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EPA 608 Core
Practice Test

The Core section covers the material every certified technician needs regardless of the equipment they work on: how refrigerants damage the ozone layer and the climate, what the Clean Air Act requires, the difference between recovery, recycling, and reclamation, how to handle and ship cylinders safely, and how to find leaks. Passing Core is a prerequisite for every Type certification, and your Core score does not carry over if you let a Type attempt lapse — you take them together.

30
Questions
25
Per Attempt
70%
To Pass
Lifetime
Cert Validity
Practice
Take the Core Practice Test
25 questions drawn at random from a bank of 30. Every answer comes with an explanation, and you can retake it as many times as you like.
Question 1 of 250 correct so far
Recovery, recycling, and reclamation

Recovering refrigerant as a liquid rather than a vapor is generally preferred because:

Scope
What EPA 608 Core Covers
Refrigerant fundamentals, regulations, safety, and recovery practice.
Ozone depletion and the Montreal Protocol
2 practice questions in the bank below.
Clean Air Act Section 608 and the AIM Act
3 practice questions in the bank below.
Refrigerant classification and substitutes
2 practice questions in the bank below.
The venting prohibition
1 practice question in the bank below.
Recovery, recycling, and reclamation
5 practice questions in the bank below.
Recovery equipment and certification
1 practice question in the bank below.
Cylinders, shipping, and storage
3 practice questions in the bank below.
Leak detection
2 practice questions in the bank below.
Dehydration and evacuation
3 practice questions in the bank below.
Safety and personal protection
5 practice questions in the bank below.
Recordkeeping and sales restrictions
3 practice questions in the bank below.
Who needs this section
Everyone. You cannot earn any Type certification without passing Core.

Key Takeaways

The EPA 608 Core exam is 25 multiple-choice questions and requires 70% to pass. It covers refrigerant fundamentals, regulations, safety, and recovery practice. Certification never expires, and the exam is open-book.

  • Free practice bank: 30 questions, every answer explained
  • 25 questions per attempt, randomized · unlimited retakes
  • Core must be passed alongside any Type section
  • Exam cost is typically $20–$40 at an EPA-approved testing organization
Answer Key
All 30 Core Questions Explained
The full bank with correct answers and the reasoning behind each one. Use it to study before you test, or to review after an attempt.

1. Which element released from CFC and HCFC refrigerants is responsible for destroying stratospheric ozone?

  1. Chlorine
  2. Fluorine
  3. Carbon
  4. Hydrogen
Answer: A — Chlorine
Ultraviolet light breaks the chlorine free from a CFC or HCFC molecule in the stratosphere, and a single chlorine atom then catalyzes the destruction of many thousands of ozone molecules before it is finally removed. Fluorine is present in these molecules but is not the ozone-destroying agent, which is why HFCs — fluorine but no chlorine — have an ozone depletion potential of zero.

2. What does a refrigerant's ozone depletion potential (ODP) of 1.0 indicate?

  1. It destroys 100% of the ozone it contacts
  2. It contributes one ton of CO2 equivalent per pound
  3. It has no effect on the ozone layer
  4. It destroys ozone at the same rate as CFC-11, the reference refrigerant
Answer: D — It destroys ozone at the same rate as CFC-11, the reference refrigerant
ODP is a relative scale with CFC-11 (R-11) set at 1.0. HCFC-22 sits near 0.05 because the hydrogen in the molecule makes it break down in the lower atmosphere before most of it reaches the stratosphere. Global warming potential is a separate scale, referenced to carbon dioxide.

3. Which refrigerant family contains no chlorine and therefore has an ozone depletion potential of zero?

  1. HFCs
  2. HCFCs
  3. CFCs
  4. Halons
Answer: A — HFCs
HFCs such as R-134a and R-410A contain hydrogen, fluorine, and carbon but no chlorine, so they do not deplete ozone. They are still regulated: most have high global warming potentials, which is why the AIM Act is phasing down HFC production, and they remain subject to the Section 608 venting prohibition.

4. Under Section 608 of the Clean Air Act, knowingly venting refrigerant during service, maintenance, or disposal has been prohibited for CFCs and HCFCs since:

  1. January 1, 1990
  2. January 1, 2010
  3. November 15, 1995
  4. July 1, 1992
Answer: D — July 1, 1992
The venting prohibition took effect July 1, 1992 for class I and class II ozone-depleting substances, and was extended to substitute refrigerants such as HFCs on November 15, 1995. Both dates appear on the exam, so read the question carefully: it is asking about CFCs and HCFCs, not substitutes.

5. Which of the following releases is NOT a violation of the venting prohibition?

  1. A de minimis release that occurs while making a good-faith attempt to recover refrigerant
  2. Releasing refrigerant to atmosphere to speed up a system teardown
  3. Opening a system to atmosphere before recovering the charge
  4. Venting a small appliance because it holds less than five pounds
Answer: A — A de minimis release that occurs while making a good-faith attempt to recover refrigerant
The rule recognizes that a small amount of refrigerant escapes when hoses are connected and disconnected even by a careful technician; those de minimis releases in the course of good-faith recovery are not violations. Nothing about a charge being small exempts it — the prohibition applies regardless of appliance size.

6. What distinguishes reclaimed refrigerant from recycled refrigerant?

  1. Reclaimed refrigerant has been passed through a filter-drier on site
  2. There is no technical difference; the terms are interchangeable
  3. Reclaimed refrigerant has been recovered into a DOT cylinder
  4. Reclaimed refrigerant has been reprocessed to AHRI Standard 700 purity and chemically verified
Answer: D — Reclaimed refrigerant has been reprocessed to AHRI Standard 700 purity and chemically verified
Reclamation means reprocessing refrigerant to at least the purity specified in AHRI Standard 700 and verifying it by chemical analysis — work that only an EPA-certified reclaimer can do. Recycling is on-site cleanup, typically oil separation and a filter-drier pass, with no purity verification, so recycled refrigerant may only go back into the same owner's equipment.

7. Refrigerant recovered from one owner's equipment may be placed into a different owner's equipment only if it has been:

  1. Reclaimed to AHRI 700 purity
  2. Filtered through a suction-line drier
  3. Recycled on site with a recovery/recycling machine
  4. Weighed and logged in a recovery record
Answer: A — Reclaimed to AHRI 700 purity
Refrigerant that changes ownership must be reclaimed. Recycled refrigerant may be returned only to equipment belonging to the same owner, because nothing has verified that contaminants, acid, or mixed refrigerants were actually removed.

8. Recovery equipment manufactured after November 15, 1993 must be:

  1. Rated for both low-pressure and high-pressure appliances
  2. Registered annually with the state fire marshal
  3. Inspected by the manufacturer every two years
  4. Certified by an EPA-approved testing organization to meet the applicable evacuation standard
Answer: D — Certified by an EPA-approved testing organization to meet the applicable evacuation standard
Recovery and recovery/recycling equipment built after that date must be tested and certified by an EPA-approved testing organization against the evacuation levels in the rule. Separately, the company that owns the equipment must notify its EPA regional office that it has acquired it and will comply with the rule.

9. How long is a Section 608 technician certification valid?

  1. It does not expire
  2. Five years
  3. Ten years
  4. Three years
Answer: A — It does not expire
Section 608 certification is issued for life under the current rule — there is no renewal, no continuing education, and no expiration date. You do have to keep a copy of the certification available at your place of business, and employers routinely ask to see the card at hire.

10. Since January 1, 2018, the sales restriction on refrigerant applies to:

  1. CFCs only
  2. CFCs and HCFCs only
  3. CFCs, HCFCs, and substitutes such as HFCs
  4. Only refrigerant sold in containers larger than 50 pounds
Answer: C — CFCs, HCFCs, and substitutes such as HFCs
The sales restriction originally covered ozone-depleting refrigerants; the 2016 rule extended it to substitutes including HFCs effective January 1, 2018, so R-410A and R-134a can only be sold to certified technicians. Small cans of refrigerant intended for motor-vehicle air conditioning and fitted with self-sealing valves are the notable exception.

11. A refrigerant recovery cylinder must never be filled beyond what percentage of its volume?

  1. 60%
  2. 70%
  3. 80%
  4. 95%
Answer: C — 80%
The 80% limit exists because liquid refrigerant expands as it warms. A cylinder filled liquid-full has no vapor space to absorb that expansion, and hydrostatic pressure can rupture it. Weigh the cylinder — do not judge fill level by feel — and remember the tare weight is stamped on the collar.

12. What is the correct color coding for a DOT-approved refrigerant recovery cylinder?

  1. White body with a black top
  2. Light blue body with a white top
  3. Green body with a red top
  4. Gray body with a yellow top
Answer: D — Gray body with a yellow top
Gray with a yellow shoulder identifies a recovery cylinder holding used, potentially mixed refrigerant — never assume its contents. Virgin refrigerant cylinders are color-coded by refrigerant, and recovery cylinders must also be DOT-approved and hydrostatically retested on the required schedule.

13. Refrigerant cylinders should never be exposed to temperatures above:

  1. 100°F
  2. 110°F
  3. 125°F
  4. 150°F
Answer: C — 125°F
Above 125°F, cylinder pressure can exceed the relief device setting. This is why you never heat a cylinder with a torch or leave one in a closed van in summer — a warm water bath under 125°F is the acceptable way to raise pressure for charging.

14. Why must nitrogen — not oxygen or compressed air — be used to pressure-test a refrigeration system?

  1. Oxygen combined with compressor oil under pressure can cause a violent explosion
  2. Nitrogen is less expensive than oxygen
  3. Compressed air cannot reach the required test pressure
  4. Nitrogen leaves no residue that interferes with a halide torch
Answer: A — Oxygen combined with compressor oil under pressure can cause a violent explosion
Oxygen and hydrocarbon oil under pressure is an explosive combination, and compressed air carries moisture into the system. Dry nitrogen is inert and dry. Always feed it through a pressure regulator with a relief valve — a full nitrogen cylinder is well over 2,000 psi and will destroy a system, or a technician, without one.

15. What is the primary hazard of a large refrigerant release in an enclosed equipment room?

  1. Refrigerant is flammable and will ignite
  2. Refrigerant is heavier than air and can displace oxygen, causing asphyxiation
  3. Refrigerant reacts with concrete and weakens the floor
  4. Refrigerant condenses on electrical panels and causes short circuits
Answer: B — Refrigerant is heavier than air and can displace oxygen, causing asphyxiation
Most common refrigerants are heavier than air, so a release pools at floor level and in pits, displacing breathable air. That is why ASHRAE Standard 15 requires refrigerant monitors, alarms, and mechanical ventilation in machine rooms — and why you never enter a suspected leak area without ventilating it first.

16. What is produced when refrigerant contacts an open flame or a very hot surface?

  1. Harmless water vapor and carbon dioxide
  2. Nothing — refrigerants are chemically stable at all temperatures
  3. Toxic decomposition products including hydrofluoric and hydrochloric acids and phosgene
  4. Ozone, which replaces what the refrigerant destroyed
Answer: C — Toxic decomposition products including hydrofluoric and hydrochloric acids and phosgene
Thermal decomposition produces acid gases and, from chlorinated refrigerants, phosgene. A sharp, acrid odor near a torch or a running engine is the warning sign. Ventilate and leave — this is a specific reason not to smoke or braze in an area where refrigerant may have collected.

17. Liquid refrigerant contacting skin or eyes causes:

  1. Immediate allergic reaction
  2. Chemical burns from acidity
  3. No injury, since refrigerants are inert
  4. Frostbite, because the liquid boils at a temperature well below freezing
Answer: D — Frostbite, because the liquid boils at a temperature well below freezing
Liquid refrigerant flashes to vapor at atmospheric pressure and absorbs its heat of vaporization from whatever it touches — including skin. Always wear safety glasses and gloves when connecting and disconnecting hoses, and treat contact as frostbite: flush with lukewarm water and seek medical attention.

18. A halide torch leak detector responds only to refrigerants that contain:

  1. Chlorine
  2. Hydrogen
  3. Fluorine
  4. Nitrogen
Answer: A — Chlorine
The flame turns green in the presence of chlorine, so a halide torch works on CFCs and HCFCs but is useless on HFCs like R-410A, which contain no chlorine. It also produces the toxic decomposition products described elsewhere in Core, which is why electronic detectors have largely replaced it.

19. Which leak-detection method is best suited to pinpointing a leak you have already narrowed down to a small area?

  1. Standing in the room and listening
  2. Soap bubble solution applied to the suspect joint
  3. A refrigerant monitor mounted on the machine room wall
  4. Comparing the system's charge weight to the nameplate
Answer: B — Soap bubble solution applied to the suspect joint
Bubble solution is cheap, unambiguous, and precise once you know roughly where the leak is. Electronic detectors and monitors are better at finding the general area; weighing the charge tells you a leak exists but nothing about where. Good practice is to work from broad to narrow.

20. Why is a deep vacuum used to dehydrate a system rather than simply blowing it out with nitrogen?

  1. A vacuum pump filters particulates out of the refrigerant
  2. A vacuum chemically neutralizes moisture
  3. A vacuum lowers the boiling point of water so moisture vaporizes and can be removed
  4. Nitrogen is not permitted inside a sealed system
Answer: C — A vacuum lowers the boiling point of water so moisture vaporizes and can be removed
Water boils at room temperature under a deep enough vacuum, which is the only practical way to get liquid moisture out of a closed system. Nitrogen sweeps help with debris and non-condensables but will not remove water that has already condensed in the lines, and moisture left behind forms acid and freezes at the metering device.

21. A micron gauge is used during evacuation because:

  1. It detects the presence of non-condensable gases directly
  2. It measures the weight of refrigerant removed
  3. It is required by DOT for cylinder transport
  4. A compound gauge cannot resolve pressures in the range where moisture boils off
Answer: D — A compound gauge cannot resolve pressures in the range where moisture boils off
A compound gauge reads in inches of mercury and its last needle-width covers the entire range that actually matters for dehydration. A micron gauge resolves that range — typical practice targets 500 microns and, more importantly, a vacuum that holds after the pump is isolated, which distinguishes a dry system from one still boiling off water or leaking.

22. Recovering refrigerant as a liquid rather than a vapor is generally preferred because:

  1. Liquid recovery is significantly faster
  2. Vapor recovery is prohibited by the rule
  3. Liquid recovery leaves less oil in the system
  4. Vapor recovery damages the recovery machine
Answer: A — Liquid recovery is significantly faster
A pound of liquid moves far faster through a hose than a pound of vapor, so pulling liquid first and finishing on vapor cuts recovery time dramatically on larger systems. Vapor recovery is entirely legal — just slow — and push-pull is the fastest method of all on systems with enough charge to justify it.

23. Before recovering refrigerant into a cylinder that has been used before, a technician should:

  1. Assume the previous contents are compatible and proceed
  2. Verify the cylinder is empty and evacuated, and never mix refrigerants
  3. Add a small amount of oil to the cylinder
  4. Pressurize the cylinder with nitrogen to 150 psig
Answer: B — Verify the cylinder is empty and evacuated, and never mix refrigerants
Mixed refrigerant cannot be reclaimed economically and is usually destroyed at the technician's expense, so a recovery cylinder should be dedicated to one refrigerant and evacuated before reuse. Recovery cylinders also need periodic hydrostatic retesting — check the stamped date before you fill one.

24. The AIM Act of 2020 directs EPA to:

  1. Ban all refrigerants with a global warming potential above 750
  2. Eliminate the venting prohibition for substitutes
  3. Phase down the production and consumption of HFCs by 85% over roughly 15 years
  4. Require annual recertification of Section 608 technicians
Answer: C — Phase down the production and consumption of HFCs by 85% over roughly 15 years
The American Innovation and Manufacturing Act authorizes a stepwise phasedown of HFC production and consumption — not an immediate ban — which is why supply of high-GWP refrigerants tightens and prices rise over time. It also drove the transition to lower-GWP A2L refrigerants in new equipment.

25. Under ASHRAE Standard 34, a refrigerant classified A2L is:

  1. Lower toxicity and non-flammable
  2. Higher toxicity and non-flammable
  3. Higher toxicity and highly flammable
  4. Lower toxicity and mildly flammable with a low burning velocity
Answer: D — Lower toxicity and mildly flammable with a low burning velocity
The letter is toxicity — A is lower toxicity, B is higher — and the number is flammability, with 2L designating mild flammability and a low burning velocity. A2L refrigerants such as R-32 and R-454B are replacing R-410A in new equipment, and they bring specific requirements for leak detection, ventilation, and spark-free service tools.

26. Which record must a certified technician be able to produce?

  1. A copy of their Section 608 certification kept at their place of business
  2. A monthly log of all refrigerant purchased in the past ten years
  3. Written approval from EPA for each recovery job
  4. A state-issued refrigerant handling permit
Answer: A — A copy of their Section 608 certification kept at their place of business
The technician-level requirement is simple: keep proof of certification at your place of business. Heavier recordkeeping — service records, leak-rate calculations, disposal verification — falls on the owners and operators of the appliances and on the companies that hold recovery equipment.

27. A "system-dependent" or passive recovery method may be used only on appliances containing:

  1. Less than 50 pounds
  2. Less than 5 pounds of refrigerant
  3. Less than 15 pounds
  4. Any amount, if time permits
Answer: B — Less than 5 pounds of refrigerant
Passive recovery relies on the appliance's own compressor or internal pressure to push refrigerant into a non-pressurized container, and the rule restricts it to appliances with five pounds or less — that is, small appliances. Anything larger requires self-contained recovery equipment with its own compressor.

28. Non-condensable gases such as air in a refrigeration system will typically cause:

  1. Lower head pressure and improved efficiency
  2. The compressor to run cooler
  3. Higher head pressure and reduced capacity
  4. No measurable effect
Answer: C — Higher head pressure and reduced capacity
Air collects in the condenser, occupies volume that should be condensing refrigerant, and adds its own partial pressure — so head pressure rises, the compressor works harder, and capacity drops. Air also carries moisture, which is the beginning of acid formation. This is why evacuation before charging is not optional.

29. Which of the following is a violation subject to Clean Air Act penalties?

  1. Recovering refrigerant into a DOT-approved recovery cylinder
  2. Selling recovered refrigerant back to the same equipment owner
  3. Using nitrogen to pressure-test a system before charging
  4. Knowingly releasing refrigerant from an appliance being scrapped
Answer: D — Knowingly releasing refrigerant from an appliance being scrapped
Disposal is one of the moments the rule specifically covers — refrigerant must be recovered before an appliance is scrapped, and the last person in the disposal chain has to verify it. EPA can assess substantial daily penalties and pays awards for information leading to enforcement, so this is not a theoretical risk.

30. When evacuating a system, using larger-diameter hoses and removing the Schrader cores primarily:

  1. Reduces restriction so the system reaches a deep vacuum faster
  2. Prevents the vacuum pump from overheating
  3. Is required by the Clean Air Act
  4. Allows the use of a compound gauge instead of a micron gauge
Answer: A — Reduces restriction so the system reaches a deep vacuum faster
At deep vacuum there is almost no pressure difference to move the remaining molecules, so restriction dominates. A Schrader core is a severe restriction at 500 microns, and a quarter-inch hose is not much better. Core removal tools and larger hoses are the difference between a 20-minute evacuation and an all-day one.
Other Sections
Keep Practicing
Practice Test

EPA 608 Type I

Small appliances — factory-sealed systems holding 5 pounds of refrigerant or less.

30 questions
Practice Test

EPA 608 Type II

High-pressure and very high-pressure appliances — residential and commercial AC, heat pumps, and refrigeration.

30 questions
Practice Test

EPA 608 Type III

Low-pressure appliances — centrifugal chillers operating below atmospheric pressure.

30 questions

Read the full EPA 608 certification guide for exam costs, testing organizations, and how to choose between Type I, II, III, and Universal.

FAQ
EPA 608 Core Questions
How many questions are on the EPA 608 Core exam?
The Core section is 25 multiple-choice questions. 25 multiple-choice questions, proctored and open-book. You need 70% — 18 of 25 — to pass, and the same threshold applies independently to each Type section.
What score do I need to pass EPA 608 Core?
You need 70% — 18 of 25 questions — to pass. Each section is scored independently, so passing Core does not offset a failing Core score, and you must pass both to be certified for core work.
Who needs EPA 608 Core certification?
Everyone. You cannot earn any Type certification without passing Core. Refrigerant fundamentals, regulations, safety, and recovery practice.
Is this practice test the real EPA 608 exam?
No. This is free study material written from the published rule in 40 CFR Part 82, Subpart F — it does not reproduce exam content. The real exam is proctored and administered by an EPA-approved certifying organization, and it is open-book, so bring your study guide.
Does EPA 608 Core certification expire?
No. Section 608 certification is issued for life under the current rule. There is no renewal requirement and no continuing education, though you must keep proof of certification at your place of business.
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