The register of a floor furnace must have a minimum walking distance width of what measurement on two adjoining sides?

The correct measurement for the minimum walking distance width of the register of a floor furnace on two adjoining sides is 18 inches. This requirement ensures that there is adequate space for safe access around the furnace, allowing for proper air circulation and preventing any obstruction that could interfere with the functioning of the furnace. It also facilitates maintenance and servicing of the unit without posing a trips or falls hazard.

This specific measurement aligns with common building and safety codes which are designed to promote safety and efficiency in mechanical installations. A width of 18 inches provides a sufficient clearance, ensuring that individuals can walk freely near the furnace without risk of injury, while also maintaining the necessary airflow around the unit for optimal performance.