EPA Section 608 Universal Certification ExamCoreHard
A technician is evaluating a new 'natural refrigerant' for use in a commercial refrigeration system. Which of the following refrigerants is considered a 'natural refrigerant' under current industry definitions and poses the primary environmental concern of flammability?
- AR-744 (CO2)
- BR-290 (propane)
- CR-410A
- DR-134a
Show answer & explanationAnswer & explanation
Correct answer: B. R-290 (propane)
R-290 (propane) is a hydrocarbon and is classified as a 'natural refrigerant' due to its very low GWP and ODP. Its primary environmental concern in applications is its high flammability, which requires strict safety protocols.
Why the other options are wrong
- A. R-744 (CO2) is a natural refrigerant, but its primary environmental concern is high operating pressure, not flammability.
- C. R-410A is an HFC blend, not a natural refrigerant, and is non-flammable.
- D. R-134a is an HFC, not a natural refrigerant. It has a high GWP but is not flammable.
Natural Refrigerants & Flammability
Natural refrigerants are naturally occurring substances (e.g., ammonia, carbon dioxide, hydrocarbons) used as refrigerants due to their low environmental impact (low ODP/GWP). Hydrocarbons like propane (R-290) are highly flammable, which is their primary safety and environmental concern.
- Low ODP and GWP.
- Hydrocarbons (R-290, R-600a) are highly flammable.
- CO2 (R-744) has high operating pressures.
- Ammonia (R-717) is toxic.
Memory trick: Natural choice, but know the fire price.