CARO Emergency Response and Safety 4 — Questions and Answers
Question 1: An operator closes valves on both ends of a liquid ammonia line without a relief path. What hazard is created?
- Oil logging
- Hydrostatic expansion that can rupture the pipe (Correct answer)
- Compressor slugging
- Non-condensable gas buildup
Correct answer: Hydrostatic expansion that can rupture the pipe
Trapped liquid expands as it warms, building enough pressure to rupture piping or valves.
Question 2: Which skin injury is most associated with direct contact with liquid anhydrous ammonia?
- Electrical burns
- Frostbite combined with chemical burns (Correct answer)
- Sunburn-type rash only
- Allergic hives
Correct answer: Frostbite combined with chemical burns
Liquid ammonia boils at about -28°F and is alkaline, causing both freezing and caustic injuries.
Question 3: What is the approximate odor threshold at which most people can detect ammonia?
- 0.01 ppm
- 5 ppm (Correct answer)
- 150 ppm
- 500 ppm
Correct answer: 5 ppm
Most people detect ammonia's pungent odor at around 5 ppm, well below hazardous levels.
Question 4: Before servicing a compressor, which OSHA standard requires energy sources to be isolated and locked out?
- 29 CFR 1910.147 (Correct answer)
- 29 CFR 1910.132
- 29 CFR 1910.157
- 29 CFR 1910.212
Correct answer: 29 CFR 1910.147
The control of hazardous energy (lockout/tagout) standard is 29 CFR 1910.147.
Question 5: After an ammonia exposure victim is removed to fresh air, which first-aid step is appropriate if clothing is contaminated?
- Leave clothing on to protect the skin
- Remove contaminated clothing and flush skin with water (Correct answer)
- Apply ointment over clothing
- Wrap the victim tightly in a blanket immediately
Correct answer: Remove contaminated clothing and flush skin with water
Contaminated clothing should be removed and the affected skin flushed with plenty of water.
Question 6: An ammonia detector in the machinery room reaches its high alarm setpoint. Which automatic action do codes such as IIAR 2 typically require?
- Start the emergency ventilation and shut down the refrigeration equipment as designed (Correct answer)
- Open all relief valves
- Shut off the lights in the room
- Increase the compressor speed
Correct answer: Start the emergency ventilation and shut down the refrigeration equipment as designed
High-level detection typically activates emergency ventilation and shuts down equipment per the design and code.
Question 7: Where is it best to stage personnel and equipment when approaching an outdoor ammonia release?
- Downwind and downhill
- Upwind and uphill (Correct answer)
- Directly in the vapor cloud for faster access
- Downwind but uphill
Correct answer: Upwind and uphill
Approaching from upwind and uphill keeps responders out of the vapor path.
CARO Emergency Response and Safety 4
An operator closes valves on both ends of a liquid ammonia line without a relief path.
What hazard is created?