Autodesk 235B1-05A761-1301 User Guide - Page 189

Duct Sizing Tools, Duct Size Calculator, Instant Duct Sizing, Calculating Duct Sizes for a Duct System

Page 189 highlights

Duct Sizing Tools There are 3 options for calculating duct sizes: ■ The Duct System Size Calculator calculates sizes to convert 1-line duct systems to sized 2-line duct systems. It can also calculate sizes for duct systems with defined shapes. ■ The Instant Sizing Calculator calculates sizes for individual duct segments. ■ Third-party, external analysis tools work in conjunction with AutoCAD MEP to analyze duct systems. You can use any of these sizing tools at any time. The duct system size calculator can be used for both preliminary designs and modifications. The instant sizing calculator is best suited for modifying discrete parts of the system. Duct Size Calculator The duct size calculator can be used to calculate duct sizes for an entire connected system or for portions of a system. With the 1-line feature, you can draw duct systems using 1-line duct objects that act as placeholders for sized duct objects. After you add supply and outlet equipment to complete the system, you can use the duct size calculator to calculate duct sizes for the entire connected network. For more information, see Calculating Duct Sizes for a Duct System on page 203. Instant Duct Sizing If you have assigned flow values to outlet equipment, you can use the instant sizing tool to calculate sizes for ductwork as you draw duct runs. You can also use the instant sizing tool when modifying existing duct runs. You can calculate duct sizes using either the equal friction method or the constant velocity method. To specify which duct sizing method to use, see Specifying a Calculation Method for Duct Sizing on page 182. The instant sizing tool calculates capacity by adding the flow values for all outlets detected in the duct run. If no flow values have been assigned to outlet devices, the capacity displayed is zero. If you are drawing a duct segment connected to an outlet device with a specified flow capacity, the flow value is detected. If you are drawing a branch that is not yet connected to outlet devices, you can select outlet devices to be considered when calculating size. You can also manually enter a flow capacity to be used for size calculations. The instant sizing tool detects flow capacity of outlet devices connected to the run. When you execute the calculate size command, the instant sizing tool performs 2 calculations. First, it calculates the exact duct size based on the flow capacity value and a fixed parameter (either friction or velocity, depending on which calculation method is specified). The exact duct size is compared to available Duct | 171

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Duct Sizing Tools
There are 3 options for calculating duct sizes:
The Duct System Size Calculator calculates sizes to convert 1-line duct systems to sized 2-line duct systems.
It can also calculate sizes for duct systems with defined shapes.
The Instant Sizing Calculator calculates sizes for individual duct segments.
Third-party, external analysis tools work in conjunction with AutoCAD MEP to analyze duct systems.
You can use any of these sizing tools at any time. The duct system size calculator can be used for both
preliminary designs and modifications. The instant sizing calculator is best suited for modifying discrete
parts of the system.
Duct Size Calculator
The duct size calculator can be used to calculate duct sizes for an entire connected system or for portions of
a system. With the 1-line feature, you can draw duct systems using 1-line duct objects that act as placeholders
for sized duct objects. After you add supply and outlet equipment to complete the system, you can use the
duct size calculator to calculate duct sizes for the entire connected network. For more information, see
Calculating Duct Sizes for a Duct System
on page 203.
Instant Duct Sizing
If you have assigned flow values to outlet equipment, you can use the instant sizing tool to calculate sizes
for ductwork as you draw duct runs. You can also use the instant sizing tool when modifying existing duct
runs.
You can calculate duct sizes using either the equal friction method or the constant velocity method. To
specify which duct sizing method to use, see
Specifying a Calculation Method for Duct Sizing
on page 182.
The instant sizing tool calculates capacity by adding the flow values for all outlets detected in the duct run.
If no flow values have been assigned to outlet devices, the capacity displayed is zero.
If you are drawing a duct segment connected to an outlet device with a specified flow capacity, the flow
value is detected. If you are drawing a branch that is not yet connected to outlet devices, you can select
outlet devices to be considered when calculating size. You can also manually enter a flow capacity to be
used for size calculations.
The instant sizing tool detects flow capacity of outlet devices connected to the run.
When you execute the calculate size command, the instant sizing tool performs 2 calculations. First, it
calculates the exact duct size based on the flow capacity value and a fixed parameter (either friction or
velocity, depending on which calculation method is specified). The exact duct size is compared to available
Duct |
171