Air Valve Selection for Competing Pipeline Project Needs

Air valve selection for water transmission mains and wastewater force mains must meet a variety of conditions to meet client needs. This includes factors such as performance, protection, cost, operations and maintenance, and owner preferences. Although AWWA M51 provides detailed guidelines for sizing and selection to meet performance criteria, this can often be in potential conflict with surge control protection. Surge control protection requires considerations such as column separation, vacuum formation and cavitation effects that often go with pumping applications or significant variation in pipeline profile. There is increasing pressure on infrastructure to avoid conflicts while emphasizing cost control and smart air valve selection can play a critical role in pipeline design. This paper will offer considerations associated with practical project design objectives, where it is necessary to satisfy both M51 and transient control criteria for satisfactory performance outcomes while also considering numerous other drivers that impact decision making. Several case studies will be reviewed that highlight different outcomes, all based on consideration of the competing needs on pipeline projects.