EPA 608 Technician Certification: Safety, Cylinders, and Shipping Concepts
Importance ★★★★☆ · 20% (estimate)
Overview
This chapter covers how to protect yourself and others when handling refrigerant and cylinders. It explains the health risks of refrigerant, the protective equipment to wear, how to tell recovery cylinders from disposable ones, safe filling, safe leak testing, and how to label cylinders for shipping.
Most refrigerant vapor is heavier than air, so a large leak in a basement or closed room can push out oxygen and cause suffocation. Breathing high levels can also cause an irregular heartbeat. Liquid refrigerant can cause frostbite, so wear gloves and safety glasses. A self-contained breathing apparatus (SCBA) is for extreme cases such as a large leak in an enclosed area.
Recovery cylinders are refillable, DOT-approved, and painted gray with a yellow top. Never fill one more than 80 percent full of liquid, because the liquid expands as it warms. Disposable cylinders must never be refilled. Never heat a cylinder with an open flame.
Pressurize for leak tests with nitrogen, never oxygen or compressed air, and always use a pressure regulator and a relief valve. Before shipping, label the cylinder with the refrigerant type and the DOT hazard classification.
Key concepts
Recovery cylinder
A refillable, DOT-approved cylinder for recovered refrigerant, painted with a gray body and a yellow top.
Memory tipGray and yellow = recovery.
Source: EPA Section 608 Test Topics · as of 2025
80 percent fill limit
A recovery cylinder should be filled no more than 80 percent full of liquid so there is room for the liquid to expand when it warms.
Memory tipUse a scale or float switch; stop at 80%.
Source: EPA Section 608 Test Topics · as of 2025
Disposable cylinder
A one-trip cylinder for new refrigerant. It must never be refilled, and any refrigerant left inside must be recovered.
Memory tipDisposable = never refill.
Nitrogen leak testing
Use dry nitrogen through a pressure regulator with a relief valve to pressurize a system for a leak test. Never use oxygen or compressed air.
Memory tipOxygen + oil = explosion risk.
Source: EPA Section 608 Test Topics · as of 2025
Oxygen deprivation
Refrigerant vapor is heavier than air and can displace oxygen in low or closed spaces, causing dizziness, unconsciousness, or death.
Memory tipBig leak indoors: ventilate, SCBA if needed.
Shipping labels
A refrigerant cylinder being shipped must be labeled with the type of refrigerant and the Department of Transportation (DOT) hazard classification.
Memory tipName the refrigerant + DOT tag.
Source: EPA Section 608 Test Topics · as of 2025
Often tested
- Wear gloves and safety glasses; liquid refrigerant causes frostbite.
- High vapor levels can cause irregular heartbeat.
- Never heat a cylinder with an open flame.
- SCBA is for large leaks in enclosed spaces.
3 sample questions
Verified practice questions from this unit.
Question 1. What colors identify a refrigerant recovery cylinder?
- ① Solid red
- ② Gray body with a yellow top
- ③ Light blue body with a black top
- ④ Green body with a white top
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Answer: ② Gray body with a yellow top
Key point: Recovery cylinder: gray body, yellow top
Refillable recovery cylinders are painted with a gray body and a yellow top so they are easy to tell apart from new-refrigerant cylinders. They must be DOT-approved.
Wrong choices
- Solid red: Solid red is not the recovery cylinder color code.
- Light blue body with a black top: Light blue is used for some new refrigerant cylinders, not recovery cylinders.
- Green body with a white top: Green and white is not the recovery cylinder color code.
Question 2. A recovery cylinder should never be filled with liquid refrigerant above what level?
- ① 95 percent of its capacity
- ② 60 percent of its capacity
- ③ 90 percent of its capacity
- ④ 80 percent of its capacity
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Answer: ④ 80 percent of its capacity
Key point: Fill recovery cylinders to 80% max
Liquid refrigerant expands when it warms. If a cylinder is too full, the liquid can fill it completely and the pressure can rise enough to burst it. Do not fill a recovery cylinder more than 80 percent full of liquid; use a scale or float switch to check.
Wrong choices
- 95 percent of its capacity: 95 percent is dangerously full.
- 60 percent of its capacity: 60 percent is safe but is not the usual limit.
- 90 percent of its capacity: 90 percent leaves too little room for the liquid to expand.
Question 3. Which gas should be used to pressurize a system for a leak test?
- ① Acetylene
- ② Compressed air
- ③ Oxygen
- ④ Nitrogen
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Answer: ④ Nitrogen
Key point: Leak test with nitrogen, never oxygen or air
Use dry nitrogen to pressurize for leak testing. Never use oxygen or compressed air: oxygen and oil under pressure can explode, and air adds moisture.
Wrong choices
- Acetylene: Acetylene is a flammable fuel gas.
- Compressed air: Compressed air brings in moisture and can create an explosive mix with oil and refrigerant.
- Oxygen: Oxygen can explode when it contacts oil under pressure.
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