What type of gas typically requires special ventilation during appliance operation?

LPG (liquefied petroleum gas) typically requires special ventilation during appliance operation due to its properties and behavior. When LPG is used, it may not mix well with air because it is heavier than air. This characteristic makes it prone to settling in low-lying areas, which can create a risk of dangerous gas accumulation if not properly ventilated. Adequate ventilation is crucial to ensure that any gas leaks can dissipate safely and that combustion occurs in an environment sufficient to sustain adequate airflow for efficient burning.

In contrast, natural gas, which is lighter than air, disperses more readily and may not necessitate the same level of ventilation precautions as LPG. Coal gas has largely fallen out of use due to safety concerns and efficiency issues, but when it was in common use, it did not have the same ventilation requirements as LPG. Therefore, while all gases have safety considerations, LPG is distinctive in its need for special ventilation during operation due to its potential hazards in enclosed spaces.