2.14.2.2
Discharge Side Ductwork
Construct ductwork on the discharge side of the fan leak-tight with joints
and seams welded, brazed, or soldered. Provide flanges with suitable
gaskets, where required. Repair damaged galvanizing with galvanizing
repair compound.
2.14.3
Fan
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NOTE: The criteria for special AMCA construction
for protective coating can be further delineated
here or incorporated into referenced paragraph, if
this is the only fan. Specify welded Class II
construction only where required.
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NOTE: See Section 15070, "Mechanical Sound,
Vibration, and Seismic Control," for guidance given
in guide specification technical notes. Definite
requirements should be specified in contract
specification for bidders' information.
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Comply with paragraph entitled "CENTRIFUGAL FANS" [, subparagraph "Utility
Set,"] in this Section and special requirements for protective coatings.
[Provide unit of all welded construction, utilizing a 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 a minimum
transmissibility of [10] [5] percent.] [Provide split sleeve or flexible
connection at fan inlet.]
2.14.4
Flexible Welding Fume Exhaust Tubing and Connectors
Provide corrosion protected, spring steel helix reinforced, neoprene
impregnated, woven fibrous glass fabric laminate, flexible tubing with
cuffed ends or equivalent construction, and with an inside diameter [and
length as shown.] of [100] [125] [150] mm [and _____ meters in length] [4]
[5] [6] inches [and _____ feet in length]. Connect to duct with clamp or
gasketed flange [and fit with swivel connected conical fume hood,
constructed of minimum 20 gage aluminum [or 26 gage galvanized steel] [or
ABS plastic] and fitted with 13 mm 1/2 inch mesh intake screen and magnets
for holding receptor in fixed location]. Secure tubing to terminal devices
by clamping. [Provide spring or weight counterbalanced supporting arms for
flexible hose section of long reach system.]
2.14.5
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
SECTION 15801N
Page 35