Refrigerant Gas Cylinders

Overview and Use 

Refrigerant gas cylinders are used for transporting gases used cooling systems such as air conditioning systems and refrigerators to absorb and release heat. 

Refrigerant gases can be flammable and/or toxic.  Refrigerant gas cylinders marked with a red top or stripe contain flammable gases in accordance with industry standards, see Refrigerant Gas Cylinder Label And Color Codes below.

Design and Construction 

Refrigerant gas cylinder design and construction include disposable (single-use, DOT-39), reusable, and recovery cylinders.  They vary in size from 1lb to 1,000 lbs or more.  

• Disposable Cylinders: Non-refillable, DOT-compliant (DOT-39), single-use containers for adding refrigerant to systems, designed to be recycled after use to prevent refrigerant release.
• Reusable Cylinders: Multiple use cylinders that meet DOT DOT-4BA, DOT-4BW specifications or ASME certifications for larger tanks. 
• Recovery Cylinders: Cylinders used to capture/receive refrigerants when they are removed from a system during system servicing/repair.  They featuring specific valve systems to allow refrigerants to be added to the cylinder in the field by a pump. 

PHOTO: Refrigerant gas cylinders: a. disposable DOT spec 39, b. resusable DOT spec 4BA, c. recovery cylinder, d. Duel certified DOT cylinder and ASME tank. 

Common Types of Refrigerant Gases

• Hydrofluorocarbons (HFCs): Widely used replacements for CFCs/HCFCs, like R-134a (cars, chillers) and R-410A (AC), but are being phased down due to high global warming potential (GWP). 
• Hydrochlorofluorocarbons (HCFCs): Like R-22, these were transitional but are being phased out due to ozone impact.
• Chlorofluorocarbons (CFCs): Older types (e.g., R-12) phased out under the Montreal Protocol due to severe ozone depletion.
• Natural Refrigerants including: 
  • • Ammonia (R-717): Used in large industrial cooling, highly efficient but toxic.
    • Carbon Dioxide (R-744): Gaining popularity for its low GWP.
    • Hydrocarbons: Like Propane (R-290) and Isobutane, used in smaller systems

Refrigerant Gas Cylinder LabelsColor, Label, and Color CodesMarkings 

Color coding of refrigerant gas cylinder should comply with Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Guideline N .   Previously, common refrigerant gasses were each assigned a specific cylinder color. AHRI discontinued specific cylinder colors for each refrigerant cylinder, except R134a.  New refrigerant gas cylinder are normally painted a standard grey. The consumer box or cylinder label may continue to use previous color for marketing purposes. 

Reading the cylinder label is the primary method for identification/recognition of refrigeration cylinders. 

PHOTO: a. previous refrigerant gas cylinders with discontinued color coding, b. new refrigerant gas cylinders with updated color code and label, c. example of a refrigerant gas cylinder label with color coded background. 

Flammable  Markings 

Cylinders containing a flammable refrigerant gas (according to AHRI definitions) should be me marked with a red top of red stripe.  

PHOTO: Refrigerant gas cylinders with a red top or red stripe to indicate a flammable refrigerant gas in accordance with AHRI definitions. 

Flammable gases used as a refrigerant are not odorized.  

Refrigerant Cylinder Markings 

Reusable refrigerant gas cylinder markings that meet DOT specifications must be stamped with information required by DOT.  

See Also Propane Cylinder Markings for more detailed information. 

 

 

 

Refrigerant Recovery Cylinders 

Refrigerant gas recovery cylinders may also be called reclaim cylinders.   They are intended to for the recovery, storage, and transport of spent refrigerant gas from HVAC and refrigeration systems.  

Recovery vesselsCylinder Colors 

• Yellow Top - recovery cylinder 
• Yellow Top and Red stripe -recovery of flammable cylinder 
• Orange Top - Commonly used for recovery of R404A.  Orange is the AHRI color associated with R404A. 
• Black Top - Recovery of a refrigerant gas 

PHOTO: a. refrigerant gas recovery cylinder, b. flammable refrigerant recovery, c. recovery of R404A, d. recovery of refrigerant gas contaminated with oil. 

Warning,Refrigerant maygas berecovery cylinders are commonly used in legal and illegal marijuana THC extraction labsoperations to store and reclaim butane due to the gas and vapor valve set up.  See also THC Extraction - Butane (BHO) Methods

 

Valves and Fittings 

• It features a Y-valve design for handling both liquid and vapor.

This

 cylinder

features

Float Switch 

A recovery vessel float sensor is a floatliquid switchlevel switch, often used in HVAC/refrigerant recovery tanks, that enablesautomatically automatic power-offdetects when the tank reaches a set fill level (usually 80%) ofand signals the capacityrecovery isequipment recovered,to effectivelyshut off, preventing overfilling

and ensuring safe operation, typically using a buoyant float that activates a reed switch inside the tank, connecting to the recovery machine via a cable and connector. 

 

 

Similar Cylinders 

Helium,DOT partyspecification containers39 disposable cylinders are used to store and transport gases other than refrigerant gases including helium, zero air, calibration gases, or welding gases. 

PHOTO: DOT Spec 39 disposable cylinders used for helium to inflate ballons are available in a variety of colors and may resemble refrigeration gas cylinders. 

Helium cylinders may be used for as part of a chemical suicide. See also Chemical SuicidesSuicide - Helium Inhalation Method 

 

PHOTO: DOT spec 39 disposable cylinders used for other industrial/specialty gases such as a. zero air and b. calibration gas may resemble a refrigerant gas cylinder.