Note:

This tool calculates the Minimum Orifice Area for Air in a safety valve, based on volumetric flow rate, absolute relieving pressure, and discharge coefficients. Proper sizing ensures efficient pressure relief and prevents system overpressure.

Understanding Parameters:

• Volumetric Flow Rate (V̇) (l/s): The total air volume that needs to be discharged per second.
• Absolute Relieving Pressure (Pᵣ) (bar a): The system pressure at which the valve will relieve air.
• Derated Coefficient of Discharge (K_dr): A correction factor accounting for discharge efficiency.
• Inlet Temperature (T) (K): The temperature of the air entering the valve, measured in Kelvin.
• Flow Area (A₀) (mm²): The minimum required orifice area to safely discharge air, calculated using:

Key Applications:

• Air Safety Valve Sizing: Ensures the valve can handle the required airflow under relief conditions.
• Compressed Air Systems: Protects systems from excessive pressure buildup.
• Industrial Pneumatic Systems: Ensures efficient air pressure regulation in industrial machinery.
• Regulatory Compliance: Ensures adherence to safety standards such as BS 6759 for pressure relief devices.

Validations & Input Constraints:

• Volumetric Flow Rate (V̇) must be positive: The discharged airflow must be a valid positive number.
• Pressure (Pᵣ) must be greater than zero: Absolute relieving pressure must be a positive value.
• Coefficient of Discharge (K_dr) must be valid: Must be within the acceptable range (0-1).
• Temperature (T) must be in Kelvin: Temperature must be a positive Kelvin value (above absolute zero).
• Check for extreme Orifice Area values: Very small or large areas may indicate incorrect input values or improper valve selection.

BS 6759 is a British Standard that specifies requirements for the performance, design, and testing of safety valves used in pressurized systems. It ensures that safety valves operate reliably to prevent overpressure in boilers, pipelines, and industrial equipment.

Conclusion:

This tool helps engineers and technicians determine the minimum orifice area required for a safety valve in air systems. Proper valve sizing enhances safety, efficiency, and compliance with industrial safety standards.