A2L Properties and Classification 2

Question 1

What does the 'A2L' classification mean in the ASHRAE 34 safety classification system?

Accepted Answer

Lower toxicity (A), lower flammability (2), with low burning velocity (L)

Answer

In ASHRAE 34: 'A' means lower toxicity, '2' means lower flammability (can burn but requires higher ignition energy), and 'L' indicates low burning velocity — flames spread slowly.

Question 2

What is the Global Warming Potential (GWP) advantage of A2L refrigerants over R-410A?

Accepted Answer

A2L alternatives typically have GWP 1/3 to 1/4 of R-410A's GWP of 2088

Answer

R-410A has a GWP of 2088. Common A2L replacements like R-32 (GWP 675) and R-454B (GWP 466) offer 67-78% lower global warming impact per unit.

Question 3

How does the burning velocity of A2L refrigerants compare to common flammable gases like propane?

Accepted Answer

A2L refrigerants burn at less than 10 cm/s — roughly 1/4 the speed of propane

Answer

A2L refrigerants have a maximum burning velocity of 10 cm/s, compared to propane at approximately 40 cm/s. This slower flame spread is a key safety advantage.

Question 4

What is the minimum ignition energy (MIE) for most A2L refrigerants and why does it matter?

Accepted Answer

Relatively high — typically 100-1000+ millijoules, much higher than common flammable gases

Answer

A2L refrigerants require significantly more energy to ignite than common flammable gases. This high MIE means common ignition sources (static discharge, small sparks) are unlikely to cause ignition.

Question 5

Which common A2L refrigerant is a single-component (non-blended) refrigerant?

Accepted Answer

R-32

Answer

R-32 (difluoromethane) is a single-component refrigerant. R-454B is a blend of R-32 and R-1234yf. Single-component refrigerants are simpler to handle since they don't fractionate.

(A2L) A2L Low GWP Flammable Refrigerant Safety Certification Practice Test

(A2L) A2L Low GWP Flammable Refrigerant Safety Certification Practice Test

A2L Properties and Classification 2