Frequent Questions

What about mold in large buildings?

EPA has a number of resources available, you can start with the Indoor Air Quality Building Evaluation and Assessment Model (I-BEAM).  I-BEAM updates and expands EPA's existing Building Air Quality guidance and is designed to be comprehensive state-of-the-art guidance for managing IAQ in commercial buildings.  This guidance was designed to be used by building professionals and others interested in indoor air quality in commercial buildings. I-BEAM contains text, animation/visual, and interactive/calculation components that can be used to perform a number of diverse tasks. See www.epa.gov/iaq/largebldgs/i-beam/index.html

See also "Building Air Quality: A Guide for Building Owners and Facility Managers".

Excerpt from the Building Air Quality: A Guide for Building Owners and Facility Managers, Appendix C - Moisture, Mold and Mildew:

How to Identify the Cause of a Mold and Mildew Problem. 

Mold and mildew are commonly found on the exterior wall surfaces of corner rooms in heating climate locations.  An exposed corner room is likely to be significantly colder than adjoining rooms, so that it has a higher relative humidity (RH) than other rooms at the same water vapor pressure.  If mold and mildew growth are found in a corner room, then relative humidity next to the room surfaces is above 70%.  However, is the RH above 70% at the surfaces because the room is too cold or because there is too much moisture present (high water vapor pressure)?

The amount of moisture in the room can be estimated by measuring both temperature and RH at the same location and at the same time.  Suppose there are two cases.  In the first case, assume that the RH is 30% and the temperature is 70oF in the middle of the room.  The low RH at that temperature indicates that the water vapor pressure (or absolute humidity) is low.  The high surface RH is probably due to room surfaces that are "too cold."  Temperature is the dominating factor, and control strategies should involve increasing the temperature at cold room surfaces.

In the second case, assume that the RH is 50% and the temperature is 70oF in the middle of the room.  The higher RH at that temperature indicates that the water vapor pressure is high and there is a relatively large amount of moisture in the air.  The high surface RH is probably due to air that is "too moist."  Humidity is the dominating factor, and control strategies should involve decreasing the moisture content of the indoor air.

For more information on mold, see our website at www.epa.gov/mold

Read the publication, "A Brief Guide to Mold, Moisture, and Your Home" at www.epa.gov/mold/moldguide.html [EPA 402-K-02-003]

Una Breve Guía para el Moho, la Humedad y su Hogar está disponible en el formato PDF www.epa.gov/mold/pdfs/moldguide_sp.pdf Documento de la agencia EPA número 402-K-03-008.

Read the publication "Mold Remediation in Schools and Commercial Buildings at www.epa.gov/mold/mold_remediation.html [EPA 402-K-01-001, March 2001]

Mold Resources are available at www.epa.gov/mold/moldresources.html

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