What is the minimum face size required for a non-mercury gauge?

The minimum face size required for a non-mercury gauge is indeed 2-1/4 inches. This specification is essential for ensuring that the readings on the gauge are clear and easily readable. A larger face size minimizes the likelihood of parallax errors and enhances visibility, which is particularly important in a high-pressure environment where precision is critical for safety and operational efficiency.

Gauges that are smaller than this specified size may not provide an adequately clear display, making it difficult for operators to interpret important pressure readings quickly and accurately. This is especially relevant in contexts where immediate action may be needed based on the gauge’s reading.

In summary, the 2-1/4 inch face size is a standard that strikes a balance between clarity and convenience, allowing for effective monitoring of boiler pressure while complying with safety regulations.