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The Air We Breathe
IAQ and network capable controls dominate the HVAC discussion.

Nothing affects employee comfort and health more directly than an HVAC system. From temperature control to indoor air quality (IAQ), these systems must be carefully monitored by facility executives. Many advances in building automation are improving the oversight and management of these huge systems through streamlined network capabilities and browser type user interfaces.

Yet as these innovations have the potential to make facility managers' lives easier, something always seems to demand attention. Over the last few years, many IAQ and health concerns-as well as litigation-have emerged regarding mold. Unfortunately, these issues are not going away.

Mold: Why Now?

Recently, mold has gotten more publicity than any other IAQ issue since asbestos. Schools close for weeks at a time, rumors and exaggerations run rampant, and the problem seems to be everywhere. But where was mold 10 years ago?

"People used to feel mold was just a concern along the east coast, the Gulf of Mexico, and the Atlantic Ocean," says Terry E. Townsend, VP of ASHRAE. "But now we're finding that mold is throughout the country, even in the middle of the heartland." Townsend explains further, "Building codes are requiring new buildings to be tighter. If you have a tight building and moisture is introduced into the facility and it is not properly treated or allowed to escape, then you're just producing a medium to promote mold. The problem is exacerbated by energy efficient equipment. With energy efficient equipment, you have a very good sensible load (measurable with a thermostat or thermometer) handling capability, but the latent load (moisture content in the air) starts diminishing," says Townsend.

Preventive Measures

One of the keys to winning the moisture management battle is to maintain positive pressure in the building so moisture ingress is held to a minimum. The vapor pressure differential draws moisture in from a wet source to a dry source, so it actually wicks itself in.

According to Townsend, one of the best ways to combat the conditions conducive to mold growth is to treat outside air with a separate system.

"You no longer should bring in the outside air-we call it raw air-filter it, and just dump it into the return plenum of the air handler unit. With this process, you have to rely on the air handler to condition it properly, dehumidify it, and reheat it if necessary. So with a separate system, you are able to condition and maintain this outside air separate from your HVAC system," says Townsend.

"Every time you bring in outdoor air, you're just dumping a load into the building," says Ted Cherubin, product manager for Syracuse, NY-based Carrier. "The CobraT [Carrier's new energy recovery unit] precools and preheats the air before it actually gets to the rooftop unit, substantially reduces the amount of energy used, and tempers the air.

Another step Carrier has taken to combat mold was to team up with Middletown, OH-based AK Steel to produce steel with coatings containing AgIONT, a silver ion-based compound that suppresses microbial growth. Simplified, silver atoms with an electrical charge are attracted to oppositely charged hydrogen atoms (commonly found in most bacteria and microbes) like a magnet. The two ions connect, and the hydrogen ions are no longer available for other chemical bonds, halting respiration and growth.

"This particular compound is approved by the EPA for a number of uses. It's also approved by the FDA for food contact applications. So you will see this compound on cutting boards, for example," says Mark Rabbia, product manager for Carrier.

More Than Just Mold

Just as facility executives begin to feel comfortable dealing with one IAQ issue, a new concern begins to emerge. The environmental health committee at ASHRAE is in the process of developing position documents on synthetic vitreous fibers and synthetic/organic compounds.

"Right now, we have to be very cautious on what we're saying about it, because this could become a potential for legal discourse in the future," says Townsend.

"Clearly, loose fibers in the airstream are a concern of facility operators. I can't point to health reasons or negative impact to occupants in the building, but it's a valid concern for people in the industry. Obviously, if you have fibers floating around the airstream, it is ultimately going to get into the space," says Rabbia.

"We recognize that concern, so we've eliminated that concern with our product. We use exclusively what we call double wall air handlers. Double wall means there is an outer piece of sheet metal, an insulation layer, and an inner piece of sheet metal. Traditionally, single wall units have an outer layer of sheet metal and insulation glued to that inner piece, and that insulation would be glued to the inner piece. That's where you have the potential for fibers to get into the airstream," says Rabbia.

What's The Good News?

In spite of setbacks, building automation systems are becoming more streamlined and interoperable. "Integrated systems have become much more network capable in the last five years. A lot of those bigger systems used to be dial-up or at least line type applications, and now we're using standard network connections. It has made it easier for facility managers to maintain a single front end view for the entire campus," says Simon James, director for offering development at Morris, NJ-based Honeywell.

According to James, building automation systems have traditionally been the domain of the facility managers. But in implementing a campus wide network, building automation may begin to step up into the IT staff's domain. But there are steps that facility managers can take to help maintain these HVAC control systems. "Check control algorithms, control sequences, and make sure nothing has been forced or put into a manual mode," says Rich Remke, product manager for Carrier.

According to Terry Hoffmann, senior systems sales executive for Milwaukee, WI-based Johnson Controls, "Things change, buildings change, the use patterns change, trees grow, and you have different reasons to have different programs operate. Building automation systems have programs that take many of these variables into account. But on the other hand, you might have implemented a particular program in an area because the area gets a tremendous amount of sunlight. Four or five years down the road, there's no need for that anymore, because the trees have grown."

The Security Risk?

As more communications technology moves to a Web-based platform for interoperability, cyber security becomes increasingly more important.

"No one to my knowledge is showing a lot of concern about the cyber security element. Automation systems can be hacked. We've jumped into the open networking world feet first, but as an industry we haven't fully considered the cyber security risk," says James. [For more info, reference "There's A Hacker In The HVAC" by Michael Endrizzi June 2003, page 54]

"Some companies, for example, have established their Web based controllers on embedded XP type software. When you get a Microsoft or blaster Virus, it's bad enough that it hits your PCs, but if that hits one of your controllers in your building automation system, that's a different issue. Your central plant may not start in the morning, because it has been compromised by some sort of virus or worm. I think everyone really enjoys the accessibility, but the downside risk hasn't fully played out yet. All the floor plans are on the Internet, and someone could get in there and have a look at that and figure out where people are. Not everyone has good intentions," James adds.

Conversely, others are not quite as concerned. "I feel that most of these risks are a little overrated, says Hoffmann. "Realistically, if someone is going to shut down an air handling unit, it would have less impact because we would find out about it in a hurry. The new systems use all of the security protection that is available. They include the ability to accept only messages from people that we know; they include 128-bit password encryption; and they include firewalls to block individuals," Hoffmann explains.

The consensus is that HVAC controls are moving towards a network-based enterprise wide solution that will include all major systems in a facility. And with this convergence will come some unexpected, but useful partnerships in technologies. One such evolution is the use of video for HVAC applications.

"Now that you have a CCTV system as part of the building management system, you're able to monitor some remote areas," says Eric Peterschmidt, marketing manager for Honeywell.

"For example, someone might routinely have to inspect part of a cooling tower, because birds nest up there, and it's a very risky place to send someone on a weekly basis. So now they can just post a camera up there and have that image brought in whenever they want," Peterschmidt adds.

In addition to the benefits of these hybrid applications, it is easier than before to learn and use these systems. According to Hoffmann, "We're making systems look and feel more like the Web browsers virtually everyone uses. My mother is 85 years old, and she communicates with the Web via e-mail. People of all ages and backgrounds are using Web browsers. They feel comfortable with the technology and once they get onto a good Web-based system, it's just like browsing."