EPA Section 609 Exam 2026 – Verified
Questions & 100% Correct Answers | Latest
Update + Grade A+
EPA SECTION 609 CERTIFICATION EXAM — 2026
Mobile Air Conditioning (MAC) Systems | Questions | Grade A+
Question 1 What refrigerant is used in most motor vehicle air conditioning systems
manufactured after 1994?
A. CFC-12 (R-12)
B. HCFC-22 (R-22)
C. HFC-134a (R-134a) ← CORRECT ANSWER
D. R-410A
E. R-502
RATIONALE: HFC-134a (R-134a) became the industry standard refrigerant for motor
vehicle air conditioning (MVAC) systems after the phase-out of CFC-12. R-134a
contains no chlorine atoms, meaning it has zero ozone depletion potential (ODP),
making it environmentally preferable to CFCs. The EPA mandated this transition under
the Clean Air Act.
Question 2 What does CFC stand for in refrigerant terminology?
A. Carbon Fluoride Compound
B. Chlorinated Fluid Chemical
C. Chlorofluorocarbon ← CORRECT ANSWER
D. Carbon Filtered Coolant
E. Chlorine Fluoride Carbon
RATIONALE: CFC stands for Chlorofluorocarbon. These compounds contain carbon,
chlorine, and fluorine atoms. CFCs such as R-12 were widely used as refrigerants until
their phase-out due to their high ozone depletion potential (ODP). When released into
the atmosphere, CFCs migrate to the stratosphere where ultraviolet radiation breaks
them down, releasing chlorine atoms that destroy ozone molecules.
,Question 3 Which refrigerant was commonly used in MVAC systems BEFORE 1994?
A. R-134a
B. R-410A
C. R-22
D. CFC-12 (R-12) ← CORRECT ANSWER
E. R-404A
RATIONALE: CFC-12 (also called R-12 or Freon-12) was the dominant refrigerant used
in automobile air conditioning systems prior to 1994. It was phased out due to its high
ozone depletion potential (ODP of 1.0) as required by the Montreal Protocol and the
U.S. Clean Air Act. After January 1, 1996, the production and import of R-12 in the U.S.
was largely banned.
Question 4 What is the ozone depletion potential (ODP) of R-134a?
A. 1.0
B. 0.5
C. 0.05
D. 0.11
E. Zero (0) ← CORRECT ANSWER
RATIONALE: R-134a (HFC-134a) has an ozone depletion potential (ODP) of zero
because it contains no chlorine or bromine atoms — the elements responsible for
destroying stratospheric ozone. This is why it replaced R-12 in MVAC systems.
However, R-134a does have a Global Warming Potential (GWP) of approximately
1,430, which is why newer alternatives like HFO-1234yf are being explored.
Question 5 R-134a belongs to which class of refrigerants?
A. CFC (Chlorofluorocarbon)
B. HCFC (Hydrochlorofluorocarbon)
C. HFC (Hydrofluorocarbon) ← CORRECT ANSWER
, D. HC (Hydrocarbon)
E. HFO (Hydrofluoroolefin)
RATIONALE: R-134a is classified as an HFC — Hydrofluorocarbon. HFCs contain
hydrogen, fluorine, and carbon but NO chlorine, giving them zero ODP. They were
introduced as replacements for ozone-depleting CFCs and HCFCs. However, HFCs are
potent greenhouse gases, leading to the Kigali Amendment which seeks to phase them
down globally.
Question 6 What is the boiling point of R-134a at atmospheric pressure?
A. +14.9°F (+8.3°C)
B. 0°F (-17.8°C)
C. -21.6°F (-29.8°C) ← CORRECT ANSWER
D. -40°F (-40°C)
E. +32°F (0°C)
RATIONALE: R-134a has a boiling point of approximately -21.6°F (-29.8°C) at
atmospheric pressure (14.7 psia). This low boiling point is essential to its function as a
refrigerant — it allows R-134a to readily absorb heat and evaporate inside the
evaporator coil of the MVAC system, producing the cooling effect inside the vehicle
cabin.
Question 7 Which of the following is TRUE about R-12?
A. It has zero ozone depletion potential
B. It is an HFC refrigerant
C. It is still produced in large quantities in the U.S.
D. It has an ODP of 1.0 and was phased out under the Clean Air Act ←
CORRECT ANSWER
E. It is approved for use in new MVAC systems
RATIONALE: R-12 (CFC-12) has an Ozone Depletion Potential (ODP) of 1.0, the
highest among common refrigerants, and was phased out in the United States under
Section 612 of the Clean Air Act and the Montreal Protocol. As of January 1, 1996, the
, domestic production and import of R-12 was essentially banned. Technicians must use
recovered/recycled R-12 for servicing older vehicles.
Question 8 What is the Global Warming Potential (GWP) of R-134a compared to CO₂?
A. 0 (no warming effect)
B. 100
C. 500
D. 1,430 ← CORRECT ANSWER
E. 4,600
RATIONALE: R-134a has a Global Warming Potential (GWP) of approximately 1,430
over a 100-year period, meaning it traps 1,430 times more heat than an equivalent
mass of CO₂. This high GWP has driven the development of alternative refrigerants with
lower environmental impact, such as HFO-1234yf (GWP of 4), which is now used in
newer model vehicles.
Question 9 What is HFO-1234yf?
A. A type of CFC refrigerant
B. A low-GWP refrigerant increasingly used in newer MVAC systems ←
CORRECT ANSWER
C. A blended refrigerant containing R-12
D. A type of refrigerant oil
E. A replacement for R-410A in stationary systems
RATIONALE: HFO-1234yf is a Hydrofluoroolefin refrigerant with a GWP of only 4,
making it nearly climate-neutral compared to R-134a (GWP 1,430). It has been adopted
by many automakers in new vehicles, especially those sold in the European Union
which mandated its use. It is EPA-approved under SNAP (Significant New Alternatives
Policy) for use in MVAC systems.
Question 10 Which of the following is a characteristic of refrigerants classified as
"blends"?
Questions & 100% Correct Answers | Latest
Update + Grade A+
EPA SECTION 609 CERTIFICATION EXAM — 2026
Mobile Air Conditioning (MAC) Systems | Questions | Grade A+
Question 1 What refrigerant is used in most motor vehicle air conditioning systems
manufactured after 1994?
A. CFC-12 (R-12)
B. HCFC-22 (R-22)
C. HFC-134a (R-134a) ← CORRECT ANSWER
D. R-410A
E. R-502
RATIONALE: HFC-134a (R-134a) became the industry standard refrigerant for motor
vehicle air conditioning (MVAC) systems after the phase-out of CFC-12. R-134a
contains no chlorine atoms, meaning it has zero ozone depletion potential (ODP),
making it environmentally preferable to CFCs. The EPA mandated this transition under
the Clean Air Act.
Question 2 What does CFC stand for in refrigerant terminology?
A. Carbon Fluoride Compound
B. Chlorinated Fluid Chemical
C. Chlorofluorocarbon ← CORRECT ANSWER
D. Carbon Filtered Coolant
E. Chlorine Fluoride Carbon
RATIONALE: CFC stands for Chlorofluorocarbon. These compounds contain carbon,
chlorine, and fluorine atoms. CFCs such as R-12 were widely used as refrigerants until
their phase-out due to their high ozone depletion potential (ODP). When released into
the atmosphere, CFCs migrate to the stratosphere where ultraviolet radiation breaks
them down, releasing chlorine atoms that destroy ozone molecules.
,Question 3 Which refrigerant was commonly used in MVAC systems BEFORE 1994?
A. R-134a
B. R-410A
C. R-22
D. CFC-12 (R-12) ← CORRECT ANSWER
E. R-404A
RATIONALE: CFC-12 (also called R-12 or Freon-12) was the dominant refrigerant used
in automobile air conditioning systems prior to 1994. It was phased out due to its high
ozone depletion potential (ODP of 1.0) as required by the Montreal Protocol and the
U.S. Clean Air Act. After January 1, 1996, the production and import of R-12 in the U.S.
was largely banned.
Question 4 What is the ozone depletion potential (ODP) of R-134a?
A. 1.0
B. 0.5
C. 0.05
D. 0.11
E. Zero (0) ← CORRECT ANSWER
RATIONALE: R-134a (HFC-134a) has an ozone depletion potential (ODP) of zero
because it contains no chlorine or bromine atoms — the elements responsible for
destroying stratospheric ozone. This is why it replaced R-12 in MVAC systems.
However, R-134a does have a Global Warming Potential (GWP) of approximately
1,430, which is why newer alternatives like HFO-1234yf are being explored.
Question 5 R-134a belongs to which class of refrigerants?
A. CFC (Chlorofluorocarbon)
B. HCFC (Hydrochlorofluorocarbon)
C. HFC (Hydrofluorocarbon) ← CORRECT ANSWER
, D. HC (Hydrocarbon)
E. HFO (Hydrofluoroolefin)
RATIONALE: R-134a is classified as an HFC — Hydrofluorocarbon. HFCs contain
hydrogen, fluorine, and carbon but NO chlorine, giving them zero ODP. They were
introduced as replacements for ozone-depleting CFCs and HCFCs. However, HFCs are
potent greenhouse gases, leading to the Kigali Amendment which seeks to phase them
down globally.
Question 6 What is the boiling point of R-134a at atmospheric pressure?
A. +14.9°F (+8.3°C)
B. 0°F (-17.8°C)
C. -21.6°F (-29.8°C) ← CORRECT ANSWER
D. -40°F (-40°C)
E. +32°F (0°C)
RATIONALE: R-134a has a boiling point of approximately -21.6°F (-29.8°C) at
atmospheric pressure (14.7 psia). This low boiling point is essential to its function as a
refrigerant — it allows R-134a to readily absorb heat and evaporate inside the
evaporator coil of the MVAC system, producing the cooling effect inside the vehicle
cabin.
Question 7 Which of the following is TRUE about R-12?
A. It has zero ozone depletion potential
B. It is an HFC refrigerant
C. It is still produced in large quantities in the U.S.
D. It has an ODP of 1.0 and was phased out under the Clean Air Act ←
CORRECT ANSWER
E. It is approved for use in new MVAC systems
RATIONALE: R-12 (CFC-12) has an Ozone Depletion Potential (ODP) of 1.0, the
highest among common refrigerants, and was phased out in the United States under
Section 612 of the Clean Air Act and the Montreal Protocol. As of January 1, 1996, the
, domestic production and import of R-12 was essentially banned. Technicians must use
recovered/recycled R-12 for servicing older vehicles.
Question 8 What is the Global Warming Potential (GWP) of R-134a compared to CO₂?
A. 0 (no warming effect)
B. 100
C. 500
D. 1,430 ← CORRECT ANSWER
E. 4,600
RATIONALE: R-134a has a Global Warming Potential (GWP) of approximately 1,430
over a 100-year period, meaning it traps 1,430 times more heat than an equivalent
mass of CO₂. This high GWP has driven the development of alternative refrigerants with
lower environmental impact, such as HFO-1234yf (GWP of 4), which is now used in
newer model vehicles.
Question 9 What is HFO-1234yf?
A. A type of CFC refrigerant
B. A low-GWP refrigerant increasingly used in newer MVAC systems ←
CORRECT ANSWER
C. A blended refrigerant containing R-12
D. A type of refrigerant oil
E. A replacement for R-410A in stationary systems
RATIONALE: HFO-1234yf is a Hydrofluoroolefin refrigerant with a GWP of only 4,
making it nearly climate-neutral compared to R-134a (GWP 1,430). It has been adopted
by many automakers in new vehicles, especially those sold in the European Union
which mandated its use. It is EPA-approved under SNAP (Significant New Alternatives
Policy) for use in MVAC systems.
Question 10 Which of the following is a characteristic of refrigerants classified as
"blends"?
