What is preferable for the pressure reading on steam gauges?

The preferable pressure reading on steam gauges is typically represented in percentages of the gauge range. In many applications, a reading of 150% is often considered an upper limit for safety and operational efficiency. This means that a gauge should be designed to accurately reflect pressures up to that percentage of its full scale.

When a steam gauge reads around 150% of its rated capacity, it provides a safety margin without exceeding the maximum allowable working pressure (MAWP) of the system. Operating at or near this level can signal an impending issue if the pressure doesn't stabilize or is sustained for too long.

While other percentages, like 100% or even higher values such as 200% or 250%, might seem relevant, they represent scenarios that can either be insufficient for safety margins or beyond the optimal range for reliable operation. Gauges exceeding 150% can lead to potential readings that are unsafe or unrepresentative of the system's actual pressures. This understanding is core for ensuring safety in boiler operation and maintaining the integrity of the system.