Category
Rotating Equipment
Subcategory
Compressor
Applicable standards
3
Issuing bodies
2
Description
Multi-stage axial-flow compressor (large industrial / utility / gas turbine inlet).
Applicable Standards (3)
API — 2 standards
API 617
Axial and Centrifugal Compressors and Expander-Compressors
Centrifugal and axial compressors plus expander-compressors for petroleum, petrochemical and gas industries.
Key requirements (10)
- Centrifugal and axial compressors — 8th edition restructured into 5 parts.
- Part 1 General; Part 2 Centrifugal/axial; Part 3 Integrally geared; Part 4 Expander-compressors; Part 5 Packagers.
- Design pressure: max suction + 110% × (max disch − min suct) — covers settle-out.
- Hydrotest: 1.5 × max allowable working pressure of casing.
- Mechanical run test: minimum 4 hours at MCS (max continuous speed) on test stand.
- Performance test per ASME PTC 10 — Class 1 (full performance) or Class 2 (verification).
- Vibration: API 670 — bearing housing < 7.6 mm/s; shaft displacement < 25 µm + 12,000/N (rpm) µm.
- Aerodynamic stall margin ≥ 10 % typical; surge protection mandatory (anti-surge controller).
- Lube/seal oil systems per API 614.
- Driver coupling per API 671.
API 670
Machinery Protection Systems
Vibration, axial-position, bearing temperature monitoring for rotating machinery.
Key requirements (7)
- Machinery protection systems for rotating equipment.
- Standard sensors: 8 mm proximity probes (eddy current), velocity sensors, accelerometers, KPH probes for speed.
- Signal: 200 mV/mil sensitivity for proximity probes (5 V across 25 mil gap).
- Standard alert/shutdown: 25 µm Alert / 50 µm Trip on shaft displacement (typical, tunable).
- Bearing temperature RTD: 100 Ω Pt; 110 °C Alert / 120 °C Trip typical.
- Casing vibration (accelerometer / velocity): 7.6 mm/s RMS typical alert for centrifugal machines.
- API 670 monitoring system has 2-out-of-3 voting for trips, with bypass keys for maintenance.
ASME — 1 standard
ASME PTC 10
Performance Test Code on Compressors and Exhausters
Performance test procedures for centrifugal and axial compressors.
Key requirements (7)
- Performance test code on compressors and exhausters.
- Two test classes: Class 1 (full load, design fluid), Class 2 (model/equivalent fluid).
- Test parameters: inlet pressure/temperature, discharge pressure/temperature, flow, power.
- Polytropic efficiency reported (not isentropic) — preferred for multistage.
- Test points: minimum 4 spanning surge to choke.
- Uncertainty: typically ±2–4% on guaranteed performance.
- Used to verify API 617/618/619 compressor compliance.