When should the local dew point alarm activate for instrument air?

The local dew point alarm should activate for instrument air when it is greater than -22°F. This specific dew point is critical because it represents the maximum level of moisture that can be present in instrument air without risking condensation. If the dew point exceeds this threshold, there is a potential for water vapor to condense inside the instrument lines, which can lead to malfunctions or damage to sensitive instruments and systems.

Setting the dew point alarm to activate at this point ensures that the air remains dry enough to prevent moisture-related issues. Maintaining instrument air below this dew point is essential for the proper functioning of pneumatic control systems and instrumentation, as condensation in these systems can lead to errors, reduced performance, or complete failure.

Understanding this concept is crucial for ensuring the reliability and accuracy of systems that rely on instrument air, making it essential to monitor and manage moisture levels effectively.