or paint with ultraviolet light inhibiting properties for ducts exposed to
sunlight. Construct metal components, when permitted to be located
interior to the duct, of Type 316 corrosion resistant steel.
2.12.3
Fasteners
Where penetration of duct surfaces is approved or specified, provide Type
316 corrosion resistant steel fastener assemblies encapsulated with
polyester on duct interior, unless total disassembly is intended. Provide
flange fastener bolts and nuts of hex type only, cadmium plated, unless
exposed to corrosive fumes; in which case provide Type 316 stainless steel.
Equip bolted assemblies with two oversized washers, except where assembled
with metallic reinforcement contact. Plastic bolting is prohibited.
2.12.4
Joint Gaskets
Provide [3 mm1/8 inch thick acid resistant chloroprene.] [3 mm1/8 inch
thick Buna N.]
2.12.5
Fabrication
Construct water washable, watertight, self-draining, and airtight ductwork
as specified or indicated. Provide required reinforcements, bracing,
provisions, and fastening to guarantee rigid construction and freedom from
vibration, airflow induced motion and noise, and excessive deflection at
specified maximum system pressure and velocity.
2.12.5.1
Flanges
Provide flanges at all branches on maximum 6 meters 20 foot centers in
ducting sized 400 mm 16 inches and under, on maximum 2.40 meters 8 foot
centers in duct sized over 400 mm 16 inches, where required for ease of
access to equipment, at hoods, enclosure connections and where indicated.
Furnish one piece, heat, adhesive, or solvent vulcanized or bonded full
face gaskets at flange joints. Provide flanges at dissimilar material
joints, such as between fiberglass reinforced plastic (FRP) and PVC.
2.12.5.2
Access Plates
Provide access plates upstream and downstream of equipment in ducts at
locations to facilitate duct cleaning, and where indicated. Locate access
openings at least 50 mm 2 inches above bottom of duct and externally frame
with welded and ground miter joint steel which is isolated from duct
interior. Contruct access plate with fiberglass on interior side, backed
with steel on exterior side. Provide Type 316 stainless steel access plate
fasteners. For ductwork cleaning access, provide 200 mm 8 inch diameter
gasketed access plates on not more than 3 meters 10 foot centers, except
where access is available through an air terminal device or other required
access provision.
2.13
VEHICLE TAIL PIPE EXHAUST SYSTEM
**************************************************************************
NOTE: Specifications included are for maintenance
work. Dynamometer applications require revised
specifications with special considerations for high
temperatures involved. Following are kW/cms
horsepower/cfm of exhaust gas recommendations for
SECTION 15801N
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