What is the maximum allowable length for hoses used on the low-pressure side of a regulator to connect to appliances other than domestic and commercial?

The correct answer is 72 inches. This length is in accordance with safety standards and regulations governing the installation and use of propane systems. Hoses that connect the low-pressure side of a regulator to specific appliances must remain within this maximum length to ensure that the system operates safely and effectively.

Using a hose that is longer than the permissible length can lead to issues such as increased friction loss, which may affect the appliance's performance and result in inefficient gas delivery. Also, longer hoses could create more opportunities for potential leaks, which poses safety concerns. Thus, adherence to the 72-inch maximum helps maintain the integrity of the propane system and ensures compliance with regulatory requirements.

In other options, lengths beyond 72 inches, such as 96 inches or 120 inches, would exceed the safety recommendations and could significantly increase risks associated with gas appliances. The 48-inch limit, while safe, is shorter than the maximum allowable length, making 72 inches the appropriate choice for flexibility in installation while ensuring safety.