The pressure gauge accuracy verification guidelines

Methods for Checking Pressure Gauge Accuracy?

Visual Inspection of Physical Integrity?

Confirm the housing is undamaged and the lens is intact. Replace immediately if cracked to ensure safety.

Check the ?lead seal? remains intact. Absence indicates possible failure/damage; professional servicing is required.

Observe pointer position: At zero pressure, the pointer must align precisely with the ?zero mark?. Deviation suggests internal malfunction.

Verify Color Zones and Readings?

Identify color-coded sectors:

Green?: Safe operating range

Red?: Insufficient pressure (requires replenishment)

Yellow?: Overpressure risk (immediately cease operation).

Read scales accurately: The pointer indicates the pressure value (e.g., "1" = 1 kgf/cm2). Note unit conversions between inner/outer scales (e.g., kgf/cm2 vs. psi) to prevent misjudgment.

Professional Calibration Verification?

Conduct ?comparative calibration? using a traceable reference gauge:

Pressurize the system incrementally via a gas cylinder.

Record readings from both test and reference gauges at each step.

If discrepancies exceed tolerance (e.g., >±0.546 MPa at critical points), recalibrate or replace.

Safety protocol?: Fine-tune pressure sources gradually; stabilize readings before comparison. Prevent overpressure leaks.

Confirm Accuracy Class and Error Limits?

Check the engraved ?accuracy class? on the dial: Smaller numbers denote higher precision (e.g., Class 1.6 indicates industrial grade).

Calculate maximum allowable error:

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Allowable Error = Full Scale × (Accuracy Class ÷ 100)  

Example: 25 MPa gauge with Class 1.6 → ±0.04 MPa error limit.

Use precision gauges (e.g., Class 0.1) for critical applications; Class 1.6 suffices for general industry.

Validate Periodic Certification?

Mandatory ?annual recalibration? (typically every 6 months). Gauges exceeding this period are invalid.

Verify valid calibration stickers/labels affixed to the housing.

Before storage/shutdown: Depressurize to zero and drain media to prevent freezing/corrosion.

Key recommendation?: Entrust accredited calibration laboratories for periodic verification to minimize measurement uncertainty.

Critical Notes?

? Never use gauges with broken seals or expired certifications.

? Avoid field adjustments (e.g., forcing pointer to zero); recalibrate professionally.

? For process-critical applications, implement ?cross-verification? using two independent gauges.