API 673 Compliant Fan

The fan specification is more like a contract requirement for oil refineries, petrochemical complexes and gas processing facilities. Every purchase order for critical process ventilation in these industries references a single standard. That is API 673 - Centrifugal Fans for Petroleum, Chemical, and Gas Industry Services. This standard is published by the American Petroleum Institute, currently in its third edition (2014). It determines what the minimum requirements for design, materials, production, testing, and documentation will be. If a fan does not have full API 673 compliance, like rotor dynamic analysis, witnessed shop test reports and a complete vendor data package then it fails the technical bid evaluation. No matter how excellent quality the fan is, it can't pass through the refinery gate without documents.

The API 673 Compliant Fans have been designed from the sketch up to easily meet every mandatory requirement of this standard. The layouts and bearing support of this fan have been designed according to AMCA 99 Arrangements 3 or 7 standards and the impeller is located between two bearings, allowing the rotor to maintain perfect stability. Lateral critical speed analysis is performed following 'Annex D' of the standard. Therefore a safe margin of at least 25% is maintained between the operating speed of the fan and any critical speed. Its impeller balance is much stricter than the 'G6.3' standard of typical industrial fans, it is considered to be ISO 1940 Grade G2.5 or better. In addition, the vibration of the bearing housing is tested according to standard procedures. The limit is stricter than the 3.0 mm/s limit of ISO 10816-3. Shaft sealing is designed to prevent the escape of toxic, corrosive or flammable process gases into the atmosphere. Continuous welding is applied throughout the housing according to AWS standards. Full access doors are provided for service inspections.

As per the mandatory rules of the standard, an API 673 Compliant Fan is designed in such a way that it can provide a minimum of 20 years of service and can operate continuously for at least 3 years between any two maintenance periods. The material (e.g. carbon steel, SS304, SS316L or alloy steel) is selected based on the datasheet of the process in which the fan will be used. At the same time, full material mill certification and traceability are provided for all its components. A complete Annex G vendor data package is supplied with each unit. This package includes rotor response plots, critical speed maps, performance test certificates, mechanical run test records and signed material certifications. All these documents are fully prepared in advance for review by the EPC contractor and submission to Project Document Control.