CFC Refrigerant Cylinder & Storage Safety 4 — Questions and Answers
Question 1: Which refrigerant cylinder marking indicates the year the cylinder must next undergo hydrostatic retesting?
- The manufacture date stamped on the collar
- The retest date stamped on the shoulder or collar of the cylinder (Correct answer)
- The color band painted around the cylinder
- The gross weight (GW) marking
Correct answer: The retest date stamped on the shoulder or collar of the cylinder
DOT requires the retest date to be stamped on the cylinder so inspectors and users can confirm the cylinder is within its certification period.
Question 2: A technician wants to store full recovery cylinders in a service van overnight. Which condition is a safety violation?
- Cylinders are upright and secured with a chain
- Cylinders are stored in the enclosed passenger compartment of the van (Correct answer)
- Cylinders are in a ventilated external storage box
- Cylinders have protective valve caps installed
Correct answer: Cylinders are stored in the enclosed passenger compartment of the van
Storing refrigerant cylinders inside an enclosed passenger area is dangerous because a leak could displace oxygen or expose occupants to toxic refrigerant vapors.
Question 3: What does the DOT specification 'DOT-4BA' on a cylinder mean?
- The cylinder is approved for flammable refrigerants only
- It designates a specific cylinder design standard specifying material, wall thickness, and test pressure (Correct answer)
- The cylinder has a 4-bar maximum pressure rating
- It indicates the cylinder was manufactured in the European Union
Correct answer: It designates a specific cylinder design standard specifying material, wall thickness, and test pressure
DOT specification codes like 4BA define the construction standard (material, design pressure, testing requirements) that the cylinder meets.
Question 4: Which practice is required when connecting a refrigerant cylinder to a manifold gauge set to prevent contamination of the refrigerant supply?
- Purge the hose with refrigerant before opening the cylinder valve (Correct answer)
- Connect the hose and immediately open the cylinder valve fully
- Use nitrogen to pressurize the hose before connecting to the cylinder
- Leave the Schrader core removed from all service ports
Correct answer: Purge the hose with refrigerant before opening the cylinder valve
Purging the manifold hose with a small amount of refrigerant before opening the cylinder fully removes air and moisture that could contaminate the refrigerant.
Question 5: Under DOT regulations, non-refillable (disposable) refrigerant cylinders may NOT be:
- Transported by road
- Used by certified technicians for service charging
- Refilled and resold (Correct answer)
- Stored in a climate-controlled room
Correct answer: Refilled and resold
DOT prohibits refilling non-refillable cylinders because they are not designed or tested for repeated pressurization cycles, creating a rupture hazard.
Question 6: When should a technician perform a leak check on a refrigerant recovery cylinder before using it?
- Only after the cylinder is full
- Before each use, especially at valve connections and relief devices (Correct answer)
- Only if the cylinder shows visible rust
- Leak checks on recovery cylinders are not required by regulation
Correct answer: Before each use, especially at valve connections and relief devices
Inspecting recovery cylinders for leaks before each use prevents refrigerant loss and ensures safe operation during recovery procedures.
Question 7: What is the correct procedure when a refrigerant cylinder's fusible plug has melted and released refrigerant?
- Replace the fusible plug in the field and continue using the cylinder
- Evacuate the area, ventilate if possible, and remove the cylinder from service (Correct answer)
- Cool the cylinder with water and reseal the opening with epoxy
- Re-pressurize the cylinder with nitrogen to test integrity
Correct answer: Evacuate the area, ventilate if possible, and remove the cylinder from service
A blown fusible plug signals that the cylinder was overheated; the cylinder must be removed from service and the area evacuated due to refrigerant release hazard.
CFC Refrigerant Cylinder & Storage Safety 4
Which refrigerant cylinder marking indicates the year the cylinder must next undergo hydrostatic retesting?