MIL-PRF-24751A(SH)
3.2 Materials. Fan shall be of spark resistant construction as defined in AMCA 99-0401 Type B construction.
Cast iron shall not be used in the construction of fans nor shall cast iron be used in motors, which are components of
fans. Materials shall be corrosion resisting or material shall be protected against corrosion after fabrication.
Material degraded during the fabrication process shall be normalized to restore those properties before assembled in
any filter. Selected materials shall be capable of meeting all of the operational and environmental requirements
specified herein.
3.2.1 Hazardous material. Materials for use in the construction of fans shall have no effect on the health of
personnel when the materials are used for intended purpose. Regardless of other requirements, materials and parts
containing asbestos, cadmium, lithium, mercury, or radioactive material shall not be used.
3.2.2 Fasteners. Material for all bolts, nuts, studs, screws and similar fasteners shall be corrosion-resistant
passivated or of a material rendered resistant to corrosion. Sheet metal screws shall not be used. Galling shall be
prevented. Tapped holes shall be reinforced where shearing of thread can occur.
3.2.3 Nonmagnetic construction. When nonmagnetic fan-motor units are specified (see 6.2), all fan parts
including the casing, vanes, impeller, impeller bushing, motor mounting, fasteners, washers, conduit box and fittings
shall be of nonmagnetic material. Nonmagnetic material is defined as a material, which has a maximum relative
permeability of less than 2.0 after fabrication.
3.2.4 Motor material. Motor material shall conform to the requirements of IEEE STD 45 or NEMA MG 1 as
applicable for nonmagnetic motors.
3.2.5 Dissimilar metals. Fans and components shall not be degraded by electrolysis as specified in
MIL-STD-889.
3.2.6 Recovered materials. Unless otherwise specified herein, all equipment, material, and articles incorporated
in the products covered by this specification shall be new and may be fabricated using materials produced from
recovered materials to the maximum extent practicable without jeopardizing the intended use. The term "recovered
materials" means materials, which have been collected or recovered from solid waste and reprocessed to become a
source of raw materials, as opposed to virgin raw materials. None of the above shall be interpreted to mean that the
use of used or rebuilt products is allowed under this specification unless otherwise expressly stipulated.
3.2.7 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally
preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the
operational and maintenance requirements, and promotes economically advantageous life cycle costs.
3.3 Painting. Equipment and component items shall be delivered with the manufacturer's standard finish,
except as to comply with the requirements of 3.2.
3.4 Welding and allied processes. Surfaces of parts to be welded or brazed shall be free from rust, scale, paint,
grease, and other foreign matter. Welding and allied processes shall be performed by personnel certified to AWS
B2.1 and B2.2. NAVSEA Technical Publication S9074-AR-GIB-010/278 shall be used for guidance.
3.5 Identification plates. Each fan shall be provided with a permanently attached corrosion-resistant
identification plate. The method of attachment of the identification plate shall be corrosion-resistant. The
identification plate shall contain the following information as a minimum:
a. Manufacturer's name, commercial and government entity, and part number
b. Fan identification code
c. PIN code
d. Direction of airflow and rotation
e. Bearing lubrication
The identification plate and a duplicate motor identification plate shall be installed on the outside of the fan
casing.
3.6 Interchangeability. In no case shall parts be physically interchangeable or reversible unless such parts are
also interchangeable or reversible with regard to function, performance, and strength.
5
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business