Refrigerant Cylinder Types
Understanding cylinder types prevents cross-contamination, improper use, and dangerous incidents. All refrigerant cylinders are DOT-regulated pressure vessels.
New Refrigerant Cylinders - Color Codes
| Refrigerant |
Cylinder Color |
Notes |
| R-11 |
Orange |
CFC - rarely seen now |
| R-12 |
White |
CFC - recycled/reclaimed only |
| R-22 |
Green |
HCFC - reclaimed only since 2020 |
| R-123 |
Light gray (with yellow stripe) |
HCFC - chiller refrigerant |
| R-134a |
Light blue (sky blue) |
HFC - automotive and medium-temp |
| R-404A |
Orange (different shade from R-11) |
HFC blend - commercial refrigeration |
| R-407C |
Chocolate (dark brown) |
HFC blend - R-22 retrofit |
| R-410A |
Rose/pink |
HFC blend - residential AC |
| R-32 |
Blue (different shade from R-134a) |
HFC - used in some mini-splits |
| R-1234yf |
Blue-green (teal) |
HFO - automotive AC |
| Nitrogen |
Black (with gray top) |
Non-refrigerant - used for pressure testing |
Recovery Cylinders
Recovery cylinders are specifically designed for storing recovered refrigerant. They are different from new refrigerant cylinders and must not be confused:
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Color: Gray body with yellow collar/top - this is the universal DOT color for recovery cylinders
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Labeling: Must be labeled with the refrigerant type being stored
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Fill limit: Never fill above 80% of water capacity by weight - overfilling creates dangerous overpressure as temperature rises
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Pressure rating: Must be rated for the refrigerant being stored
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Never mix refrigerants - mixing renders the entire contents unrecyclable and unreclaimable
? 80% Fill Limit Is CriticalRefrigerant cylinders must never be filled above 80% of capacity. As temperature increases, liquid refrigerant expands. An overfilled cylinder can become "liquid full" with rising temperature, creating hydraulic pressure that ruptures the cylinder or activates the pressure relief valve uncontrollably. This is a life-threatening hazard.
Cylinder Storage Requirements
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Position: Store cylinders upright (valve up) unless the cylinder is specifically designed for horizontal use
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Temperature: Store in cool, dry, well-ventilated areas away from heat sources. Maximum recommended storage temperature: 125?F (52?C)
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Secured: Chain or strap cylinders to prevent tipping. A falling cylinder with a broken valve becomes a dangerous projectile.
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Segregated: Keep full and empty cylinders separated and clearly labeled. Keep flammable refrigerants (A2L, A2, A3) away from ignition sources.
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Away from exits: Do not block doorways with cylinder storage
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No direct sunlight: Avoid direct sun exposure which can raise cylinder temperature and pressure
Cylinder Transportation
Transporting refrigerant cylinders is governed by DOT regulations (49 CFR):
- Cylinders must have valve protection caps installed during transport
- Cylinders must be secured to prevent movement in the vehicle
- Shipping papers required for quantities above DOT exemption limits
- Do not transport cylinders in an enclosed passenger vehicle - transport in open truck bed or van with adequate ventilation
- Cylinders must display the appropriate DOT labels/placards for the refrigerant hazard class
Cylinder Inspection and Rejection
Before using any cylinder, inspect it. Reject any cylinder showing:
- Corrosion, pitting, or visible damage to the cylinder body
- Damaged or missing valve protection cap
- Damaged valve or valve threads
- Absence of the required DOT requalification date (cylinders must be re-qualified every 5 years)
- Unknown contents - never use an unlabeled or incorrectly labeled cylinder