Is Ultra-Violet (UV)
Light the Right Solution for Mold Remediation?
By
Edward R Close, PhD and Jacquelyn A Close
©
EJC Advantage, July 22, 2016
Ultra-Violet
Light (UV) is best known for its ability to eliminate bacteria. And the effectiveness
of germicidal UV has not only been recognized but also incorporated in the
Facilities Standards for Public Buildings as follows:
"Ultraviolet
light (C band, UVC) 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."
You
need to know, however, that while UV emitters placed in the airflow downstream
of AC coils and drip pans may help improve the air quality coming from HVAC
systems, they will have no effect on mold colonies growing elsewhere in a
building. In addition, the effectiveness
of UV in HVAC systems depends on a number of factors such as: rate of air flow,
humidity, placement and distance between the UV light and the microorganisms it
targets, irradiation time, as well as other variables occurring in real world
environments that make calculation of effective UV dosage very difficult.
It
is true that UV light will destroy the DNA of harmful microorganism given a
high enough dosage over a sufficient length of time. And germicidal UV systems
may be successfully utilized in hospitals and public buildings to inhibit
microbial growth in HVAC systems, thereby improving the quality of indoor air
and decreasing the risk of bacterial and fungal infections in people with
compromised immune systems and/or open wounds. But the question is this: Is it an effective solution for remediating a
building infested with mold? In a word: NO.
The
problem with UV or UVC systems for addressing mold infestations is the fact
that they only treat the airstream within the HVAC system, and cannot safely
address the many sources of mold spores that may exist in a building in places
other than inside the air-handling system.
Sources
of mold around leaks, in moisture from humidity condensation, and other conditions
that lead to the growth of mold super-colonies, are not affected by the air flowing
through an HVAC system. Sources of mold spores can be also be found on
surfaces, such as the exterior of HVAC ductwork, walls, floors, in bathrooms, in
fact almost any surface inside or under a building. While some spores in the
air flowing through a UV system may be killed, UV only treats the air that
flows through the system and nothing more.
For
UV light to destroy mold spores, one must have two things —
- Sufficient UV light intensity, which decreases rapidly with distance from the bulb, and
- Sufficient “dwell time” which is the time that the mold spore is actually exposed to the UV light.
The
amount of exposure time required to destroy a mold spore varies greatly for the
different species of mold. Some spores are destroyed after a few seconds —
others require 8,000 seconds or more. That’s more than 2 hours.
The
air traveling in an air duct is moving at a minimum of 100 feet per minute. You
have to ask: what are the chances that a mold spore in the airstream inside the
ductwork will be exposed to the UV light for a sufficient length of time?
Pretty slim.
And
while the air may be re-circulated, mold spores can fall out anywhere along the
path from the outflow vent to the intake vent, and never be returned to the UV
system for additional treatment.
“UV lights have been
shown to reduce mold when exposed continuously to the coils of the HVAC system.
Cleaning the coils periodically would accomplish the same result.”
Cleaning with essential oils and essential-oil-based cleaners will be far less
costly.
So, UV and UVC systems may be helpful in improving indoor air quality, however, they are not effective in eliminating most mold infestations and may pose health dangers if not properly installed, shielded and maintained. In general, they are far more costly and less effective than using essential oils and essential oil-based cleaners.
So, UV and UVC systems may be helpful in improving indoor air quality, however, they are not effective in eliminating most mold infestations and may pose health dangers if not properly installed, shielded and maintained. In general, they are far more costly and less effective than using essential oils and essential oil-based cleaners.
Limitations of UV or
UVC Systems
- They cannot address many sources of or surfaces infested with mold
- Intensity and “dwell time” requirements do not address all mold species
- Humans have DNA, and since UV and UVC are known to destroy the DNA of microorganisms, special handling of lamps, installation of shielding, and added protection for human inhabitants increase the risk of damaging the DNA of humans that come in contact with the light, as well as increasing the costs associated with its installation and maintenance.
Is UV right for your
mold problem?
The
best answer is that it depends on the building and the budget. It is only one
of a number of options that can be utilized for improving air quality as part
of the solution for a building with a mold problem. It is not a solution in and
of itself, and not necessarily even a part of the best possible solution for a
given mold problem. There are far more cost-effective options available that
can help you address all sources, surfaces, and air streams.
We have more than 20 years of mold remediation experience, over 10 years experience using The Close Protocol to Remediate Mold in Buildings, and many hundreds of personally-supervised mold remediation projects where The Close Protocol was employed, and we have found that essential oils and essential-oil based cleaners have proven far more cost effective as well as more effective and complete in addressing and remediating mold in buildings.
We have more than 20 years of mold remediation experience, over 10 years experience using The Close Protocol to Remediate Mold in Buildings, and many hundreds of personally-supervised mold remediation projects where The Close Protocol was employed, and we have found that essential oils and essential-oil based cleaners have proven far more cost effective as well as more effective and complete in addressing and remediating mold in buildings.
Many
discussions of mold remediation options and detailed answers to questions about
using the Close Protocol for Mold Remediation in Buildings are freely provided
on this website. For those of you who require additional help, please contact us.
Basic
information about the ten-step protocol is presented in Chapter 7 of our book, Nature’s Mold Rx, The Non-Toxic Solution to Toxic Mold. The book also
discusses twenty (20) case studies in detail, and most of the questions that may
arise when the protocol is applied are answered in the book.
Be
blessed richly and may you always enjoy Vibrant Health!
Very
Sincerely,
Dr.
Ed And Jacqui Close
EJC
Advantage LLC
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