Experience with open systems offers lessons for facilities executives

Three decades ago, building automation systems - sensors, control devices and wiring - were installed around a single product from a single manufacturer. Proprietary equipment, often from the lowest bidder, meant that facilities executives were locked into a system that might not be the most cost effective in the long run. A replacement part had to come from the original equipment manufacturer, and there was no guarantee that it would be the least expensive. Even worse, changing the building automation system meant changing everything from the control panel and front end to the network and setup.

In organizations with many buildings, the problem multiplied each time a new system was installed. That's one reason that large organizations have been leaders in the move to BACnet, an open data communication protocol for building automation and control networks. Developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the protocol allows the open connectivity of BACnet-compliant equipment from different manufacturers and delivers system information to a single front end. It became an ASHRAE/ANSI standard in 1995 and an ISO standard in 2003.

During that time, BACnet has become well-established and widely used, with a growing number of manufacturers offering an increasingly broad array of BACnet-compliant products. Those systems and devices are being used in facilities of all types and sizes. But it is large organizations that pose some of the toughest challenges for open systems. And a look at applications in those organizations shows how BACnet is handling demanding real-world tests.

Open at OSU

Ron Sharpe, manager for building automation at The Ohio State University in Columbus, has had his share of headaches with proprietary building automation systems. He has been involved with control systems since the 197Os, and he knew even then that efficient building control systems had to be interoperable.

"We needed a way that any manufacturer's system would work with any other manufacturer's system," says Sharpe. "If you go with a proprietary system, you get locked in with the low bid. The hook is set."

BACnet has taken Sharpe and other facilities executives like him off the hook. "BACnet is a true open protocol," Sharpe says.

Sharpe, a member and past chair of the BACnet Interest Group - North America, has had his eye on the protocol since its beginning in 1987. He admits it wasn't love at first sight. "We'd hoped for plug-and-play," he said. "When I read the first review, I was disappointed that it wasn't plug-and-play."

Input from potential users improved early versions of the protocol. When Sharpe finally got his hands on a working panel in 1999, it could do everything that he wanted it to do.

"Our local integrator brought out a panel to try," he says. "I gave it to my head supervisor and said, 'see what's wrong with it.' After two weeks of testing, he came back and said, "I like it. It did everything I wanted it to do, and it is easy to use."

About the same time, Sharpe faced a catastrophic equipment failure in a lab building and had to decide whether to repair the old system or scrap it and start over. Replacing the system was not much more than buying the parts needed to get the old system running.

The choice was easy. And when installed, the new BACnet system worked as reliably as the test panel. Since then, OSU has consolidated nine building automation systems with different protocols and different front ends to five. Sharpe wants to streamline the operation to one front-end system within the next five years.

"We needed to have a platform that could communicate with multiple vendors to eliminate different front ends and multiple computers," Sharpe says. "We need to improve compatibility among systems."

The reason is obvious. OSU has about 12 million square feet of academic and research space. That number is growing as the school continues capital improvement projects. BACnet is installed in about 25 percent of the university's 149 academic and research buildings. The protocol is used for direct digital control, variable speed drives, chillers, fume hoods and fire alarms. With BACnet, Sharpe and his staff get systems information faster and easier than before.

"If I can't convert a vendor over to BACnet, we replace it with new," he says. "We use buildings for about 50 years. If they are historic, we use them longer than that. Most electronics last 10 years. BACnet is good way of staying on top of all that."

BACnet can also be used for lighting control and other building automation functions. At OSU, for example, elevators will be the next system brought online. With BACnet, the supervisor in charge of that system will be able to monitor their condition and know immediately when and why a car might stop moving. BACnet's flexibility will allow a customized Web page to pop up when there is a problem.