MIL-PRF-18953C(SH)
3.6 Interchangeability. In no case shall fan parts (excluding motor parts) be physically interchangeable or
reversible unless such parts are also interchangeable or reversible with regard to function, performance, and strength.
3.7 Operating life. The equipment shall have an operating life of not less than 223,800 hours (equivalent to
approximately 30 years of operation). Any part identified as planned replacement parts shall have an operating life,
prior to replacement, of approximately 37,300 hours (equivalent to approximately 5 years of ship operation).
3.8 Human engineering. The fan shall be arranged so as to achieve safe, reliable, and effective performance by
the operator and maintenance personnel and to optimize personnel skill requirements. ASTM F1166 shall be
utilized as a guideline in applying human engineering design criteria for the fan-motor unit.
3.9 Maintainability. The fan shall be constructed so that:
a.
Fan impeller shall be mounted on the motor shaft in such a manner that it is removable using
commonly available tools.
b.
Bearings shall be removable using commonly available tools.
c.
Parts shall be match marked or attached so that reinstallation will be in the same position as originally
installed.
d.
Motor shall be removable using commonly available tools.
3.10 Design requirements.
3.10.1 Aerodynamic design parameters. The quantities of blades and vanes shall be designed to avoid interacting
frequencies within the audible range. The axial distance between blades and vanes shall be designed with minimum
noise amplitude in accordance with Table I. The maximum blade tip clearance (radial clearance) shall not exceed ¼ of
1 percent of the casing minimum inside diameter.
7
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business