HVAC Safety Practices 3

Question 1

Which safety device is required on a refrigerant recovery cylinder to prevent over-pressurization?

Accepted Answer

A pressure relief valve or fusible plug

Answer

Recovery cylinders must have a pressure relief valve or fusible plug to safely vent refrigerant if internal pressure becomes dangerously high.

Question 2

What is the purpose of evacuating an HVAC system to 500 microns or lower before charging with refrigerant?

Accepted Answer

To remove air and moisture that would cause system damage and reduced efficiency

Answer

Deep evacuation removes non-condensables (air) and moisture, both of which degrade system performance and can cause acid formation and corrosion.

Question 3

A technician needs to work on an HVAC unit energized at 480V. According to NFPA 70E, what PPE category likely applies for this voltage level?

Accepted Answer

PPE Category 2 or higher — arc flash suit and face shield

Answer

480V systems typically require PPE Category 2 or higher per NFPA 70E, including arc-rated clothing, face shield, and insulated gloves.

Question 4

Why should a technician NEVER use oxygen to pressurize an HVAC refrigerant system for leak testing?

Accepted Answer

Oxygen combined with refrigerant oil can create an explosive mixture

Answer

Oxygen combined with compressor oil and refrigerant can form an explosive mixture that can detonate under pressure.

Question 5

Which OSHA standard specifically governs lockout/tagout procedures for HVAC equipment with stored energy?

Accepted Answer

29 CFR 1910.147 — Control of Hazardous Energy

Answer

OSHA 29 CFR 1910.147 (Control of Hazardous Energy) governs lockout/tagout procedures to prevent unexpected energization of equipment during maintenance.

HVAC Practice Test

HVAC Practice Test

HVAC Safety Practices 3