with rims tight against ceiling. Sponge rubber gaskets shall be provided
between ceiling and surface mounted diffusers for air leakage control.
Suitable trim shall be provided for flush mounted diffusers. Duct collar
connecting the duct to diffuser shall be airtight and shall not interfere
with volume controller. Return or exhaust units shall be similar to supply
diffusers.
2.10.5.2
Registers and Grilles
Units shall be four-way directional-control type, except that return and
exhaust registers may be fixed horizontal or vertical louver type similar
in appearance to the supply register face. Registers shall be provided
with sponge-rubber gasket between flanges and wall or ceiling. Wall supply
registers shall be installed at least 150 mm 6 inches below the ceiling
unless otherwise indicated. Return and exhaust registers shall be located
150 mm 6 inches above the floor unless otherwise indicated. Four-way
directional control may be achieved by a grille face which can be rotated
in 4 positions or by adjustment of horizontal and vertical vanes. Grilles
shall be as specified for registers, without volume control damper.
2.10.6
Louvers
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NOTE: The designer will ensure that louver
selection includes consideration of parameters such
as pressure drop and water penetration.
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Louvers for installation in exterior walls which are associated with the
air supply and distribution system shall be as specified in Section 07600
FLASHING AND SHEET METAL.
2.11
FACTORY PAINTING
Units which are not of galvanized construction according to ASTM A 123/A
123M or ASTM A 653/A 653M shall be factory painted with a corrosion
resisting paint finish. Internal and external ferrous metal surfaces shall
be cleaned, phosphated and coated with a paint finish which has been tested
according to ASTM B 117, ASTM D 1654, and ASTM D 3359. Evidence of
satisfactory paint performance for a minimum of 125 hours for units to be
installed indoors and 500 hours for units to be installed outdoors shall be
submitted. Rating of failure at the scribe mark shall be not less than 6,
average creepage not greater than 10, no failure. On units constructed of
galvanized steel which have been welded, exterior surfaces of welds or
welds that have burned through from the interior shall receive a final shop
docket of zinc-rich protective paint in accordance with ASTM D 520, Type I.
PART 3
EXECUTION
3.1
INSTALLATION
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NOTE: Reference NFPA 31 for oil-fired units.
Reference NFPA 54 for gas-fired units.
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The warm air heating installation shall conform to the requirements
contained in NFPA 90A or NFPA 90B, as applicable. Combustion air supply
and ventilation shall be in accordance with [NFPA 31] or [NFPA 54].
SECTION 15566A
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