For the last decade or so, the building automation industry has been abuzz over interoperability. Many companies have been advertising their ability to tie all building systems together, making it easier for building owners/operators to manage every system in a building at the touch of a button. Tying everything together into one neat little package is definitely appealing to the end-user.

But true interoperability hasn’t always been easy to implement. Many contractors and engineers have either been involved in, or heard the stories about, trying to get systems to talk to one another — the expense, trouble, and confusion — and they’re not always willing to put their reputations on the line in order to be pioneers in this area.

Interoperability is becoming an increasingly important feature, however, and building owners are demanding reliable networking in commercial and residential operations to meet the needs of a new generation of computer-savvy occupants. That means contractors and engineers need to do whatever is necessary to deliver what the customer wants.

They want interoperability.


Whether or not interoperability is achievable really depends on your definition. Some think it means “plug and play,” similar to how it’s possible to attach just about any VCR to any TV and have it work.

Not to burst any bubbles, but the industry is nowhere near this point yet. However, the industry, either intentionally or unintentionally, has led many end users to believe that interoperability really does mean plug and play. This can lead to high expectations, which the industry can’t deliver on.

“I think the whole plug and play thing is a misnomer,” says Catherine Mason, senior industry analyst, Frost & Sullivan, San Antonio, TX. “I think for us to think that we’re going to plug something in and just begin to operate it on a system as large as a building system, that’s a pretty strong expectation. If we can’t do that with a game computer at home, then to have the expectation that we’re going to pull in a vertical management system and it’s going to work the first time is not going to happen.”

Mason’s definition of interoperability is to be able to operate a multivariate system as a seamless network, one that shares information. The interoperability part can come with standardization, which manufacturers are providing through BACnet and LonWorks protocols. “The systems can seamlessly operate together, but it does require quite a bit of energy to get there,” she notes.

One of the reasons why interoperability is not always easy to achieve is that every building and every situation is unique. A facility such as a university or a hospital — both of which can have multiple buildings as well as a remote chiller plant supplying the buildings — is quite different from a 22-story commercial building.

In addition, some buildings have elevators, some don’t; some buildings have lighting control systems, others don’t. “It’s the uniqueness of the application that makes it not able to be plug and play and not easy,” says Mason.


Probably everyone would agree that it’s easier to put a building automation system into a brand-new building, or else at least have it be a total replacement. It’s when an existing system is in place and the building owner wants to add a new system to what’s already there that can cause problems — particularly if the existing system is proprietary.

That’s why engineers and contractors need to be tenacious. “Engineers are typically the ones who design the system. As long as they’re keen on their game and familiar with what’s pre-existing, then to tie into the existing network really isn’t a problem on paper,” says Mason. “But when you bring in the contractor, now we have interpretation, and that can cause problems. If those who are making the decisions are fully aware of what they need to do and have an understanding of a pre-existing system, there’s not a problem.”

The problem comes whenever the engineer or contractor thinks the existing system was installed in a certain way. For example, if a stranger comes into your house looking for a hammer, he’s probably not going to find it. That’s because you are not going to put your hammer where the stranger thinks it should be.

It’s no different in a 110-story building. Everybody thinks, “This is the way leaving chilled-water temperature should have been maintained,” but when they start crawling through the plenum, they find out that’s not the case.

Another issue is that the skill set often is not available in the industry. Many “systems integrators” out there are self-taught to a degree. The lack of knowledge can cause problems for the end user if the systems aren’t designed and/or installed correctly.

Mason says that one of the largest restraints to growth in the hvac industry is lack of skilled technicians. “They just aren’t there. And to say that someone knows about building automation systems, it’s a whole different game. It’s electronics, it’s technologies, it’s understanding communication protocols. I think it’s too different. But that isn’t to say that it wouldn’t be accessible to someone that you could bring on board who would be totally turned on by the whole high-tech thing.”

In Mason’s opinion, the best way to achieve interoperability is to possibly use BACnet as the backbone and LonWorks as the fieldbus coming off of that. She says that LonWorks is a better approach for looking at something at the device level because it is less expensive. “But BACnet is truly open. It’s not owned by a single company, and the way the technology works, you’re able to communicate better in many applications. In fact, I’m starting to see a lot of jobs come down using that scenario.”

She adds that achieving interoperability would certainly be a lot easier if we as an industry could put more emphasis on training and making sure that information is disseminated. “I’d like to see people start having an attitude to absorb information as opposed to feeling they know everything. The ego gets in the way and all of a sudden the learning curve is flat. That’s a tragedy.”

With more IT-minded people entering the hvac industry, however, that may change. These people are often risk takers, and as we start to integrate more of that mind-set into our industry, perhaps the road to interoperability will be a little less bumpy.

Frost and Sullivan provides strategic market consulting and training. They recently published the report, titled “North American Building Automation Systems Markets.” The company can be reached at (website).

Publication date: 12/10/2001