Codes and standards are intended to provide a minimum level of protection for the public’s health, safety and welfare. And, generally, these documents accomplish that intended purpose in the urban/metropolitan areas of the United States. However, that may not be accurate when one gets into the rural or more isolated areas of the country. It also requires that design professionals have the appropriate knowledge of fittings and flow patterns to assure the system works as intended.
Recently there was a post on the ASPE Connect “Open Forum” regarding “Circuit Venting — Horizontal vs. Vertical Connections.” The correspondent was trying to get a better understanding of how the circuit or loop venting system operated. They had done some research in the IPC (International Plumbing Code), UPC (Uniform Plumbing Code) and the NSPS (National Standard Plumbing Code) to gain knowledge about how these venting methods correctly worked.