UV Mold Remediation & Mold Removal

If high levels of mold are observed or suspected people should not attempt mold cleaning. To avoid damage of the property and potential health effects, the services of mold remediation experts should be acquired for mold testing and creating a mold remediation plan. The only way to know if the mold removal is successful is to inspect and test after the remediation. Indoor air samples should be taken and mold and mold spores tests should be performed before and after the mold cleaning. Mold remediators and building occupants should be protected from exposure to mold.

To better understand the potential benefits of germicidal UV (UVC) technology for mold removal and, with other methods, for mold remediation we should take a look at how mold grows and reproduces. The growth of different types of mold is affected by many factors and conditions but three main factors are required in the indoor environments for mold to start growing in homes, offices, schools and public buildings. The three main factors are:

• mold spores
• organic matter
• moisture

By recognizing and controlling these factors we can prevent mold for spreading indoors. No mold remediation is complete without taking measures against all these factors.

Spores: Most molds reproduce by forming spores that disperse into the air. Outdoor air normally contains some level of these airborne mold spores. Most mold spores are microscopic and therefore, invisible to the naked eye. It is not uncommon to find hundreds or even thousands of mold spores per cubic foot of outdoor air. Some mold types produce light and buoyant spores that easily become airborne which is why they are frequently recovered in outdoor air tests.

Spore Viability: Not all spores produced by the organism are capable of growing a new colony. Microbiologists use the terms viable and non-viable to indicate their ability to reproduce and in lay terms, these spores are considered alive or dead. It is very important to recognize that spores retain their adverse health characteristics regardless of their ability to reproduce. In other words, non-viable spores are still allergens, contain toxins, etc. This trait not only has significance on exposure to molds, but also greatly influences testing methods.

Size Range of Spores: Most mold spores range from 1 to 100 microns in size with many types between 2 and 20 microns. This small size has numerous impacts on dealing with mold. They are so tiny that they infiltrate our environments with air and they are essentially invisible so cleaning them up without special equipment and procedures is next to impossible.

Spore Infiltration: Since outdoor air normally contains some quantity of mold spores, infiltration of airborne mold into living and working environments occurs naturally. Therefore, even in structures without active mold colonies, the presence of airborne fungal materials is probable.

When mold is growing in a closed indoor environment, it releases millions of spores causing indoor levels to reach concentrations that are hundreds of times higher than outdoors... levels that can be detrimental to even healthy people. Airborne mold spores are particles and generally settle out with time but they can be disrupted and re-aerosolized.

It is generally accepted that a proper germicidal UV light (UVC), installed in the HVAC system will break the DNA of the microscopic organisms and will sterilize them. Therefore as the indoor air recirculates throughout the system virtually all airborne mold spores will be rendered non-viable or with other words dead. The dead mold spores can not form new colonies so the mold has been denied its most common way of spreading indoors. Since the dead mold spores still represent a health hazard, it is strongly recommended that the UVC light should be used in conjunction with a HEPA filter. Some HEPA filters capture particles smaller than 1 micron, i.e. the smallest mold spores would be captured and removed from indoor air. If only a HEPA filter is used without the UVC light, the filter itself will become a breeding ground for new mold colonies.

Organic matter: For molds, the food of choice is organic matter (things that are or once were living). Building materials including wood, paper, natural fabrics, leather, and even the starch in wallpaper paste are common examples of dead organic matter preferred by filamentous molds. Grasses, plants, trees, etc. provide examples of living organics for parasitic fungi and animal or human tissue provides a source of living nutrients for many pathogenic fungi.

Eliminating mold growth by controlling food sources is effective in instances where moisture is unavoidable. Using inorganic substrates together with routine cleaning of organic dust/dirt/debris typically controls growth.

It has been proven that colony forming microorganisms, put in perfect conditions, will not grow or reproduce if they are directly irradiated with appropriate germicidal UV light. Direct surface UVC irradiation is used in hospitals and clean rooms but currently in most cases direct UVC is not practical to use in the average residential settings, because the home environment does not normally require this high level of irradiation and the UVC must be turned off when people are in the room(s). However, direct surface germicidal UV light (UVC) can be well utilized in HVAC systems to irradiate the coils and dripping pans. This is an effective solution for mold inhibition and mold remediation. It is recommended that the coils, dripping pans and HVAC ducts are cleaned of mold growth by a licensed mold remediation expert prior to installing the UVC light. Homeowners and non-specialists should not attempt mold cleaning on their own if high levels of mold are present or suspected.

Moisture: Without water, mold growth and reproduction will not occur. The amount of water for optimum growth varies by species and is also influenced by environmental factors such as temperature and the types of nutrients available. Some species can grow at relatively low moisture levels, levels that would not be considered 'wet' in ordinary terms (think of mold growing on bread). Other types of fungi require significant amounts of moisture for optimum growth.

Eliminating mold growth by controlling moisture is considered the key in mold remediation. Take away water and growth simply will not occur. Quick response in drying all materials impacted by plumbing breaks, rain intrusion, etc. and controlling humidity is of paramount importance.

As mentioned earlier, in many cases the draining pans and the coils of the HVAC system present the moisture needed and mold colonies form there. As the mold colonies grow they produce millions of spores that are blown through the ducts and distributed in the indoor environments. Once the spores are spread inside they just need food and water in order to start growing, reproducing and forming countless new colonies that release countless new spores. This is the mechanism of infesting the indoor environment of some contemporary airtight buildings with mold to such extent that it becomes impossible for people to live, work or study there. All this leads to lawsuits, big expenses for mold cleaning, huge losses and worst of all health problems for many people. This nightmare could be avoided by installing a specially designed germicidal UV light that shines directly on the coils and draining pans.

The effectiveness of germicidal UV (UVC) has been recognized by the
U. S. General Services Administration Office of the Chief Architect and incorporated in the Facilities Standards for the Public Buildings as follows: "Ultraviolet light (C band) emitters/lamps shall be incorporated downstream of all cooling coils and above all drain pans to control airborne and surface microbial growth and transfer. Applied fixtures/lamps must be specifically manufactured for this purpose." >Full Text

In conclusion, germicidal UV light has been successfully utilized in hospitals and public buildings to inhibit microbial growth, spreading of infections and to increase indoor air quality. UVC can also help against mold problems for mold remediation and mold inhibition by rendering airborne mold particles and mold spores non-viable and even sterilizing surface mold colonies if they are directly irradiated with UVC light. Germicidal UV has a cumulative effect so the circulation of indoor air throughout the cooling or heating systems, with installed in-duct UVC air cleaner, will eventually deliver enough UV dosage to break the DNA of the airborne mold spores.

These American Air & Water resources show mold/mildew irradiation dosages and indoor air testing results for mold and mold spores:

UVC Irradiation Dosage for Mold and Mold Spores Eradication

Mold Tests Before and After UV Installation

If you suspect or know that you have a mold problem in your home or public building you should contact an independent licensed mold inspector. Mold inspectors specialize in mold testing and know how to establish what type or types of mold are present in your environment. The information on mold and mold related health problems is presented as a courtesy and should not be solely relied upon. See Our Disclaimer