1. Why Calibration Is Necessary

In any pressurized system, especially air compressor systems, safety relief valves and pressure gauges are critical components for safe operation and accurate monitoring.

• A safety relief valve protects against overpressure. If it's not properly calibrated, it may fail to open on time, leading to system failure or explosion.

• A pressure gauge provides the operator with real-time pressure data. If inaccurate, it may lead to poor decisions, unsafe conditions, or damage to equipment.

     Regular calibration ensures:

• Safe operating conditions

• Accurate pressure readings

• Regulatory compliance

• Extended equipment lifespan

2. Calibration of Safety Relief Valve

 Purpose:

• Ensure the valve opens at the correct set pressure (e.g., 10 bar)

• Prevent premature discharge or delayed activation during overpressure situations

 Regulatory Requirements in Malaysia:

• Under DOSH (Department of Occupational Safety and Health) / JKKP, safety valves on pressure vessels must be inspected and calibrated annually

• A Competent Person (CP) or certified third-party must carry out the calibration

• Calibration records are required for audits and inspections

 General Calibration Process:

• Remove valve from system (if not inline testable)

• Apply pressure using a calibrated test rig

• Record set pressure (when it opens) and reseating pressure

• Adjust if necessary or replace the valve

• Attach calibration label and issue a calibration certificate

3. Calibration of Pressure Gauge

 Purpose:

• Ensure pressure readings are accurate and within acceptable error limits

• Support safe operation and reliable system monitoring

 Recommended Calibration Frequency:

• Every 6 to 12 months, depending on:

  • Usage frequency

  • Environmental conditions

  • Criticality of the application

• For high-precision or safety-critical systems: every 3 to 6 months

 General Calibration Procedure:

• Connect the gauge to a calibrated pressure source (e.g., hand pump with digital master gauge)

• Check gauge readings at various test points (0%, 25%, 50%, 75%, 100%)

• Compare with the reference standard

• Adjust if possible, or replace if outside of tolerance

• Label and document results in a calibration report

4. Important Notes and Best Practices

• Calibration must be performed by qualified personnel using traceable standard equipment

• Ensure devices are clean and in good condition before calibration

• Maintain full documentation, including:

  • Calibration date

  • Technician name

  • Equipment used

  • Results and next due date

• Replace any valve or gauge that fails calibration

5. Summary Table

Proper calibration of safety relief valves and pressure gauges is a critical part of preventive maintenance. It ensures system safety, compliance with Malaysian regulations (DOSH), and prevents costly failures or accidents.

 Recommendation: Schedule regular calibration with certified personnel, and always maintain records for audit and traceability purposes.