How far must the sides of a pit or excavation be held back from the appliance?

The correct distance for holding back the sides of a pit or excavation from the appliance is 12 inches. This requirement ensures proper ventilation, accessibility for maintenance, and safety of the appliance. Maintaining this distance helps prevent issues such as water accumulation or debris falling into the appliance area, which can lead to operational failures or safety hazards.

In many mechanical codes, including the International Mechanical Code, specific clearances are mandated for various installations to ensure safe operation and maintenance. These clearances also help delineate safe working environments for technicians when they are conducting repairs or inspections on the appliance. Reducing the distance could compromise these considerations, making the recommended 12 inches a crucial standard in ensuring the appliance operates safely and effectively.