The minimum allowable distance to be maintained from a 50,000 Btuh water heater flue outlet to grade level is:

The minimum allowable distance from a 50,000 Btuh water heater flue outlet to grade level is specified as 12" (300mm). This requirement is in place to ensure safety and proper ventilation of exhaust gases. Adequate clearance helps prevent the buildup of potentially harmful exhaust emissions, which could be detrimental to the health of individuals nearby, especially in enclosed or low-ventilation areas.

Setting this distance allows for better dispersion of exhaust gases. It also reduces the likelihood of obstruction from snow, ice, or debris that could compromise the efficient operation of the water heater and potentially lead to dangerous situations, such as carbon monoxide buildup.

This specific distance is aligned with the broader standards that cover the safe installation and operation of gas appliances, emphasizing both safety and operational efficiency. Maintaining this clearance helps ensure that the system functions correctly, adheres to safety regulations, and protects occupants from possible hazards associated with flue gas emissions.