Category
Rotating Equipment
Subcategory
Fan / Blower
Applicable standards
3
Issuing bodies
2
Description
Axial-flow fan (cooling towers, air-cooled exchangers, tunnel ventilation).
Applicable Standards (3)
API — 2 standards
API 661
Petroleum, Petrochemical, and Natural Gas Industries — Air-Cooled Heat Exchangers
Air-cooled heat exchangers for refining/petchem/gas. Identical to ISO 13706.
Key requirements (9)
- Air-cooled heat exchangers (ACHE) for petroleum, petrochemical, natural gas.
- Forced draft (fan below tubes) or induced draft (fan above tubes).
- Standard tube: 1" OD, 11 fpi (fins per inch), 1/2" fin height typical.
- Tube types: embedded G-fin (high temp), extruded bimetal (medium), L-foot/wrapped (low cost).
- Air-side face velocity: typically 3–4 m/s.
- Fan blade tip speed: ≤ 60 m/s.
- Plenum geometry minimums per Section 5.6.
- Vibration: fan natural frequency well separated from rotational frequency.
- Louvers / variable-pitch fans for cold-climate temperature control.
API 673
Centrifugal Fans for Petroleum, Chemical and Gas Industry Services
Centrifugal fans for refinery / petrochemical service (FCC, FD/ID, etc.).
Key requirements (8)
- Centrifugal fans for petroleum, chemical, gas industries.
- Hydrotest: not applicable (atmospheric); structural test instead.
- Mechanical run test: 4 hours minimum.
- Maximum allowable speed: 105% rated for warning, 110% for trip.
- Vibration: bearing housing typically ≤ 7.6 mm/s rms.
- Performance test per ASME PTC 11.
- Materials: CS housing, CS or SS impeller depending on service.
- Bearing L10 life: 25,000 hrs continuous typical.
ASME — 1 standard
ASME PTC 11
Performance Test Code on Fans
Performance testing of industrial fans and blowers.