General

Equiduct returns multiple alternative duct sizes that are similar to an input duct size. The number of alternative sizes returned can vary from a few to several dozen, depending on the parameters used to determine equivalency.

There are two versions of Equiduct — a licensed version intended for ductwork systems design professionals and an unlicensed version for all other users.

Equivalency

The alternative duct sizes are returned in a color‑coded table, where the colors generally indicate “Good”, “Better”, and “Best” with respect to equivalency.

Default parameters are included for evaluating equivalency; however, all of the parameters can be adjusted by the user.

Alternative rectangular duct sizes are calculated using the equation developed by Huebscher (1948).

Alternative flat oval duct sizes are calculated using the equations developed by Heyt and Diaz (1975).

Unlicensed Version

The unlicensed version of Equiduct is intended for Architects, Contractors, and building Owners interested in the possibilities for alternative sizes and/or shapes for ducts that meet the design intent for the ductwork systems on a mechanical systems drawing (or in a building model). The unlicensed version allows for that use with minimal technical knowledge necessary and with relatively few inputs required.

In general, the unlicensed version is identical to the licensed version with the exception of the following:

• Input airflows are limited to 100, 1,000, 10,000, and 100,000.
• Printout notes are not editable.
• Printouts have watermarks.

The unlicensed version of Equiduct is freely distributable.

Features

• Supports both Inch‑Pound (IP) and International System (SI) units.
• Supports round, rectangular, and flat oval duct shapes, and converts between the three shapes.

Limitations

Equiduct does not support gasses other than air.