CARO - Certified Assistant Refrigeration Operator Ammonia Refrigeration Safety Questions and Answers — Questions and Answers
Question 1: A facility has an ammonia refrigeration system containing 12,000 pounds of anhydrous ammonia. Which of the following OSHA standards is the primary regulation they must follow for safety management?
- The General Duty Clause
- 29 CFR 1910.119 - Process Safety Management (PSM) (Correct answer)
- 29 CFR 1910.134 - Respiratory Protection
- 29 CFR 1910.120 - HAZWOPER
Correct answer: 29 CFR 1910.119 - Process Safety Management (PSM)
OSHA's Process Safety Management (PSM) standard (29 CFR 1910.119) is required for facilities that have more than 10,000 pounds of anhydrous ammonia. This standard outlines requirements for managing hazards associated with processes using highly hazardous chemicals.
Question 2: An operator is responding to an ammonia leak in a machinery room where the ammonia concentration is unknown but a visible cloud is present. What is the minimum level of Personal Protective Equipment (PPE) required for entry?
- Level C: Full-face air-purifying respirator and chemical-resistant clothing
- Level D: Standard work uniform with safety glasses and gloves
- Level B: Self-contained breathing apparatus (SCBA) with chemical-resistant clothing
- Level A: Fully encapsulating, vapor-tight suit with a self-contained breathing apparatus (SCBA) (Correct answer)
Correct answer: Level A: Fully encapsulating, vapor-tight suit with a self-contained breathing apparatus (SCBA)
Level A protection is required when the greatest potential for exposure to hazards exists, such as an unknown concentration or a visible vapor cloud, providing the highest level of skin, respiratory, and eye protection. It includes a positive-pressure SCBA and a totally encapsulated, chemical- and vapor-protective suit.
Question 3: According to IIAR standards, what is the required action for the emergency ventilation system in an ammonia machinery room when an ammonia detector is activated at a concentration of 150 ppm?
- A visual alarm should activate, but the fans remain off.
- The ventilation system must automatically activate. (Correct answer)
- An operator must manually start the emergency fans within 5 minutes.
- The system should shut down all power to the machinery room.
Correct answer: The ventilation system must automatically activate.
IIAR standards, such as IIAR 2, mandate that the mechanical exhaust ventilation system must be automatically activated when an ammonia leak detection system registers a concentration of 150 ppm. This ensures a rapid response to ventilate the space and reduce the concentration of ammonia.
Question 4: During a routine tour, a Certified Assistant Refrigeration Operator (CARO) discovers a small, weeping leak from a valve stem packing nut. There is a faint smell of ammonia, but no visible cloud, and the area's ammonia detector is not in alarm. What is the most appropriate initial action?
- Immediately activate the full emergency shutdown for the entire facility.
- Attempt to tighten the packing nut using a standard adjustable wrench.
- Evacuate the machinery room and call 911.
- Notify the supervising operator or chief engineer immediately and keep a safe distance. (Correct answer)
Correct answer: Notify the supervising operator or chief engineer immediately and keep a safe distance.
As an assistant operator, the correct protocol for a non-emergency, or incidental, release is to report it immediately to a supervisor. Attempting a repair without authorization or proper procedure could worsen the leak. A full emergency shutdown is not warranted for a minor, manageable leak, and calling 911 is premature before the situation has been assessed by a qualified senior operator.
Question 5: Which of the following is a key requirement for an emergency shutdown procedure in an ammonia refrigeration facility?
- It must be reviewed and updated every 10 years.
- Only certified emergency responders are allowed to initiate a shutdown.
- It must define conditions for shutdown and assign responsibility to qualified operators. (Correct answer)
- The procedure must be posted only in the main office.
Correct answer: It must define conditions for shutdown and assign responsibility to qualified operators.
Both OSHA PSM and IIAR standards require that written operating procedures include emergency shutdown protocols. These procedures must clearly state the conditions under which a shutdown is necessary and assign shutdown responsibility to specific, qualified operators to ensure it is done safely and effectively.
Question 6: The IIAR 2 standard specifies requirements for the safe design of ammonia refrigeration systems. What is the minimum required discharge velocity for emergency ventilation fans from a machinery room?
- 500 feet-per-minute
- 1,000 feet-per-minute
- 2,500 feet-per-minute (Correct answer)
- 5,000 feet-per-minute
Correct answer: 2,500 feet-per-minute
The IIAR-2 standard requires emergency ventilation fans to discharge ammonia vapor upwards at a minimum velocity of 2,500 feet-per-minute. This high velocity helps propel the ammonia high into the atmosphere, promoting rapid dilution and dispersal to minimize risk at ground level.
