LOW GWP REFRIGERANT SAFETY:
FLAMMABLE AND MILDLY FLAMMABLE
REFRIGERANTS IN HVACR EXAM 2026
What must be maintained for each type of gas stored onsite according to NFPA
requirements? - ANSWER-Safety Data Sheets (SDS).
What should be done if a refrigerant leak occurs? - ANSWER-Ensure the area is
well ventilated to prevent oxygen displacement and suffocation.
What is the purpose of a Hazardous Materials Management plan? - ANSWER-
To ensure safe handling and storage of hazardous materials.
What is the role of the National Fire Protection Association (NFPA) in
refrigerant safety? - ANSWER-To establish fire safety storage requirements for
hazardous materials.
What is the purpose of keeping a Class B fire extinguisher nearby when
working on 2L equipment? - ANSWER-To be prepared in case of an emergency
involving fire.
What must be ensured about 2L equipment before installation? - ANSWER-It
must be approved for installation and use in the designated area.
What does the burning velocity of a combustible gas indicate? - ANSWER-It is
the rate at which a flame front spreads relative to the unburned gas ahead.
,What is the burning velocity of 2L refrigerants? - ANSWER-10 cm/s (3.9
inches per second) or less.
What is the significance of a refrigerant's Lower Flammability Limit (LFL)? -
ANSWER-It is the minimum concentration of a flammable substance that can
ignite in a sufficient mixture of air.
What is the LFL for R-32 refrigerant? - ANSWER-14.4%.
What is the Auto Ignition Temperature for R-454B? - ANSWER-440°C
(824°F).
What does Minimum Ignition Energy (MIE) refer to? - ANSWER-The
minimum energy required to ignite a flammable substance.
What is the MIE for R-1234yf? - ANSWER-5,000 - 10,000 mJ.
How does the heat of combustion (HOC) relate to refrigerants? - ANSWER-It
indicates the energy released during combustion; lower HOC means less energy
released.
What are Refrigerant Concentration Limits (RCL)? - ANSWER-The maximum
concentration of a refrigerant allowed in an occupied space, considering
toxicity, oxygen deprivation, and flammability.
What are the two most common torch kits used for brazing? - ANSWER-
Oxyacetylene and air acetylene.
What is a key difference between oxyacetylene and air acetylene setups? -
ANSWER-Oxyacetylene requires both acetylene and oxygen tanks, while air
acetylene uses ambient air for oxygen.
, What is the flame temperature produced by oxyacetylene? - ANSWER-About
5400°F.
What type of air discharge do mini-split systems typically have? - ANSWER-
Side air discharge.
Why is it important to clean the coil in a refrigeration system? - ANSWER-To
ensure proper airflow and heat transfer.
What should be verified before applying a cleaner to a coil? - ANSWER-That
the chemical is compatible with the coil design.
What is the purpose of energizing an indoor fan when using flammable
refrigerants? - ANSWER-To keep the leaking refrigerant below its lower
flammability level (LFL).
What is mitigation in the context of refrigeration systems? - ANSWER-
Minimizing or reducing the possibility of an ignition event or accident.
What is a blended refrigerant? - ANSWER-A mixture of two or more
refrigerants classified as azeotropic, near-azeotropic, or zeotropic.
What characterizes an azeotropic refrigerant blend? - ANSWER-It behaves like
a single compound and does not separate into its components.
What is temperature glide in zeotropic refrigerants? - ANSWER-The range of
different boiling temperatures at a given pressure.
FLAMMABLE AND MILDLY FLAMMABLE
REFRIGERANTS IN HVACR EXAM 2026
What must be maintained for each type of gas stored onsite according to NFPA
requirements? - ANSWER-Safety Data Sheets (SDS).
What should be done if a refrigerant leak occurs? - ANSWER-Ensure the area is
well ventilated to prevent oxygen displacement and suffocation.
What is the purpose of a Hazardous Materials Management plan? - ANSWER-
To ensure safe handling and storage of hazardous materials.
What is the role of the National Fire Protection Association (NFPA) in
refrigerant safety? - ANSWER-To establish fire safety storage requirements for
hazardous materials.
What is the purpose of keeping a Class B fire extinguisher nearby when
working on 2L equipment? - ANSWER-To be prepared in case of an emergency
involving fire.
What must be ensured about 2L equipment before installation? - ANSWER-It
must be approved for installation and use in the designated area.
What does the burning velocity of a combustible gas indicate? - ANSWER-It is
the rate at which a flame front spreads relative to the unburned gas ahead.
,What is the burning velocity of 2L refrigerants? - ANSWER-10 cm/s (3.9
inches per second) or less.
What is the significance of a refrigerant's Lower Flammability Limit (LFL)? -
ANSWER-It is the minimum concentration of a flammable substance that can
ignite in a sufficient mixture of air.
What is the LFL for R-32 refrigerant? - ANSWER-14.4%.
What is the Auto Ignition Temperature for R-454B? - ANSWER-440°C
(824°F).
What does Minimum Ignition Energy (MIE) refer to? - ANSWER-The
minimum energy required to ignite a flammable substance.
What is the MIE for R-1234yf? - ANSWER-5,000 - 10,000 mJ.
How does the heat of combustion (HOC) relate to refrigerants? - ANSWER-It
indicates the energy released during combustion; lower HOC means less energy
released.
What are Refrigerant Concentration Limits (RCL)? - ANSWER-The maximum
concentration of a refrigerant allowed in an occupied space, considering
toxicity, oxygen deprivation, and flammability.
What are the two most common torch kits used for brazing? - ANSWER-
Oxyacetylene and air acetylene.
What is a key difference between oxyacetylene and air acetylene setups? -
ANSWER-Oxyacetylene requires both acetylene and oxygen tanks, while air
acetylene uses ambient air for oxygen.
, What is the flame temperature produced by oxyacetylene? - ANSWER-About
5400°F.
What type of air discharge do mini-split systems typically have? - ANSWER-
Side air discharge.
Why is it important to clean the coil in a refrigeration system? - ANSWER-To
ensure proper airflow and heat transfer.
What should be verified before applying a cleaner to a coil? - ANSWER-That
the chemical is compatible with the coil design.
What is the purpose of energizing an indoor fan when using flammable
refrigerants? - ANSWER-To keep the leaking refrigerant below its lower
flammability level (LFL).
What is mitigation in the context of refrigeration systems? - ANSWER-
Minimizing or reducing the possibility of an ignition event or accident.
What is a blended refrigerant? - ANSWER-A mixture of two or more
refrigerants classified as azeotropic, near-azeotropic, or zeotropic.
What characterizes an azeotropic refrigerant blend? - ANSWER-It behaves like
a single compound and does not separate into its components.
What is temperature glide in zeotropic refrigerants? - ANSWER-The range of
different boiling temperatures at a given pressure.
