28 Core Practice Questions & Answers

1. 1. The protective ozone layer that shields the Earth from ultraviolet radiation is located in which layer of the atmosphere?

   • A.The mesosphere, directly above the ionosphere
   • B.The stratosphere, roughly 6 to 30 miles above the Earth✓ Answer
   • C.The thermosphere, at the outer edge of the atmosphere
   • D.The troposphere, the layer closest to the ground

   The ozone (O3) that absorbs harmful ultraviolet radiation is concentrated in the stratosphere, roughly 6 to 30 miles above the surface. Ozone formed near the ground in the troposphere is not protective at all — it is a pollutant and a component of urban smog, which is why 'good up high, bad nearby' is the standard distinction.

   Source: EPA Section 608 core topic: Environmental Impacts — stratospheric ozone; 40 CFR Part 82 Subpart F, Appendix D (Group 1)Report a problem with this question

2. 2. How can a single chlorine atom released from a CFC molecule destroy an enormous number of ozone molecules?

   • A.It acts as a catalyst: it strips an oxygen atom from ozone to form ClO, is then regenerated, and repeats the cycle over and over✓ Answer
   • B.It makes ozone soluble in water so the ozone rains out of the stratosphere
   • C.It bonds permanently with one ozone molecule and is consumed in that single reaction
   • D.It absorbs ultraviolet light and re-emits it as heat, which burns off the ozone around it

   Chlorine destroys ozone catalytically rather than being used up: Cl + O3 yields ClO + O2, and the chlorine atom is then freed again to attack more ozone, so one atom can destroy thousands of ozone molecules (figures up to about 100,000 are commonly cited). Elevated chlorine monoxide (ClO) measured in the stratosphere is the direct evidence of this chain, and the presence of stratospheric fluorine — which has no natural source — is a key reason the depletion is attributed to manufactured compounds rather than to natural chlorine from sea salt, which dissolves in rain long before it reaches the stratosphere.

   Source: EPA Section 608 core topic: Ozone depletion science (Cl + O3 catalytic cycle); 40 CFR Part 82 Subpart F, Appendix DReport a problem with this question

3. 3. Which statement correctly describes ozone depletion potential (ODP) among the major refrigerant families?

   • A.CFCs have the highest ODP, HCFCs are lower, and HFCs have an ODP of zero✓ Answer
   • B.HCFCs have a higher ODP than CFCs because the added hydrogen makes them more reactive
   • C.HFCs have the highest ODP because they contain fluorine
   • D.All halogenated refrigerants share the same ODP value of 1.0

   ODP is measured against CFC-11 (R-11), which is assigned the reference value of 1.0. CFCs contain chlorine and no hydrogen, so they are extremely stable and carry their chlorine intact to the stratosphere. HCFCs contain hydrogen, which lets much of the molecule break down in the lower atmosphere, giving a far smaller ODP (R-22 is about 0.05). HFCs such as R-134a and R-410A contain no chlorine at all, so their ODP is zero — although they still have a global warming potential.

   Source: EPA Section 608 core topic: ODP of refrigerant families; CFC-11 defined as ODP = 1.0 referenceReport a problem with this question

4. 4. R-134a contains no chlorine and has an ozone depletion potential of zero. Under EPA rules, what does that mean for a technician servicing an R-134a system?

   • A.It may be released as long as the system charge is under 50 pounds
   • B.It is unregulated, because Section 608 covers only ozone-depleting substances
   • C.It may be vented once the charge has been isolated from the rest of the appliance
   • D.Venting it is still illegal, and the recovery, technician certification, and sales rules still apply✓ Answer

   Zero ODP does not mean unregulated. Effective November 15, 1995, EPA extended the venting prohibition from CFCs and HCFCs to substitute refrigerants, including HFCs and HFC blends. Recovery before opening an appliance, use of certified recovery equipment, technician certification, disposal verification, and the sales restriction all apply to HFCs as well; HFCs are regulated because of their global warming potential rather than ozone depletion.

   Source: 40 CFR 82.154(a) — venting prohibition extended to substitute refrigerants effective November 15, 1995Report a problem with this question

5. 5. The Montreal Protocol is best described as:

   • A.An industry standard published by AHRI that sets refrigerant purity levels
   • B.An agreement among U.S. states restricting the sale of refrigerant
   • C.A U.S. federal statute enacted in 1990 that created EPA's refrigerant regulations
   • D.A 1987 international treaty under which participating nations agreed to phase out ozone-depleting substances✓ Answer

   The Montreal Protocol, signed in 1987, is an international agreement — not a U.S. law — committing signatory nations to phase out production of ozone-depleting substances such as CFCs, halons, and HCFCs; it has been strengthened by later amendments (London 1990, Copenhagen 1992, Kigali 2016). The United States implements its treaty obligations domestically through Title VI of the 1990 Clean Air Act Amendments, which is the separate statute that gave EPA authority to write the Section 608 rules.

   Source: Montreal Protocol on Substances that Deplete the Ozone Layer (1987); Clean Air Act Amendments of 1990, Title VIReport a problem with this question

6. 6. A technician services the air conditioning system in a customer's passenger car. Which EPA program governs that work?

   • A.No EPA program; motor vehicles are regulated only by DOT
   • B.Section 609, which covers motor vehicle air conditioning✓ Answer
   • C.Section 612 (SNAP), because vehicle refrigerants are substitutes
   • D.Section 608, because all refrigerant handling falls under it

   Under Title VI of the Clean Air Act, Section 608 covers stationary refrigeration and air conditioning appliances, while Section 609 covers motor vehicle air conditioners (MVACs). Motor vehicle A/C is specifically excluded from the Section 608 rule, and MVAC service requires a Section 609 certification, which is a separate credential from Type I/II/III/Universal.

   Source: Clean Air Act Title VI, Sections 608 and 609; 40 CFR 82.152 (definition of appliance excludes MVAC)Report a problem with this question

7. 7. What is the purpose of EPA's SNAP (Significant New Alternatives Policy) program under Section 612 of the Clean Air Act?

   • A.To review substitutes for ozone-depleting substances and list them as acceptable or unacceptable for specific end uses✓ Answer
   • B.To set the purity specification that reclaimed refrigerant must meet
   • C.To issue production allowances for newly manufactured CFCs
   • D.To certify the technicians who are allowed to handle substitute refrigerants

   SNAP is EPA's review program under Section 612: it evaluates proposed substitutes for ozone-depleting substances on overall risk to human health and the environment — ozone impact, climate impact, flammability, and toxicity — and then lists each substitute as acceptable, acceptable with use conditions, or unacceptable for a particular end use. It is a substance-listing program, not a technician-certification or purity-standard program.

   Source: Clean Air Act Section 612; 40 CFR Part 82 Subpart G (SNAP program)Report a problem with this question

8. 8. Knowingly venting CFC and HCFC refrigerants to the atmosphere during the maintenance, service, repair, or disposal of appliances has been prohibited since:

   • A.November 15, 1995
   • B.January 1, 1990
   • C.July 1, 1992✓ Answer
   • D.January 1, 1996

   The Clean Air Act venting prohibition took effect for class I and class II ozone-depleting refrigerants — the CFCs and HCFCs — on July 1, 1992. The commonly confused companion date, November 15, 1995, is when the same prohibition was extended to substitute refrigerants such as HFCs; January 1, 1996 is the end of U.S. CFC production, which is a different rule entirely.

   Source: 40 CFR 82.154(a); Clean Air Act Section 608(c)(1) — venting prohibition effective July 1, 1992Report a problem with this question

9. 9. The venting prohibition was extended to substitute refrigerants such as HFCs and HFC blends effective:

   • A.July 1, 1992
   • B.November 15, 1995✓ Answer
   • C.November 14, 1994
   • D.January 1, 1996

   Clean Air Act Section 608(c)(2) prohibits knowingly venting substitutes for class I and class II refrigerants effective November 15, 1995, which is why releasing HFCs such as R-134a, R-404A, or R-410A is illegal even though those refrigerants do not deplete ozone. November 14, 1994 is a different milestone — the date by which technicians had to be certified — and July 1, 1992 applies only to CFCs and HCFCs.

   Source: Clean Air Act Section 608(c)(2); 40 CFR 82.154(a) — substitutes covered as of November 15, 1995Report a problem with this question

10. 10. Which of the following refrigerant releases would NOT be a violation of the venting prohibition?

    • A.A technician opens a system and lets the charge escape because the recovery machine is out of service
    • B.A technician adds nitrogen to a system that still holds an R-22 charge so the mixture can be released legally
    • C.A small amount of refrigerant escapes from the hoses when the technician disconnects them after making a good-faith effort to recover the charge✓ Answer
    • D.A shop empties a cylinder holding a mixture of different recovered refrigerants that cannot be reclaimed

    The regulation excepts 'de minimis' releases that occur in connection with good-faith attempts to recover, recycle, or safely dispose of refrigerant — such as the trace amount left in hoses when they are purged or disconnected. Deliberately diluting a refrigerant charge with nitrogen in order to claim an exemption is expressly prohibited, and neither a broken recovery machine nor an unwanted mixed cylinder excuses a release; mixed refrigerant must be sent out for destruction, not vented.

    Source: 40 CFR 82.154(a)(1)–(2) — de minimis releases and prohibition on adding nitrogen to claim the exemptionReport a problem with this question

11. 11. Production and import of CFC refrigerants for use in the United States ended on:

    • A.January 1, 1996✓ Answer
    • B.January 1, 2020
    • C.January 1, 2010
    • D.July 1, 1992

    Under the U.S. phaseout schedule implementing the Montreal Protocol, new production and import of CFCs such as R-11, R-12, and R-502 ended January 1, 1996. The ban applies to new supply, not to use: existing, recovered, and reclaimed CFC stock may still be used to service equipment and may be sold to certified technicians. The 2010 and 2020 dates belong to the separate HCFC-22 phaseout.

    Source: Clean Air Act Title VI phaseout schedule; 40 CFR Part 82 Subpart A — class I substance production ban January 1, 1996Report a problem with this question

12. 12. A technician services and disposes of small appliances, high-pressure equipment, and low-pressure chillers. Which Section 608 certification does that technician need?

    • A.Type I only
    • B.Universal certification, or Type I, Type II, and Type III held individually✓ Answer
    • C.Type II only
    • D.Type III only, because it is the most advanced type

    Section 608 divides technician certification by equipment class: Type I covers small appliances, Type II covers high-pressure and very high-pressure appliances, and Type III covers low-pressure appliances. A technician who works across all three classes must pass all three technical sections, which together with the core section constitutes Universal certification; the types are not ranked, so a higher-numbered type does not include the others.

    Source: 40 CFR 82.161(a) — Type I, II, III and Universal technician certificationReport a problem with this question

13. 13. Which statement about Section 608 technician certification is correct?

    • A.It becomes void when the technician changes employers
    • B.It must be renewed every two years through continuing education credits
    • C.It must be renewed every five years by retaking the core section
    • D.It does not expire, and the technician must keep proof of certification at his or her place of business✓ Answer

    Certification has been required since November 14, 1994, is issued by an EPA-approved certifying program, and carries no expiration date, renewal requirement, or continuing-education obligation. It belongs to the individual technician rather than the employer, and the rule requires that proof of certification be kept at the technician's place of business.

    Source: 40 CFR 82.161(b) and (d) — certification does not expire; proof retained at place of businessReport a problem with this question

14. 14. A parts counter employee is asked to sell a 30-pound cylinder of R-410A to a walk-in customer. What must the employee verify before completing the sale?

    • A.Nothing; the sales restriction applies only to CFCs and HCFCs
    • B.That the customer owns the equipment being serviced
    • C.That the buyer is an EPA-certified technician, or is purchasing on behalf of one✓ Answer
    • D.That the cylinder weighs less than 20 pounds

    The Section 608 sales restriction allows regulated refrigerant to be sold only to technicians certified under Section 608 or Section 609, or to people buying for such a technician, so that refrigerant does not end up in untrained hands. Effective January 1, 2018 the restriction was extended to substitutes including HFCs such as R-410A; the only notable exception is small containers of R-134a holding less than two pounds and equipped with a self-sealing valve, sold for motor vehicle A/C.

    Source: 40 CFR 82.154(c) — refrigerant sales restriction; extended to substitutes effective January 1, 2018Report a problem with this question

15. 15. Recovery and recycling equipment manufactured or imported on or after November 15, 1993 must:

    • A.Be certified by an EPA-approved third-party laboratory as meeting AHRI/ARI Standard 740✓ Answer
    • B.Be inspected annually by the nearest EPA regional office
    • C.Be registered with the state in which it is used
    • D.Meet the AHRI/ARI Standard 700 purity specification

    EPA requires recovery and recycling equipment made or imported on or after November 15, 1993 to be tested and certified by an EPA-approved third-party laboratory (such as UL, Intertek/ETL, or AHRI) against AHRI/ARI Standard 740, which sets the recovery efficiency the machine must achieve; such equipment must also be fitted with low-loss fittings. Standard 700 is a different document — it specifies the purity of reclaimed refrigerant, not the performance of equipment.

    Source: 40 CFR 82.158 — recovery/recycling equipment certification to AHRI/ARI Standard 740, November 15, 1993 cutoffReport a problem with this question

16. 16. A scrap metal recycler receives a household refrigerator that still contains its refrigerant charge. Who is responsible for making sure the refrigerant is removed?

    • A.No one; small appliances are exempt from the disposal rules
    • B.The original equipment manufacturer
    • C.The homeowner who discarded the appliance
    • D.The last person in the disposal chain — the recycler — who must recover the refrigerant or obtain a signed statement that it was already removed✓ Answer

    EPA places the duty on the last person in the disposal chain, because that is the party in a position to keep refrigerant out of the scrap stream. That person must either recover the refrigerant using certified equipment or obtain and retain a signed statement from the supplier confirming that the refrigerant was already recovered. Small appliances are covered by the rule, not exempt from it.

    Source: 40 CFR 82.156(f) — verification of refrigerant removal by the last person in the disposal chainReport a problem with this question

17. 17. How long must the person who takes the final step in the disposal process keep the signed statements verifying that refrigerant was recovered from appliances?

    • A.Thirty days
    • B.Three years✓ Answer
    • C.Ten years
    • D.One year

    The recordkeeping provisions of Subpart F require the verification statements — along with the name and address of the person from whom the appliance was received — to be retained for three years, so that EPA inspectors can confirm after the fact that refrigerant was not simply released when the equipment was scrapped. The same three-year retention period applies to other Section 608 records, such as service invoices showing refrigerant added.

    Source: 40 CFR 82.166 — recordkeeping and reporting; three-year retention of verification statementsReport a problem with this question

18. 18. Under EPA's definitions, to 'recover' refrigerant means to:

    • A.Pull a deep vacuum on a system to remove air and moisture before charging
    • B.Remove it in any condition from an appliance and store it in an external container, without necessarily testing or processing it✓ Answer
    • C.Reprocess it to new-product purity and verify the result by chemical analysis
    • D.Clean it on site by oil separation and filtration so it can be reused in the same owner's equipment

    Recovery is defined simply as removing refrigerant in any condition from an appliance and storing it in an external container, with no requirement to test or process it. Cleaning it on site is recycling, reprocessing it to new-product specification is reclamation, and pulling a deep vacuum is evacuation — three different operations that candidates commonly confuse with recovery.

    Source: 40 CFR 82.152 — definition of 'recover'Report a problem with this question

19. 19. A shop passes recovered R-22 through its recycling machine's replaceable-core filter-driers to remove moisture, acid, and particulates. What may legally be done with that refrigerant?

    • A.It may be returned to equipment belonging to the same owner it came from, but it may not be sold to a different owner✓ Answer
    • B.It may be sold to any certified technician as reclaimed refrigerant
    • C.It must be destroyed, because used refrigerant may never be reused
    • D.It may be sold to a new owner as long as the cylinder is labeled 'recycled'

    On-site cleaning of this kind is recycling, not reclamation: it reduces contaminants but does not verify that the refrigerant meets a purity specification. Recycled refrigerant may be charged back into the same owner's equipment, but only refrigerant that has been reclaimed to AHRI/ARI Standard 700 purity by an EPA-certified reclaimer may change ownership.

    Source: 40 CFR 82.152 (definitions of 'recycle' and 'reclaim'); 40 CFR 82.154 — restriction on transfer of used refrigerantReport a problem with this question

20. 20. Refrigerant that has been reclaimed must:

    • A.Have passed at least three times through a replaceable-core filter-drier
    • B.Meet the purity specification of AHRI/ARI Standard 700, verified by chemical analysis, and be processed by an EPA-certified reclaimer✓ Answer
    • C.Contain no more than 10 percent of the original system oil charge
    • D.Have been removed using passive, system-dependent recovery equipment

    Reclamation means reprocessing refrigerant to the same purity as virgin product, which in practice requires distillation and always requires a chemical analysis of a sample to confirm the AHRI/ARI Standard 700 specification has been met. Only an EPA-certified reclaimer may perform it, and reclamation is the only route by which used refrigerant can lawfully be sold to a different owner.

    Source: 40 CFR 82.152 (definition of 'reclaim'); 40 CFR 82.164 — reclaimer certification and AHRI/ARI Standard 700Report a problem with this question

21. 21. What is the difference between recovery and evacuation?

    • A.Recovery uses a vacuum pump, while evacuation uses the appliance's own compressor
    • B.Recovery removes the refrigerant from the appliance into an external container; evacuation uses a vacuum pump to pull air and moisture out of the opened system before recharging✓ Answer
    • C.They are two names for exactly the same procedure
    • D.Evacuation removes the refrigerant, while recovery removes the compressor oil

    Recovery and evacuation are sequential but distinct steps. Recovery captures the refrigerant charge into an external cylinder so it is not vented. Evacuation (dehydration) happens after the system has been opened and repaired: a vacuum pump lowers the internal pressure so that any water boils at ambient temperature and is drawn out along with non-condensable air, which would otherwise raise head pressure and form acids in the system.

    Source: 40 CFR 82.152 (definition of 'recover'); EPA Section 608 core topic: recovery techniques and dehydration evacuationReport a problem with this question

22. 22. For an appliance containing 50 or more pounds of an ozone-depleting refrigerant, the leak repair requirements are triggered when the annual leak rate exceeds:

    • A.15% for comfort cooling and 35% for commercial refrigeration
    • B.30% for industrial process refrigeration, 20% for commercial refrigeration, and 10% for comfort cooling and all other appliances✓ Answer
    • C.10% for every appliance category, regardless of use
    • D.35% for industrial process refrigeration and 15% for all other equipment

    The leak repair rule applies to appliances with a full charge of 50 or more pounds and sets a trigger rate that depends on how the equipment is used: 30 percent per year for industrial process refrigeration, 20 percent for commercial refrigeration, and 10 percent for comfort cooling and all other appliances. The 35 percent / 15 percent pair appears in older study guides and reflects the pre-2016 thresholds, which are no longer the applicable values.

    Source: 40 CFR 82.157 — leak repair thresholds for appliances containing 50 or more poundsReport a problem with this question

23. 23. When an appliance subject to the leak repair rule exceeds its applicable leak rate, the owner or operator generally must:

    • A.Replace the entire appliance within one year
    • B.Repair the leaks within 30 days and then perform initial and follow-up verification tests confirming the repairs were successful✓ Answer
    • C.Notify EPA of the leak within ten days
    • D.Simply continue adding refrigerant as needed and log each addition

    Exceeding the threshold obligates the owner or operator to repair the leaks — normally within 30 days of discovery — rather than continuing to top off the charge, because repeated additions are exactly the ongoing emissions the rule is meant to stop. The repair must then be proven: an initial verification test performed before the appliance is returned to normal operating pressure, and a follow-up verification test performed after the system is back in operation.

    Source: 40 CFR 82.157(c) and (i) — 30-day repair requirement; initial and follow-up verification testsReport a problem with this question

24. 24. Refrigerant vapor leaking into a closed equipment room is dangerous primarily because:

    • A.It reacts with humidity in the air to form an explosive mixture
    • B.It is lighter than air and collects at the ceiling where the alarms are mounted
    • C.It is heavier than air and settles in low or confined areas, displacing oxygen and causing asphyxiation✓ Answer
    • D.It is highly flammable at ordinary room temperature

    Most refrigerant vapors are considerably heavier than air, so a leak pools in pits, basements, and low areas of a machine room and pushes breathable air out, which can cause oxygen deprivation and suffocation with little warning. This is why ASHRAE Standard 15 requires machine-room ventilation and refrigerant monitors, why the room must be ventilated before entry, and why self-contained breathing apparatus is required to enter a high-concentration atmosphere.

    Source: EPA Section 608 core topic: safety — refrigerant vapor density and oxygen deprivation; ASHRAE Standard 15 machinery room requirementsReport a problem with this question

25. 25. Breathing a high concentration of refrigerant vapor can cause cardiac sensitization. This means that:

    • A.The heart becomes hypersensitive to adrenaline, which can produce an irregular heartbeat or cardiac arrest✓ Answer
    • B.The refrigerant chemically burns lung tissue on contact
    • C.The blood loses its ability to clot
    • D.Body temperature rises rapidly, producing heat stroke

    At high vapor concentrations refrigerants sensitize the heart to the body's own adrenaline, so a sudden surge of adrenaline — from panic or exertion during an emergency — can trigger an irregular heartbeat or cardiac arrest. That is why a victim should be moved to fresh air and kept calm. Liquid refrigerant poses a different hazard, frostbite, on contact with skin or eyes, which is why goggles and butyl or rubber-lined gloves are the baseline PPE.

    Source: EPA Section 608 core topic: safety — cardiac sensitization, frostbite, and personal protective equipmentReport a problem with this question

26. 26. When pressure-testing a refrigeration system for leaks, a technician should use:

    • A.Dry nitrogen fed through a pressure regulator, with a relief valve in the line✓ Answer
    • B.Oxygen, because it is readily available in cylinders
    • C.Refrigerant vapor at full cylinder pressure
    • D.Compressed air from the shop compressor, since it is dry and inexpensive

    Oxygen must never be used: in contact with compressor oil it can detonate. Compressed air must not be used either, because it carries moisture and oxygen into the system. Dry nitrogen is inert and moisture-free, but a nitrogen cylinder holds roughly 2,000 psi, far above any system's design pressure, so it must always be fed through a pressure regulator, with a relief valve downstream in case the regulator fails. Pressurizing with refrigerant alone is also improper, since any leak then vents refrigerant to the atmosphere.

    Source: EPA Section 608 core topic: safety — pressurizing systems with dry nitrogen; ASHRAE Standard 15Report a problem with this question

27. 27. A refillable refrigerant recovery cylinder is identified by which color scheme, and how full may it be filled?

    • A.Blue body with a red top; filled to 80 percent by volume as read on a sight glass
    • B.Green body with a white top; filled to 100 percent by weight
    • C.Gray body with a yellow top or shoulder; never filled beyond 80 percent of capacity by weight✓ Answer
    • D.Entirely yellow; filled to 90 percent by volume

    Refillable recovery cylinders are standardized as gray with a yellow top or shoulder so that recovered refrigerant is not mistaken for virgin product, and they must be DOT-approved (for example DOT 4BA or 4BW). The 80 percent limit exists because liquid refrigerant expands as it warms; a cylinder filled past 80 percent can become liquid-full and rupture from hydrostatic pressure. Fill must be judged by weighing the cylinder on a scale, never estimated.

    Source: EPA Section 608 core topic: refrigerant cylinders; DOT cylinder requirements — gray/yellow recovery cylinder, 80 percent fill limitReport a problem with this question

28. 28. Which of the following practices is acceptable when handling and shipping refrigerant cylinders?

    • A.Shipping a DOT-approved refillable recovery cylinder that was hydrostatically retested within the last five years and is labeled with its contents and hazard classification✓ Answer
    • B.Refilling a disposable (DOT-39) cylinder with recovered refrigerant
    • C.Combining two different recovered refrigerants in one cylinder to save space
    • D.Continuing to use a refillable recovery cylinder whose last hydrostatic test date is twelve years old

    DOT rules require refillable cylinders to be hydrostatically retested and stamped every five years, and every cylinder offered for transport must be labeled both with what it contains and with the correct hazard class — recovered refrigerant normally ships as a Class 2.2 non-flammable gas. Disposable DOT-39 cylinders are one-trip containers that must never be refilled; they are depressurized and rendered unusable before scrapping. Mixing different refrigerants in one cylinder is prohibited because the mixture cannot be reclaimed and must be paid to be destroyed.

    Source: 49 CFR Parts 173 and 180 — DOT cylinder marking, Class 2.2 labeling, five-year hydrostatic retest, DOT-39 single-use restrictionReport a problem with this question

Practice questions modeled on the EPA Section 608 Technician Certification content (Clean Air Act §608; 40 CFR Part 82). Not affiliated with or endorsed by the U.S. Environmental Protection Agency or any approved certifying organization. Study the official EPA program materials before testing. Official EPA 608 →