2.3.1
Fan Impeller Blades
Air-foil type [with stationary guide vanes], designed to provide the
efficiency [and sound level] indicated. In fan selection, consider and
account for any losses due to the size of the motor in relation to the fan
hub diameter. Impeller blades of direct-driven fans shall be adjustable to
permit varying performance over a range of volume and pressure. Index the
hub to facilitate setting the angle of the blades uniformly and accurately
from minimum to maximum angle; provide stops to avoid overloading motor.
Furnish motor with the factory blade maximum setting included in the fan
nameplate data.
2.3.2
Fan Casings
Cylindrical, or welded steel construction, with flanged inlets and outlets.
Assemble motor support [and guide vanes] by welding. Provide casings with
bolted or hinged access plates adequate for inspection and servicing of
internal parts.
2.4
BASIC MATERIALS
2.4.1
Coated and Uncoated Carbon Steel Sheets, Plates, and Shapes
2.4.1.1
Mill Galvanized Steel Sheet
ASTM A 653/A 653M, lock forming quality, Coating G-90[, 204 degrees C 400
degrees F, maximum].
2.4.1.2
Mill Galvanized Steel Shapes
ASTM A 36/A 36M galvanized in accordance with [ASTM A 123/A 123M] [ASTM A
653/A 653M].
2.4.1.3
Uncoated (Black) Carbon Steel Sheet
ASTM A 569/A 569M.
2.4.1.4
Uncoated (Black) Carbon Steel Plates and Shapes
ASTM A 36/A 36M.
2.4.2
Corrosion Resistant (Stainless) Steel
ASTM A 167, Type 304L or Type 316L with mill finish, except as otherwise
specified.
2.4.3
Corrosion Protection
Treat equipment fabricated from ferrous metals that do not have a zinc
coating conforming to [ASTM A 123/A 123M] [ASTM A 653/A 653M] for
prevention of corrosion with a factory coating or paint system that will
withstand 125 hours in a salt-spray fog test except that equipment located
outdoors shall withstand 500 hours. Perform salt-spray fog test in
accordance with ASTM B 117. Each specimen shall have a standard scribe
mark as defined in ASTM D 1654. Upon completion of exposure, evaluate and
rate the coating or paint system in accordance with procedures A and B of
ASTM D 1654. The rating of failure at the scribe mark shall be not less
than six (average creepage not greater than 3 mm 1/8 inch). The rating of
SECTION 15801N
Page 20
Previous Page
