5 Core Section Practice

Scope of the Core exam

The Section 608 Core exam covers environmental impacts, refrigerant regulations, recovery and handling practices, refrigeration fundamentals, safety, and shipping. The Core exam is shared across certification types, but passing it alone does not authorize every type of equipment work. Technicians who may compromise a refrigerant circuit generally need the appropriate EPA Section 608 certification.

Ozone depletion and climate impact

Stratospheric ozone absorbs harmful ultraviolet radiation. Certain refrigerants that contain chlorine can reach the stratosphere, where ultraviolet light releases chlorine atoms that break down ozone. Increased UV-B exposure can raise risks such as skin cancer and cataracts, and can harm plants and aquatic ecosystems.

Ozone-depletion potential (ODP) compares a substance’s ozone-depleting effect with the reference substance CFC-11. Global-warming potential (GWP) compares a substance’s heat-trapping effect with carbon dioxide over a specified period. Ozone depletion and climate impact are distinct: a refrigerant can have zero ODP and still have climate impact because of its GWP.

For identifying common refrigerants, R-12 is a CFC, R-22 is an HCFC, and R-134a is an HFC. CFCs and HCFCs contain chlorine and can deplete ozone. HFCs do not contain chlorine and have zero ODP, but some have high GWP.

Regulations and certification

Section 608 of the Clean Air Act establishes refrigerant-management requirements for stationary air-conditioning and refrigeration. The regulations generally prohibit intentionally venting ozone-depleting refrigerants and covered substitutes while servicing, repairing, maintaining, or disposing of equipment. Narrow exceptions include small incidental releases during good-faith recovery efforts; these exceptions do not permit deliberate releases. Motor-vehicle air conditioning is principally covered by Section 609.

Technicians must hold the certification appropriate to the equipment:

• Type I: small appliances.

• Type II: high- or very-high-pressure appliances.

• Type III: low-pressure appliances.

• Universal: all three categories.

Certification requires passing an EPA-approved exam through an approved organization. The Core exam must be proctored to count toward Universal certification.

The United States phased out CFC production in the 1990s, and HCFCs were phased out later. Beginning in 2020, new production and import of HCFC-22 for servicing were prohibited. Previously produced, recycled, or reclaimed refrigerant may still be used to service existing equipment. A production or import phaseout does not mean that every existing system must immediately be discarded.

Recover, recycle, and reclaim

Recover means removing refrigerant from equipment and storing it in an external container; the refrigerant need not be tested or cleaned. Recycle means cleaning recovered refrigerant for reuse, generally in equipment owned by the same person, without meeting the full reclamation standard. Reclaim means reprocessing refrigerant to the applicable purity standard and verifying it through the required analysis; reclamation is done by an EPA-certified reclaimer.

If recovered refrigerant changes ownership, it generally must be reclaimed before resale. Do not mix refrigerants: mixed or unidentified refrigerant can be difficult or impossible to reuse and may require special handling. Identify and label refrigerant and cylinders clearly.

Recovery equipment and cylinders

Use EPA-certified recovery equipment where required, follow the manufacturer’s instructions, and meet the applicable evacuation requirements for the appliance. Recovery efficiency can be affected by equipment capacity, ambient temperature, and hose length and diameter. Use suitable hoses and equipment, and avoid unnecessary hose restrictions or length.

At the end of service, a vacuum pump removes air and moisture from the system. This evacuation is distinct from recovering refrigerant into a cylinder.

Use a proper reusable recovery cylinder, not a disposable cylinder, and never fill it beyond its rated safe limit. Refrigerant expands as temperature rises, so overfilling can create dangerous hydraulic pressure. Check the cylinder label and approved capacity; do not rely on color alone to identify the contents.

Refrigeration fundamentals

Refrigerant changes between liquid and vapor as it circulates through a system. In general, it absorbs heat as it evaporates at low pressure and releases heat as it condenses at higher pressure. Pressure and saturation temperature are linked, so a pressure reading is meaningful only when interpreted for the correct refrigerant and conditions.

Do not assume refrigerants are interchangeable or use a substitute as a “drop-in” replacement. Refrigerants may require different oils, materials, components, and service procedures.

Safety and pressure testing

Refrigerants can present asphyxiation, toxicity, frostbite, cardiac, flammability, and pressure-related hazards. A leak in a confined or poorly ventilated area can displace oxygen. Follow the product safety data sheet and equipment instructions, use suitable eye and hand protection, and ventilate the work area. Do not enter an oxygen-deficient or otherwise unsafe area without appropriate training and respiratory protection.

Escaping liquid refrigerant can freeze skin or eyes. Heating refrigerant with a flame or hot surface can produce hazardous decomposition products.

For pressure testing, use dry nitrogen, never oxygen or compressed air. Use a regulator and pressure-relief protection, and do not exceed the equipment’s specified test pressure. Oxygen or air can react with oil or refrigerant and create fire or explosion hazards.

Applying the core distinctions

Use these checks to distinguish the central Core concepts:

• Does R-134a deplete stratospheric ozone? No. As an HFC, it has zero ODP, although it can still have climate impact because of its GWP.

• How do recovery and reclamation differ? Recovery removes refrigerant into an external container; reclamation reprocesses it to a verified purity standard.

• May a technician intentionally vent refrigerant during service? Generally no. Covered refrigerants and substitutes must be recovered; only narrow regulatory exceptions apply.

• Why must a recovery cylinder not be overfilled? Refrigerant expands as it warms, and excess liquid can cause dangerous pressure.

• What gas is used for pressure testing, and what protection is needed? Use nitrogen with a pressure regulator and relief protection; never use oxygen or compressed air.

Keep the distinctions clear: ozone depletion is not the same as climate impact; recovery, recycling, and reclamation are different processes; and refrigerant handling requires approved equipment, appropriately rated cylinders, and attention to health and physical hazards.