How to Choose Accuracy Class for Industrial Gauges
A Practical Guide for Buyers and Engineers
Introduction
Accuracy class is one of the most frequently misunderstood specifications when purchasing industrial pressure gauges.
Many buyers assume that higher accuracy is always better, while in reality, incorrect accuracy selection can increase costs, reduce gauge lifespan, and even cause unstable readings in real operating conditions.
This guide explains how accuracy classes work, when higher accuracy is truly necessary, and how to choose the right class for your application.
What Is Accuracy Class?
Accuracy class defines the maximum permissible error of a pressure gauge, expressed as a percentage of the full-scale value.
For example:
- A Class 1.6 gauge with a full scale of 100 bar may have an error of ±1.6 bar.
- A Class 1.0 gauge under the same range may have an error of ±1.0 bar.
Most industrial gauges follow standards such as EN 837 or ASME B40.100.
Common Accuracy Classes and Their Typical Uses
| Accuracy Class | Typical Application |
| 2.5 | General indication, non-critical systems |
| 1.6 | Standard industrial applications |
| 1.0 | Process control and monitoring |
| 0.6 / 0.4 | Calibration, testing, laboratories |
Why Higher Accuracy Is Not Always Better
Choosing a higher accuracy class does not automatically improve system performance.
In real-world industrial environments, factors such as:
- Vibration
- Pressure pulsation
- Temperature fluctuations
can negatively affect high-accuracy gauges, sometimes making them less stable than lower-class alternatives.
For example, a Class 0.6 gauge installed on a vibrating hydraulic system may lose accuracy faster than a Class 1.6 liquid filled gauge.
Accuracy vs. Operating Conditions
Accuracy selection must be matched with operating conditions.
Stable Conditions
- Low vibration
- Constant pressure
- Controlled environment
➡ Higher accuracy classes (1.0 or better) may be justified.
Harsh Conditions
- High vibration
- Frequent pressure spikes
- Outdoor exposure
➡ Moderate accuracy (1.6) combined with vibration resistance often delivers better long-term reliability.
At GIC, application conditions are always reviewed together with accuracy requirements during specification confirmation.
Accuracy and Pressure Range Selection
Accuracy class and pressure range work together.
Best practice:
- Normal operating pressure should be 60–70% of full scale
- Avoid continuous operation near maximum range
Incorrect range selection often causes more accuracy loss than choosing a lower accuracy class.
Common Buyer Mistakes
- Selecting accuracy based only on price comparison
- Using laboratory-grade accuracy in industrial environments
- Ignoring vibration and temperature influence
- Over-specifying accuracy for non-critical monitoring
These mistakes often lead to unnecessary replacement and recalibration costs.
Practical Recommendation for Buyers
Before selecting an accuracy class, consider:
- System function (monitoring vs control)
- Environmental conditions
- Applicable standards
- Long-term maintenance expectations
Providing application details during RFQ helps suppliers recommend a balanced solution, rather than an over-engineered one.
Conclusion
Accuracy class should be chosen based on real operating conditions, not assumptions.
A correctly selected Class 1.6 gauge can often outperform a higher-accuracy gauge when installed in demanding industrial environments.
At GIC, accuracy selection is treated as part of system reliability planning—not just a line item on a datasheet.