What is the fundamental objective of adequate ventilation in B28 mechanical rooms?

• A. To maximize air exchange rate to remove all refrigerants.
• B. To keep air temperature constant.
• C. To reduce noise levels.
• D. To dilute any leaked refrigerant so its concentration remains below the lower flammable limit (LFL).

Answer: (D)

Adequate ventilation in B28 mechanical rooms is about diluting any leaked flammable refrigerant so its concentration stays below the lower flammable limit. When a leak occurs, the vapor mixes with the room air. If the concentration rises to the LFL or higher, ignition is possible if there’s an ignition source. By providing sufficient air exchange, the vapor is diluted enough to keep the mixture too lean to ignite, substantially reducing the fire risk. This focus on limiting flammable vapor concentration is more important for safety than trying to remove every trace of refrigerant, maintaining a constant temperature, or reducing noise. Proper design ensures the ventilation rate and exhaust pathways keep the vapor from accumulating while not creating other hazards.