Often confused · Refrigerant safety
Recovery cylinders: gray body, yellow top, DOT rules
A refrigerant recovery cylinder is the reusable container that used refrigerant goes into during service and travels in afterward; on the EPA 608 it's the gray-bodied, yellow-topped cylinder, and its label, rather than its paint, says what is inside.
Part of Refrigerant safety in the Study guide
Recovery cylinder or disposable cylinder
Reusable recovery cylinders compared with disposable refrigerant cylinders
| Item | Recovery cylinder | Disposable cylinder |
|---|---|---|
| What it carries | Used refrigerant recovered from equipment | New refrigerant from the supplier |
| Paint | Gray body, yellow top | Varies by refrigerant under an industry color guideline, which isn't a Section 608 rule |
| Built for | Repeated filling, DOT-approved for that service | One fill at the factory |
| Takes recovered refrigerant | Yes, within the 80% fill limit | No; the test topics keep disposables out of recovery |
| Shipping label | Refrigerant identity plus the DOT classification tag | Refrigerant identity plus the DOT classification tag |
| Empty cylinder after 2027 | Reused | AIM Act heel-removal rule from January 1, 2028; not on the 608 exam |
Yellow edge: the two columns say different things on this row.
Colors, refilling and labels: EPA test topics, Core safety and shipping, checked October 7, 2026. Heel removal: 40 CFR 84.116, eCFR as of October 5, 2026, an AIM Act rule.
What to read on the cylinder
What the paint does and doesn't tell you
Gray with a yellow top says one thing: the container is a recovery cylinder for used refrigerant. It's the same paint for R-22, R-410A or a cylinder of mixed refrigerant. The contents are identified by the label, which for shipping carries the refrigerant's identity and the DOT classification tag (EPA test topics, Core shipping, checked October 7, 2026). Color codes for new-refrigerant cylinders come from an industry guideline, and the exam doesn't treat them as an EPA rule.
The stamps matter as much as the paint. Water capacity and tare weight set how much the cylinder may hold, and the retest date says whether it is still in service. A cylinder that looks right but carries an expired date or no readable stamps isn't ready for a recovery job.
Before a cylinder goes on the scale, two other topics decide what you put in it: the fill limit, worked out in the 80% fill rule, and keeping refrigerants apart, covered on the mixed refrigerant page. The parent topic, refrigerant safety, has the PPE and pressure items that sit next to cylinders in the Core section.
Cylinder checks
Keep apart what the paint, the stamps and the label each tell you before you pick.
0 right · 0 of 8 answered
Which property makes a refrigerant recovery container different from a standard refrigerant cylinder?
Why each option is right or wrong
Answer: C. They are DOT-approved for higher pressures and have a gray body/yellow top
- AWrong: recovery cylinders are pressure vessels; refrigerant could not be stored in a non-pressurized container.
- BWrong: recovery cylinders have no temperature control; you keep them cool by where you store and use them.
- CCorrect: reusable recovery cylinders are DOT-rated pressure vessels painted with a gray body and yellow top to set them apart from new-refrigerant cylinders.
- DWrong: single-use describes disposable cylinders, which must never be used for recovery.
Recovery containers are specifically designed with a gray body and yellow top, and they are DOT-approved for higher pressures to safely contain used refrigerant that may contain contaminants.
When is it acceptable to use disposable refrigerant cylinders for recovery?
Why each option is right or wrong
Answer: B. Never; only approved recovery cylinders may be used
- AWrong: no amount is small enough; disposable cylinders aren't made to be refilled.
- BCorrect: disposable (single-use) cylinders must never be refilled; recovered refrigerant goes only into DOT-approved recovery cylinders.
- CWrong: the age of the appliance doesn't matter; the ban is on refilling disposable cylinders.
- DWrong: even if the refrigerant is going straight to a reclaimer, it has to travel in a proper recovery cylinder.
EPA's test topics say disposable cylinders are never refilled; recovered refrigerant goes into reusable, DOT-approved recovery cylinders, which are built for it (EPA test topics, checked October 7, 2026).
Which agency is responsible for regulating the transportation of recovered refrigerants?
Why each option is right or wrong
Answer: D. Department of Transportation (DOT)
- AWrong: OSHA covers worker safety on the job, not the shipping of refrigerant cylinders.
- BWrong: EPA regulates refrigerant handling under Section 608, but shipping cylinders falls under DOT hazardous materials rules.
- CWrong: FEMA handles disaster response; it doesn't regulate refrigerant transport.
- DCorrect: DOT regulates how compressed-gas cylinders, including recovered refrigerant, are labeled, specified, and shipped.
The Department of Transportation (DOT) regulates the transportation of hazardous materials, including recovered refrigerants. DOT requirements cover cylinder specifications, labeling, and transportation safety procedures.
What should be done with a recovery cylinder that has reached its hydrostatic test date?
Why each option is right or wrong
Answer: D. It must be recertified through testing or taken out of service
- AWrong: there is no one-year grace period; once a cylinder is past its retest date, it can't be refilled until it is retested.
- BWrong: a supervisor can't extend a DOT retest date; only a requalification test can.
- CWrong: an out-of-date cylinder isn't safe for any refrigerant, including CFCs.
- DCorrect: requalify the cylinder with a hydrostatic retest, or take it out of service.
Recovery cylinders that have reached their hydrostatic test date must be recertified through proper testing before further use, or taken out of service, to ensure they can safely contain refrigerant under pressure.
Which must be verified before a cylinder of recovered refrigerant is transported off-site?
Why each option is right or wrong
Answer: A. The cylinder is properly labeled and valves are leak-tight.
- ACorrect: before transport, the cylinder is labeled with its contents and DOT classification, and its valves are closed and leak-tight (DOT shipping rules, which EPA's test topics list).
- BWrong: no rule requires chilling a cylinder before transport; just keep it away from heat.
- CWrong: filtering out oil is part of recycling or reclaiming, not a condition for shipping.
- DWrong: no minimum pressure is required, and adding pressure would only increase the hazard.
DOT shipping rules (listed in EPA's test topics) call for the cylinder to be in good condition, labeled for the refrigerant it holds, and leak-tight at every valve and connection before it travels.
What must a technician verify before recovering refrigerant into a recovery cylinder?
Why each option is right or wrong
Answer: C. The cylinder's rating, evacuation status, and test date
- AWrong: weight is only one check; the rating, evacuation status, and retest date also matter.
- BWrong: knowing the manufacturer tells you nothing about whether the cylinder is safe to fill.
- CCorrect: confirm the cylinder is rated for the refrigerant's pressure, has been evacuated, and is within its hydrostatic test date.
- DWrong: color helps identify a recovery cylinder, but it doesn't confirm the rating or test status.
A technician must verify the cylinder is rated for the refrigerant type and pressure, and check that it has been evacuated and tested within the required timeframe.
What should a technician do to a recovery cylinder before using it for the first time?
Why each option is right or wrong
Answer: D. Evacuate it to remove air and moisture
- AWrong: recovery cylinders already come gray with a yellow top, and painting them isn't a preparation step.
- BWrong: the tare weight is stamped on the cylinder; the essential first-use step is evacuation.
- CWrong: a nitrogen fill isn't the standard preparation step, and the nitrogen would have to be removed again before recovery.
- DCorrect: evacuate a new cylinder to remove air and moisture so they don't contaminate the recovered refrigerant.
Recovery cylinders must be evacuated before first use to remove air and moisture. The presence of these contaminants would mix with the recovered refrigerant and potentially damage systems where the refrigerant is later used.
What is the primary risk associated with storing recovery cylinders in high-temperature locations?
Why each option is right or wrong
Answer: B. Excessive pressure buildup that can exceed the cylinder's pressure rating
- AWrong: refrigerant doesn't lose its cooling properties from heat; the danger is pressure.
- BCorrect: heat raises the pressure in the cylinder and expands the liquid, which can open the relief valve or rupture the cylinder.
- CWrong: normal storage heat doesn't break down refrigerant; decomposition takes open flame or very hot surfaces.
- DWrong: corrosion comes from moisture and damage over time, not mainly from heat.
Storing recovery cylinders in high-temperature locations primarily risks excessive pressure buildup that can exceed the cylinder's pressure rating. This can activate relief valves or potentially cause cylinder rupture, resulting in refrigerant release and possible injury.
More practice across all four sections: Practice test · Timed mock
Before you fill or ship one
What do the WC and TW stamps on a recovery cylinder mean?
WC is water capacity, the weight of water that fills the cylinder completely; TW is tare weight, the empty cylinder. Together with the refrigerant's density they give the stop weight for a fill, worked through on the 80% fill rule page.
Is a recovery cylinder the same as a reclaim cylinder?
In shop talk the names overlap, but the rule treats recovery and reclaim as different acts (40 CFR 82.152, eCFR as of October 5, 2026). Recovery is removing refrigerant into a container like this one; reclaim is reprocessing it to AHRI 700 purity at a certified reclaimer. The gray-and-yellow cylinder is usually how recovered refrigerant travels to a reclaimer, which is why the recover, recycle, reclaim definitions belong next to this page.