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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.

100
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 100. Every answer comes with an explanation, and you can retake it as many times as you like.
Question 1 of 250 correct so far
Clean Air Act Section 608 and the AIM Act

Which type of certification does a technician need to work on all sizes and types of equipment?

Scope
What EPA 608 Core Covers
Refrigerant fundamentals, regulations, safety, and recovery practice.
Ozone depletion and the Montreal Protocol
8 practice questions in the bank below.
Clean Air Act Section 608 and the AIM Act
10 practice questions in the bank below.
Refrigerant classification and substitutes
9 practice questions in the bank below.
The venting prohibition
8 practice questions in the bank below.
Recovery, recycling, and reclamation
13 practice questions in the bank below.
Recovery equipment and certification
7 practice questions in the bank below.
Cylinders, shipping, and storage
10 practice questions in the bank below.
Leak detection
8 practice questions in the bank below.
Dehydration and evacuation
8 practice questions in the bank below.
Safety and personal protection
11 practice questions in the bank below.
Recordkeeping and sales restrictions
8 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: 100 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 100 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.

31. In what year was the Montreal Protocol on Substances that Deplete the Ozone Layer originally signed?

  1. 1979
  2. 1996
  3. 1992
  4. 1987
Answer: D — 1987
The Montreal Protocol was signed in 1987 and is the international agreement that set the phaseout schedules for ozone-depleting substances. 1992 and 1996 are dates people often confuse with it: 1992 is when the U.S. venting prohibition took effect, and 1996 is when U.S. CFC production ended.

32. Where in the atmosphere does the ozone layer that the Montreal Protocol protects sit?

  1. The troposphere
  2. At ground level
  3. The mesosphere
  4. The stratosphere
Answer: D — The stratosphere
The protective ozone layer is in the stratosphere, roughly 10 to 30 miles up, where it absorbs ultraviolet-B radiation. Ozone at ground level in the troposphere is a pollutant and a component of smog — it is chemically the same molecule but it does nothing to shield the surface from UV.

33. Increased ultraviolet-B radiation reaching the earth is associated primarily with which human health effect?

  1. Hearing loss
  2. Bone density loss
  3. Kidney failure
  4. Skin cancer and cataracts
Answer: D — Skin cancer and cataracts
Thinning stratospheric ozone lets more UV-B through, and the documented consequences are increased skin cancers, cataracts, and suppressed immune response, along with damage to crops and to marine phytoplankton. This is the health rationale behind the entire Section 608 program.

34. A refrigerant is described as having a high GWP but an ODP of zero. What does that combination mean?

  1. It is harmless and unregulated
  2. It damages ozone but not the climate
  3. It can be vented legally
  4. It does not deplete ozone but does contribute to climate change
Answer: D — It does not deplete ozone but does contribute to climate change
An ODP of zero means the molecule carries no chlorine or bromine to attack stratospheric ozone, which is true of HFCs. A high GWP means it still traps heat far more effectively than carbon dioxide. That pairing is exactly why HFCs escaped the Montreal Protocol phaseout but are now being phased down under the AIM Act — and why venting them is still illegal.

35. Why does an HCFC generally have a lower ozone depletion potential than the CFC it replaced?

  1. It contains no fluorine
  2. It contains bromine instead of chlorine
  3. It is heavier than air
  4. The added hydrogen makes it break down in the lower atmosphere before much of it reaches the stratosphere
Answer: D — The added hydrogen makes it break down in the lower atmosphere before much of it reaches the stratosphere
The hydrogen atom in an HCFC gives the molecule a reaction pathway in the troposphere, so a large share of it is destroyed before it can rise to the stratosphere and release chlorine. Less chlorine delivered to the ozone layer means a lower ODP — but not zero, which is why HCFCs were phased out too, just on a later schedule.

36. Which refrigerant has the highest ozone depletion potential?

  1. R-134a
  2. R-22
  3. R-410A
  4. R-12
Answer: D — R-12
R-12 is a CFC and carries an ODP of 1.0, the reference value against which all others are measured. R-22 is an HCFC at roughly 0.05, while R-134a and R-410A are HFC-based and have an ODP of zero because they contain no chlorine at all.

37. Under the AIM Act, what is EPA phasing down?

  1. Hydrochlorofluorocarbons
  2. Carbon dioxide
  3. Ammonia
  4. Hydrofluorocarbons
Answer: D — Hydrofluorocarbons
The American Innovation and Manufacturing Act of 2020 directs EPA to phase down production and consumption of hydrofluorocarbons by 85% by 2036. HCFCs were already handled under the Montreal Protocol and Title VI; the AIM Act is the authority aimed specifically at high-GWP HFCs such as R-410A and R-134a.

38. A technician certification issued under Section 608 is valid for how long?

  1. Two years
  2. Five years
  3. Ten years
  4. For life, with no renewal requirement
Answer: D — For life, with no renewal requirement
Section 608 technician certification does not expire and there is no continuing-education or renewal requirement attached to it. That is unlike NATE, which runs on a two-year cycle. Losing the card is a paperwork problem — you request a duplicate from the certifying organization — not a re-testing one.

39. Which agency administers the Section 608 technician certification program?

  1. OSHA
  2. The Department of Labor
  3. The Department of Transportation
  4. The Environmental Protection Agency
Answer: D — The Environmental Protection Agency
EPA administers Section 608 under Title VI of the Clean Air Act and approves the organizations that write and proctor the exams. OSHA governs workplace safety and DOT governs cylinder transport — both touch this work, but neither issues the 608 card.

40. What is the maximum civil penalty structure Congress attached to knowingly venting refrigerant in violation of Section 608?

  1. A written warning only
  2. A flat $500 fine
  3. Loss of certification only
  4. Fines that can reach tens of thousands of dollars per day, per violation
Answer: D — Fines that can reach tens of thousands of dollars per day, per violation
The Clean Air Act authorizes substantial civil penalties assessed per day and per violation, and the figures are adjusted for inflation over time. EPA also pays awards for information leading to enforcement. Treating a vented charge as a minor infraction badly misreads the exposure.

41. Who is legally responsible for making sure refrigerant is recovered before an appliance is scrapped?

  1. Only the EPA
  2. Nobody, once the appliance is out of service
  3. Only the original equipment manufacturer
  4. The last person in the disposal chain, unless they verify recovery already happened
Answer: D — The last person in the disposal chain, unless they verify recovery already happened
The rule places the obligation on the final person in the disposal chain — the scrap dealer or recycler — but it lets them discharge it by obtaining signed verification that refrigerant was already recovered by a certified technician. That is why the signed statement matters: it moves the liability, and without it the last handler owns the violation.

42. Does Section 608 certification authorize a technician to purchase refrigerant?

  1. No, purchase requires a separate license
  2. Only for small appliances
  3. Only with an employer letter
  4. Yes — certified technicians may buy regulated refrigerant, which uncertified people may not
Answer: D — Yes — certified technicians may buy regulated refrigerant, which uncertified people may not
The sales restriction limits purchase of regulated refrigerant to certified technicians, so the 608 card is both a permission to handle and a permission to buy. An uncertified person cannot lawfully purchase it, which is the practical reason apprentices test early.

43. Which type of certification does a technician need to work on all sizes and types of equipment?

  1. Type I
  2. Type II
  3. Type III
  4. Universal
Answer: D — Universal
Universal is not a fifth exam section — it is the credential you hold once you have passed Core plus Types I, II, and III. Each of those sections is scored independently at 70%, so a strong Core cannot carry a failed Type when you are testing for Universal.

44. What does the "A" mean in the ASHRAE safety classification A2L?

  1. Azeotropic
  2. Low flammability
  3. Approved for all appliances
  4. Lower toxicity
Answer: D — Lower toxicity
In the ASHRAE 34 scheme the letter is toxicity and the number is flammability. "A" means lower toxicity and "2L" means mildly flammable with a slow burning velocity. R-32 and R-454B are A2Ls, which is why their service procedures differ from the A1 refrigerants technicians have handled for decades.

45. What distinguishes an azeotropic refrigerant blend from a zeotropic one?

  1. An azeotrope contains only one chemical
  2. An azeotrope cannot be recovered
  3. An azeotrope is always flammable
  4. An azeotrope behaves like a single refrigerant, boiling and condensing at essentially one temperature
Answer: D — An azeotrope behaves like a single refrigerant, boiling and condensing at essentially one temperature
An azeotropic blend behaves as though it were a single compound, so it has essentially no temperature glide. A zeotropic blend separates over a temperature range, which is why zeotropes must be charged as a liquid — drawing vapor off the cylinder would change the composition of what is left behind.

46. Why should a zeotropic blend be charged into a system as a liquid?

  1. Vapor charging would fractionate the blend and change its composition
  2. Liquid charges faster
  3. Liquid prevents compressor damage
  4. It is a DOT requirement
Answer: A — Vapor charging would fractionate the blend and change its composition
The components of a zeotropic blend boil at different temperatures, so pulling vapor from the cylinder removes the more volatile component preferentially and leaves the remainder off-specification. Charging liquid keeps the proportions correct. Where liquid must be metered into the suction side, a throttling device is used to avoid slugging the compressor.

47. Two different refrigerants are accidentally mixed in one recovery cylinder. What is the correct disposition?

  1. Reclaim it to AHRI 700 purity
  2. Recycle it on site and reuse it
  3. Vent the smaller quantity
  4. Send it for destruction or to a reclaimer that accepts mixed refrigerant, and label it as mixed
Answer: D — Send it for destruction or to a reclaimer that accepts mixed refrigerant, and label it as mixed
Mixed refrigerant cannot be reclaimed to AHRI 700 in the normal way and must never be charged into equipment, because the pressure-temperature relationship is unknown. It is labelled as a mixture and sent for destruction or to a facility equipped to separate it. Venting is never the answer, whatever the quantity.

48. What does the number designation in R-410A versus R-410B indicate?

  1. Different proportions of the same component refrigerants
  2. The flammability class
  3. The manufacturer
  4. The cylinder colour
Answer: A — Different proportions of the same component refrigerants
The trailing capital letter distinguishes blends made from the same components in different proportions. It is not decorative — the blends have different properties, so a system designed for one is not automatically suited to the other.

49. R-717 is the ASHRAE designation for which refrigerant?

  1. Ammonia
  2. Carbon dioxide
  3. Propane
  4. Water
Answer: A — Ammonia
The 700 series covers inorganic compounds, numbered by molecular weight added to 700: ammonia has a molecular weight of about 17, giving R-717. Carbon dioxide is R-744 and water is R-718. Ammonia is a B2L — higher toxicity and mildly flammable — which is why it appears mostly in large industrial plants with trained operators.

50. A refrigerant cylinder shows a band of green. What should a technician conclude?

  1. It definitely contains R-134a
  2. Colour alone is not a reliable identification — read the label
  3. It is empty
  4. It is a recovery cylinder
Answer: B — Colour alone is not a reliable identification — read the label
Colour coding is an industry convention, not a regulatory guarantee, and it has been reused and revised over the years. The printed label and, where doubt remains, a refrigerant identifier are what establish contents. Charging a system on the strength of a cylinder colour is how cross-contamination happens.

51. On what date did the Section 608 prohibition on venting CFC and HCFC refrigerants take effect?

  1. July 1, 1992
  2. November 15, 1995
  3. January 1, 2019
  4. August 8, 1995
Answer: A — July 1, 1992
July 1, 1992 is when knowingly venting CFCs and HCFCs during maintenance, service, repair, or disposal became illegal. The prohibition was extended to non-ozone-depleting substitutes such as HFCs on November 15, 1995 — a separate date candidates routinely swap for this one.

52. Which release falls under the de minimis allowance rather than counting as illegal venting?

  1. A de minimis release that occurs while making or breaking connections in good faith
  2. Releasing the charge before cutting a line
  3. Venting a small appliance because the charge is under a pound
  4. Releasing refrigerant to test a gauge
Answer: A — A de minimis release that occurs while making or breaking connections in good faith
The rule allows de minimis releases that happen in the course of good-faith service — the small puff when a hose is connected or disconnected. It does not create an allowance based on charge size, and it does not excuse a deliberate release. Intent and good faith are what separate a de minimis release from a violation.

53. Is releasing nitrogen used to pressure-test a system that has been evacuated of refrigerant a violation?

  1. Yes, all releases are violations
  2. No — releasing pure nitrogen from a system emptied of refrigerant is permitted
  3. Only if over 100 psig
  4. Only in low-pressure systems
Answer: B — No — releasing pure nitrogen from a system emptied of refrigerant is permitted
Nitrogen is not a regulated refrigerant, and once the system has been evacuated of refrigerant the nitrogen used for leak testing may be released. The violation would be releasing a nitrogen-and-refrigerant mixture, which is why the refrigerant comes out first and the pressure test comes second.

54. Does the venting prohibition apply to HFC refrigerants such as R-410A?

  1. Yes — the prohibition was extended to substitutes in 1995 and still applies
  2. No, HFCs have zero ODP so they are exempt
  3. Only in California
  4. Only above 50 pounds of charge
Answer: A — Yes — the prohibition was extended to substitutes in 1995 and still applies
Zero ozone depletion potential does not equal zero regulation. The venting prohibition was extended to non-ozone-depleting substitutes on November 15, 1995, and the 2020 rulemaking that rescinded the leak-repair extension for substitutes left the venting prohibition, technician certification, recovery, and sales restrictions in place for them.

55. A technician purges a line set to atmosphere to clear contaminants before brazing. Is this permitted?

  1. Yes, purging is always permitted
  2. No, if the purge releases regulated refrigerant
  3. Yes, if it takes less than 30 seconds
  4. Only with R-22
Answer: B — No, if the purge releases regulated refrigerant
Purging with regulated refrigerant is a deliberate release and therefore a violation. The accepted practice is to recover the refrigerant, then purge or sweep with dry nitrogen, which may be released. Duration has no bearing on whether a release is lawful.

56. Refrigerant is left in a system being sent to a landfill. Who may have committed a violation?

  1. The technician, the owner, and the final disposer, depending on who knew what
  2. Only the equipment owner
  3. Only the landfill
  4. Nobody — landfills are exempt
Answer: A — The technician, the owner, and the final disposer, depending on who knew what
Liability follows the chain. A technician who signs off without recovering, an owner who conceals the charge, and a final disposer who accepts equipment without verification can each be exposed. The signed verification statement exists precisely to document where the responsibility passed.

57. Which of these is specifically exempted from the venting prohibition?

  1. Refrigerant released during a purge to atmosphere
  2. Small releases of refrigerant that result from purging hoses when the technician uses low-loss fittings in good faith
  3. Any release under four ounces
  4. Releases during holidays
Answer: B — Small releases of refrigerant that result from purging hoses when the technician uses low-loss fittings in good faith
The exemption is framed around good-faith practice with equipment designed to minimise loss, not around a quantity threshold. Low-loss fittings — which close automatically when disconnected — are the expected tooling, and using them is part of what makes a residual release de minimis rather than negligent.

58. What distinguishes reclamation from recycling?

  1. Reclamation processes refrigerant to AHRI 700 purity and is verified by chemical analysis; recycling only reduces contaminants
  2. Reclamation happens on site; recycling happens off site
  3. They are the same process
  4. Recycling requires EPA certification; reclamation does not
Answer: A — Reclamation processes refrigerant to AHRI 700 purity and is verified by chemical analysis; recycling only reduces contaminants
Recycling reduces contaminants through oil separation and filter-drier passes, usually on site, and the result may only go back into the same owner\u2019s equipment. Reclamation restores refrigerant to AHRI 700 specification, is confirmed by laboratory analysis, and may only be performed by an EPA-certified reclaimer — which is what allows reclaimed refrigerant to be resold.

59. Recovered refrigerant may be returned to the same owner\u2019s equipment without reclamation under what condition?

  1. If it is recycled on site and stays with the same owner
  2. Only if it is R-22
  3. Never
  4. Only if it is sold first
Answer: A — If it is recycled on site and stays with the same owner
Refrigerant recovered from an owner\u2019s equipment may be cleaned on site and put back into that same owner\u2019s equipment without going to a reclaimer. The moment it changes hands or is sold, it must be reclaimed to AHRI 700 by a certified reclaimer first.

60. What purity standard must reclaimed refrigerant meet?

  1. ASHRAE 15
  2. UL 1963
  3. AHRI 700
  4. DOT 4BA
Answer: C — AHRI 700
AHRI Standard 700 sets the specification for reclaimed refrigerant, covering moisture, acidity, non-condensables, and particulates. ASHRAE 15 is a safety standard for refrigeration systems, UL 1963 covers recovery equipment, and DOT 4BA is a cylinder specification — all real standards, none of them the purity spec.

61. What is the definition of "recovery" as the rule uses the term?

  1. Cleaning refrigerant to specification
  2. Removing refrigerant from an appliance and storing it in an external container, without necessarily testing or processing it
  3. Selling used refrigerant
  4. Charging a system
Answer: B — Removing refrigerant from an appliance and storing it in an external container, without necessarily testing or processing it
Recovery is simply getting the refrigerant out of the appliance and into a container. It carries no cleaning or testing obligation of its own — that is what separates it from recycling, which reduces contaminants, and reclamation, which restores the refrigerant to specification and proves it by analysis.

62. A recovery cylinder is being filled with liquid refrigerant. What is the fill limit?

  1. 80% by weight of its rated capacity
  2. 100% of the cylinder volume
  3. 50% by volume
  4. There is no limit
Answer: A — 80% by weight of its rated capacity
Cylinders are filled to no more than 80% by weight of rated capacity so there is vapour space for the liquid to expand into as temperature rises. Overfilling turns a cylinder into a hydraulic vessel, and liquid is effectively incompressible — a modest temperature rise then produces enormous pressure.

63. Which practice speeds up recovery from a system?

  1. Using the longest hoses available
  2. Cooling the recovery cylinder and the appliance equally
  3. Recovering liquid first where the equipment allows, and using short large-diameter hoses
  4. Restricting the suction line
Answer: C — Recovering liquid first where the equipment allows, and using short large-diameter hoses
Pulling liquid out first moves far more mass per minute than pulling vapour, and short, large-diameter hoses reduce the pressure drop that throttles the recovery machine. Chilling the recovery cylinder relative to the appliance also helps by lowering the pressure the machine has to push against.

64. Why does recovering into a cylinder that is warmer than the appliance slow the process?

  1. It does not affect recovery
  2. The cylinder pressure rises and the machine must work against a higher discharge pressure
  3. Warm cylinders leak
  4. It damages the refrigerant
Answer: B — The cylinder pressure rises and the machine must work against a higher discharge pressure
Recovery runs on a pressure difference. A warm cylinder sits at a higher saturation pressure, so the recovery machine has to lift the refrigerant against a bigger head and moves less of it per minute. Placing the cylinder in cool water or ice is a standard way to restore the differential.

65. What should be done with the oil drained from a recovery machine\u2019s oil separator?

  1. Pour it down a drain
  2. Reuse it in the next system
  3. Dispose of it as used oil under applicable waste rules
  4. Burn it on site
Answer: C — Dispose of it as used oil under applicable waste rules
Oil removed during recovery is contaminated and is handled as used oil under the applicable federal and state waste rules, not poured out or reused. It can also hold dissolved refrigerant, which is a second reason it is never simply dumped.

66. Recovery equipment manufactured after November 15, 1993 must be certified by whom?

  1. An EPA-approved testing laboratory
  2. The technician using it
  3. The refrigerant supplier
  4. OSHA
Answer: A — An EPA-approved testing laboratory
Equipment made after November 15, 1993 must be tested and certified by an EPA-approved laboratory such as UL or ETL against the required recovery efficiency. The certification belongs to the equipment model, not to the technician, and the label on the machine is the evidence.

67. What does "self-contained" recovery equipment mean?

  1. It runs on batteries
  2. It contains its own refrigerant
  3. It has its own compressor and can pull refrigerant out without relying on the appliance\u2019s compressor
  4. It needs no cylinder
Answer: C — It has its own compressor and can pull refrigerant out without relying on the appliance\u2019s compressor
Self-contained (active) recovery equipment brings its own pump or compressor, so it can draw a charge out of an appliance whose own compressor is dead. System-dependent (passive) recovery instead relies on the appliance\u2019s compressor or its internal pressure, which is why passive methods are limited to small appliances.

68. Why must recovery hoses have shutoff devices near the ends?

  1. To make them easier to coil
  2. To limit the refrigerant lost when hoses are disconnected
  3. To increase flow rate
  4. To meet DOT shipping rules
Answer: B — To limit the refrigerant lost when hoses are disconnected
Shutoff valves within twelve inches of the service end trap the refrigerant sitting in the hose instead of letting it escape each time you disconnect. Across a working week that residual adds up, and low-loss fittings are part of what makes a remaining release count as de minimis rather than careless.

69. Before using recovery equipment on a different refrigerant than it last handled, a technician should:

  1. Evacuate and purge the machine per the manufacturer\u2019s instructions to avoid cross-contamination
  2. Do nothing — machines are universal
  3. Add oil
  4. Replace the compressor
Answer: A — Evacuate and purge the machine per the manufacturer\u2019s instructions to avoid cross-contamination
Residual refrigerant and oil left inside a recovery machine will contaminate the next charge. Manufacturers publish a changeover procedure — typically evacuating the machine and changing the filter — and following it protects both the recovered refrigerant\u2019s resale value and the next system you charge.

70. What does a recovery machine\u2019s filter-drier do?

  1. Adds refrigerant
  2. Cools the cylinder
  3. Removes moisture and acid from the recovered refrigerant stream
  4. Measures the charge
Answer: C — Removes moisture and acid from the recovered refrigerant stream
The filter-drier captures moisture, acid, and particulates on the way to the cylinder, which protects both the machine and the quality of what you recover. It is a consumable — a saturated drier stops protecting anything, which is why manufacturers specify a change interval and a change after any burnout.

71. After a compressor burnout, what extra step does recovery call for?

  1. No change in procedure
  2. Use of a suction-line filter-drier and a filter change on the recovery machine, because acid contaminates the stream
  3. Venting the acid vapour
  4. Doubling the recovery time
Answer: B — Use of a suction-line filter-drier and a filter change on the recovery machine, because acid contaminates the stream
A burnout floods the system with acid and carbon. Recovery still happens normally, but you protect the machine with additional filtration and change its filter afterwards, and the recovered refrigerant goes for reclamation rather than straight back into equipment.

72. What are the standard colours of a refrigerant recovery cylinder?

  1. Gray body with a yellow shoulder
  2. Solid green
  3. Solid white
  4. Blue body with a red shoulder
Answer: A — Gray body with a yellow shoulder
Recovery cylinders are gray with a yellow top, a convention that flags them as holding used or mixed refrigerant rather than virgin product. Confusing a recovery cylinder with a virgin one is how a system gets charged with something nobody has analysed.

73. How often must a DOT recovery cylinder be hydrostatically retested?

  1. Every year
  2. Every ten years
  3. Every five years
  4. Never
Answer: C — Every five years
Refillable DOT cylinders used for recovery carry a five-year hydrostatic retest interval, and the test date is stamped into the collar. An out-of-date cylinder should not be filled or shipped — suppliers and reclaimers routinely refuse them.

74. May a disposable (non-refillable) refrigerant cylinder be refilled with recovered refrigerant?

  1. Yes, if it is clean
  2. Yes, up to 80%
  3. No — refilling a non-refillable cylinder is prohibited
  4. Only for the same refrigerant
Answer: C — No — refilling a non-refillable cylinder is prohibited
Disposable cylinders are built for a single fill and are not rated or tested for repeated pressurisation, so refilling one violates DOT rules and creates a genuine rupture risk. Empty disposables are depressurised, marked, and recycled as scrap metal.

75. Where should refrigerant cylinders be stored?

  1. In direct sunlight so moisture evaporates
  2. In a cool, dry, well-ventilated area away from heat sources, secured upright
  3. Lying on their side near a furnace
  4. Outdoors, unsecured
Answer: B — In a cool, dry, well-ventilated area away from heat sources, secured upright
Heat raises cylinder pressure, so storage is cool, dry, and ventilated, away from ignition and heat sources, with cylinders secured so they cannot fall. Upright storage keeps the relief device in the vapour space where it can do its job.

76. What does the tare weight stamped on a recovery cylinder tell you?

  1. The weight of the empty cylinder, which you subtract to find the refrigerant weight
  2. The maximum pressure
  3. The hydrostatic test date
  4. The refrigerant type
Answer: A — The weight of the empty cylinder, which you subtract to find the refrigerant weight
Tare weight is the empty cylinder\u2019s own weight. Subtracting it from the reading on the scale gives the net refrigerant weight, which is how you confirm you are inside the 80% fill limit rather than guessing from a gauge.

77. When transporting refrigerant cylinders in a service vehicle, they should be:

  1. Loose in the bed so they can vent
  2. Stacked horizontally under tools
  3. Secured upright and protected from rolling or impact
  4. Stored in the passenger cabin
Answer: C — Secured upright and protected from rolling or impact
Cylinders are secured upright so they cannot roll, fall, or be struck, and so a relief device stays in the vapour space. A cylinder that shears a valve becomes a projectile, and DOT rules on hazardous-material transport apply to the load.

78. What is the purpose of a cylinder\u2019s pressure relief device?

  1. To let a technician vent refrigerant intentionally
  2. To release pressure before the cylinder ruptures if it is overheated
  3. To measure the charge
  4. To connect the hose
Answer: B — To release pressure before the cylinder ruptures if it is overheated
The relief device is a last-resort safety feature that vents before the shell fails. It is not a service port and it is never to be used deliberately to release refrigerant — doing so is both a venting violation and a sign the cylinder has been overfilled or overheated.

79. Why is a halide torch of no use for detecting an HFC leak?

  1. The colour change depends on chlorine, which HFCs do not contain
  2. HFCs are too heavy
  3. The torch is illegal
  4. HFCs do not leak
Answer: A — The colour change depends on chlorine, which HFCs do not contain
A halide torch turns the flame green when chlorine from a CFC or HCFC contacts the hot copper element. HFCs carry no chlorine, so there is nothing to produce the colour change. Halide torches are also largely obsolete on safety grounds — an open flame decomposes refrigerant into toxic products.

80. What is the advantage of an electronic leak detector over soap bubbles?

  1. It works without any refrigerant present
  2. It is cheaper
  3. It can find much smaller leaks and reach areas you cannot see or coat
  4. It repairs the leak
Answer: C — It can find much smaller leaks and reach areas you cannot see or coat
Electronic detectors resolve leak rates far below what a bubble solution will show, and they work on joints you cannot easily reach or wet. Bubbles remain useful for pinpointing a leak once the electronic detector has narrowed the area, so the two are complementary rather than competing.

81. Fluorescent dye leak detection requires what to read the result?

  1. A halide torch
  2. An ultraviolet lamp
  3. A micron gauge
  4. A manometer
Answer: B — An ultraviolet lamp
The dye circulates with the oil and fluoresces under UV light at the leak site, leaving a visible mark that persists after the refrigerant has escaped. That persistence is the method\u2019s strength on intermittent leaks — but the dye must be one the equipment manufacturer approves, or it can void warranty and foul the oil.

82. A standing pressure test with dry nitrogen is used to:

  1. Charge the system
  2. Confirm the system holds pressure over time before refrigerant is introduced
  3. Remove moisture
  4. Check the oil level
Answer: B — Confirm the system holds pressure over time before refrigerant is introduced
The system is pressurised with dry nitrogen and the pressure is watched over a period, with ambient temperature changes accounted for. It proves integrity before you commit refrigerant, and because nitrogen is not a regulated refrigerant it may be released afterwards.

83. What must a technician account for when interpreting a standing pressure test?

  1. Cylinder colour
  2. Oil type
  3. Ambient temperature change, which moves the pressure independently of any leak
  4. Line length only
Answer: C — Ambient temperature change, which moves the pressure independently of any leak
Gas pressure tracks temperature, so a system left overnight will read lower on a cold morning with no leak at all — and higher in the afternoon sun. Without correcting for temperature you will chase leaks that do not exist, or miss ones that do.

84. Ultrasonic leak detection works by sensing what?

  1. Refrigerant odour
  2. The high-frequency sound of gas escaping through a small opening
  3. Temperature change
  4. Oil residue
Answer: B — The high-frequency sound of gas escaping through a small opening
Escaping gas generates turbulence and a high-frequency sound signature that an ultrasonic detector picks up. Because it responds to the sound rather than to the gas chemistry, it works on any refrigerant — and on nitrogen, which makes it useful during a pressure test.

85. Why is moisture in a refrigeration system harmful?

  1. It improves heat transfer
  2. It combines with refrigerant and oil to form acids, and can freeze at the metering device
  3. It raises the boiling point
  4. It has no effect
Answer: B — It combines with refrigerant and oil to form acids, and can freeze at the metering device
Water reacts with refrigerant and oil to form acids that attack windings and metal, and free water can freeze at the expansion device and block flow. Both failure modes are slow and expensive, which is why evacuation is a measured step rather than a quick pull.

86. What instrument measures a deep vacuum accurately?

  1. A compound gauge on the manifold
  2. A thermometer
  3. A micron (vacuum) gauge
  4. A clamp meter
Answer: C — A micron (vacuum) gauge
A manifold compound gauge cannot resolve anything meaningful below roughly 28 inches of mercury — the whole working range of a deep vacuum sits inside its last needle width. A micron gauge reads the range where moisture actually boils off, which is the range that matters.

87. What does a triple evacuation accomplish?

  1. It charges the system three times
  2. Breaking the vacuum with dry nitrogen between pulls dilutes and carries away remaining moisture
  3. It tests the compressor
  4. It replaces a filter-drier
Answer: B — Breaking the vacuum with dry nitrogen between pulls dilutes and carries away remaining moisture
Each pull removes most of what is present; breaking the vacuum with dry nitrogen mixes the remaining moisture into a gas that the next pull can carry out. Three cycles reach a far drier result than one long pull on a system that was badly contaminated.

88. Why should a vacuum pump\u2019s oil be changed regularly?

  1. To make it quieter
  2. Moisture and acid absorbed into the oil raise the pump\u2019s achievable vacuum
  3. To increase its speed
  4. It is a DOT requirement
Answer: B — Moisture and acid absorbed into the oil raise the pump\u2019s achievable vacuum
A vacuum pump works by compressing what it removes into its oil, so the oil loads up with the very moisture you are trying to extract. Contaminated oil has a higher vapour pressure and the pump simply stops reaching a deep vacuum — often the real reason a system "will not pull down".

89. During evacuation, the micron reading rises and then levels off after the pump is valved off. What does this suggest?

  1. A perfect vacuum
  2. The gauge is broken
  3. Remaining moisture boiling off, or a leak if the rise does not level
  4. Too much refrigerant
Answer: C — Remaining moisture boiling off, or a leak if the rise does not level
A rise that levels out at a stable value points to moisture still vaporising inside the system. A rise that continues without levelling points to a leak drawing air in. Reading the shape of the curve, not just the number, is what separates the two.

90. What is the primary hazard of a large refrigerant release in a confined space?

  1. Fire
  2. Oxygen displacement leading to asphyxiation
  3. Electrocution
  4. Corrosion
Answer: B — Oxygen displacement leading to asphyxiation
Most common refrigerants are heavier than air and non-toxic in the ordinary sense — the danger is that they displace oxygen in a low or enclosed space and a person suffocates without warning. That is why machinery rooms carry refrigerant monitors and mechanical ventilation.

91. Why must oxygen never be used to pressurise a refrigeration system?

  1. It is too expensive
  2. Oxygen under pressure reacts violently with refrigerant oil and can explode
  3. It causes corrosion
  4. It freezes the lines
Answer: B — Oxygen under pressure reacts violently with refrigerant oil and can explode
Compressed oxygen in contact with hydrocarbon oil can ignite explosively. Dry nitrogen is the correct pressurising gas, and it is always used through a regulator so system pressure never approaches the cylinder pressure.

92. What forms when refrigerant contacts an open flame or a very hot surface?

  1. Harmless water vapour
  2. Pure nitrogen
  3. Toxic decomposition products including hydrofluoric and hydrochloric acids and phosgene
  4. Ozone
Answer: C — Toxic decomposition products including hydrofluoric and hydrochloric acids and phosgene
Thermal decomposition produces acid gases and, from chlorinated refrigerants, phosgene. The sharp, acrid smell is the warning sign to ventilate and leave. It is also the reason brazing is done on a system that has been recovered and purged, not one still holding refrigerant.

93. What protective equipment is appropriate when handling liquid refrigerant?

  1. Cotton gloves only
  2. Safety glasses and impermeable gloves
  3. A dust mask
  4. No equipment is needed
Answer: B — Safety glasses and impermeable gloves
Liquid refrigerant boils at well below freezing at atmospheric pressure, so a splash produces immediate frostbite, and an eye exposure can cause permanent damage. Splash-resistant eye protection and gloves that liquid cannot soak through are the minimum.

94. A technician is splashed in the eye with liquid refrigerant. What is the correct first response?

  1. Rub the eye vigorously
  2. Flush with clean water for at least 15 minutes and get immediate medical attention
  3. Apply ice directly
  4. Wait to see if vision clears
Answer: B — Flush with clean water for at least 15 minutes and get immediate medical attention
Flush gently with plenty of clean lukewarm water for at least fifteen minutes and get medical help straight away — this is a cold burn to tissue that cannot tolerate it. Rubbing drives the injury deeper and ice compounds the freezing.

95. Why must a nitrogen cylinder always be used with a pressure regulator?

  1. To measure flow
  2. To keep the nitrogen dry
  3. Cylinder pressure far exceeds system working pressure and would rupture components
  4. To comply with EPA rules
Answer: C — Cylinder pressure far exceeds system working pressure and would rupture components
A full nitrogen cylinder sits at a couple of thousand psi, against system components rated for a small fraction of that. Without a regulator the first crack of the valve can burst a line or a coil. A relief valve in the regulated line is a sensible second layer.

96. How long must records of recovery-equipment testing and technician certification generally be retained?

  1. 30 days
  2. 1 year
  3. 3 years
  4. Indefinitely, with no defined period
Answer: C — 3 years
The rule\u2019s general retention period for these records is three years. Certifying organizations also keep technician records, which is how a lost card is replaced — but the employer\u2019s own obligation to hold the documentation does not disappear because a third party has a copy.

97. What record must a technician who disposes of a small appliance be able to produce?

  1. A purchase receipt
  2. Nothing
  3. A signed statement verifying that refrigerant was recovered, retained by the final disposer
  4. A photograph of the appliance
Answer: C — A signed statement verifying that refrigerant was recovered, retained by the final disposer
The final person in the disposal chain must either recover the refrigerant themselves or hold signed verification that a certified technician already did. That statement is what discharges their liability, and it is the document an inspector asks for.

98. Since the sales restriction took effect, who may purchase regulated refrigerant in containers larger than the small-can exemption?

  1. Anyone over 18
  2. Certified technicians, or those purchasing for a certified technician\u2019s use
  3. Only equipment manufacturers
  4. Only reclaimers
Answer: B — Certified technicians, or those purchasing for a certified technician\u2019s use
Sale is restricted to certified technicians and to purchases made for use by one, and suppliers are expected to verify certification and keep the record. The narrow exemption historically applied to very small cans of certain refrigerants for motor-vehicle use, not to service cylinders.

99. An owner of equipment must keep servicing records that show what?

  1. Only the technician\u2019s name
  2. Only the invoice total
  3. The refrigerant added and recovered, dates, and quantities
  4. Nothing is required
Answer: C — The refrigerant added and recovered, dates, and quantities
Servicing records establish how much refrigerant went in and came out, and when. They are what makes a chronic leak visible as a pattern rather than a series of unrelated top-ups, and they are the basis for any leak-rate calculation on covered appliances.

100. What must a certified technician be able to present on request at a job site?

  1. A high school diploma
  2. A state contractor bond
  3. Evidence of Section 608 certification
  4. A recovery machine receipt
Answer: C — Evidence of Section 608 certification
A technician must be able to show proof of 608 certification — the wallet card or an equivalent record from the certifying organization. Employers are also expected to keep a copy on file, since it is the employer who is asked to demonstrate that servicing staff are certified.
Other Sections
Keep Practicing
Practice Test

EPA 608 Type I

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

100 questions
Practice Test

EPA 608 Type II

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

100 questions
Practice Test

EPA 608 Type III

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

100 questions
Full Exam

EPA 608 Universal

All four sections in one 100-question attempt, scored section by section.

100 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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