Case Study

By Nancy T. Zacharek, O'Brien & Gere Engineers, Inc.

To remain competitive in today's engineering marketplace demands taking advantage of sophisticated computer technology.

We are using, for example, a computer software engineering tool at O'Brien & Gere Engineers, Inc. to help us better design water and wastewater systems. This, in turn, is helping our engineering firm remain competitive by reducing design time and improving engineering accuracy.

Based in Syracuse, NY, O'Brien & Gere has been using Design Flow Solutions' DesigNet software since 1999. The software tool, developed by ABZ, Inc. of Northern Virginia, assist engineers with the design of network systems handling liquids and gases that flow through pipes and process lines.

The computer program contains complete hydraulic analysis of complex piping systems that include up to 9,000 branches and 1,000 tees. Network branches can consist of any combination of pipe, fittings and valves, with virtually no limit on the number or type of components.

DesigNet also includes a utilities package used for creating, modifying and managing data files generated by the core program. It provides users the ability to manipulate data files for fluid properties, pipe specifications, material specifications, component information, pumps and unit conversions. Using these utilities, our engineers can customize the DesigNet program data to include information that is most useful to them.

The company purchased a muti-user license for the software so that several employees can access it simultaneously. This software is compatible with our operating systems -- Windows 95, Windows 98 and Windows 200.

Automating Calculations

Prior to purchasing this software, our engineers performed calculations either by using alternate software systems or by hand. I preferred using hand calculations.

Despite which method our engineers choose to use, the same preparations are necessary. Gathering project-specific information requires performing hydraulic calculations -- such as piping layout plans, identifying fluid properties, site conditions, flow-rate ranges and materials of construction.

Once preparatory work has been completed, hand calculations require gathering information from engineering tables or manufacturers' cut sheets to determine individual looses through each piping component. This task can be very time-consuming.

One of the advantages of DesigNet is that it contains a library of this information within the software program. In other words, it does the information gathering for you. As a result, hydraulic calculations are performed more quickly and more efficiently with less chance of human error.

The library contains fluid properties for over 50 common liquids and gases. User-specified fluid properties also can be added easily. The software allows us to individualize the program to the specific water/wastewater stream we are working on -- right down to fluid properties, such as temperature, pressure, specific gravity, density and viscosity.

Another challenge our engineers routinely have to meet is dealing with changes made in system designs. Changes inevitably occur as designs progress -- such as pipe sizes and flow rates, and even switching to different type valves and pumps. These changes often can affect our entire calculations.

When done by hand, these recalculations were extremely time consuming. But with DesigNet these changes are made easily by imputed them into the computer and the software automatically does the recalculations in a fraction of the time it previously took us. For example, it changes flowrates with the stroke of a key.


While solving problems is important, it also is important to see the results. Another advantage our engineers obtain from this software is flexibility in preparing reports. Output from the program can be presented using a variety of standard reports or creating customized reports.

These reports are an excellent way to document calculations and provide a neat and concise output to our clients. Equations, summaries or intricate tables detailing every system component can be made with this software.

Graphic displays also can be made showing valuable information throughout each step of the network, such as friction losses, pressure, flowrates, velocity, pipe diameter, etc.

All these factors certainly enhance our design capabilities and provide us with an excellent hydraulics modeling software program that helps us remain competitive by reducing design time and improving engineering accuracy.

Industrial Wastewater Application

This software is especially useful in water/wastewater applications -- a market we specialize in. We have been heavily involved in designing such systems, especially for New York communities and industries, since our founding in 1945.

We recently were involved with the design and construction of a new industrial wastewater transfer system that was developed with the use of the DesigNet software.

Computer Model

A portion of our task was to size pumps, piping, equipment and instruments associated with the system, and estimate system line losses for this particular application. The computer model generated with DesigNet represents the industrial wastewater (a water-like fluid) that was to be pumped via three new end-suction centrifugal pumps from a 12,000-gallon storage tank to any of seven destinations.

The model was set up in two portions -- the suction side of the pumps and the discharge side. This arrangement made it easy to determine pumping capacity required by simply subtracting the pressures across the networks where the pumps would be.

The model even estimates required horsepower of the transfer pumps. System output is used to develop a system curve to aid in selecting the right pump for the conditions.

The modeling was extremely helpful in establishing pumping capacities for the maximum flow condition, and could easily be manipulated to determine performance for the average and minimum flow conditions as well.

This saved time by eliminating recalculation iterations by hand for different flowrates and site conditions -- such as pumping from empty tank versus full tank, or pumping to a combination of destinations. It also was very helpful in estimating inlet pressures for a multitude of flow control valves associated with this system, so that these valves could be sized properly for each flow condition.

In addition, pressure gauges were sized using model output to estimate the correct scale of gauge. Since the model provides velocity information, it also is a quick and convenient method for properly sizing pipe.

User Friendly

The DesigNet program, which is very user-friendly, has an extensive system Help menu and technical support by phone. We have always found the ABZ support personnel to be very responsive and helpful, as well as technically proficient.

If additional help is required for a particular network file, the software program contains an inherent command to download the file into a debug file, which can then be sent to ABZ via e-mail.

Program Help files also contain examples of typical problems, which serve as a good starting tutorial for new users. All these features are found right within the software, even the technical help telephone number is on-line for convenience.

Through the use of the DesigNet software, we have been able to streamline our ability to readily generate baseline hydraulic calculations, which has made our project teams more efficient.

Our efficiencies on specific projects are essential in maintaining our competitive edge in the marketplace and controlling costs on active projects. While it is difficult to link specific monetary savings to the use of this software, we are confident that our investment in the ABZ software has more than paid for itself on the projects already performed.

About The Author

Nancy Zacharek is a project engineer at O'Brien & Gere Engineers, Inc. -- which employees over 800 professionals in offices around the United States and in Puerto Rico, Mexico, Canada and the United Kingdom. The company provides start-to-finish engineering, construction, analytical, specialty manufacturing, operations and property development services to industry, municipalities and government agencies. To compliment its core competencies, it offers site development and civil engineering, environmental compliance and remediation, facilities infrastructure, and project management services.

For more information about O'Brien & Gere call 315-437-6100.