CARO Ammonia Refrigeration Safety 2 — Questions and Answers
Question 1: What is the OSHA permissible exposure limit (PEL) for ammonia as an 8-hour time-weighted average?
- 25 ppm
- 35 ppm
- 50 ppm (Correct answer)
- 300 ppm
Correct answer: 50 ppm
OSHA 29 CFR 1910.1000 sets the ammonia PEL at 50 ppm as an 8-hour TWA.
Question 2: At what concentration does NIOSH consider ammonia Immediately Dangerous to Life or Health (IDLH)?
- 50 ppm
- 150 ppm
- 300 ppm (Correct answer)
- 1,000 ppm
Correct answer: 300 ppm
NIOSH lists the ammonia IDLH at 300 ppm.
Question 3: Because ammonia vapor is lighter than air, where should a technician expect a vapor cloud from a warm-gas leak to move first?
- It pools along the floor
- It rises toward the ceiling (Correct answer)
- It stays at breathing height
- It sinks into floor drains
Correct answer: It rises toward the ceiling
Ammonia's molecular weight of about 17 makes dry vapor lighter than air, so it rises.
Question 4: A worker gets liquid ammonia splashed in their eyes. What is the correct first-aid action?
- Apply a neutralizing vinegar solution
- Flush with clean water for at least 15 minutes (Correct answer)
- Cover the eyes with a dry bandage and wait for EMS
- Rinse briefly and apply eye drops
Correct answer: Flush with clean water for at least 15 minutes
Immediate, prolonged flushing with water for at least 15 minutes is the accepted first aid for ammonia eye exposure.
Question 5: Under OSHA's Process Safety Management standard (1910.119), what quantity of anhydrous ammonia triggers PSM coverage?
- 500 lb
- 1,000 lb
- 10,000 lb (Correct answer)
- 50,000 lb
Correct answer: 10,000 lb
Facilities with more than 10,000 lb of anhydrous ammonia in a process are covered by PSM.
Question 6: Which metals should NOT be used in ammonia refrigeration piping or components?
- Carbon steel and stainless steel
- Copper and brass (Correct answer)
- Cast iron and ductile iron
- Aluminum-free steel alloys
Correct answer: Copper and brass
Ammonia attacks copper and copper alloys such as brass, so steel is used instead.
Question 7: Approximately what is the flammable range of ammonia in air by volume?
- 1% to 7%
- 5% to 15%
- 16% to 25% (Correct answer)
- 30% to 45%
Correct answer: 16% to 25%
Ammonia is flammable at roughly 16% to 25% by volume in air.
CARO Ammonia Refrigeration Safety 2
What is the OSHA permissible exposure limit (PEL) for ammonia as an 8-hour time-weighted average?