What should be the minimum pressure graduation rate for a gauge on the high side of a system?

The minimum pressure graduation rate for a gauge on the high side of a system is set to be 1.2 times the design pressure to ensure accurate readings and maintain safety margins. This additional buffer allows for fluctuations and variations in the system pressure that can occur during operation. By establishing the gauge's graduation at this level, it provides a greater range for monitoring the pressure while also accommodating any potential surges or transient pressures that may arise.

Specifically, using a gauge with this graduation rate ensures that it remains operational and provides reliable data even under higher than normal pressure conditions. This practice is crucial for systems where pressure stability is vital for safety and performance. The choice of 1.2 times the design pressure balances both safety and functionality without unduly complicating the gauge's design or operation.