2.1.3
Copper Sheets
ASTM B 152/B 152M, light cold rolled temper.
2.1.4
Corrosion Resisting (Stainless) Steel Sheets
ASTM A 167.
2.1.5
Duct-Liner Adhesives
Fire-resistant adhesive.
2.2
DUCTS OF PRESSURE CLASSES
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NOTE: Do not use insulation liners for ductwork at
infectious areas in hospitals, such as operational
suites, nurseries, pathological facilities,
intensive care units, and surgical wards; use
factory prefabricated sound attenuators instead.
For brig facilities, fibrous glass ductwork should
not be used in inmate housing area, areas accessible
to inmates, nor areas with concrete, gypsum board,
or plaster ceilings. Do not use fibrous glass ducts
within 300 mm 12 inches of electric or fuel fired
heaters.
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Ducts of pressure classes 1000 to 2500 Pa 4 to 10 inch water gage.
Construct ducts of [galvanized steel] [stainless steel].
2.2.1
Construction
Provide duct construction, metal gages, and hangers and support
reinforcements.. Ducts shall not pulsate or vibrate when in operation.
Pressure sensitive tape shall not be used as a primary sealant on ductwork.
Air leakage shall be less than one percent of the system capacity. Curved
elbows shall have a centerline radius not less than 1 1/2 times the width
of ducts.
2.2.2
Joints
Construct joints to meet the requirements of the leakage test specified
herein. Duct components shall fit so that joints are not mismatched. Do
not use duct sealant and tape to compensate for mismatched connections.
Longitudinal locks or seams known as "button-punch snap-lock" will not be
permitted. Apply fire-resistant sealing compound to exposed male part of
fittings collars so that sealer will be on inside of joint and fully
protected by the metal of the duct and fitting. Apply one brush coat of
sealing compound over outside of joint to at least 50 mm 2 inchband width
covering screwheads and joint gap. When tape is used, apply a single wrap
of a duct tape over the wet sealer. Tape provided shall be as recommended
by the sealer manufacturer to permit proper curing of the sealer. Dents in
the male portion of the slip fitting collar will not be acceptable.
2.2.3
Fittings
Provide square elbows, round elbows, fittings, branch take-offs,
transitions, splitters, duct volume dampers, fire dampers, flexible
SECTION 15810N
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