2.9.3
Radius Elbows
Fabricated from butt welded specified piece gore sections or from formed
welded or seamless tubing to a minimum centerline radius of [2.0] [2.5]
[_____] diameters. Assemble, weld, and finish ground gore sections to
eliminate internal projections. Construct gored elbow in accordance with
the following:
400 mm diameter and less
Over 400 mm diameter
16 inches diameter and less
Over 16 inches diameter
90 degree - 5 piece minimum
90 degree - 7 piece minimum
60 degree - 4 piece minimum
60 degree - 6 piece minimum
45 degree - 3 piece minimum
45 degree - 5 piece minimum
30 degree - 3 piece minimum
30 degree - 4 piece minimum
15 degree - 2 piece minimum
15 degree - 3 piece minimum
2.9.4
Gasketed with full face gaskets 3 mm 1/8 inch thick red or black rubber as
specified under paragraph, "Miscellaneous Materials," in this section.
2.9.5
Access Doors
Provide hinged, gasketed, and fitted with snap-action closures access
doors. Equip access door with gaskets of common weather stripping type,
foamed, closed-cell, elastomer with pressure sensitive adhesive back.
Provide cleanout adjacent to every bend and vertical riser. In horizontal
duct runs, locate cleanout door with maximum of spacing of 4 meters 12 feet
for ducts 300 mm 12 inches or less in diameter and 6 meters 20 feet for
larger ducts.
2.9.6
Flexible Connectors
[Provide drawband secured flexible connectors, conforming to requirements
specified under paragraph, "Miscellaneous Materials," in this section,
utilizing 3 mm 1/8 inch thick reinforced elastomer, fabricated into a
cylindrical shape by vulcanizing or otherwise bonding longitudinal seam.]
[Provide flange secured flexible connectors, conforming to requirements
specified under paragraph entitled "Miscellaneous Materials," in this
section, utilizing bellows type metal expansion joint. Where service
temperature exceeds 149 degrees C 300 degrees F, insert 25 mm one inch
thickness of mineral wool.]
2.10
PROTECTIVELY COATED STEEL DUCTS
Ductwork, Protectively Coated Steel, For Corrosive Fume and Vapor Exhaust:
2.10.1
General Requirements for Protectively Coated Steel Ductwork
Fabricate [_____] system ductwork from black carbon steel with welded
seams, flanged and gasketed joints and protectively coated interior
surfaces including flange faces. Construct ductwork to handle [_____]
[fumes] [condensing] [noncondensing] [vapors] containing [_____]. Spiral
welded duct is prohibited. Provided ductwork in accordance with best
SECTION 15801N
Page 27
Previous Page
