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Surge Margin Calculator

API 617 Anti-Surge Control

Surge Margin Analysis
Calculate surge margin, control line positioning, and minimum stable flow for centrifugal compressor anti-surge control per API 617. Includes safety margin verification and operating zone classification.

Flow Parameters

ACFM
Current operating flow rate at suction conditions
ACFM
Minimum stable flow from performance curve

Control Parameters

% above surge
Typical: 10% per API 617
% above control
Additional buffer for process upsets

Head Parameters (Optional)

ft or ratio
Head or Pressure Ratio at operating point
ft or ratio
Maximum head at surge point

Surge Margin Requirements

  • Minimum: 10% per API 617
  • Variable load: 15-20% recommended
  • Control line: 10% above surge limit
  • Safety line: 5% above control line

Standards & References

  • API 617
    Axial and Centrifugal Compressors
  • GPSA
    Section 13: Compressors and Expanders