2.11.6
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.
2.11.6.1
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.
2.11.6.2
Access Plates
Provide access plates upstream and downstream of equipment in ducts at
locations to facilitate duct cleaning, and where indicated. Locate access
openings a minimum of 50 mm 2 inches above bottom of duct and externally
frame with welded and ground miter joint steel which is isolated from duct
interior. Construct access plate with PVC on interior side, backed with
steel on exterior side. Provide stainless steel access plate fasteners.
For ductwork cleaning access, provide 200 mm 8 inchdiameter gasketed access
plates on maximum 3 meters 10 foot on centers, except where access is
available through an air terminal device or other required access.
2.12
FIBERGLASS DUCTWORK
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NOTE: Duct systems of plastic material may be used
to handle only nonflammable corrosive fumes and
vapor when conventional metal duct systems will not
be adequate.
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Ductwork, Fiberglass for Nonflammable [Corrosive] [Fume] [Vapor] Exhaust:
2.12.1
Fiberglass Ductwork
Construct ductwork, fittings, accessories, and material of construction in
accordance with NFPA 91, and ASTM C 582. Fabricate supplementary steel in
accordance with the AISC 335.
2.12.2
Basic Ductwork Materials
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NOTE: Fill in resin characteristics from ASTM C 582
if necessary. Verify suitability of Type 316
stainless steel for the specific chemical exposure;
for example, chromic acid attacks Type 316 stainless
steel. Revise as required.
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Fabricate ducts, accessories and components in sheet form from materials
conforming to ASTM C 582 [, RTP _____]. Provide exterior gel coat, coating
SECTION 15801N
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