How do you conduct and interpret a centrifugal compressor performance test?

Test per ASME PTC-10: measure inlet/outlet pressures and temperatures, flow rate, speed, and gas composition. Calculate: polytropic head, efficiency, power, and surge margin. Compare to guarantee point considering tolerances (typically 4% head, 4% efficiency). Account for: gas property variations from design, operating speed differences using fan laws with appropriate correction, and inlet conditions. Degradation assessment compares current test to original data. Field tests use installed instruments; shop tests use more accurate instrumentation.