HVAC contractors may service an occasional indoor pool, but the niche has turned into 50 percent of the business for Mills' 18-year-old contracting/service company.
According to Mills, indoor air quality (IAQ) problems in many North American hotel/motel natatoriums are increasing at an alarming rate. He has performed extensive IAQ corrections on more than three dozen failing indoor pools - mostly owned, managed, or franchised under the hotel/motel industry's top 50 brands, he said.
Hotel/motel indoor pools could be the next major category of IAQ problems and could be following the pattern of respiratory and other health-related problems associated with mold, mildew, and fungus, according to Mills. "What surprises me is that local health inspectors haven't jumped on the mold bandwagon because it's really becoming a health issue everywhere else," he said. "No hotel chain is exempt from this IAQ problem."
The basis of the problem is uncontrolled humidity and chemicals from pool water treatment. Contributing factors can include inadequate ventilation, poor housekeeping practices, and problems with the building envelope.
Corrosion And DecayWhen it comes to malfunctioning pool areas, mechanical systems contractors may first hear about problems relating to temperature control, "not being able to maintain temperature and humidity set points," Mills said.
On examination of the HVAC system, "you'll see a lot more wear and tear. If they're not taking proper care of the pool environment, you'll be seeing a lot of coil and heat exchanger corrosion and deterioration."
Housekeeping problems associated with natatorium HVAC decay aren't so much related to things not being done, but rather are associated with chemical storage. "They've put such a big investment into the mechanical equipment, then somebody winds up storing chemicals in the mechanical room," Mills bemoaned.
"Nine times out of 10, they start using the mechanical room as a general storage room." Even though water-cleaning chemicals are stored in sealed containers, they will leech out. "I've seen more unit damage caused by bad housekeeping than by anything else."
If a servicer notices rapid mechanical system decay and temperature control problems, Mills said, it's time to look around the room for further signs of rust and decay in walls and on metal fixtures. "Our industry is out of sight, out of mind," he said. "As long as it's working, it's fine. You've got to scrape below the surface just a little bit."
Pool water and high concentrations of chemicals can cause severe structural damage; it's in a contractor's best interest, Mills said, to save the customer from such destruction. "You must think outside the box. You generally find that one problem begets another, begets another, begets another. You're kind of working at the middle of the problem instead of at the beginning."
Breaking It DownIf it's a natatorium design problem, Mills said, retrofits that resolve IAQ issues could cost upwards of hundreds of thousands of dollars in construction costs. Poorly operating equipment could cost anywhere from a service call charge to tens of thousands of dollars in equipment replacement.
The top-three problems Mills sees on a recurring basis are:
1. No vapor barrier or one that is not sealed or installed properly.
2. Conventional HVAC equipment, "just plain regular-type heat exchangers and air handlers," Mills said; "no epoxy coating, open-type bearings, not really meant for those types of applications. You're looking for trouble." Specially designed dehumidification equipment is a better solution, he added, specifically if it is designed for use in corrosive environments. "Look at the type of equipment used in coastal areas, especially down in the Caribbean," he said. "Down there it's not unlike conditions of a pool environment."
3. Poor air distribution design. "Think of the way a defrost works on a car window," he explained.
"If it's blowing up and over, then you've got good airflow."
Proper design of all three disciplines is outlined in the ASHRAE (American Society of Heating, Refrigerating, Air-Conditioning Engineers) Handbook.
Vapor Barrier ProblemsThe vapor barrier (a plastic sheet that hermetically envelops the top, bottom, and sides of the pool room) is critical in keeping the room dry of condensation. Mills sees this vital part missing in many engineers' designs.
However, even rooms with vapor barriers can experience moisture infiltration. Many times a vapor barrier isn't sealed properly during construction, doesn't envelop the entire room, or has holes poked into it accidentally or unknowingly by installation people, according to Mills.
He recalls a major hotel chain site he recently consulted for that had interior walls bowing inward. The exterior brickwork also showed signs of deterioration due to interior wall moisture accumulations. "I knew immediately there was a vapor barrier problem; that was without opening the wall to inspect it," said Mills.
The worst hotel case he has seen to date was an indoor natatorium with no vapor barrier at all. The three-year-old facility was already suffering from deteriorating structural block walls that were crumbling due to moisture infiltration and freeze/thaw cycles. There was heavy growth of mold and other biological contaminants.
"Most HVAC service people tend to only look at the mechanical equipment, and they think I'm crazy for including the architectural design in the troubleshooting," said Mills. "However, failing to meet set point temperatures is not always due to poorly operating mechanical equipment, but due to the inefficiencies of the pool room design."
Finding The SolutionMills said many contractors err when they try to solve high-humidity conditions with conventional air conditioners or furnaces. The heavy humidity loads produced by a quickly evaporating, 84 degree F pool require the use of commercial dehumidifiers.
On the other hand, too many hotel owners and managers settle for the cheapest HVAC equipment that either doesn't include dehumidification, or they dehumidify without providing energy savings in the long run, he said. "They might put in some cosmetic touches like marble that offer a nice appearance, but the behind-the-scenes aspects, such as providing proper environmental conditions that don't deteriorate the building structure or make inhabitants sick, are oftentimes neglected."
Concept Air & Mechanical services all brands of dehumidification systems. The company is an area specialist for Dectron's Dry-O-Tronâ„¢ system. The product's heat recovery method provides free pool water heating while removing excess moisture and cooling or heating the space, the company says.
When it comes to airflow, Mills said proper airflow design should combine underdeck ductwork for upward movement, and overhead perimeter ductwork for downward airflow, especially in the critical case of windows.
Walls of windows and/or skylights also have ribs that protrude three or more inches away from the glass, blocking airflow from broadcasting entirely across the glass.
Generally, Mills thinks the hotel/motel industry should start preparing for the future by planning better pool rooms and reviewing the performance characteristics of existing sites. Until that happens, he and other contractors will continue fixing those problems after the fact.
"People call us through a network of engineers, inspectors, builders, and it's gone from there," he said of his business.
"It can be a little frustrating; you're constantly telling people, there's a right way of doing this, and 60 percent of the time it's still done the wrong way. You have to get involved with architects, designers, and end users. You have to convince them that cutting corners is not cost effective.
Publication date: 11/07/2005