The following information is intended to help explain the causes of mold, what should be done to address and eliminate mold or mildew inside your home or building, and how you can avoid it in the future. Actually, avoiding mold is quite simple if you understand it. This section of our site, put here as a result of the problems associated with the recent Hurricanes that created monumental issues for Floridians, is intended to help people understand what they should do to address the mold that many of us are experiencing. Note that mold is a recurring problem in Florida and these suggestions should be helpful in avoiding it in our buildings.
Our firm does a lot of work for Building Facility Owners and Managers on problems related to Energy, Indoor Environmental Air Quality, and Building HVAC Systems in general, but most often we are called to develop solutions to address Indoor Air Quality ( IAQ) as well as Mold and Mildew problems. Once we get on site for the investigation we are often referred to as the "Mold Guys" and actually, mold is very often the reason that we get called in the first place. Many times, IAQ problems are sometimes ignored until the "mold" issue is raised. Mold gets immediate action. Mold however, while a serious health threat, can be readily controlled and eliminated if we understand it, and take the necessary action required to get it under control and the corrective actions to avoid it in the future.
First of all Mold are microfungi that grow in the natural environment and are useful in decomposing materials. Mold spores are found everywhere in the environment including the indoor environment. The spores travel freely through the air and only become problems when the conditions are right for the development of mold. In order for the spores to develop into mold & mildew food, oxygen, water and comfortable conditions (for the mold) are required. Unless all of these conditions exist the spores that are everywhere will not develop into mold.The temperatures mold likes is generally between 40 to 100 degrees Farenheight, but it really does well in places when the temperature is above 70 F and the relative humidity is above 60%. The food that mold requires is ever present. Water is the key control mechanism for mold. Given the microscopic size of spores, the amount of food required for mold to develop, and the temperatures they like it seems unlikely that we could control them easily, but we can! We simply need to eliminate the water or moisture inside the building! Mold needs water to grow, without it they will not develop into a problem. Actually, moisture and/or water shouldn't be in the building anyway.
If you have a mold problem, it is in fact a moisture or water problem. If you have leaks from the recent storms or the building envelope has pathways for humid air or rain, you can have moisture or water enter the space and start the problems. Moisture from the entry of unconditioned (warm humid) air in your building provides the moisture that can help mold grow. If the moisture and water were to be eliminated, the mold would become inactive and effectively be gone. You do, however want to clean it up and get rid of all contaminated and saturated porous materials to help in future moisture excursions. Well, think about it-should you have a water problem inside a building-No! OK lets discuss this whole aspect a little more.
Recent hurricanes have demonstrated the water-mold connection dramatically. Many buildings have been experiencing mold problems resulting from water and building envelope leaks from the storm. Actually, a lot of buildings in Florida (and many other places) experience mold problems most of the time unnecessarily due to the same issue, water or moisture in buildings. If you have water, high levels of moisture or relative humidity in a building you will have mold.
Think about it:
Spores are everywhere
Food (for spores) is also everywhere
If you have water leaks, infiltration of warm humid air, damp spots, or high humidity levels in buildings
Mold will grow!
What should you do, call someone to test the air or clean the ducts? No!
First try to eliminate the water and moisture in the building and fix the leaks. Remove standing water, dry out the area, remove saturated materials that cannot be dried.
Monitor the humidity levels (check the relative humidity of the area) and use dehumidifiers to reduce the relative humidity to less that 60%, target 50%.
Clean up the mold using elbow grease as described in the references below.
Basically, the approach is to clean (scrub) non porous materials to get rid of the mold, to remove and replace porous materials that have been saturated for move than 48 hours. In all instances the major thing is to start action immediately to get the area dry and cleaned up ASAP. First of all stop the leaks or openings through which water or moisture can get into the space and use things like wet vacuums, dehumidifiers, etc. to help dry the place out.
Eliminate the mold and the water/moisture and/or high humidity levels and you will address the existing problem and can avoid mold in the future.
First and foremost, focus on any water or moisture issues and Stop them. Next, start to clean up following recommended procedures as suggested by the Florida State Department of Health, http://www.doh.state.fl.us/. in their IAQ information, the Environmental Protection Agency, OSHA and others. The State, EPA and OSHA web sites have clear instructions on what to do, what to use etc. as well as links to other organizations and agencies.
Other Useful Links
U.S. Environmental Protection Agency (EPA)
http://www.epa.gov/iaq/molds/U.S. Department of Health and Human Services
Centers for Disease Control and Prevention (CDC)
http://www.cdc.gov/nceh/airpollution/mold/California Department of Health Services
http://www.cal-iaq.org/mold0107.htm or
http://www.cal-iaq.org/mold0107.pdfFlorida Cooperative Extension, University of Florida
http://edis.ifas.ufl.edu/TOPIC_Moisture_Mold_and_MildewNew York City Department of Health
http://www.ci.nyc.ny.us/html/doh/html/epi/moldrpt1.htmlNorth Carolina Department of Health and Human Services
http://www.epi.state.nc.us/epi/oii/mold/Texas Department of Health
http://www.tdh.state.tx.us/beh/IAQ/protecting_your_home_from_mold.html
http://www.tdh.state.tx.us/beh/IAQ/Mold_Rem3.htm
Questions asked:
Should I test for mold? Test the air and Clean the ducts is what many people think about doing first because that's what they read in the paper and hear about. Generally neither of these will solve the problem. If it looks like mold and smells like mold it is mold! Why test? Don't waste your time and money unless this is a legal or health issue beyond your control. If you have mold you want to get it under control quickly. Focus on eliminating the problem!
How do I clean up after mold? The above links have detailed recommendations on cleaning up after mold.
How can I avoid Mold in the Future?
As soon as possible clean up (water, debris, wet stuff etc.) and dry out the buildings and all wet materials, clean mold up. If porous materials like wallboard, insulation etc. have been wet for more than 24 to 48 hours they should be discarded and replaced as indicated in EPA guidelines.
Create a positive pressure ( or at least avoid negative pressure) in the building to help keep warm humid air from leaking into the building. See the article below describing a system we recommend for commercial buildings, Indoor Air Quality, Improvement & Protection System.
Monitor & control humidity (RH) levels (below 60%) in problem areas of buildings. Inexpensive RH indicators are available from Radio Shack or similiar places.
Treat every water leak in the building envelope as an IAQ Issue and fix the leaks immediately.
Check your AC Unit, especially the filter and the condensate drain and drain pan if it is readily accessible. You should have a good filter in the unit. If you can see through it it's not a filter. It ids recommended that residential and light commercial buildings units use pleated filters (with Filter Ratings of MERV 6 or 7) that will capture most mold spores. Such filters are readily available in Hardware and Building supply stores. Note that the greater the efficiency (MERV level) the more restriction it will present to the air flow, so don't use higher rated filters unless the fan on the AC unit can be adjusted to handle the increase in pressure loss.
Another point to consider in your long range plan to avoid mold in Florida is the size of your Air Conditioner. Actually, the size of your AC should be as small as it can be and meet the peak loads. An oversized AC will often not be able to maintain the humidity levels you want in your residential type building. Keep in mind as far as moisture is concerned, smaller is better.
Often we find that people try to run their air conditioner more (lower the thermostat) in order to get rid of the moisture. Actually, an AC system does remove moisture from the air, but when you have a mold problem often you have a saturated environment that has a lot of moisture to give up to the air and the AC cannot solve your problem. While the AC may help a little initially, actually lowering the temperature may well increase the relative humidity in the space, compounding the mold problem by providing more moisture. Note that it is the Relative Humidity (or Dew Point) that is the issue. If you cool air and it's temperature drops, then in the steady state (when things calm down after the change) the relative humidity tends to increase because the air's ability to hold moisture decreases with temperature (the relative humidity increases). Dry the air with a dehumidifier, not the air conditioner. Sop up water, warm or dehumidify the air, do whatever you can to get rid of water and moisture so that the relative humidity level falls (at least) to between 50 & 60%. and the mold will become inactive and you can start your cleanup. Relative humidity is the key to a Mold problem!
Occupants of buildings expect a healthy, comfortable and productive environment. In the hot, humid climates of the Southeast and Caribbean outside air contains a large quantity of moisture that provides an unforgiving environment for architects and engineers. Unless the building envelope and the heating ventilating and air conditioning (HVAC) system can maintain proper humidity levels inside the building mold and mildew will most certainly appear. Maintaining positive internal building pressure and humidity levels below 60% is absolutely essential to provide proper indoor air quality in buildings.
Exhausting air from spaces like restrooms employee break rooms and other areas without replacing it creates a negative pressure that draws unconditioned air through exterior walls and cracks at windows and doors. As the outside air is drawn into a building by the negative pressure that is created by breezes or exhausts, the moisture in the air often condenses when it comes in contact with the cooler surfaces and condenses. The condensation provides the moisture fungi requires for growth. The stage is now set for mold growth and a major IAQ problem that could have been avoided by taken preventative actions or implementing systems such as those discussed in this section. Learn to recognize mold and initiate action to eliminate it!
Temperature of: 770F to 880F
Relative Humidity: 70% to 93%
Healey & Associates has developed a system capable of improving and protecting the Indoor Air Quality (IAQ) in existing Commercial, Institutional and Industrial (C&I) buildings. The approach consists of adding a dedicated "Outdoor Air (OA) pre-treatment system" with appropriate Components and Controls to the fresh air intake of buildings to pre-condition the outdoor (fresh) air that enters the building. The Outdoor Air System, originally developed to address one of the major causes of poor air quality inside buildings, mold and mildew resulting from moisture and high humidity levels, has been reconfigured and refined to reduce the vulnerability of buildings to threats from external air borne contamination including smoke or toxic releases.
Once the OA System, consisting of a filtration system, cooling/heating coils, dampers, associated controls and components, is installed, all outdoor air entering a building would be pre-conditioned (filtered, dehumidified etc.). The OA system would be designed to pressurize the building or selected area and eliminate the entry of unconditioned, outdoor air into the building. The System would serve to reduce the moisture levels in the building, one of the primary causes of poor IAQ in existing buildings, as well as the load on the existing HVAC System. The removal of the moisture load would permit the supply air temperature to be raised (temperature reset), and the heating (for humidity control) to be reduced, providing better humidity control and an economic benefit by virtue on an energy reduction. Implementation of such a system can provide an energy cost savings that will repay the cost of the installation over time by virtue of a reduction in the cooling load on the buildings HVAC Equipment and a reduction or elimination of the Outdoor Air load during unoccupied times.
While the specific economics will vary from project to project, the long-term economics will generally be positive, essentially providing a payback for a project that addresses a multitude of health and safety problems. At the present time, it simply is not possible to seal the buildings to protect the occupants from a threat (smoke or toxic emissions) from the outside air. Additionally, numerous buildings are presently suffering from reported IAQ problems resulting from high humidity levels. The approach developed by Healey & Associates is designed to help address both of these problems. The recommended system is not intended to take the place of a full scale building renovation to address IAQ problems, rather it is designed as a method of quickly addressing one of the major causes of poor IAQ (high humidity levels-mold and mildew) and providing a means of minimizing, and reacting to, contaminants external to the building in a cost effective and complimentary manner.
Numerous IAQ investigations have been conducted, and remediation projects developed, only to be delayed because of the magnitude of the costs and the disruption the remedial work would create to the functioning of a C&I Building. This approach, that can be implemented without disruption to the building or its occupants, is designed to address IAQ Health and Safety problems in such a way as to complement long range solutions to the problems while reducing (to some extent) operating costs of the HVAC system. The "OA System" can be installed with very little disruption to a building’s operation, provide an immediate improvement in indoor air quality, and a reduction of the vulnerability of a building to contaminants or threats from outside the building.
If your building has humidity problems or there are concerns over the possibility of airborne contamination from the outdoors, the system as described in this paper that has been installed in numerous healthcare and government facilities may be useful in your building. Contact Henry Healey, P.E., President of Healey & Associates, for additional information.