How should pressure sensing lines be positioned relative to the discharge isolation valve?

The pressure sensing lines should be positioned before the discharge isolation valve. This is crucial because positioning the sensing lines in this manner ensures that they can accurately gauge the pressure of the water supply before any influence from the valve occurs. By having the sensing lines before the isolation valve, you avoid potential inaccuracies in pressure readings, which can happen if the lines were placed after the valve where pressure could vary due to valve adjustments or flow restrictions.

Properly placing the pressure sensing line before the valve allows for timely and reliable readings, essential for the operation of sprinkler systems that depend on precise pressure measurements to activate or function correctly. This practice supports the system's responsiveness and promotes safety and performance efficiency in fire protection systems.