Pass608

    EPA 608 Core: the 40 topics, the numbers and the traps

    Core is the 25-question section that sits in every EPA 608 test: Type I, Type II, Type III and Universal. It covers ozone science, the Clean Air Act rules, recovery and reclaim, and shop safety, and EPA lists exactly 40 topics for it on its Test Topics page (last updated Dec 5, 2025).

    Who does what: EPA sets the rules and writes the question bank, and releases that bank "only to approved technician certification programs" (40 CFR 82.161(c)). One of the 87 approved programs on EPA's list (updated Aug 20, 2026) gives you the test and issues your card. Pass608 is an independent study tool. We write original practice questions to EPA's published topics.

    How Core is scored

    • Length. Each Type test is 25 Core questions plus 25 for the Type (50). Universal is 100: Core plus 25 each for Types I, II and III (40 CFR 82 subpart F, Appendix D).
    • Pass mark. 70% on the closed-book test. Most programs score it as 18 of 25 in each section. SkillCat scores 70% overall on each exam and does not carry Core over between exams. A Type I mail-in test needs 84% (21 of 25). Most programs use 84% for open-book Type I too; SkillCat's open-book Type I passes at 70%.
    • Open book. EPA: "Core tests taken as an open book exam cannot be used to get your Universal Certification."
    • Time. EPA sets no time limit; your program does. Our certification hub has each program's rules, with dates.

    The 40 topics in 7 groups

    Numbers 1–40 cover every Core topic on EPA's page, in plain English. Where EPA's wording carries the answer, we quote it.

    1. Ozone and refrigerant families (7 topics)

    1. Chlorine destroys stratospheric ozone.
    2. CFCs and HCFCs contain chlorine.
    3. Telling the families apart. EPA's own examples: "R-12 is a CFC, R-22 is an HCFC, R-134 is an HFC."
    4. Ozone-depletion potential runs CFC > HCFC > HFC.
    5. Atmospheric effects of each refrigerant type.
    6. Health and environmental effects of ozone depletion.
    7. The evidence for ozone depletion and the role of CFCs and HCFCs.

    The numbers behind it: EPA's SNAP tables (updated March 19, 2026) list an ODP of 0 for R-410A, R-134a and R-32, with GWPs of about 2,090, 1,430 and 675. No ozone damage does not mean no climate impact. That is why HFCs now have their own rules under the AIM Act.

    2. Phaseouts and the Montreal Protocol (3 topics)

    1. CFC phaseout. CFCs are Class I substances. "The ban on production and import of other Class I ODS—excluding methyl bromide—took effect on January 1, 1996." Halons ended January 1, 1994 (EPA, updated March 10, 2026).
    2. R-22 phaseout. Production and import of R-22 ended in 2020. Reclaimed and previously produced R-22 can still be used to service existing equipment (EPA Technicians and Contractors FAQ, updated March 10, 2026).
    3. Montreal Protocol. In EPA's words, "the international agreement to phase out production of ozone-depleting substances."

    3. Venting, the Clean Air Act and penalties (5 topics)

    1. No venting during service.
    2. No venting at disposal.
    3. No venting of substitute refrigerants.
    4. The Clean Air Act venting prohibition itself.
    5. The maximum Clean Air Act penalty.

    The dates: Clean Air Act section 608 made knowing venting of CFC and HCFC refrigerant unlawful "Effective July 1, 1992." It extended the ban to substitutes "Effective 5 years after November 15, 1990", which is November 15, 1995 (42 U.S.C. 7671g).

    Some substitutes are exempt. 40 CFR 82.154(a)(1) lists them: carbon dioxide, nitrogen and water "in any application", ammonia in commercial or industrial process refrigeration or absorption units, and propane, isobutane and R-441A in named end uses such as household refrigerators. R-410A, R-134a and the A2Ls (R-32, R-454B) are not on that list. EPA says venting A2Ls "is prohibited" (86 FR 24458, 2021).

    The penalty: $124,426 per day per violation (42 U.S.C. 7413(b); 40 CFR 19.4, for penalties assessed on or after January 8, 2025). No 2026 adjustment had been published in the eCFR dated Sept 21, 2026. Older guides print older limits: $27,500 applied 1997–2004 and $37,500 applied 2009–2015. Separately, EPA may pay an informant up to $10,000 (42 U.S.C. 7413(f)). That figure is not inflation-adjusted.

    4. What the rule covers and who can buy (3 topics)

    1. High- vs low-pressure refrigerants. 40 CFR 82.152 sets the classes by saturation pressure at 104 °F, in psia: low below 45, medium 45–170, high 170–355, very high above 355 (or critical temperature below 104 °F). The CFR's own examples: R-11 and R-123 are low; R-12 and R-134a are medium; R-22 and R-410A are high; R-13 and R-23 are very high.
    2. Covered equipment. EPA's topic wording is "all air-conditioning and refrigeration equipment containing CFCs or HCFCs except motor vehicle air conditioners." Since January 1, 2018, the certification rule also covers "any non-exempt substitute refrigerant" (40 CFR 82.161), so HFCs are in. Motor-vehicle AC is Section 609, a different credential.
    3. The sales restriction. Since January 1, 2018, the ban on selling refrigerant to uncertified buyers covers non-exempt substitutes as well as CFCs and HCFCs (40 CFR 82.154). EPA says only certified technicians may buy them, "with limited exceptions." The DIY exception is small cans of motor-vehicle refrigerant (2 lb or less) with unique fittings and self-sealing valves (EPA, updated March 23, 2026).

    5. Recovery, recycling and reclaim (8 topics)

    1. System-dependent vs self-contained. Self-contained equipment removes refrigerant "without the assistance of components contained in the appliance." System-dependent equipment "requires the assistance of components contained in an appliance" (40 CFR 82.152).
    2. Third-party certification of recovery equipment. Machines must be certified under 40 CFR 82.158. Equipment made or imported after January 1, 2017 is certified under Appendix B3 (non-flammable refrigerants) or B4 (flammable refrigerants) (EPA, updated July 6, 2026).
    3. The reclaim standard. Reclaimed refrigerant must meet Appendix A to subpart F, "based on AHRI Standard 700-2016." AHRI's current edition is 700-2024, but the CFR and EPA's topic list both still name 700-2016.
    4. Recover: "to remove refrigerant in any condition from an appliance and to store it in an external container without necessarily testing or processing it in any way."
    5. Recycle: "to extract refrigerant from an appliance (except MVACs) and clean it for reuse in equipment of the same owner without meeting all of the requirements for reclamation."
    6. Reclaim: "to reprocess recovered refrigerant to all of the specifications in appendix A of this subpart," then verify it with that appendix's lab method (40 CFR 82.152, checked Sept 24, 2026).
    7. Never mix refrigerants.
    8. Recovery speed. EPA names ambient temperature, the size of the recovery or recycling equipment, and hose length and diameter.

    6. Refrigerants, oils and the system (7 topics)

    1. There are no "drop-in" replacements.
    2. Oils. Substitute refrigerants don't mix with many CFC and HCFC lubricants, and the reverse. EPA's examples: esters with R-134, alkylbenzenes for HCFCs.
    3. Fractionation. EPA's definition: the "tendency of different components of blends to leak at different rates." EPA's GreenChill retrofit guideline (EPA 430-R-11-012, Aug 2011, p. 20) adds: "For blend refrigerants in the ASHRAE 400 series, remove liquid from the cylinder to ensure correct composition." That is best-practice guidance, not a regulation.
    4. Refrigerant state (vapor or liquid) and pressure at each point in the cycle, and where cooling happens. EPA's GreenChill fact sheet (May 2014): "Inside an evaporator, liquid refrigerant boils, or evaporates, absorbing heat as it changes to a vapor." "Compressors pump the low pressure vapor refrigerant from the evaporators and compress it to a high pressure and temperature." "The condenser transfers the heat from the high-pressure vapor refrigerant to the surrounding air or a water supply, causing the refrigerant to convert back into a liquid." The metering device then drops the liquid back to low pressure on its way to the evaporator (shop basics, not EPA wording).
    5. Gauges: color codes, ranges and proper use. In the shop, manifold gauge sets are color-coded blue for the low side, red for the high side and yellow for the center hose. That is trade convention, not an EPA rule.
    6. Leak detection.
    7. At the end of service, evacuate to remove air and moisture.

    7. Safety and cylinders (7 topics)

    1. Exposure risks. EPA lists "oxygen deprivation, cardiac effects, frost bite, long-term hazards."
    2. PPE. Gloves and goggles, plus a self-contained breathing apparatus "in extreme cases."
    3. Recovery vs disposable cylinders. Recovery cylinders must be DOT-approved, and EPA's topic list expects you to know their yellow-and-gray color code. Never refill a disposable.
    4. Never fill a cylinder more than 80 percent full.
    5. Pressurizing for leak tests. Use nitrogen, never oxygen or compressed air.
    6. Nitrogen hardware. Use a pressure regulator and a relief valve.
    7. Cylinder labels. Refrigerant identification and the DOT classification tag.

    On colors: AHRI Guideline N-2017 says refrigerant containers "should" be light green-gray (RAL 7044), with a red band on the shoulder or top for flammables, and that "Colors should not be relied upon exclusively" to identify the refrigerant. That is an industry guideline, not a legal rule. Read the label.

    The Core traps

    1. Recover, recycle, reclaim. Recycled refrigerant goes back into "equipment of the same owner." Only reclaim means AHRI 700 spec, verified by analysis.
    2. 80% vs 80%. The 80% cylinder fill limit is a Core safety topic. The 80% and 90% figures for small appliances are Type I recovery requirements (40 CFR 82.156(b)): 80% with equipment made before Nov 15, 1993; with newer equipment, 90% if the compressor runs and 80% if it doesn't; or evacuate to 4 in. Hg vacuum.
    3. Stale penalty figures. $27,500 and $37,500 are history. Know $124,426 and its date. EPA's bank is secret, so we can't tell you which figure a given test form uses. Know the current number and the rule behind it: per day, per violation.
    4. "CFCs and HCFCs only." EPA's topic wording predates 2018. The rule now covers non-exempt substitutes for certification, sales and venting.
    5. Oxygen or shop air for a leak test. Always wrong. Nitrogen, with regulator and relief valve.
    6. "R-22 is banned." Production and import ended in 2020. Servicing with reclaimed or previously produced R-22 continues.
    7. psig vs psia. Pressure classes are defined in psia. Gauges read psig. EPA's Type II topics say to add 14.7 to convert. More on the Type II page.
    8. Open-book Core. It cannot count toward Universal.

    The 2026 question bank

    ESCO Institute offers a "2018" and a "2026" EPA exam. ACHR News reported on September 19, 2026, quoting ESCO, that the new bank adds general-knowledge questions on A2L and A3 refrigerants and that exams from the previous bank "can be administered only through Jan. 1, 2027." EPA has not posted the change on its own pages as of September 24, 2026. EPA wrote in 2021 that its bank "already includes questions concerning A2L refrigerants" (86 FR 24468). Details: the 2026 bank explainer and A2L refrigerants.

    Practice Core

    Every EPA 608 test includes a 25-question Core section, whichever Type you take. Start the free Core section — free account, no card. Paid tiers are one-time: Core + Type II $15, Universal $29 (pricing).

    Sources

    All checked September 23–24, 2026.