at each muffler. Flexible sections and expansion joints shall have flanged
connections. Flexible sections shall be multiple-ply stainless steel
expansion bellows type with standard 38 and 76 mm 1.5 and 3 inch allowable
axial expansion. Elements in the flexible sections shall be capable of
absorbing vibration from the engine and compensating for thermal expansion
and contraction.
2.8.2
Exhaust Muffler
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NOTE: Muffler locations and mountings should be
shown on the plans. The designer should consider
the use of first cost versus life-cycle cost
analysis to determine the appropriate metal to use.
Stainless steel Series 321 and aluminized steel
should be considered in lieu of painted steel
materials.
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A chamber type exhaust muffler shall be provided. The muffler shall be
fabricated of welded steel and designed for [outside] [inside] [vertical]
[horizontal] mounting. Eyebolts, lugs, flanges, or other items shall be
provided as necessary for support of the muffler in the location and
position indicated on the plans. The pressure drop through the muffler
shall not exceed the recommendations of the engine manufacturer. Outside
mufflers shall be fabricated from [aluminized steel] [stainless steel].
The muffler shall have a drain valve, nipple, and cap at the low-point of
the muffler. The muffler shall be supplied complete with any necessary
soot boxes or inspection ports required for adequate operation and
maintenance. The entire exhaust system shall be sized appropriately so
that the operation of the engine is not affected by the exhaust system.
2.8.3
Exhaust Piping
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NOTE: Exhaust piping should be sized at a gas
velocity of less than 25.4 m/p sec (5,000 fpm). The
exhaust piping location and routing should be shown
on the plans.
**************************************************************************
Horizontal sections of the exhaust piping shall be sloped downward away
from the engine to a condensate trap and drain valve. Changes in direction
shall be made utilizing long radius fittings. Exhaust piping not covered
in this paragraph shall be run in accordance with paragraph PIPING
INSTALLATION. Exhaust piping, mufflers, and silencers shall be insulated
with ASTM C 533 calcium silicate insulation, minimum of 75 mm 3 inch
thickness or an appropriate thickness to limit the surface temperature to
values below 80 degrees C 175 degrees F. Insulation shall be secured with
not less than 9.525 mm 0.375 inch width Type 304 stainless steel bands
spaced no farther apart than 200 mm 8 inches on center. An aluminum jacket
encasing the insulation shall be provided. The aluminum jacket shall have
a minimum thickness of 0.406 mm 0.016 inch with a factory-applied
polyethylene and kraft paper moisture barrier. The jacket shall be secured
with not less than 13 mm 0.5 inch wide stainless steel bands, spaced no
farther apart than 200 mm 8 inch on centers. Longitudinal and
circumferential seams of the jacket shall be lapped not less than 75 mm 3
inch. Jackets on horizontal lines shall be installed so that the
longitudinal seams are on the bottom side of the pipe. The seams of the
SECTION 15133A
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