locking setscrew. Unless otherwise indicated, the locking-type quadrant
operators for dampers, when installed on ducts to be thermally insulated,
shall be provided with stand-off mounting brackets, bases, or adapters to
provide clearance between the duct surface and the operator not less than
the thickness of the insulation. Stand-off mounting items shall be
integral with the operator or standard accessory of the damper
manufacturer. Volume dampers shall be provided where indicated.
2.10.3.4
Air Deflectors and Branch Connections
Air deflectors shall be provided at duct mounted supply outlets, at takeoff
or extension collars to supply outlets, at duct branch takeoff connections,
and at 90 degree elbows, as well as at locations as indicated on the
drawings or otherwise specified. Conical branch connections or 45 degree
entry connections may be used in lieu of deflectors or extractors for
branch connections. All air deflectors, except those installed in 90
degree elbows, shall be provided with an approved means of adjustment.
Adjustment shall be made from easily accessible means inside the duct or
from an adjustment with sturdy lock on the face of the duct. When
installed on ducts to be thermally insulated, external adjustments shall be
provided with stand-off mounting brackets integral with the adjustment
device, to provide clearance between the duct surface and the adjustment
device not less than the thickness of the thermal insulation. Air
deflectors shall be factory-fabricated units consisting of curved turning
vanes or louver blades designed to provide uniform air distribution and
change of direction with minimum turbulence or pressure loss. Air
deflectors shall be factory or field assembled. Blade air deflectors, also
called blade air extractors, shall be approved factory fabricated units
consisting of equalizing grid and adjustable blade and lock. Adjustment
shall be easily made from the face of the diffuser or by position
adjustment and lock external to the duct. Stand-off brackets shall be
provided on insulated ducts and are described herein . Fixed air
deflectors, also called turning vanes, shall be provided in all 90 degree
elbows.
2.10.4
Duct Sleeves, Framed Prepared Openings, Closure Collars
2.10.4.1
Duct Sleeves
Duct sleeves shall be provided for round ducts 375 mm 15 inches in
diameter or less passing through floors, walls, ceilings, or roof, and
installed during construction of the floor, wall, ceiling, or roof. Round
ducts larger than 375 mm 15 inches in diameter and square, rectangular, and
oval ducts passing through floors, walls, ceilings, or roof shall be
installed through framed prepared openings. The Contractor shall be
responsible for the proper size and location of sleeves and prepared
openings. Sleeves and framed openings are also required where grilles,
registers, and diffusers are installed at the openings. Framed prepared
openings shall be fabricated from 1.0 mm (20 gauge) 20 gauge galvanized
steel, unless otherwise indicated. Where sleeves are installed in bearing
walls or partitions, black steel pipe, ASTM A 53/A 53M, Schedule 20 shall
be used. Sleeve shall provide 25 mm 1 inch clearance between the duct and
the sleeve or 25 mm 1 inch clearance between the insulation and the sleeve
for insulated ducts.
2.10.4.2
Framed Prepared Opening
Openings shall have 25 mm 1 inch clearance between the duct and the opening
or 25 mm 1 inch clearance between the insulation and the opening for
SECTION 15566A
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