Why is high-pressure propane not usable directly by appliances?

The correct choice highlights that appliances designed for propane operation are specifically built to function with low-pressure gas systems. These appliances are calibrated to work optimally at a certain pressure range, which allows for proper combustion and operational efficiency.

Using high-pressure propane directly would result in an inability to control the amount of fuel delivered, leading to unsafe conditions and inefficiencies. High pressure could also result in improper flame characteristics, which are crucial for devices such as heaters, stoves, and dryers that rely on a consistent and controlled flame for safe operation. This mismatch could cause appliance damage or malfunctions and poses safety risks such as gas leaks or explosions.

While high-pressure propane is indeed flammable and could theoretically cause wear on appliances, the primary concern centers around the designated pressure levels that appliances are engineered to handle, underscoring the importance of adhering to equipment specifications for safe and effective use. Regulatory approvals may be required for high-pressure systems, but the fundamental operational principle remains that appliances are specifically designed for low-pressure use for safety and efficiency.