All commercial garage drains shall be a minimum size of _______ inches.

The minimum size for commercial garage drains being 4 inches is established to ensure adequate drainage. This size is essential for effectively handling the volume of water and potential contaminants, such as oil and grease, that may accumulate in a commercial garage setting. A drain that is 4 inches in diameter allows for a sufficient flow rate, reducing the risk of clogging and ensuring that standing water does not accumulate, which could lead to hazardous conditions and promote the growth of mold or bacteria. Additionally, larger drains help accommodate heavy rainfall and possible spills that are common in commercial garages, providing a better solution for maintaining hygiene and safety standards.

Other sizes, such as 2, 3, or 5 inches, do not meet the specified requirements placed by the plumbing code for such installations in commercial settings, which highlights the importance of adhering to the established standards for proper drainage systems.