A steam drum pressure gauge is calibrated in which unit?

The correct unit for calibrating a steam drum pressure gauge is pounds per square inch (psi). This unit is commonly used in the United States for measuring pressure in industrial applications, including boilers and steam systems. Psi signifies the force exerted by one pound of force acting on an area of one square inch, making it a practical choice for capturing the pressures typically encountered in steam systems.

While other units such as bar, kilopascals, and atmospheres are valid for measuring pressure, they are more prevalent in different regions or applications. For example, bar is a metric unit often used in Europe, while kilopascals (kPa) are frequently used in scientific contexts. Atmospheres, too, is a unit that can express pressure but is less common in direct boiler applications within the U.S. Therefore, emphasizing psi as the standard in the context of steam drum pressure gauges reflects industry practices and conventions specific to this field.