EPC Interactive Guide: Anti-Surge Valve Design Review
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Ensure all necessary documentation is present, complete, and compliant with project specifications and international standards.
| Status | Check Point | Key Considerations |
|---|---|---|
| Vendor Document Register (VDR) | Confirm all required documents are listed and their submission schedule aligns with the project timeline. | |
| Datasheet | Cross-check with process data, P&ID, and control philosophy. Ensure all fields are complete. | |
| Piping and Instrumentation Diagram (P&ID) | Verify valve tag number, type, size, fail-safe position, and associated instrumentation are correctly represented. | |
| Compliance to Standards (API 670) | Verify adherence to relevant standards, especially API 670 for Machinery Protection Systems. | |
| Material Certificates (EN 10204 3.1) | Request and review material certificates for all wetted parts. | |
| Inspection and Test Plan (ITP) | Review the ITP for necessary tests and witness points for EPC/client. |
The correct sizing is fundamental. An undersized valve can't prevent surge; an oversized one causes instability.
| Status | Check Point | Key Considerations |
|---|---|---|
| Sizing Calculations (Cv) | Independently verify the flow coefficient ($C_v$) for all operating cases (start-up, normal, trip). | |
| Velocity and Noise | Check exit velocity to prevent erosion and ensure noise is within limits (typically < 85 dBA). Review noise attenuation trim design. | |
| Choked Flow | Verify that the valve avoids choked flow conditions during normal modulating service. |
The mechanical design must be robust enough for demanding service conditions.
| Status | Check Point | Key Considerations |
|---|---|---|
| Valve Body and Trim Materials | Verify materials are suitable for the process fluid, temperature, and pressure. Check for corrosion/erosion potential. | |
| Trim Design | For high-pressure drops, confirm a multi-stage or cage-guided trim is used to prevent cavitation, flashing, and excessive noise. | |
| Seat Leakage Class | Confirm the seat leakage class (e.g., ANSI/FCI 70-2 Class IV, V, or VI) is appropriate for the application. Tight shut-off is often critical. |
The speed and accuracy of the actuator are paramount for an effective anti-surge response.
| Status | Check Point | Key Considerations |
|---|---|---|
| Stroking Speed | CRITICAL: Verify the valve can stroke from fully closed to the required open position in 1-2 seconds. | |
| Fail-Safe Action | Confirm the fail-safe action (e.g., Fail Open) matches the P&ID and control philosophy. This is a critical safety function. | |
| Positioner Type | Ensure a high-performance, fast, and accurate digital positioner with advanced diagnostics is specified. | |
| Volume Boosters / Quick Exhaust | Verify inclusion and proper sizing of volume boosters or quick exhaust valves to achieve the required stroking speed. |
Thorough testing provides the ultimate verification of the valve's performance and build quality.
| Status | Check Point | Key Considerations |
|---|---|---|
| Factory Acceptance Test (FAT) Protocol | Ensure the FAT includes hydrostatic test, seat leakage test, and functional tests. | |
| FAT Witness: Stroking Speed Test | CRITICAL WITNESS POINT: The stroking speed test must be witnessed by the EPC/client to confirm compliance. | |
| Painting and Coating | Verify that the painting and coating specifications meet the project's environmental and durability requirements. |