences.
Scope
Ammonia refrigeration is addressed in OSHA standards for general industry.
Regulatory citations
The following standards relate to ammonia refrigeration:
- 29 CFR 1910.38 — Emergency action plans
- 29 CFR 1910.119 — Process safety management of highly hazardous chemicals
- 29 CFR 1910.120 — Hazardous waste operations and emergency response
- 29 CFR 1910.132 — General requirements
- 29 CFR 1910.133 — Eye and face protection
- 29 CFR 1910.134 — Respiratory protection
- 29 CFR 1910.138 — Hand protection
- 29 CFR 1910.307 — Hazardous (classified) locations
- 29 CFR 1910.1000 — Air contaminants
- 29 CFR 1910.1200 — Hazard communication
Key definitions
- Ammonia: A colorless, pungent gas extensively used to manufacture fertilizers and a wide variety of nitrogen-containing organic and inorganic chemicals.
Summary of requirements
Employers are required to:
- Communicate the hazards associated with working with ammonia to appropriate employees.
- Develop an emergency response plan if using refrigeration systems that utilize anhydrous ammonia as a cooling agent.
- Develop a plan for emergency evacuation.
- Complete a compilation of written process safety information before conducting any process hazard analysis (this applies only to systems containing 10,000 lbs. of ammonia or greater).
- Provide — at no cost to employees — personal protective equipment needed to carry out duties.