shown on the drawings, but shall in no case exceed 1.5 m 5 feet. Runouts
shall be preinsulated, factory fabricated, and shall comply with NFPA 90A
and UL 181. Provide either field or factory applied vapor barrier.
Provide not less than 0.60 L 20 ounce glass fabric duct connectors coated
on both sides with neoprene. Where coil induction or high velocity units
are supplied with vertical air inlets, use a streamlined, vaned and mitered
elbow transition piece for connection to the flexible duct or hose. The
last elbow to these units, other than the vertical air inlet type, shall be
a die-stamped elbow and not a flexible connector. Insulated flexible
connectors may be used as runouts. The insulated material and vapor
barrier shall conform to the requirements of Section 15080 THERMAL
INSULATION FOR MECHANICAL SYSTEMS. The insulation material surface shall
not be exposed to the air stream.
2.6.1.3
General Service Duct Connectors
Provide a flexible duct connector approximately 150 mm 6 inches in width
where sheet metal connections are made to fans or where ducts of dissimilar
metals are connected. For round/oval ducts, secure the flexible material
by stainless steel or zinc-coated, iron clinch-type draw bands. For
rectangular ducts, install the flexible material locked to metal collars
using normal duct construction methods. The composite connector system
shall comply with UL 214 and be classified as "flame-retarded fabrics" in
UL Bld Mat Dir.
2.6.1.4
High Temperature Service Duct Connections
Material shall be approximately 2.38 mm 3/32 inch thick, 1.2 to 1.36 kg per
square meter 35 to 40-ounce per square yard weight, plain weave fibrous
glass cloth with, nickel/chrome wire reinforcement for service in excess of
650 degrees C 1200 degrees F.
2.6.1.5
Aluminum Ducts
ASTM B 209M ASTM B 209, alloy 3003-H14 for aluminum sheet and alloy 6061-T6
or equivalent strength for aluminum connectors and bar stock.
2.6.1.6
Copper Sheets
ASTM B 152/B 152M, light cold rolled temper.
2.6.1.7
Corrosion Resisting (Stainless) Steel Sheets
ASTM A 167
2.6.2
Ductwork Accessories
2.6.2.1
Duct Access Doors
**************************************************************************
NOTE: Provide duct access doors at regular
intervals to facilitate the cleaning of duct systems
for applications requiring clean air supplies, such
as hospitals, laboratories, electronics servicing
and similar activities.
**************************************************************************
Provide hinged access doors conforming to SMACNA HVAC Duct Const Stds in
ductwork and plenums where indicated and at all air flow measuring
SECTION 15895
Page 17
Previous Page
