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Calculates the pressure loss of a series of ducts and fittings to enable the fan pressure for a ductwork system to be determined. The user enters the ducts starting from the fan and working down towards a selected terminal. For each duct entered the fittings are selected and the program then calculates the pressure loss in each length of duct and each fitting. Supply ducts and fittings are entered on one screen and return ducts are entered on a second screen.

DOLPHIN can also size individual ducts based on an entered Pressure drop per metre, maximum duct velocity and a size increment. The Colbrook-White formula is used to size the duct. The program however also displays a range of equivalent sizes either side of the �design size� based on a nominated fixed height, fixed width or fixed aspect ratio.

Duct fitting pressure loss calculations are based on the fitting loss coefficient (k) and duct velocity. A comprehensive range of fittings and their associated loss coefficients as a function of air flow, shape, etc are stored in the program. The data for these duct fittings have been extracted from the AIRAH Duct Design Application Manual DA2 on which the program is based. It is a ductulator on the computer with the added feature that it also calculates the pressure drop of fittings. Screen Shots


duct sizing, duct and fitting pressure loss, fan pressure



Expertise Required

Knowledge of ductwork systems is of advantage but the program is simple to use with on screen Help readily available.


15 companies in Australia and New Zealand.


HVAC design engineers and contractors, local government and university teaching departments.


The input data is via two screens laid out in spreadsheet format so that the calculations can be viewed for each duct and its fittings. The program has many features that make data input easy including a convenient selection form for fittings. A graphical display of each fitting helps users check they are using the correct fitting. Ducts can be circular, rectangular or oval and a range of duct materials can be selected for setting the duct surface roughness. Duct sizes can be entered as clear internal dimensions or as sheet metal sizes in which case the program deducts the insulation thickness from the entered duct height and width or diameter. Comprehensive range and data checking is provided on all input items and default values for fitting parameters (e.g. R/D ratio) are provided to reduce input data time. Comprehensive help is provided on all screens and all items of input data.


The detailed calculations for each duct and fitting are displayed on the supply and return ducts spreadsheet pages which can be exported to Excel for further manipulation or printing.

The Summary results include the total pressure loss of the supply and return ducts and fittings, and the Air Handling Unit pressure losses can be entered to give the total system (fan) pressure loss. The maximum velocity in the supply and return ducts is also displayed.

Computer Platform

Windows 98/NT/2000/ME/XP

Programming Language

Visual Basic


The program has many features that make the inputting of data quite simple and user friendly.







18 High Street
Glen Iris, Victoria 3146


+61 (3) 9885 6586


+61 (3) 9885 5974




Contact ACADS-BSG or visit web site for more information. Price: AUD$440 for single machine copy with significant discounts for multi-machine copies. Demonstration copy available for $50.