Free EPA 608 Practice Test · Exam Section
EPA 608 Core Practice Test
30 exam-style questions, one at a time — just like exam day. Score and full explanations at the end. Free, no signup.
Core is the section every EPA 608 candidate must pass — it is not a certification by itself, but no Type certification exists without it. These 30 questions cover the ground the real 25-question Core section draws from: ozone depletion and chlorine chemistry, the Clean Air Act and Montreal Protocol, the Section 608 venting prohibition, recovery, recycle, and reclaim definitions, refrigerant identification and safety, cylinder shipping rules, the refrigerant sales restriction, and the HFC phasedown under the AIM Act. Every explanation tells you why the right answer is right and why the tempting wrong one is wrong.
Want the full exam-day experience instead? Take the free 105-question Universal simulator — it runs this section alongside the other three, in the order the real exam presents them.
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Exam-simulator mode: picking an answer saves it and automatically moves you to the next question. You will not see right/wrong until you finish — just like the EPA 608 exam.
Question 1 of 30.The ozone layer that shields the Earth from harmful ultraviolet radiation is located in which region of the atmosphere?
Prefer to read? All 30 questions with answers
The ozone layer that shields the Earth from harmful ultraviolet radiation is located in which region of the atmosphere?
- The stratosphere (correct answer)
- The mesosphere
- At ground level, where it forms as smog
- The ionosphere
Protective ozone is concentrated in the stratosphere, roughly 9 to 31 miles above the Earth's surface, where it absorbs ultraviolet (UV-B) radiation before it reaches the ground. Ground-level ozone is the tempting distractor because ozone does exist there, but tropospheric ozone is a harmful air pollutant and a component of smog — it does nothing to protect against UV radiation.
A single chlorine atom released from a CFC molecule in the stratosphere can destroy approximately how many ozone molecules?
- One
- About 10
- About 100
- About 100,000 (correct answer)
Chlorine destroys ozone catalytically: after breaking apart an ozone molecule, the chlorine atom is regenerated and attacks again, destroying on the order of 100,000 ozone molecules before it is finally removed from the stratosphere. The answer 'one' is tempting if you assume chlorine is used up like an ordinary reactant, but it is precisely because chlorine is not consumed that even small CFC releases cause serious ozone destruction.
The ozone depletion potential (ODP) of every refrigerant is measured against which reference refrigerant?
- R-12
- R-22
- R-134a
- R-11 (correct answer)
R-11 (CFC-11) is the benchmark, assigned an ODP of exactly 1.0; all other refrigerants are rated relative to it. R-12 is the tempting distractor because it was the most widely used CFC, but its ODP is measured against R-11 just like every other refrigerant. R-22 is an HCFC with an ODP of only about 0.05, and R-134a is an HFC with an ODP of zero.
Which element, released from refrigerant molecules in the stratosphere, is responsible for the catalytic destruction of ozone?
- Hydrogen
- Fluorine
- Chlorine (correct answer)
- Carbon
Chlorine is the ozone-destroying element — it is found in CFC and HCFC refrigerants but not in HFCs such as R-134a and R-410A, which is why HFCs have an ODP of zero. Fluorine is the tempting distractor because it appears in the names of all three refrigerant families, but fluorine does not participate in the catalytic destruction of ozone. Hydrogen and carbon are likewise present in many refrigerants without harming the ozone layer.
R-22 is classified as which type of refrigerant?
- CFC
- HCFC (correct answer)
- HFC
- HFO
R-22 contains hydrogen, chlorine, fluorine, and carbon, making it a hydrochlorofluorocarbon (HCFC) — a Class II substance with a low but nonzero ODP. CFC is the tempting choice because R-22 does contain chlorine, but CFCs such as R-11 and R-12 contain no hydrogen; the hydrogen atom in R-22's molecule is what distinguishes it and shortens its atmospheric life. HFCs and HFOs contain no chlorine at all.
Why do HCFC refrigerants such as R-22 have a much lower ozone depletion potential than CFC refrigerants such as R-12?
- HCFC molecules contain no chlorine atoms
- HCFCs are used only in small appliances such as window units, so far less refrigerant is ever released
- HCFC vapor is too heavy to rise out of the lower atmosphere
- The hydrogen in the HCFC molecule causes most of it to break down before reaching the stratosphere (correct answer)
The hydrogen atom in an HCFC molecule makes the compound chemically less stable, so most HCFC molecules decompose in the troposphere before their chlorine can reach the stratosphere. Saying HCFCs contain no chlorine is the tempting error — R-22 does contain chlorine, which is why its ODP is low but not zero; refrigerants with no chlorine at all are the HFCs.
Under the Clean Air Act, CFC refrigerants such as R-12 and HCFC refrigerants such as R-22 are grouped, respectively, as which classes of ozone-depleting substances?
- CFCs are Class I; HCFCs are Class II (correct answer)
- CFCs are Class II; HCFCs are Class I
- Both are Class I substances
- CFCs are Class A; HCFCs are Class B
Class I substances are the most damaging ozone depleters — CFCs and halons — while the less-damaging HCFCs make up Class II. Reversing the classes is the tempting error; remember that Class I was phased out first (CFC production ended in the U.S. at the end of 1995) precisely because those substances have the highest ODP. 'Class A/Class B' describes ASHRAE toxicity ratings, not Clean Air Act classes.
Under Section 608 of the Clean Air Act, knowingly venting an ozone-depleting refrigerant to the atmosphere while servicing, maintaining, repairing, or disposing of a stationary appliance has been prohibited since:
- July 1, 1992 (correct answer)
- November 15, 1995
- January 1, 2018
- January 1, 2020
The venting prohibition for CFC and HCFC refrigerants took effect July 1, 1992. November 15, 1995 is the tempting distractor because that is the date the prohibition was extended to substitute refrigerants such as HFCs — not the original ban. January 1, 2018 is when the refrigerant sales restriction was extended to HFCs, and January 1, 2020 is when U.S. production and import of R-22 ended.
Which of the following refrigerant releases is permitted under the Clean Air Act's venting prohibition?
- Opening a system to the atmosphere to speed up a repair
- A de minimis release that occurs during a good-faith attempt to recover refrigerant (correct answer)
- Venting an HFC refrigerant, because it has an ozone depletion potential of zero
- Venting the charge of any appliance holding less than five pounds of refrigerant
De minimis releases — the small, unavoidable losses that occur during good-faith recovery, recycling, or safe disposal, such as the puff of vapor escaping when hoses are connected or disconnected — are not violations. Venting an HFC is the tempting answer because HFCs do not deplete ozone, but the prohibition was extended to substitute refrigerants on November 15, 1995, largely because of their high global warming potential. There is no charge-size exemption: even a small appliance's charge must be recovered, not vented.
The American Innovation and Manufacturing (AIM) Act of 2020 requires U.S. production and consumption of HFC refrigerants to be phased down by what amount by 2036?
- 40 percent from baseline levels
- 60 percent from baseline levels
- 85 percent from baseline levels (correct answer)
- 100 percent — a complete ban on HFCs
The AIM Act phases down HFC production and consumption 85 percent below baseline levels by 2036, through stepwise cuts that began with a 10 percent reduction in 2022. A complete ban is the tempting distractor, but the AIM Act is a phasedown, not a phaseout — a limited supply of HFCs remains available for servicing existing equipment. This phasedown drives the industry transition from high-GWP refrigerants like R-410A toward lower-GWP options such as R-32.
The Montreal Protocol is best described as:
- A United States law that prohibits venting refrigerants during service
- An international treaty that phases out the production of ozone-depleting substances worldwide (correct answer)
- An industry standard that sets purity requirements for reclaimed refrigerant
- An international treaty that originally regulated the global warming potential of HFC refrigerants
The Montreal Protocol is the 1987 international agreement committing member nations to phase out production and consumption of ozone-depleting substances such as CFCs and HCFCs; the United States implements it through Title VI of the Clean Air Act. Calling it a U.S. law is the tempting error — the venting prohibition comes from the Clean Air Act, not the treaty itself. HFCs were added only later, by the 2016 Kigali Amendment, because HFCs harm the climate rather than the ozone layer.
Since January 1, 2020, a technician who needs R-22 to service an existing air-conditioning system may legally obtain it from which source?
- Newly manufactured R-22 produced in the United States
- Newly imported R-22 from countries that still produce it
- No source — existing R-22 systems must be retrofitted or replaced immediately
- Recovered, recycled, or reclaimed R-22, or pre-2020 stockpiles (correct answer)
Under the Montreal Protocol's HCFC phaseout schedule, production and import of R-22 for the U.S. market ended January 1, 2020, so servicing now relies on recovered, recycled, or reclaimed refrigerant and pre-2020 stockpiles — which is why recovery of R-22 is so valuable. The claim that existing systems must be retrofitted immediately is the tempting distractor: the phaseout stopped new supply, but it remains perfectly legal to operate and service existing R-22 equipment.
Under the refrigerant sales restriction, who may legally purchase a 25-pound cylinder of R-410A for charging stationary air-conditioning equipment?
- Any adult, because R-410A contains no ozone-depleting chlorine
- Anyone who has completed a manufacturer's installation course
- A technician holding EPA Section 608 certification (correct answer)
- Only technicians holding EPA Section 609 certification
Since January 1, 2018, the sales restriction covers non-exempt substitute refrigerants such as R-410A, so the buyer must hold Section 608 certification (employers may also buy for their certified technicians). 'Any adult' is tempting because R-410A has zero ODP, but the restriction was extended to HFCs anyway; the only consumer exception is small cans of two pounds or less of motor-vehicle refrigerant with self-sealing valves. Section 609 certification covers motor vehicle air conditioning, not stationary equipment.
A wholesaler who sells refrigerant to certified technicians must keep invoices showing the purchaser's name, the date of sale, and the quantity purchased for how long?
- 1 year
- 2 years
- 3 years (correct answer)
- 5 years
EPA regulations require records made under Section 608 — including wholesalers' sales invoices — to be retained for a minimum of three years. Five years is the tempting answer because some business records carry longer retention periods under other laws, but the Section 608 requirement is three years. The same three-year period applies to many other Section 608 records, such as disposal and leak-repair documentation.
Removing refrigerant in any condition from an appliance and storing it in an external container, without necessarily testing or processing it in any way, is the definition of:
- Recovery (correct answer)
- Recycling
- Reclaiming
- Retrofitting
Recovery is simply capturing the refrigerant into an external container — no cleaning or testing is implied. Recycling is the tempting distractor because it also happens in the field, but recycling goes further: it reduces contaminants using oil separation and filter-driers. Reclaiming means reprocessing refrigerant to a purity standard verified by laboratory analysis, and retrofitting means converting a system to run on a different refrigerant.
Before used refrigerant can be sold to a new owner, it generally must be:
- Recycled on-site with a certified recovery machine
- Reclaimed to the AHRI Standard 700 purity specification (correct answer)
- Passed through a filter-drier at least twice
- Stored in a sealed recovery cylinder for at least 30 days
Refrigerant changing ownership generally must be reclaimed — reprocessed to the AHRI Standard 700 purity specification with laboratory verification, something only an EPA-certified reclaimer can perform. Recycling is the tempting answer because it does clean refrigerant, but field recycling equipment cannot verify purity, so recycled refrigerant is limited to reuse in equipment belonging to the same owner. Filter-drier passes and storage time do not establish purity.
Which statement best describes recycled refrigerant?
- Refrigerant that has been chemically analyzed and certified to meet AHRI Standard 700
- Refrigerant that has been vented and recondensed from the atmosphere
- Refrigerant that may be sold freely to any new owner
- Refrigerant cleaned for reuse by oil separation and passage through devices such as filter-driers (correct answer)
Recycling cleans refrigerant in the field using oil separation and single or multiple passes through replaceable-core filter-driers, which reduce moisture, acidity, and particulate matter. The AHRI 700 answer is the tempting one, but laboratory-verified purity is the definition of reclaimed refrigerant, not recycled. Because its purity is never verified, recycled refrigerant normally returns to the same system or another system owned by the same owner rather than being sold.
A technician wants to know the exposure limits, first-aid measures, and safe-handling procedures for a refrigerant before using it. Where is this information found?
- On a pressure-temperature chart
- On the technician's Section 608 certification card
- On the refrigerant's Safety Data Sheet (SDS) (correct answer)
- Stamped on the shoulder of the cylinder
The Safety Data Sheet, required under OSHA's Hazard Communication Standard, lists a substance's hazards, exposure limits, first-aid measures, and handling and storage precautions. The cylinder stamp is the tempting distractor because cylinders do carry required DOT markings, but those identify the cylinder's specification and test dates — not health and safety data. A PT chart gives only saturation pressures and temperatures.
A large refrigerant leak in an enclosed equipment room is dangerous to anyone inside primarily because the vapor:
- Is lighter than air and collects near the ceiling
- Is heavier than air and displaces oxygen in low-lying spaces (correct answer)
- Is toxic at very low concentrations even in ventilated spaces
- Is absorbed rapidly through the skin
Refrigerant vapors are substantially heavier than air — typically two and a half to four times as dense, and roughly five times for low-pressure refrigerants such as R-123 — so they sink and silently displace breathable oxygen near the floor, which is why a technician entering a room after a major release needs a self-contained breathing apparatus (SCBA); an ordinary cartridge respirator supplies no oxygen. 'Lighter than air' is the tempting reversal, and it is exactly wrong: the danger concentrates in pits, basements, and machine rooms, not at the ceiling. Toxicity is a secondary concern — most common refrigerants have low acute toxicity, and the primary killer in an enclosed space is simple oxygen displacement.
To raise system pressure when leak-testing a refrigeration system, a technician should use:
- Compressed shop air
- Oxygen
- Dry nitrogen (correct answer)
- Acetylene
Dry nitrogen is inert and moisture-free, and because it is stored at very high cylinder pressure it must always be used with a pressure regulator and a relief valve downstream of the regulator. Compressed shop air is the tempting choice because it is cheap and available, but air introduces moisture and oxygen and can form a combustible mixture with refrigerant and oil inside the system. Oxygen is worse still — it can explode violently on contact with compressor oil — and acetylene is a fuel gas, never a test gas.
Cylinders used to hold recovered refrigerant are identified by which color scheme?
- Gray body with a yellow top (correct answer)
- White body with an orange top
- Green body with a black top
- Solid yellow body
Recovery cylinders follow the industry convention (AHRI Guideline K) of a gray body with a yellow top or shoulder, which distinguishes them at a glance from the colored disposable cylinders that hold virgin refrigerant. The other schemes are tempting because virgin-refrigerant cylinders have historically carried various brand colors, but none of those identify a recovery vessel. Whatever its color, a cylinder used to transport recovered refrigerant must also be DOT-approved for that service.
A refillable recovery cylinder should never be filled beyond what portion of its capacity?
- 50 percent
- 60 percent
- 80 percent (correct answer)
- 95 percent
The safe fill limit for recovery cylinders is 80 percent of capacity, leaving headspace for the liquid refrigerant to expand as temperature rises. Ninety-five percent is the tempting answer because the cylinder is nowhere near 'full' at 80 percent, but a cylinder that becomes hydrostatically full of liquid has no vapor space left, and further warming builds pressure extremely fast — enough to rupture the cylinder. Many recovery machines use float switches or scales to stop automatically at the 80 percent level.
What should a technician do with a disposable refrigerant cylinder once the usable refrigerant has been withdrawn?
- Refill it with recovered refrigerant for reuse
- Use it as a recovery cylinder, provided it is filled to less than 80 percent
- Discard it in the trash with the remaining vapor inside
- Recover the remaining vapor, render the cylinder useless, and recycle the steel (correct answer)
An 'empty' disposable cylinder still contains refrigerant vapor that must be recovered before the cylinder is marked empty, rendered useless (for example, by opening the valve), and sent for steel recycling. Refilling is the tempting shortcut, but disposable cylinders are non-refillable by design, and refilling one violates DOT regulations and risks rupture — the same reason one can never serve as a recovery cylinder at any fill level. Trashing it with vapor inside is illegal venting.
If a technician recovers R-22 into a recovery cylinder that already contains R-410A, the resulting mixture will most likely have to be:
- Sent for destruction, often at the owner's expense (correct answer)
- Separated back into pure R-22 and R-410A by any local wholesaler at little cost
- Sold as a new refrigerant blend
- Charged into any system that can tolerate either refrigerant
Different refrigerants mixed in one cylinder generally cannot be separated by normal reclamation, so reclaimers will refuse the mixture or charge a substantial fee to have it destroyed. Easy separation is the tempting assumption, but distilling apart refrigerants with overlapping pressure-temperature characteristics is technically difficult and rarely economical. This is why a dedicated, properly labeled recovery cylinder should be used for each refrigerant, and why mixed refrigerant must never be charged into any system.
An electronic leak detector indicates a leak somewhere near a group of fittings, but the exact leak point cannot be identified. What is the best next step to pinpoint the leak?
- Add more refrigerant until the leak becomes audible
- Apply a soap-bubble solution to each joint and watch for bubbles (correct answer)
- Evacuate the system and listen for hissing
- Replace all of the fittings in the suspect area
Electronic detectors are extremely sensitive and excellent for finding the general area of a leak, but refrigerant vapor drifts, so a soap-bubble solution is the standard way to pinpoint the exact joint — bubbles form right at the leak. Adding refrigerant to make the leak louder is the tempting answer, but deliberately charging a known leaking system wastes refrigerant and can amount to venting. Listening to an evacuated system finds only very large leaks, and replacing every fitting is wasteful guesswork.
A comfort-cooling chiller containing 100 pounds of R-22 must have its leak repaired when the annual leak rate exceeds:
- 10 percent of the full charge (correct answer)
- 20 percent of the full charge
- 30 percent of the full charge
- 35 percent of the full charge
For appliances holding 50 or more pounds of an ozone-depleting refrigerant, the leak-rate triggers are 10 percent for comfort cooling, 20 percent for commercial refrigeration, and 30 percent for industrial process refrigeration. The 20 and 30 percent figures are tempting because they are real trigger rates, but they apply to the refrigeration categories, not comfort cooling — comfort cooling has the strictest trigger. Similar leak-repair requirements now also extend to larger HFC appliances under the AIM Act regulations.
To check a recovery cylinder of refrigerant for noncondensables (air), a technician lets the cylinder stabilize at a known room temperature and compares its gauge pressure to a pressure-temperature chart. Air is present in the cylinder if the measured pressure is:
- Significantly lower than the saturation pressure shown on the PT chart
- Exactly equal to the saturation pressure shown on the PT chart
- Significantly higher than the saturation pressure shown on the PT chart (correct answer)
- Fluctuating while the temperature stays constant
A cylinder containing pure saturated refrigerant at a known temperature must sit at the PT chart's saturation pressure; air does not condense at these temperatures, so any air present adds its own partial pressure on top and pushes the reading above the chart value. 'Lower than the chart' is the tempting reversal, but a low reading suggests an undercharged cylinder holding only vapor, not air contamination. This same principle explains why noncondensables in a running system raise head pressure.
A closed cylinder containing both liquid and vapor R-410A warms from 70°F to 100°F. What happens to the cylinder pressure?
- It stays the same, because the cylinder is sealed
- It rises, following the refrigerant's saturation curve (correct answer)
- It falls as the liquid expands
- It changes only if the cylinder is completely full of liquid
With liquid and vapor present, the refrigerant sits at saturation, so pressure is determined entirely by temperature — warm the cylinder and the pressure climbs the PT curve. 'Stays the same because it is sealed' is the tempting intuition, but sealing a container fixes its volume, not its pressure. This relationship is why cylinders must be kept away from heat sources and never warmed with an open flame, and why an overfilled cylinder that goes hydrostatically full can rupture with only a modest temperature rise.
What is the primary purpose of evacuating a refrigeration system to a deep vacuum before charging it?
- To remove the oil charge from the compressor
- To test whether the compressor can pull its rated amperage
- To test the system for leaks
- To remove moisture and noncondensables such as air (correct answer)
Deep vacuum dehydrates the system: lowering the pressure makes any trapped water boil off at room temperature so the vacuum pump can remove it along with air and other noncondensables. Moisture left behind reacts with refrigerant and oil to form corrosive acids and sludge, while noncondensables collect in the condenser and drive up head pressure. Leak testing is the tempting distractor because a vacuum that will not hold does hint at a leak, but pressure testing with nitrogen — not evacuation — is the proper leak test; evacuation exists to clean up the system, and it never removes the oil charge.
Which instrument accurately measures the deep vacuum achieved during system dehydration?
- The compound gauge on a service manifold
- An electronic micron (vacuum) gauge (correct answer)
- A sight glass in the liquid line
- A thermistor-type electronic leak detector
Deep vacuum is measured in microns, and only an electronic micron gauge can resolve the difference between, say, 5,000 microns and the roughly 500-micron level commonly targeted to confirm thorough dehydration. The manifold's compound gauge is the tempting answer because it does read vacuum, but its scale bottoms out around 30 inches of mercury and cannot distinguish a good deep vacuum from a poor one. A sight glass shows refrigerant condition during operation, and a leak detector senses escaping refrigerant, not vacuum level.
FAQ: The EPA 608 Core Exam
Is the EPA 608 Core exam a certification by itself?
No. Core is the foundation section every candidate must pass, but it certifies nothing on its own — it only counts together with at least one Type exam (I, II, or III). One important wrinkle: to earn Universal certification later, your Core must have been taken proctored. An open-book Core (from the Type I open-book route) cannot be applied toward Universal — you would retake Core under a proctor.
What does the Core section actually cover?
Foundation material that applies to every equipment class: ozone depletion and chlorine chemistry, the Clean Air Act and Montreal Protocol, the Section 608 venting prohibition, the definitions of recover, recycle, and reclaim, refrigerant identification and safety, shipping and cylinder rules, the refrigerant sales restriction, and the transition to substitutes under the AIM Act HFC phasedown — including the move from R-410A to lower-GWP A2L refrigerants in new equipment.
Why does this Core practice test have 30 questions when the real section has 25?
Our verified Core bank runs 30 questions, so we give you all of them — five more than the real 25-question section — because Core is the section every single candidate must pass. The passing benchmark here is still 70 percent (21 of 30), matching the regulatory pass mark; on the real exam that works out to 18 of 25 correct.
Are these questions taken from the real EPA 608 exam?
No. Real exam items belong to the EPA-approved certifying organizations (ESCO Institute, Mainstream Engineering, and others) and are confidential — be wary of any site claiming to have them. Our questions are original, written to mirror the style, difficulty, and published EPA test topics for each section. Scoring well here is strong evidence you are ready, not a preview of the exact questions you will see.
What score do I need to pass the real EPA 608 exam?
The regulation sets the pass mark at 70 percent per section, which in practice means 18 of 25 correct (72 percent) on each 25-question section. The one exception is the open-book Type I route, which requires 84 percent — 21 of 25 — in both its Core and Type I sections. Certification never expires once earned, so passing is a one-time job.
Is this practice test really free?
Yes. Every question, explanation, and score report on HVACTechTest is free, with no signup, no credit card, and no trial that expires. Retake any test as many times as you want.
The Other EPA 608 Sections
25 questions
Type I — Small Appliances
Factory-sealed appliances with 5 lb of refrigerant or less: the small-appliance definition and the 90%/80% recovery requirements.
25 questions
Type II — High-Pressure Appliances
Split systems, heat pumps, rooftop units, and supermarket refrigeration: evacuation levels, leak-rate triggers, and P-T relationships.
25 questions
Type III — Low-Pressure Appliances
Centrifugal chillers running in a vacuum: 25 mm Hg evacuation, the 10 psig leak-test ceiling, and ASHRAE 15 equipment rooms.
Scoring above 70%? Time to book the real exam
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