RSES Safety Procedures 4 — Questions and Answers
Question 1: An ammonia (R-717) refrigeration system develops a large leak in a machinery room. What is the FIRST action the technician on site should take?
- Begin recovering ammonia using standard refrigerant recovery equipment
- Activate the emergency shutdown, evacuate personnel, and alert emergency services (Correct answer)
- Increase ventilation fans to dilute the ammonia concentration
- Don a standard dust mask before investigating the leak source
Correct answer: Activate the emergency shutdown, evacuate personnel, and alert emergency services
Ammonia is toxic and immediately dangerous to life at 300 ppm; emergency shutdown, evacuation, and contacting emergency services are the immediate priorities.
Question 2: What is the significance of the ASHRAE 15 standard for refrigeration safety?
- It specifies the maximum operating temperatures for all refrigerant types
- It establishes safety requirements for refrigerating systems including machinery room design and refrigerant limits (Correct answer)
- It defines the correct refrigerant charge weights for residential equipment
- It sets the EPA recovery efficiency requirements for technicians
Correct answer: It establishes safety requirements for refrigerating systems including machinery room design and refrigerant limits
ASHRAE Standard 15 covers safety requirements for refrigerating systems including machinery room ventilation, occupancy classification, refrigerant quantity limits, and equipment requirements.
Question 3: Why should a technician NEVER use oxygen or compressed air to pressure test a refrigeration system?
- These gases are too expensive for routine pressure testing
- Oxygen mixed with refrigerant oil can create a flammable or explosive mixture (Correct answer)
- Air contains humidity that clogs the service valves permanently
- Oxygen at high pressure damages copper tubing instantly
Correct answer: Oxygen mixed with refrigerant oil can create a flammable or explosive mixture
Oxygen mixed with compressor oil creates a potentially explosive combination, and compressed air introduces moisture; only dry nitrogen is safe for pressure testing refrigerant systems.
Question 4: According to EPA Section 608 regulations, which refrigerants are subject to mandatory recovery requirements before servicing equipment?
- Only CFC refrigerants such as R-11 and R-12
- Only HFC refrigerants used in systems with more than 50 pounds of charge
- All refrigerants regulated under Clean Air Act Section 608, including CFCs, HCFCs, and HFCs (Correct answer)
- Only refrigerants with an ODP greater than 0.1
Correct answer: All refrigerants regulated under Clean Air Act Section 608, including CFCs, HCFCs, and HFCs
EPA Section 608 regulations require recovery of all regulated refrigerants—CFCs, HCFCs, and HFCs—from appliances before service, maintenance, or disposal.
Question 5: A refrigeration system shows extremely high discharge pressure but normal suction pressure. What safety risk does this present to the technician?
- Risk of compressor motor burnout causing electrical shock
- Risk of high-side component rupture from overpressure, potentially causing projectile hazards (Correct answer)
- Risk of evaporator freeze-up causing slipping hazards
- Risk of refrigerant undercharge causing compressor cavitation
Correct answer: Risk of high-side component rupture from overpressure, potentially causing projectile hazards
Abnormally high discharge pressure can exceed the design limits of high-side components, risking rupture of fittings, hoses, or vessels and creating dangerous projectile or spray hazards.
Question 6: What is the purpose of an oxygen-depletion sensor in a refrigerant machinery room?
- To monitor refrigerant purity and detect contamination
- To detect when oxygen levels drop below safe limits due to refrigerant displacement, triggering alarms (Correct answer)
- To measure combustion efficiency of gas-fired equipment in the machinery room
- To verify that nitrogen purge gas is not leaking into the machinery room
Correct answer: To detect when oxygen levels drop below safe limits due to refrigerant displacement, triggering alarms
Oxygen-depletion sensors alarm when O2 drops below approximately 19.5%, indicating that refrigerant or other gases have displaced enough oxygen to create an immediately dangerous atmosphere.
Question 7: A technician needs to transport refrigerant cylinders in a service vehicle. Which practice is a safety violation?
- Securing cylinders upright with a strap or chain in the cargo area
- Transporting cylinders in a fully enclosed trunk or passenger compartment without ventilation (Correct answer)
- Using a cylinder cart to move cylinders within the vehicle load area
- Keeping cylinders out of direct sunlight during transport
Correct answer: Transporting cylinders in a fully enclosed trunk or passenger compartment without ventilation
Transporting pressurized refrigerant cylinders in an enclosed, unventilated passenger compartment is dangerous because leaks can displace oxygen or accumulate flammable concentrations.
RSES Safety Procedures 4
An ammonia (R-717) refrigeration system develops a large leak in a machinery room.
What is the FIRST action the technician on site should take?