This specification covers centrifugal and axial fans and blowers with airstream components fabricated of fiber-reinforced thermoset plastics (FRP) for corrosion resistance. Internal structures may include encapsulated metal fastening devices, hubs, and shafts.Reinforcing materials other than fibrous glass may be used in the fabrication, provided the fans and blowers produced meet all the requirements of this specification. The term "fans" as used in this specification includes fans and blowers, both centrifugal and axial.The purpose of this specification is to provide users, system designers, specifiers, and manufacturers of FRP fans with minimum standards for fan construction and a common basis for determining safe operating speeds. The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided for information only. Note 1 -There is no similar or equivalent ISO standard. Note 2 -Appendix X2 contains a list of documents that may be of interest to designers of fan systems. 1.6 This standard does not puport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and helath practices and determine the applicability of regulatory limitations prior to use.