Low GWP Refrigerant Safety Exam ESCO
A2L Flammable Mildly Flammable
Refrigerants Actual Exam 2026/2027 with
Detailed Rationales | Complete Exam-Style
Questions | Pass Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: ASHRAE REFRIGERANT SAFETY CLASSIFICATIONS & STANDARDS Q1 –
Q10
══════════════════════════════════════
Question 1 of 50
A technician is reviewing the safety documentation for a new split-system heat pump charged
with R-32 before beginning installation. The customer asks about the refrigerant's official
ASHRAE safety classification. What classification should the technician report?
A. A1, because R-32 is non-toxic and non-flammable
B. A2, because R-32 is non-toxic and highly flammable with a burning velocity above 10 cm/s
C. A2L, because R-32 is non-toxic and mildly flammable with a burning velocity below 10
cm/s ✓ CORRECT
D. A3, because R-32 is non-toxic and extremely flammable with a burning velocity above 100
cm/s
Correct Answer: C
Rationale: Under ASHRAE Standard 34, R-32 is classified as A2L, meaning it is non-toxic (A),
flammable (2), and has a low burning velocity (L) of less than 10 cm/s, which distinguishes it
from higher-risk A3 refrigerants like propane. Selecting A1 would be incorrect because R-32 is
not non-flammable, and A2 would be wrong because its burning velocity of approximately 6.7
cm/s falls below the 10 cm/s threshold that defines the A2L subclassification. Technicians
must verify the exact classification on the cylinder label and safety data sheet before
handling any new refrigerant.
Question 2 of 50
During a safety seminar, an instructor asks a group of apprentices to identify the maximum
burning velocity that separates an A2L refrigerant from an A2 refrigerant under ASHRAE
Standard 34. Which value should the apprentice state?
,A. 5 cm/s
B. 10 cm/s ✓ CORRECT
C. 15 cm/s
D. 20 cm/s
Correct Answer: B
Rationale: ASHRAE Standard 34 establishes 10 cm/s as the critical threshold dividing A2L
refrigerants, which have low burning velocities below this limit, from A2 refrigerants that burn
faster. A refrigerant with a burning velocity of 10 cm/s or greater would be classified as A2
rather than A2L, making 15 cm/s and 20 cm/s clearly incorrect for the A2L category. This
distinction is fundamental to understanding why A2L refrigerants like R-32 and R-1234yf can
be used in residential applications with moderate safety precautions.
Question 3 of 50
A contractor is designing a refrigeration system for a small commercial kitchen and is
considering a refrigerant with a B2L safety classification. The owner wants to know what the
"B" designation signifies compared to an "A" refrigerant like R-454B. What should the
contractor explain?
A. The "B" indicates higher global warming potential
B. The "B" indicates lower flammability risk
C. The "B" indicates non-toxic properties
D. The "B" indicates toxicity at lower concentrations ✓ CORRECT
Correct Answer: D
Rationale: In ASHRAE Standard 34 and ISO 817, the letter "B" in the safety classification
denotes toxicity, specifically that the refrigerant exhibits some degree of toxicity at
concentrations below 400 parts per million, whereas "A" refrigerants are non-toxic at those
levels. The "2L" suffix still indicates mild flammability with a low burning velocity, so B2L
refrigerants share the same flammability characteristics as A2L but carry additional toxicity
concerns. Contractors must consult both the safety data sheet and ASHRAE Standard 15
when designing systems for B-class refrigerants to ensure adequate ventilation and exposure
controls.
Question 4 of 50
A service manager is updating the shop's reference materials to include the international
standard that defines refrigerant designations and safety classifications alongside ASHRAE
Standard 34. Which standard document should be added to the library?
A. ISO 817 ✓ CORRECT
B. ISO 9001
C. ASHRAE Standard 15
, D. UL 60335-2-40
Correct Answer: A
Rationale: ISO 817 is the international standard that parallels ASHRAE Standard 34 by
establishing refrigerant numbering designations and identical safety group classifications
including A1, A2L, and B2L. ISO 9001 is a quality management standard unrelated to
refrigerant safety, while ASHRAE Standard 15 addresses installation and machinery room
requirements rather than classification definitions. Maintaining both ASHRAE Standard 34
and ISO 817 ensures technicians can cross-reference domestic and international
nomenclature when working with imported equipment.
Question 5 of 50
While reviewing the safety data sheet for R-454C, a technician notices it is classified as A2L.
The technician is trying to explain to a junior apprentice why R-454C is not classified as A3.
What is the primary reason?
A. R-454C has a lower global warming potential than A3 refrigerants
B. R-454C is toxic at low concentrations
C. R-454C has a burning velocity below 10 cm/s ✓ CORRECT
D. R-454C is non-flammable
Correct Answer: C
Rationale: R-454C carries the A2L classification because it is non-toxic and mildly flammable
with a burning velocity below the 10 cm/s threshold, whereas A3 refrigerants like propane
have burning velocities significantly higher than 10 cm/s and are considered highly
flammable. R-454C is indeed flammable, so stating it is non-flammable would be incorrect,
and its GWP value does not determine the safety classification letter. Technicians must
understand that the A2L classification specifically reflects controlled flammability
characteristics that permit use in systems with charge size limitations.
Question 6 of 50
A homeowner asks a technician to recommend the safest refrigerant for a window air
conditioner in a bedroom with minimal ventilation. The technician knows that A3 refrigerants
require strict charge limits. Which of these refrigerants is classified as A3 and would
therefore demand the most restrictive installation precautions?
A. R-32
B. R-290 ✓ CORRECT
C. R-454B
D. R-1234yf
Correct Answer: B
A2L Flammable Mildly Flammable
Refrigerants Actual Exam 2026/2027 with
Detailed Rationales | Complete Exam-Style
Questions | Pass Guaranteed – A+ Graded
══════════════════════════════════════
SECTION 1: ASHRAE REFRIGERANT SAFETY CLASSIFICATIONS & STANDARDS Q1 –
Q10
══════════════════════════════════════
Question 1 of 50
A technician is reviewing the safety documentation for a new split-system heat pump charged
with R-32 before beginning installation. The customer asks about the refrigerant's official
ASHRAE safety classification. What classification should the technician report?
A. A1, because R-32 is non-toxic and non-flammable
B. A2, because R-32 is non-toxic and highly flammable with a burning velocity above 10 cm/s
C. A2L, because R-32 is non-toxic and mildly flammable with a burning velocity below 10
cm/s ✓ CORRECT
D. A3, because R-32 is non-toxic and extremely flammable with a burning velocity above 100
cm/s
Correct Answer: C
Rationale: Under ASHRAE Standard 34, R-32 is classified as A2L, meaning it is non-toxic (A),
flammable (2), and has a low burning velocity (L) of less than 10 cm/s, which distinguishes it
from higher-risk A3 refrigerants like propane. Selecting A1 would be incorrect because R-32 is
not non-flammable, and A2 would be wrong because its burning velocity of approximately 6.7
cm/s falls below the 10 cm/s threshold that defines the A2L subclassification. Technicians
must verify the exact classification on the cylinder label and safety data sheet before
handling any new refrigerant.
Question 2 of 50
During a safety seminar, an instructor asks a group of apprentices to identify the maximum
burning velocity that separates an A2L refrigerant from an A2 refrigerant under ASHRAE
Standard 34. Which value should the apprentice state?
,A. 5 cm/s
B. 10 cm/s ✓ CORRECT
C. 15 cm/s
D. 20 cm/s
Correct Answer: B
Rationale: ASHRAE Standard 34 establishes 10 cm/s as the critical threshold dividing A2L
refrigerants, which have low burning velocities below this limit, from A2 refrigerants that burn
faster. A refrigerant with a burning velocity of 10 cm/s or greater would be classified as A2
rather than A2L, making 15 cm/s and 20 cm/s clearly incorrect for the A2L category. This
distinction is fundamental to understanding why A2L refrigerants like R-32 and R-1234yf can
be used in residential applications with moderate safety precautions.
Question 3 of 50
A contractor is designing a refrigeration system for a small commercial kitchen and is
considering a refrigerant with a B2L safety classification. The owner wants to know what the
"B" designation signifies compared to an "A" refrigerant like R-454B. What should the
contractor explain?
A. The "B" indicates higher global warming potential
B. The "B" indicates lower flammability risk
C. The "B" indicates non-toxic properties
D. The "B" indicates toxicity at lower concentrations ✓ CORRECT
Correct Answer: D
Rationale: In ASHRAE Standard 34 and ISO 817, the letter "B" in the safety classification
denotes toxicity, specifically that the refrigerant exhibits some degree of toxicity at
concentrations below 400 parts per million, whereas "A" refrigerants are non-toxic at those
levels. The "2L" suffix still indicates mild flammability with a low burning velocity, so B2L
refrigerants share the same flammability characteristics as A2L but carry additional toxicity
concerns. Contractors must consult both the safety data sheet and ASHRAE Standard 15
when designing systems for B-class refrigerants to ensure adequate ventilation and exposure
controls.
Question 4 of 50
A service manager is updating the shop's reference materials to include the international
standard that defines refrigerant designations and safety classifications alongside ASHRAE
Standard 34. Which standard document should be added to the library?
A. ISO 817 ✓ CORRECT
B. ISO 9001
C. ASHRAE Standard 15
, D. UL 60335-2-40
Correct Answer: A
Rationale: ISO 817 is the international standard that parallels ASHRAE Standard 34 by
establishing refrigerant numbering designations and identical safety group classifications
including A1, A2L, and B2L. ISO 9001 is a quality management standard unrelated to
refrigerant safety, while ASHRAE Standard 15 addresses installation and machinery room
requirements rather than classification definitions. Maintaining both ASHRAE Standard 34
and ISO 817 ensures technicians can cross-reference domestic and international
nomenclature when working with imported equipment.
Question 5 of 50
While reviewing the safety data sheet for R-454C, a technician notices it is classified as A2L.
The technician is trying to explain to a junior apprentice why R-454C is not classified as A3.
What is the primary reason?
A. R-454C has a lower global warming potential than A3 refrigerants
B. R-454C is toxic at low concentrations
C. R-454C has a burning velocity below 10 cm/s ✓ CORRECT
D. R-454C is non-flammable
Correct Answer: C
Rationale: R-454C carries the A2L classification because it is non-toxic and mildly flammable
with a burning velocity below the 10 cm/s threshold, whereas A3 refrigerants like propane
have burning velocities significantly higher than 10 cm/s and are considered highly
flammable. R-454C is indeed flammable, so stating it is non-flammable would be incorrect,
and its GWP value does not determine the safety classification letter. Technicians must
understand that the A2L classification specifically reflects controlled flammability
characteristics that permit use in systems with charge size limitations.
Question 6 of 50
A homeowner asks a technician to recommend the safest refrigerant for a window air
conditioner in a bedroom with minimal ventilation. The technician knows that A3 refrigerants
require strict charge limits. Which of these refrigerants is classified as A3 and would
therefore demand the most restrictive installation precautions?
A. R-32
B. R-290 ✓ CORRECT
C. R-454B
D. R-1234yf
Correct Answer: B
