by Ron Rajecki, senior editor

Despite the near-hysteria that sometimes accompanies media stories about mold growth in homes, mold is much more likely to be “the next radon” rather than “the next asbestos.”

That was the consensus of a group of experts convened in a public session at the winter meeting of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).

“Mold causes allergies, not cancer,” said David Golden, representing the National Association of Independent Insurers, Des Plains, IL. “It’s a naturally occurring substance that humans have lived side-by-side with for a long time. Like radon, we’re going to find ways to manage it.”

Next to preventing or abating mold, the biggest battle HVAC contractors need to fight is debunking the bad information that often accompanies media reports of mold infestation, Golden added.

“Offer quality information to homeowners. Help them separate fact from fiction. Stress maintenance. And, for your own sake, work with an insurer who understands what you do,” Golden advised.

Is Mold Being Built In?

One of the possible reasons for the increasing incidence of mold is changes in building materials.

“More biodegradable construction materials are used in modern construction,” noted Philip Morey, Ph.D, of Air Quality Sciences, Inc., Gettysburg, PA. For example, mold begins to form within 48 hours on water-soaked gypsum board.

The irrepressible Joseph Lstiburek, Ph.D., P.Eng., Building Sciences Corp., Westford, MA, took Morey’s contention a little further.

“The materials we’re building homes with today are basically mold food,” he said. “Plywood is mold candy. To mold, oriented strand board is the tasty ‘Spam’ of wood.”

Lstiburek said building methods need to change to address the fact that in northern climates, moisture moves from inside a house to outside, while in southern climates, moisture moves from outside to inside. Building homes the same way across the country without taking this fundamental difference into account basically reduces homes’ ability to dry, and drying is where the focus of mold prevention should be.

“We’ve always had moisture and water in homes, but now the water hangs around longer, because vapor barriers reduce the structure’s ability to dry,” Lstiburek said. “Mold forms when the rate of wetting exceeds the rate of drying. Therefore, what we should really be focusing on is ways to help buildings dry.”

A representative from the National Association of Homebuilders (NAHB), however, disputed the contention that new building materials and methods are at the heart of the mold issue.

Thomas Kenney, P.E., from the NAHB’s Research Center in Upper Marlboro, MD, cited an NAHB telephone survey of 2,000 U.S. homeowners. Respondents were asked 50 questions about unwanted water, water leaks, high indoor humidity levels, use of bathroom fans, etc. The survey found that mold is found in homes of all ages: 27% of respondents in homes older than 10 years old reported mold, compared to 15% in homes newer than 10 years old. Among all the respondents, 80% characterized the mold as mild, and two-thirds said it was limited to the bathroom only. The survey didn’t address hidden mold.

According to Kenney, NAHB’s message is that not every incidence of mold is a cause for alarm, and mold can be handled if it’s addressed promptly and properly.

NAHB also has an eye on the financial consequences of mold.

“Mold paranoia and frivolous lawsuits are creating affordability issues,” Kenney said. “NAHB is trying to address this by educating home buyers and homeowners, and by working closely with trade contractors.”

Proper System Design is Critical

Most contractors are aware that mold loves to grow in warm, dark, moist conditions. That makes it critical that HVAC systems don’t become those places.

Ray Patenaude, P.E., works with consulting and forensic engineers The Holmes Agency, Inc., St. Petersburg, FL. He suggested that contractors and system designers remember to view the home as a system, and not just concentrate on selling and installing a unit. In addition, he advised controlling outside air at the source and paying careful attention to the control of condensation created by HVAC equipment.

“Remember that bigger isn’t necessarily better when it comes to HVAC systems,” Patenaude said. “Oversized air conditioning systems can lead to moisture problems.” He also offers three words for contractors to preach to their customers to help them avoid mold or other problems with their HVAC systems: “Maintenance, maintenance, maintenance.”

As a member of ASHRAE’s board of directors, Patenaude also advised contractors and builders to study ASHRAE Standards 52, 55, 62, and 90, and to order a copy of ASHRAE’s Humidity Control Design Guide.

Glenn Hourahan, the Air Conditioning Contractors of America’s vice president of research and technology, echoed Patenaude’s warnings about oversizing systems, and said moisture control is achievable through accurate load determination and proper equipment selection. He offered five simple steps to ensure proper sizing and selection:

  • Establish building design and system criteria requirements, and match the HVAC system to the building application.
  • Determine the design load by using ASHRAE procedures or ACCA Manuals J or N.
  • Don’t arbitrarily increase the load as a “safety factor” after performing your load calculations. If you must “round off” numbers, always round down instead of up.
  • Ascertain the system’s true capacities using manufacturers’ application data.
  • Always be sure to evaluate both the sensible and latent loads.

“If a manufacturer’s standard equipment can’t satisfy both full-load and part-load latent requirements, consider other options to deliver comfort to your customers, including using different equipment; implementing additional control strategies; using variable speed equipment; optimizing the evaporator coils by splitting them or increasing the number of rows; or reducing the evaporator coil’s operating temperature by downsizing it or reducing the airflow over it,” Hourahan advised. “Ask manufacturers for what you need, not just what they have.”

Long Arm of the Law

Bad news for contractors who are trying to avoid having anything to do with mold: “Everyone who has anything to do with buildings is being targeted in lawsuits,” said Maralynne Flehner, Esq., J.D., King of Prussia, PA. She noted that mold-related litigation is up 300% since 1999, and plaintiffs in mold lawsuits are charging negligence, breach of contract, breach of expressed or implied warranties, fraud, misrepresentation, and even assault and battery.

Although Flehner chairs the ASHRAE task group on general legal education, in true lawyer fashion she cautioned that the advice she rendered at the public session constituted her opinion as a trial lawyer in New York and Pennsylvania, and didn’t constitute an official ASHRAE position. She also noted that laws vary from state to state.

Beyond the disclaimers, Flehner offered several lines of defense to protect yourself from mold-related claims.

The first line of defense is to protect your personal assets by doing business as a corporation.

The second line of defense is education and disclosure. “Inform your customers about the risks of mold, involve them in the equipment selection process, and include instruction on proper use and maintenance of the equipment,” she said.

Third and most important is the contract. Have a lawyer in your state write up a disclaimer provision for your customers to read and sign.

“Clearly state that if a customer does not promptly notify you of any problem or defect with the system, your liability is limited to what the repairs would have been had you been notified promptly,” Flehner explained.

In addition to this limitation of liability clause, ask your lawyer about a clause prohibiting recovery of consequential damages, an indemnification clause, attorney’s fee clause, and an arbitration clause.

The next line of defense is vigilance. Inspect structures before you accept a job. If you come across mold or a situation that will cause mold, notify the owner immediately.

Good documentation is next. Keep copies of all disclosures made to homeowners or building tenants regarding mold, thoroughly document any mold-related situations with photos and notes, and keep lists of the design and filtration options you offered the client, as well as all instructions regarding operation and maintenance of the system.

The second last line of defense is your insurance, so be aware of any mold limitations and exclusions in your policy.

The last line of defense? The one everyone wants to avoid: Hire a good lawyer.

Ron Rajecki can be reached at 216/931-9298 or rrajecki@penton.com.