3.1.5.1
Slope
Slope horizontal ducts [25] [_____] mm in [12] [_____] meters [one] [_____]
inch in [40] [_____] feet in the direction of airflow or [25] [_____] mm in
[3] [_____] meters [one] [_____] inch in [10] [_____] feet in opposite to
the direction of airflow. Where necessary, slope duct to common drainage
point.
3.1.5.2
Drains
Provide drains at all low points, at internal drainage restrictions, at
base of risers, and where indicated. Provide drain connections of 25 mm
one inch IPS couplings with polytetrafluoroethylene paste lubricated plug
where drainage piping is not indicated, and where piping is indicated,
provide PVC Type DWV piping conforming to ASTM D 2665 to points indicated.
Provide a trap of one inch greater depth than the positive or negative
pressure in the duct but not less than 50 mm 2 inches.
3.1.5.3
Duct Supports
Isolate duct support contact surfaces from supporting steel by 6 mm 1/4 inch
thick closed-cell foamed cellular elastomer insulation material of a width
greater than support. Design duct supporting system to include additional
weight due to collection of condensate and washing water in nondrainable,
deflected surface and other areas.
3.1.6
Miscellaneous Sheet Metal Work
Provide [_____] and [_____], fabricated from [mill galvanized steel] [black
steel and protectively coated] [aluminum] [_____], as indicated. Sheet
metal thickness, reinforcement and fabrication, where not indicated, shall
conform to SMACNA Industry Practice.
3.1.7
Building Penetrations
3.1.7.1
General Penetration Requirements
Provide properly sized, fabricated, located, and trade coordinated sleeves
and prepared openings, for duct mains, branches, and other item
penetrations, during the construction of the surface to be penetrated.
Provide sleeves for round duct 380 mm 15 inches and smaller and prepared
openings for round duct larger than 380 mm 15 inches and square or
rectangular duct. Fabricate sleeves, except as otherwise specified or
indicated, from 20 gage, 1.00 mm 0.0396 inch thick mill galvanized sheet
metal. Sleeves penetrating load bearing surfaces shall be standard weight
galvanized steel pipe. Provide roof penetrations as shown in SMACNA
Industry Practice.
3.1.7.2
Framed Opening
Provide framed openings in accordance with approved shop drawings. Refer
to paragraph entitled "Fire Dampers," in this section, for related work.
3.1.7.3
Clearances
Provide a minimum 25 mm one inch clearance between penetrating and
penetrated surfaces. Fill clearance space with bulk fibrous glass or
mineral wood [or foamed silicone] and seal and close.
SECTION 15801N
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