Company cases about Understanding the Accuracy Class of Pressure Gauges: The Relationship Between Error and Class
Understanding the Accuracy Class of Pressure Gauges: The Relationship Between Error and Class
2025-09-28
The accuracy class of a pressure gauge refers to the maximum allowable error range between its measured value and the actual value, usually expressed as a percentage of the full-scale range. The following are the key points:
01 Common Accuracy Classes
Standard Classes: The accuracy classes commonly used in China and internationally (in descending order of accuracy) are:
★ Class 0.1, Class 0.16, Class 0.25 (high accuracy, used in laboratories or for calibration purposes)
★ Class 0.4, Class 0.5 (high industrial accuracy)
★ Class 1.0, Class 1.6 (most commonly used, suitable for general industrial scenarios)
★ Class 2.0, Class 2.5, Class 4.0 (low accuracy, used in occasions with low requirements)
European and American Standards: They may be marked as Class 0.5, Class 1.0, etc., which correspond to the domestic accuracy classes.
02 Calculation of Allowable Error
Formula: Allowable Error = ± (Full-scale Range × Accuracy Class %)
Example: For a Class 1.6 pressure gauge with a full-scale range of 0~1MPa, the allowable error is ± (1MPa × 1.6%) = ±0.016MPa
03 Selection Recommendations
High Accuracy Requirements (e.g., verification, scientific research): Choose Class 0.1 to Class 0.4.
General Industry (e.g., process control): Choose Class 1.0 or Class 1.6.
Rough Monitoring (e.g., non-critical equipment): Class 2.5 can be selected.
04 Other Factors Affecting Accuracy
Ambient Temperature: Exceeding the operating temperature range may affect accuracy.
Medium Characteristics: For corrosive media, special materials (such as 316L stainless steel) must be selected.
Overload Capacity: It is generally recommended to use 1/3 to 2/3 of the full-scale range to improve service life and accuracy.
05 Relevant Standards
China: GB/T 1226-2017
International: EN837, ASME B40.1
06 Notes
The accuracy class is usually marked on the gauge dial (e.g., 1.6).
Higher accuracy means higher cost, so it is necessary to balance according to actual needs.
If you need selection recommendations for specific application scenarios, you can provide more parameters (such as the medium, pressure range, etc.).
