By Bob Baker

For many, the Pelican Bay Condos in South Pasadena, Florida represent the ultimate fantasy. Even when approaching you get the sense of a different world. You pass the ornate campus of Eckerd College of Law and suddenly, on the left you see the grand entrance of the Pasadena Yacht and Tennis Club where they are located. Once you are cleared through the security gate you drive through a perfectly manicured golf course, past palatial homes and around winding curves. Even the water hazards on this course are special.

The twin condo towers with their connecting parking garage and lush landscaping present a clean but elegant profile. On a visit, you will enter through a massive door that automatically swings open at the electronic command of your host. You enter and are greeted by a spacious and tastefully appointed lobby with a curving staircase that goes up to a lounge and meeting areas on the second floor. It is clear that this is not project housing. In fact, a person with a balance sheet showing less than a million dollars in assets is well advised to look elsewhere for housing.

The picture of near perfection becomes complete as you enter your host's apartment and take in the breathtaking view. Apartments on one side look at the graceful arches of the Sunshine Skyway Bridge that marks the entrance to Tampa Bay. Those on the other look across Boca Ceiga Bay into the Gulf of Mexico. This is truly a land of sun, sea, and tropical foliage gently waving in the breeze.

A Foul Odor in Paradise

On a mild fall day in late 1996, however, things at Pelican Point were not so pleasant. What greeted a visitor entering the massive front door was not only the attractive furnishings but also a very unattractive stench. The lobby, halls, and other common areas were filled with an odor not unlike that you might encounter in a poorly maintained public restroom. What was worse, was that the same odor was beginning to invade several of the apartments on the upper floors.

The problem began about three months following a major upgrade of the HVAC systems serving the common areas of the building. The building was built in 1981 and there had been complaints over the years that the halls were warm and humid on hot summer days. The board decided to correct the problem once and for all. They had the original roof mounted package units replaced with 2 new 3000 cfm high efficiency package units that included wrap around heat pipes for enhanced dehumidification and economy of operation. We were called out by Metro Air the installing contractor and a long time user of our products. They were mystified that a system enhancement that would normally be expected to dramatically improve the overall environmental quality had brought on an IAQ problem where none had existed before.

Diagnosis was Difficult

Diagnosing the problem was complicated by the mechanical design. The supply and return ducts that ran the full height of the building at both the north and south ends of the building were sealed in concrete. They had been installed in a concrete block chase adjacent to the fire stairs. You could only inspect the system from the air handler location on the roof or through supply and return grill openings on each floor. In attempting to look down the duct systems from the roof, our efforts were frustrated. Instead of the unobstructed 14-story view that we had expected from the plan documents, ducts that ended at the floor below greeted us. Although we could see a side outlet at the bottom of each duct, we had no idea of where it went.

Out came the jack hammers and concrete saws. In order to better inspect the system, we created access openings into each chase on the seventh and fourteenth floors. Once we looked in these, the problem became immediately apparent. The reason the ducts appeared to end one floor below the roof was that flexible connections has been installed at that point interchanging the ducts. (Supply became return and return became supply.) The design of the duct system had been arranged so that the vertical main supply duct was central and horizontal ducts on each floor would lead to supply grills blowing the length of the central hall. The return duct and its associated return grills on each floor in contrast were off to the side and air return was from alcoves off the main hall. Unfortunately, the installing contractor discovered that the roof penetrations had been placed so that the supply and return connections on the air handlers were over the wrong openings. The air handlers could not be re-positioned without disrupting condenser air flow and service access.

To cope with this unexpected situation, the contractor came up with the field fix of exchanging the ducts on the top floor before they entered the air handler. This fix however profoundly affected the design and thus operational characteristics of the system and set up the situation that eventually led to a serious IAQ problem. Two things happened: a) the greater volume of air put out by the new units led to failure of some of the joints where the crossovers were constructed in the chases and b) The colder air provided by the new units and exiting at those points caused water to condense out of the moist air in the chases. This fueled massive fungal growth in the duct chases. The odor that was present in the chases when they were opened made it obvious what the source of the offensive odors throughout the building was. Although we will never know for sure, we feel that the reason a problem had not shown up before the new units were installed was that the original units were lower enough in efficiency that neither the air flow nor the air temperature were at a level that would trigger the problem. In addition, as the joint sealing materials aged, they became weaker while, at the same time, the air flow from the old unit fell off as it aged and lost efficiency. Conditions in this building were probably always on the edge but it took the new units to push them over.

Correcting the Problem

As difficult as it was to identify the source of the malodors, correcting the problem was a bigger challenge. Replacing the duct system was not an option because the building design made it economically impractical. In addition, we decided that we had to maintain a transition between the two ducts at the top floor. Finally, we had to remove or kill the mold growing in the chase and prevent its return. The owners did not want additional openings cut into the chase unless absolutely necessary. The one good thing was that there was little growth in the ducts themselves and they were still reasonably clean. Thus we did not face the challenge of cleaning which would have been very difficult.

First, the contractor removed all of the existing transitions. HEPA equipped vacuums were then used to remove debris that were serving as food sources for the fungi in the open chases on the seventh and fourteenth floors. In addition, the duct surfaces that were reachable from the open chases on the top floor were vacuumed to remove active growth at those points. We then designed a new transition system that relieved the restrictions and sharp bends of the previous system. After the new transitions were installed, we used a fog generator to fog a biocide registered by EPA for walls, floors, and HVAC systems into the chases. By placing the chase at the seventh floor opening under negative pressure, we were able to draw the antimicrobial fog from the top floor down to the seventh.

Finally, we sprayed the same antimicrobial into both air handlers. This product has a residual activity that is believed to retard regrowth for up to six months. The contractor has re-applied the treatment in the air handlers every six months since. In addition, the above ceiling spaces, walls, and floors in two of the apartments with high odors were treated with the same biocide.

The residents have reported a total absence of odors since the work was completed. Some have even asserted that the air "smells cleaner" than before the problem started. Part of the difficulty with this project was obtaining objective evidence that the problem was corrected. Microbiological air samples were taken before and after the project was completed. Although counts in the chase at the top floor seemed quite high, none of the other samples taken either before or after the work were at levels usually felt to be indicative of an IAQ problem. In fact, two of the locations showed slightly higher counts after the work than before. (The outdoor count was higher on that day and that could have influenced the inside counts.)

Conclusion

This case illustrates that microbiological testing is not always helpful in diagnosing growth related IAQ problems. It also suggests that many systems are in delicate balance when it comes to whether they operate in a satisfactory manner or cause problems. Although design standards should provide a margin of safety, compromises made during construction and the passage of time can remove that margin. The result is often IAQ problems. Because of structural or economic limitations, it may never be possible to achieve a margin of safety in these systems. Regular preventative maintenance including periodic application of a growth retarding antimicrobial can be one way to maintain a positive balance. It would be interesting to know if the antimicrobial treatment alone would have maintained balance in this system. Unfortunately, there is no way we can ever know.

If we are to prevent such occurrences as this, we need to rethink our preventative maintenance activities. Mechanical inspections and filter changes may not be enough.

Mr. Baker's field of expertise is the control of contamination in air-conditioning and ventilating systems by mold, mildew and bacteria. He writes and speaks frequently about the efficacy, legal risks, and regulatory issues involved in various control strategies. He serves on ASHRAE Technical Committee TC 2.3, TC 2.4, TC 9.8, and Sampling of Airborne Particulate Concentration in Commercial and Residential Buildings GPC 17P. He also serves as a member of ASTM D22.06 (Indoor Air Quality) and is on the Board of Directors of the Indoor Air Quality Association and the Florida Public Health Foundation. Because HVAC applications encompass new uses from an U.S. EPA regulatory standpoint, Mr. Baker works closely with the EPA and industry groups, including serving as the chair of the IAQ committee of the Consumer Specialty Products Association, to help formulate policy in this area.

Bob Baker is Chairman and CEO of BBJ Environmental Solutions, Inc., a company specializing in providing clean air through environmentally responsible products, such as BBJ MicroBiocide , BBJ Micro Coil Clean , "FreshDuct Odor Eliminator ", and BBJ Mold and Mildew Remover™ as well as the revolutionary new Power Coil Clean™. For additional information, Mr. Baker can be reached at (800) 889-2251 or through the company web site at http://www.bbjenviro.com.