liter per second per square meter [10] [25] cfm per square foot of damper
face area at 500 Pa 2 inch w.g. pressure difference.
2.12.7
Louvers
[Manual] [Fixed] type. Fold or bead the edges of louver blades to exclude
driving rain. [Louvers blades shall be oriented to minimize the
entrainment of rainwater.] Make louver frames of [16] [18] gage
[galvanized steel] [or] [aluminum]. Provide bird (insect) screen
constructed of the same type metal as the louvers.
2.12.7.1
Bird Screens
ASTM E 437, general industrial-use wire cloth, Grade C, medium light or
heavier, nominal 2 mesh 1.60 mm 0.063 inch wire diameter, [aluminum] [or]
[galvanized steel] bird screens. Provide removable insect screens of
grooved type, with vinyl or neoprene spline insert for securing screen
cloth.
2.12.7.2
Louvered Penthouse
Low-silhouette, curb-mounted, dome-type roof [intake] [exhaust] unit
equipped with waterproof top and rainproof louvers around the sides.
Provide a removable roof constructed of not less than 2 mm 0.081 inch thick
[aluminum] [or] [galvanized] steel sheet insulated with 25 mm one inch
thick glass fiber with vapor barrier attached to underside of roof.
Internally brace the unit with not less than 50 by 50 by 3 mm 2 by 2 by 1/8
inch aluminum or galvanized steel angles. Provide curb tie-downs and bird
screens. The entire assembly shall have been factory tested to withstand a
200 kilometer per hour 125 mphwind force. Provide [aluminum] [or]
[stainless steel] bolts or screws in the assembly.
PART 3
EXECUTION
3.1
INSTALLATION
Except as specified or indicated otherwise, conform to NFPA 90A, SMACNA
HVAC Duct Const Stds [and SMACNA FGDCS]. Provide mounting and supporting
of ductwork and accessories including, but not limited to, structural
supports, hangers, vibration isolators, stands, clamps and brackets, access
doors, and dampers. Provide electrical isolation between dissimilar
metals. Electrical isolation may be fluorinated elastomers or
sponge-rubber gaskets. Install ductwork accessories as indicated and as
recommended by manufacturer's printed instruction. Allow clearance for
inspection, repair, replacement, and service. Louvers in accordance with
AMCA 501.
3.1.1
Ductwork
Air distribution systems shall operate with no chatter or vibration.
3.1.1.1
Field Changes to Ductwork
Those required to suit the sizes of factory-fabricated equipment actually
furnished, shall be designed to minimize expansion and contraction. Use
gradual transitions in field changes as well as modifications to connecting
ducts. [Provide jumper ducts for discharging air into duct junctions as
indicated.]
SECTION 15810N
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