EPA 608 Core

1. Stratospheric Ozone Depletion

   • Purpose of Ozone Layer: The stratospheric ozone layer shields Earth from harmful ultraviolet (UV) rays from the sun.
   • Ozone Depletion Potential (ODP): This measures how much a substance can destroy ozone in the stratosphere. CFCs (Chlorofluorocarbons) and HCFCs (Hydrochlorofluorocarbons) have high ODP due to chlorine, which is a major contributor to ozone depletion.
   • Health and Environmental Impact:
     • Human Health: Increased UV exposure leads to higher skin cancer rates and more cases of cataracts.
     • Environmental Damage: Causes lower crop yields and damages marine life, especially plankton and coral reefs.
   • Controversy: Some early theories suggested natural sources (like volcanoes) contributed to stratospheric chlorine, but studies found human-made CFCs and HCFCs are the main sources. NASA’s data shows a direct correlation between CFC/HCFC emissions and rising chlorine levels in the stratosphere.

2. How Chlorine Depletes Ozone

   • Ozone Molecule (O₃): Composed of three oxygen atoms.
   • Depletion Process:
     • A chlorine atom from CFC or HCFC molecules breaks off and attacks an ozone molecule, removing one oxygen atom to form chlorine monoxide (ClO) and leaving an O₂ molecule.
     • ClO can collide with another ozone molecule, release its oxygen atom, and continue to destroy up to 100,000 ozone molecules before becoming inactive.
   • Persistence: A single chlorine atom can stay active in the stratosphere for up to 120 years.

3. Types of Refrigerants

   • CFCs (Chlorofluorocarbons): Contain chlorine, fluorine, and carbon; have the highest ODP and severely harm ozone. Examples: R-11, R-12.
   • HCFCs (Hydrochlorofluorocarbons): Similar to CFCs but contain hydrogen, making them slightly less harmful. Examples: R-22, R-123.
   • HFCs (Hydrofluorocarbons): Contain hydrogen, fluorine, and carbon with no chlorine; do not harm the ozone but have high GWP. Examples: R-134a, R-410A.
   • HFOs (Hydrofluoroolefins): Have low GWP and no ODP, with mild flammability. They are suitable for HVACR equipment. Example: R-1234yf.
   • HCs (Hydrocarbons): Made of hydrogen and carbon; have no ODP and low GWP but are highly flammable. Examples: Isobutane (R-600a), Propane (R-290).

4. Global Warming Potential (GWP)

   • Purpose: Compares the warming impact of gases over time, with CO₂ as the baseline (GWP = 1).
   • HFCs: High GWP, impacting climate change.
   • HFOs and HCs: Low GWP; more eco-friendly refrigerant options.

5. Refrigerant Characteristics & ASHRAE Ratings

   • ASHRAE Classification: Refrigerants are categorized based on toxicity (Class A: safer; Class B: more toxic) and flammability (1 = no flammability, 2 = low, 3 = high).
   • Types of Blends:
     • Azeotropic Blends: Behave as single components with constant boiling points.
     • Zeotropic Blends: Have temperature glide, meaning they evaporate/condense at varying temperatures, affecting charging methods.

6. EPA Regulations - Montreal Protocol & Clean Air Act (Section 608)

   • Montreal Protocol: International treaty aiming to phase out substances harmful to the ozone layer.
   • Section 608: Governs refrigerant handling, requiring technicians to be certified to handle and purchase regulated refrigerants. Violations can result in hefty fines and loss of certification.
   • Prohibited Actions: Venting CFCs, HCFCs, and HFCs; topping off R-22 systems with other refrigerants (such as R-410A).

7. Refrigerant Recovery, Recycling, and Reclaiming

   • Recover: Remove refrigerant from a system to store in approved containers.
   • Recycle: Clean refrigerant for reuse within the same owner’s systems.
   • Reclaim: Process refrigerant to meet new product standards (AHRI 700), allowing for resale.

8. Leak Detection

   • Use electronic or ultrasonic detectors and soap bubbles to identify leak locations.
   • Nitrogen is recommended for pressurizing new systems during leak tests. Adding a trace of system refrigerant with nitrogen helps in detecting leaks.

9. System Dehydration

   • Purpose: Removes moisture to prevent acid formation.
   • Evacuation: Typically done to 500 microns or lower, using large-diameter, short vacuum lines to improve efficiency.
   • Indicators of Issues: Rising pressure indicates leaks or moisture; stable low pressure indicates successful dehydration.

10. Safety and Handling Procedures

    • Always wear safety glasses, gloves, and follow equipment guidelines.
    • Avoid using open flames around refrigerants; some refrigerants can release toxic gases if overheated.
    • Use proper grounding when recovering flammable refrigerants.

11. Cylinder Handling and Disposal

    • Filling: Only up to 80% of the cylinder’s capacity.
    • Disposal: Recover all refrigerant before recycling cylinders.
    • DOT Compliance: Follow Department of Transportation (DOT) regulations when transporting cylinders, including labeling and positioning upright.

12. Shipping Regulations

    • DOT requires specific tagging and labeling for cylinders containing used refrigerants.
    • Identify refrigerant type on recovery cylinders to avoid accidental mixing, ensuring safe transport and processing.