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Comply with paragraph entitled "Centrifugal Fans," in this section [,
subparagraph "Utility Set,"] and special requirements for protective
coatings. [Provide unit of all welded construction, utilizing minimum
14-gage carbon steel in AMCA Class II construction.] [Internal and external
protective coating shall be manufacturer's standard, engineered quality
type, with properties comparable to [air-dry or baked phenolic,] [or]
[epoxy] applied in multiple coats of 0.10 to 0.15 mm 4 to 6 mil dry film
thickness.] [Mount entire assembly for vibration isolation on structural
steel base and spring or elastomer type isolators with minimum
transmissibility of [10] [5] percent.] [Provide split sleeve or flexible
connection at fan inlet.]
2.13.4
Flexible Tail Pipe Exhaust Tubing and Connectors
Provide interlocking helical seam metallic type construction of 0.3 mm
0.012 inch minimum thickness up to and including 150 mm 6 inch diameter and
0.51 mm 0.020 inch minimum thickness over 150 mm 6 inches diameter Type
302, 304, or 321 corrosion-resistant steel [with inside diameter] [and
length as shown.] [of] [80] [100] [125] [150] [200]mm and [_____] meters in
length [3] [4] [5] [6] [8] [inches] and [_____] feet in length. Connect to
duct by welding or with screws or flanged joint with gasket [and fit with
tail pipe adapters constructed of minimum 20 gage Type 300 or 400 Series
stainless steel, and which include provisions for secure tail pipe
attachment]. Secure hose terminal connections by screws, clamps, or
flanged connections. [Provide winch operated hose assembly.]
2.13.5
Supporting Elements
Support ducting [as indicated] with anti-sway bracing to resist perceptible
movement in response to forces imposed by flexible tubing location on
handling. Suspend tubing from overhead location and provide means to raise
and lower for use. Assemble suspension system with rigid pulley restraint,
3 mm 1/8 inch diameter aircraft cable, pulleys, and manually operated
winch fitted with safety ratchet lock and slip resistant hand grip.
2.14
WELDING FUME EXHAUST SYSTEM
2.14.1
General Requirements for Welding Fume Exhaust System
Provide a [hanging] [long reach type] welding fume exhaust system as
specified and indicated. Construct and install in accordance with
applicable requirements of NFPA 91.
2.14.2
Ductwork
Construct ducts and stamped fittings with galvanized steel. Duct sheet
metal gages shall conform to Class I in SMACNA Rectangle Duct Const and
SMACNA Rnd Duct Const.
2.14.2.1
Suction Side Ductwork
Construct suction side ductwork with lock groove seam longitudinal joints.
Connect circumferential joints between sections with push-on or crimp and
bead type, secured with a minimum 4 rivets or screws up to and including
100 mm 4 inches diameter, and with screws or rivets a maximum 80 mm 3 inches
on center on larger sizes of duct. Lap joints in the direction of air
flow.
SECTION 15801N
Page 34
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