What are the dimensions of the access opening and passageway for a furnace mounted below the floor?

The dimensions of the access opening and passageway for a furnace mounted below the floor are established by safety and accessibility standards to ensure that maintenance can be performed effectively. The correct answer, which specifies an opening of 2-1/2 feet by 2-1/2 feet, meets the minimum requirements set by industry codes, allowing adequate space for technicians to access the furnace for inspection, repair, and maintenance tasks.

This specific size not only facilitates entry but also ensures that any necessary tools and equipment can be maneuvered properly. Codes often require these dimensions to accommodate the size of most standard furnaces and provide a comfortable working area for professionals, minimizing the risk of injury while performing maintenance.

Other options present dimensions that are either too small or not compliant with codes, which may restrict accessibility or pose safety issues for workers attempting to service or operate the furnace.