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© CASCO C.A.SCHROEDER, INC. All
rights Reserved 2007® |
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Council Website Representing North America’s Leading Manufacturers of Flexible Air Ducts and Air
Connectors |
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In designing, fabricating and installing
fibrous glass duct systems, the principle of Modular Duct Construction (MDC)
is used. This is based on use of the 48” (1220mm)(nominal)* duct module for
both straight duct runs and fittings of most types. The remaining pages of this section show
how these objectives are met using the MDC principle. Use of the MDC principle enhances
productivity, minimizes the number of circumferential joints, simplifies and
improves the quality of workmanship. *For actual installed length, subtract
shiplap length from nominal: |
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PRINCIPLES
OF MODULAR DUCT CONSTRUCTION |
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DUCTBOARD SHIPLAP INSTALLED THICKNESS LENGTH DUCT LENGTH 1” (25mm) 7/8”(22mm)
47 1/8”(1200mm) 1½”(38mm) 1 3/8”(35mm) 46 5/8”(1185mm) 2” (51mm)
1 7/8”(48mm) 46 1/8”(1170mm) |
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Application of the MDC principle involves
the following design considerations: · The modified shiplap groove is used in
preference to the V-groove method. · Elbows and tees are designed to be
throatless. · Transition are extended to maintain the
module dimension. · Sweep and radius fittings are not used. · The male shiplap end of the duct section is
always installed facing the fan or equipment. · Branch taps should be made from shiplap
panels wherever possible. · The integrity of the module should be
maintained as consistently as possible throughout the system during design,
fabrication and installation. Shop drawings and blueprints should reflect
this. |
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MDC LAYOUT (Click Image to View) |
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• DUCTBOARD |
