2.6.6
Duct Sleeves and Framed Openings
Duct sleeves shall be provided for all round ducts 375 mm 15 inch diameter
or less passing through floors, walls, ceilings, or roofs. Sleeves in
non-load bearing walls shall be fabricated of 1.0 mm (20 gauge) 20 gauge
steel sheets conforming to ASTM A 924/A 924M. Sleeves in load-bearing
walls shall be fabricated of standard-weight galvanized steel pipe
conforming to ASTM A 53/A 53M. Round ducts larger than 375 mm 15 inch
diameter and all square and rectangular ducts passing through floors,
walls, ceilings, or roofs shall be installed through framed openings.
Structural steel members for framed openings shall conform to ASTM A 36/A
36M. Framed openings shall provide 25 mm 1 inch clearance between the duct
and the opening. Closure collars of galvanized steel not less than 100 mm
4 inches wide shall be provided on each side of walls or floors where
sleeves or framed openings are provided. Collars for round ducts 375 mm 15
inch diameter or less shall be fabricated from 1.0 mm (20 gauge) 20 gauge
galvanized steel. Collars for round, square or rectangular ducts with
minimum dimension over 375 mm 15 inches shall be fabricated from 1.2 mm (18
gauge) 18 gauge galvanized steel.
2.7
EXHAUST HOSE SYSTEM
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NOTE: The following may be used as a guide in
selecting materials based on maximum temperature for
exhaust hose. A variety of hose is available that
can handle various temperature as suitable for the
application.
a. Galvanized steel, 315 degrees C (600 degrees F)
(for 0.3 mm (0.012) thickness).
b. Stainless steel, (for 0.3 mm (0.012 inch
thickness)) 540 degrees C (1000 degrees F).
c. Heat-resistant wire reinforced glass fiber and
neoprene, 120 degrees C (250 degrees F).
d. Heat-resistant wire reinforced glass fiber and
silicone, 315 degrees C (600 degrees F).
e. Heat resistant thermoplastic, reinforced with a
layer of polyester rated for 149 degrees C (300
degrees F).
f. Double layered, chemically treated, woven glass
fabric mechanically joined to an outer steel coil.
Temperature resistance is to 815.5 degrees C (1500
degrees F).
Also of importance is that the design incorporate
adjustment or shut-off dampers at each adapter or
receptor.
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2.7.1
Tailpipe Adapters
Adapters shall be of the tapered-cone type with spring clips or other
SECTION 15940A
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