In a large municipal trunk line, how often should isolation valves be placed?

Isolation valves are critical components in water distribution systems, particularly in large municipal trunk lines. They allow for the isolation of specific sections of the piping system for maintenance or repairs without shutting down the entire water supply. Proper placement is essential for operational efficiency and safety.

Placing isolation valves every 300 to 600 feet strikes a balance between accessibility and cost. This spacing ensures that a significant length of the trunk line can be accessed quickly for repairs or maintenance, minimizing disruption to the water supply. By having valves at these intervals, operators can effectively manage the system by isolating sections without imposing excessively long outages on customers.

This range of spacing also considers factors such as the diameter of the pipes, the potential for leaks, and the operational requirements of the water distribution system. Closer valve spacing could lead to higher costs and unnecessary complexity, while wider spacing might make isolating sections too cumbersome, delaying necessary maintenance and repairs.

Overall, the recommendation of placing isolation valves every 300 to 600 feet is based on optimizing both the operational efficiency of the water distribution system and the practicality of conducting future maintenance work.