After a large R-11 leak in an equipment room, where is the refrigerant vapor most likely to collect?

Safety · EPA 608 Type III. The correct answer, and the reasoning behind it.

ASHRAE Standard 15 equipment-room requirements and refrigerant sensors.

The question

After a large R-11 leak in an equipment room, where is the refrigerant vapor most likely to collect?

• ANear the ceiling
• BEvenly through the room within seconds
• COnly inside the chiller cabinet
• DNear the floor and in pits or low spotsCorrect answer

Why “Near the floor and in pits or low spots” is correct

Fluorocarbon refrigerant vapors are heavier than air, so they settle to the floor and fill pits, trenches and basements. That is where oxygen can be pushed out first and where the danger to workers is greatest.

Source: EPA: Test Topics; ASHRAE Standard 15

Why the other answers are wrong

• Near the ceiling — R-11 vapor is heavier than air and sinks rather than rises.
• Evenly through the room within seconds — Heavy vapor does not mix evenly; it settles.
• Only inside the chiller cabinet — Leaked vapor spreads into the room and settles low.

Practice more of this

More EPA 608 Type III practice questions, or see every EPA 608 practice test.