Preventing mold is a good idea

Good IAQ and comfort begin with proper design and construction techniques, and continue through effective operations and maintenance. Exposure to mold and bacteria can cause allergic reactions and general health problems, ruin building materials, and create unpleasant odors. Even if you decide not to pursue this credit, taking steps to prevent mold is a really good idea.

You have to earn some other credits first

This can be an easy credit to achieve, but it takes a lot of coordination among the design team, contractors and subcontractors, and the school’s operations staff.  To achieve IEQc10, projects first have to achieve the following credits, which contain key steps that will contribute to your overall success with preventing mold:

• IEQc3.1: Construction IAQ Management Plan—During Construction;
• IEQc7.1: Thermal Comfort—Design;
• And IEQc7.2: Thermal Comfort—Verification.

Start by verifying that each of the three required credits can and will be achieved by your project.

In addition, you must control and limit relative humidity during occupied and unoccupied hours to at or below 60%. That means that you’ll need mechanical equipment that can regulate humidity, and it must have appropriate set points. 

Note that because of the construction-related aspects of these credits, IEQc10 is a construction-phase credit, even though it was listed on some LEED checklists as a design-phase credit.

Develop an IAQ management plan

You also have to develop an IAQ management plan for the ongoing prevention of mold and indoor air quality problems. The IAQ plan has to be based on the US EPA’s “Building Air Quality: A Guide for Building Owners and Facility Managers.”

Although the credit’s primary intent is to prevent mold growth, the IAQ management plan will need to address more than just mold-related problems. When writing your IAQ plan, pay close attention to Section 4: Developing an IAQ Profile and Developing an IAQ Management Plan in Section 5 of the EPA document.

Since IEQc3.1, a LEED construction phase submittal, has to be achieved before a project can be approved for this credit, don’t bother to submit IEQc10 until the LEED construction submittal. This does not mean that you should hold off until after design to plan for achieving this credit, however!

What’s the plan?

In general, your IAQ plan should cover the following items:

• The scope, goals and responsible party for the IAQ plan.
• Contractor- and subcontractor-related IAQ management issues such as steps for prevention of moisture buildup during construction and the remediation of building materials that become wet or moldy.
• HVAC operations and maintenance to, among other things, limit relative humidity, address indoor environmental complaints, ventilate right, replace filters, dehumidify, and clean drain pans.
• Education of staff and facility managers that may include, overviews of activities that impact IAQ, mold awareness, open communication about IAQ problems, and responsible parties for IAQ-related issues.
• Regular inspection and ongoing maintenance for prevention of poor indoor air quality and the remediation of mold during the building’s operation.
• Strategies for resolving IAQ problems such as, removal of standing water, repairing leaks, and general housekeeping.
• Project teams should also consider including design recommendations for the architect and mechanical engineer.

An IAQ plan can be created by the contractor, architect, mechanical engineer, facilities manager, or owner; however, ideally it is a collaboration of as many of these parties as possible.

The fact that you must earn three other IEQ credits prior to this one does not mean your project team should defer addressing IEQc10 early in the project. You need to confirm that your project can comply right at the outset. And, even if your project is not able to attain the other three IEQ credits, following a mold prevention plan is in your project’s and the students’ best interests.

Regional variations

Hot, humid climates, are especially susceptible to mold problems because they offer lots of opportunities for condensation and poor drying conditions. Pay special attention to air-sealing, adequate dehumidification, and good wall, roof, and foundation details to prevent leaks. Also, watch out for “over cooling” which can drop surface temperatures below the dew point. Focus on areas in contact with the earth and equipment with condensate pans and drip tubes. Also, regularly wetting of the exterior surfaces of buildings with poorly designed, poorly aimed, irrigation systems can be problematic.

In all climates, even dry ones, mold growth can easily occur, especially in building areas with kitchens, bathrooms, laundry facilities, and swimming pools. Air-conditioning is common in almost all parts of North America in some seasons, and is often associated with mold problems due to the potential for condensation on cold surfaces, from humid outside air.

Designing and operating for mold prevention

Mold needs food, oxygen and moisture in any form. Food (in the form of dust) and oxygen are everywhere, so the only ingredient you can really control is moisture. Buildings are susceptible to mold growth from flooding, humidity conditions that exceed surface dew point temperatures and leaks, which can be from both rain and from plumbing. Absorptive building materials such as drywall, wood, insulation, and carpet, which provide a food source for mold are especially susceptible to mold growth.

Reducing or eliminating moisture is the key to a successful mold prevention plan. This credit requires controlling humidity, because high humidity leads to condensation on cool surfaces and keeps wet things from drying out. But keeping bulk moisture (from rain, sprinklers, or melting snow) from getting into the building is at least as important. Air sealing and flashing details are key to controlled bulk moisture intrusion, and wall assemblies have to be designed carefully so that any water that does get in can dry out.