Illinois Plumbing Code Practice

The correct minimum size for gas and oil interceptors in facilities as specified in subsection (a) is indeed 6 cubic feet. This size is determined based on the capacity needed to effectively separate and contain gas and oil from wastewater before it enters the municipal sewer system. Proper sizing is critical for ensuring the interceptor can adequately handle the expected flow and volume of contaminants without risking overflow or system failure. While larger sizes, such as 7 cubic feet or 8 cubic feet, provide additional capacity, the code explicitly sets the minimum requirement at 6 cubic feet to ensure compliance without necessitating larger and potentially more costly systems. Choosing a smaller size, such as 5 cubic feet, would not meet the operational and regulatory standards necessary for effective interceptor function, which could lead to environmental compliance issues and potential contamination problems.