Guest guest Posted March 24, 2010 Report Share Posted March 24, 2010 After getting sick several years ago from my workplace ventilation system, our maintenance department insisted it was working properly and nothing could be done. An indoor air quality specialist from Ohio Bureau of Workers' Compensation thought otherwise. He found the system to not be dehumidifying sufficiently because Freon pressure was too low to cool adequately, there was internal fiberglass insulation which was a biomass harbor, inadequate filtration, corroded cooling coils, and a rusty drain pan. He recommended it be replaced (it stayed another two years), and further stated that all commercial HVAC should be thorougly cleaned with detergent solution, followed by clean rinsing, twice per year, followed each time by disinfection with chlorine disinfectant (bleach or Oxine). Last, he recommended slow release chlorine disinfectant tablets be placed in the drain pan. As others on this board have mentioned, these are available at Lowes, Home Depot, and most commercial HVAC supply companies. Needless to say, my employer (Cognis Corporation) followed his instructions a few times, then never again, leading to my health related early retirement nine years ago. I'm assuming you are asking this question because you or someone you know is getting sick and believe it to be HVAC related. You are probably right. I worked in a building with no obvious water intrusion problems and no carpet, but the mold smell was quite obvious from one particular HVAC unit. It must be emphasized that thorough cleaning is a must, more important than disinfection. You must get rid of most of what mold needs to grow on. Disinfection without cleaning might eliminate the problem for a while, killing all easy to reach mold spores. But nutrient will remain, and depending on just how sensitized victims have become, health reactions may resume in a few weeks or less. Gil Posted by: " Jefferson Cajucom " neo_jepot@... neo_jepot Date: Tue Mar 23, 2010 1:56 pm ((PDT)) Please advice if HVAC need to be disinfect? If yes, what will be the frequency? Thanks and Regards, Jefferson _________________________________________________________________ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. http://clk.atdmt.com/GBL/go/210850552/direct/01/ Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 24, 2010 Report Share Posted March 24, 2010 Gil, you make some very good points. It should also be noted that sanitizers, even those that are EPA-registered for air duct systems are approved only for use in metal only ducts. Water-based sanitizing agents should not be applied to internally lined ductwork or other HVAC components. Connie Morbach, M.S., CHMM, CIE > > > After getting sick several years ago from my workplace ventilation system, our maintenance department insisted it was working properly and nothing could be done. An indoor air quality specialist from Ohio Bureau of Workers' Compensation thought otherwise. He found the system to not be dehumidifying sufficiently because Freon pressure was too low to cool adequately, there was internal fiberglass insulation which was a biomass harbor, inadequate filtration, corroded cooling coils, and a rusty drain pan. He recommended it be replaced (it stayed another two years), and further stated that all commercial HVAC should be thorougly cleaned with detergent solution, followed by clean rinsing, twice per year, followed each time by disinfection with chlorine disinfectant (bleach or Oxine). Last, he recommended slow release chlorine disinfectant tablets be placed in the drain pan. As others on this board have mentioned, these are available at Lowes, Home Depot, and most commercial HVAC supply companies. Needless to say, my employer (Cognis Corporation) followed his instructions a few times, then never again, leading to my health related early retirement nine years ago. > > I'm assuming you are asking this question because you or someone you know is getting sick and believe it to be HVAC related. You are probably right. I worked in a building with no obvious water intrusion problems and no carpet, but the mold smell was quite obvious from one particular HVAC unit. It must be emphasized that thorough cleaning is a must, more important than disinfection. You must get rid of most of what mold needs to grow on. Disinfection without cleaning might eliminate the problem for a while, killing all easy to reach mold spores. But nutrient will remain, and depending on just how sensitized victims have become, health reactions may resume in a few weeks or less. > > > > Gil > > > > > > Posted by: " Jefferson Cajucom " neo_jepot@... neo_jepot > Date: Tue Mar 23, 2010 1:56 pm ((PDT)) > > Please advice if HVAC need to be disinfect? If yes, what will be the frequency? > > Thanks and Regards, > Jefferson > > > _________________________________________________________________ > Hotmail: Trusted email with Microsoft's powerful SPAM protection. > http://clk.atdmt.com/GBL/go/210850552/direct/01/ > > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 24, 2010 Report Share Posted March 24, 2010 Connie, I truly appreciate your professional contributions to this group. And you do it in a way which educates and clarifies. Welcome. As for disinfecting ducting other than sheet metal, I'd like to add to what you and Gil have already contributed: the predominant standard, NADCA ACR 2006, states the ducting shall be removed because it can't be sufficiently cleaned or disinfected. Carl Grimes Healthy Habitats LLC (fm my Blackberry) [] Re: HVAC disinfection Gil, you make some very good points. It should also be noted that sanitizers, even those that are EPA-registered for air duct systems are approved only for use in metal only ducts. Water-based sanitizing agents should not be applied to internally lined ductwork or other HVAC components. Connie Morbach, M.S., CHMM, CIE > > > After getting sick several years ago from my workplace ventilation system, our maintenance department insisted it was working properly and nothing could be done. An indoor air quality specialist from Ohio Bureau of Workers' Compensation thought otherwise. He found the system to not be dehumidifying sufficiently because Freon pressure was too low to cool adequately, there was internal fiberglass insulation which was a biomass harbor, inadequate filtration, corroded cooling coils, and a rusty drain pan. He recommended it be replaced (it stayed another two years), and further stated that all commercial HVAC should be thorougly cleaned with detergent solution, followed by clean rinsing, twice per year, followed each time by disinfection with chlorine disinfectant (bleach or Oxine). Last, he recommended slow release chlorine disinfectant tablets be placed in the drain pan. As others on this board have mentioned, these are available at Lowes, Home Depot, and most commercial HVAC supply companies. Needless to say, my employer (Cognis Corporation) followed his instructions a few times, then never again, leading to my health related early retirement nine years ago. > > I'm assuming you are asking this question because you or someone you know is getting sick and believe it to be HVAC related. You are probably right. I worked in a building with no obvious water intrusion problems and no carpet, but the mold smell was quite obvious from one particular HVAC unit. It must be emphasized that thorough cleaning is a must, more important than disinfection. You must get rid of most of what mold needs to grow on. Disinfection without cleaning might eliminate the problem for a while, killing all easy to reach mold spores. But nutrient will remain, and depending on just how sensitized victims have become, health reactions may resume in a few weeks or less. > > > > Gil > > > > > > Posted by: " Jefferson Cajucom " neo_jepot@... neo_jepot > Date: Tue Mar 23, 2010 1:56 pm ((PDT)) > > Please advice if HVAC need to be disinfect? If yes, what will be the frequency? > > Thanks and Regards, > Jefferson > > >_________________________________________________________________ > Hotmail: Trusted email with Microsoft's powerful SPAM protection. > http://clk.atdmt.com/GBL/go/210850552/direct/01/ > > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 25, 2010 Report Share Posted March 25, 2010 Thank you Carl. \ ________________________________ From: on behalf of Carl Grimes Sent: Thu 3/25/2010 1:10 AM Subject: Re: [] Re: HVAC disinfection Connie, I truly appreciate your professional contributions to this group. And you do it in a way which educates and clarifies. Welcome. As for disinfecting ducting other than sheet metal, I'd like to add to what you and Gil have already contributed: the predominant standard, NADCA ACR 2006, states the ducting shall be removed because it can't be sufficiently cleaned or disinfected. Carl Grimes Healthy Habitats LLC (fm my Blackberry) Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 25, 2010 Report Share Posted March 25, 2010 Hi Carl and all: I haven't posted in some time but need to share my experience to help others. You are right Carl. Couple years ago I had mold in my flex ducts. Have two story house. Used NADCA company plus consultant and their recommended HVAC company. Downstairs air ducts very difficult to replace since much sheetrock would have had to be cut. They assured me they could clean the flex ducts downstairs, we used a safe fog after ducts cleaned. Upstairs, with easy access, we replaced ducts. Was expensive operation plus the A/C system totally cleaned in attic. A few weeks later saw mold growing again downstairs air duct register, they recleaned. I think we did this several times and assured me the system is clean. Turned into a nightmare, the NADCA company never having to deal with a chemical sensitive person, the NADCA company disagreeing with the consultant and never getting it right. Unfortunately I became ill in the house, last year I had to have the downstairs air ducts replaced, sheetrock cut out and when I saw the moldy air ducts was very upset. I called both the air duct cleaning company and consultant and was told it's my fault because I didn't use their regular disinfectant; the consultant told me it's difficult to clean flex air ducts. So, I was out close to $10,000 dollars plus ill health. Hope my experience will help others. I still have pictures of the moldy air ducts removed that had been guaranteed cleaned and safe. Rosie _____ From: [mailto: ] On Behalf Of Connie Morbach Sent: Thursday, March 25, 2010 5:42 AM Subject: RE: [] Re: HVAC disinfection Thank you Carl. \ ________________________________ From: @ <mailto:%40> on behalf of Carl Grimes Sent: Thu 3/25/2010 1:10 AM @ <mailto:%40> Subject: Re: [] Re: HVAC disinfection Connie, I truly appreciate your professional contributions to this group. And you do it in a way which educates and clarifies. Welcome. As for disinfecting ducting other than sheet metal, I'd like to add to what you and Gil have already contributed: the predominant standard, NADCA ACR 2006, states the ducting shall be removed because it can't be sufficiently cleaned or disinfected. Carl Grimes Healthy Habitats LLC (fm my Blackberry) Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 25, 2010 Report Share Posted March 25, 2010 Carl, Connie, Gil etc., All good points but let's not forget the most important issue after cleaning and disinfecting: installation of proper filtration. All the microbial problems stem from the accumulation of biodegradable dust on the linings and coils. The most important function of filtration is not cleaning the air for breathing, it's filtering out the biodegradable particles (skin scales, lint fibers, pollen, etc.) from the air so they don't accumulate on the wet coil and fuel microbial growth. HEPA filtration (MERV 14-16) is really overkill for removing biodegradable particles. MERV 8 is a minimum and MERV 11 is ideal. In fact, anything that moves air over a coil (AC, dehumidifier, Air-to-air heat exchanger) should have a media filter with a minimum of MERV-8 efficiency. Pre-filtering the return air (at the grilles) is very helpful in reducing the dust accumulations in return ducts and prolonging the life of the media filter. May May Indoor Air Investigations www.mayindoorair.com > > Thank you Carl. \ > > ________________________________ > > From: on behalf of Carl Grimes > Sent: Thu 3/25/2010 1:10 AM > > Subject: Re: [] Re: HVAC disinfection > > > Connie, > > I truly appreciate your professional contributions to this group. And you do it in a way which educates and clarifies. Welcome. > > As for disinfecting ducting other than sheet metal, I'd like to add to what you and Gil have already contributed: the predominant standard, NADCA ACR 2006, states the ducting shall be removed because it can't be sufficiently cleaned or disinfected. > > Carl Grimes > Healthy Habitats LLC > (fm my Blackberry) > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 25, 2010 Report Share Posted March 25, 2010 Rosie, Thanks for your story. NADCA and others are a starting point but not a guarantee. Point well made. Carl Grimes Healthy Habitats LLC (fm my Blackberry) Re: [] Re: HVAC disinfection Connie, I truly appreciate your professional contributions to this group. And you do it in a way which educates and clarifies. Welcome. As for disinfecting ducting other than sheet metal, I'd like to add to what you and Gil have already contributed: the predominant standard, NADCA ACR 2006, states the ducting shall be removed because it can't be sufficiently cleaned or disinfected. Carl Grimes Healthy Habitats LLC (fm my Blackberry) Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 25, 2010 Report Share Posted March 25, 2010 Jeff, Your recommendation for good filtration on the HVAC system addresses an important issue that is often overlooked. I am surprised at the number of homes in which I still see flimsy fiberglass filters in the HVAC systems. However, caution must be exercised when upgrading filtration. Some older furnaces do not have the blower capacity to handle the resistance associated with higher efficiency filters. The resistance can obstruct airflow, which can cause a furnace to short cycle and AC coils to freeze up, which can result in floods and significant water damage to finished basements. Another point to make is that most HVAC airducts are not sealed at the seams. Airflow through the supply ducts can pull contaminants from the basement, attic or crawlspace into the ducts. Quite often I see HEPA bypass systems and no duct sealing – what a waste this is. Regarding filters on return grilles, I have not seen this. What type of product do you recommend? Is there any concern regarding obstructed airflow with certain types of filtration devices on grilles? Connie Morbach Sanit-Air, Inc. cleanlinest.wordpress.com > > Carl, Connie, Gil etc., > > All good points but let's not forget the most important issue after cleaning and disinfecting: installation of proper filtration. > > All the microbial problems stem from the accumulation of biodegradable dust on the linings and coils. > > The most important function of filtration is not cleaning the air for breathing, it's filtering out the biodegradable particles (skin scales, lint fibers, pollen, etc.) from the air so they don't accumulate on the wet coil and fuel microbial growth. > > HEPA filtration (MERV 14-16) is really overkill for removing biodegradable particles. MERV 8 is a minimum and MERV 11 is ideal. In fact, anything that moves air over a coil (AC, dehumidifier, Air-to-air heat exchanger) should have a media filter with a minimum of MERV-8 efficiency. > > Pre-filtering the return air (at the grilles) is very helpful in reducing the dust accumulations in return ducts and prolonging the life of the media filter. > > May > May Indoor Air Investigations > www.mayindoorair.com > > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 26, 2010 Report Share Posted March 26, 2010 As Jeff has mentioned, proper filtration is necessary to prevent dust from contaminating the cooling coils and drain pans to become food for mold. There are also other factors. A few years ago, I had a new high efficiency furnace/air conditioner installed, with one of the extra thick filter housings for the 4 or 5 inch thick pleated filters. After installers left, I opened the system and looked inside, only to find that the filter housing was not completely attached to the fan chamber, allowing a small amount of basement air to be sucked in unfiltered. Installers must do the job right, or any money spent on these extras is simply wasted. Another factor is operating conditions. For mold to grow, high relative humidity is required. So, furnace humidifiers contribute to mold growth. Also contributing is water left in the drain pans of air conditioners when the fan stops. That means drain pans must be installed to facilitate complete drainage. That is often not the case. On warm days, water condenses on the coils, dehumidifying your house. When evening coolness arrives, cooling is not needed and the AC shuts off. The air handler gradually warms to room temperature, and drain pan water evaporates into the small air chamber on the furnace. Warm very high RH air is now in the air handler, promoting mold growth. Newer high efficiency furnaces have a variable speed fan. By leaving the fan running continuously, instead of cycling with the AC, the fan slows when AC is off, but has the benefit of keeping the air moving in the air handler, evaporating drain pan water back into the air. Relative humidity in the air handler thus will never exceed relative humidity in the house. Therefore mold growing conditions are eliminated. You can do the same thing with a single speed blower, letting the fan run an hour or two after cooling stops to dry out the drain pan. Re: HVAC disinfection Posted by: " healthier4all@... " healthier4all@... healthier4all Date: Thu Mar 25, 2010 2:13 pm ((PDT)) Hi Carl and all: I haven't posted in some time but need to share my experience to help others. You are right Carl. Couple years ago I had mold in my flex ducts. Have two story house. Used NADCA company plus consultant and their recommended HVAC company. Downstairs air ducts very difficult to replace since much sheetrock would have had to be cut. They assured me they could clean the flex ducts downstairs, we used a safe fog after ducts cleaned. Upstairs, with easy access, we replaced ducts. Was expensive operation plus the A/C system totally cleaned in attic. A few weeks later saw mold growing again downstairs air duct register, they recleaned. I think we did this several times and assured me the system is clean. Turned into a nightmare, the NADCA company never having to deal with a chemical sensitive person, the NADCA company disagreeing with the consultant and never getting it right. Unfortunately I became ill in the house, last year I had to have the downstairs air ducts replaced, sheetrock cut out and when I saw the moldy air ducts was very upset. I called both the air duct cleaning company and consultant and was told it's my fault because I didn't use their regular disinfectant; the consultant told me it's difficult to clean flex air ducts. So, I was out close to $10,000 dollars plus ill health. Hope my experience will help others. I still have pictures of the moldy air ducts removed that had been guaranteed cleaned and safe. Rosie _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/210850553/direct/01/ Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 27, 2010 Report Share Posted March 27, 2010 Connie, You raise a good point but one that is too often cited as an excuse for not spending the extra money on a pleated media filter. Unfortunately, most furnace and central A/C installations will only allow for a one-inch filter. The resistance to air flow, measured by the filter's " static pressure, " (measured in inches of a water column)depends both on its efficiency and thickness (depth and surface area of media). So whereas a highly efficient MERV-11 one-inch filter may offer as much as .25 inches of static pressure (resistence ot air flow), a six-inch deep Aprilaire media filter only offers .05 inches of static pressure (5 times less). The manufacturer recommends that the filter be replaced when the static pressure, due to clogging from dust, has risen to .1 inches. This typically takes about a year. ASHRAE recommends that all A/C equipment be operated with a minumum of MERV-8. I suspect that any quality, one-inch MERV-8 filter can readily be substituted for the nearly useless fiberglass furnace filter that most folks use. I tested a one-inch MERV-11 filter in a furnace system to see how the air flow would change because I was concerned about the filter's static pressure rating of .25 inches. The air flow (measured in feet/minute of air flow) at a register dropped about 10% when I switched from the fiberglass furnace filter to the more restrictive media filter. The total staitc pressure in a duct system depends on the duct design and varies (I am not certain about this) from about .5 inches to 1 inch. So the Aprilaire filter does not change much. I would never hesitate to try out a MERV-8 filter on a central system. Don't just take anyone's word that it will not work. (Short cycling and freeze ups should be apparent is there is any serious problem.) To keep the static pressure to a minimum, just remember to change a one-inch media filter at least twice a year, more often in a very dusty environment. May May Indoor Air Investigations LLC www.mayindoorair.com P.S. I think that you meant " return " ducts in your comment: " Airflow through the supply ducts can pull contaminants from the basement, attic or crawlspace into the ducts. " > > Jeff, > Your recommendation for good filtration on the HVAC system addresses an important issue that is often overlooked. I am surprised at the number of homes in which I still see flimsy fiberglass filters in the HVAC systems. However, caution must be exercised when upgrading filtration. Some older furnaces do not have the blower capacity to handle the resistance associated with higher efficiency filters. The resistance can obstruct airflow, which can cause a furnace to short cycle and AC coils to freeze up, which can result in floods and significant water damage to finished basements. > Another point to make is that most HVAC airducts are not sealed at the seams. Airflow through the supply ducts can pull contaminants from the basement, attic or crawlspace into the ducts. Quite often I see HEPA bypass systems and no duct sealing – what a waste this is. > > Regarding filters on return grilles, I have not seen this. What type of product do you recommend? Is there any concern regarding obstructed airflow with certain types of filtration devices on grilles? > > Connie Morbach > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted March 27, 2010 Report Share Posted March 27, 2010 Good information Jeff, I am saving it for future reference. > > > > Jeff, > > Your recommendation for good filtration on the HVAC system addresses an important issue that is often overlooked. I am surprised at the number of homes in which I still see flimsy fiberglass filters in the HVAC systems. However, caution must be exercised when upgrading filtration. Some older furnaces do not have the blower capacity to handle the resistance associated with higher efficiency filters. The resistance can obstruct airflow, which can cause a furnace to short cycle and AC coils to freeze up, which can result in floods and significant water damage to finished basements. > > Another point to make is that most HVAC airducts are not sealed at the seams. Airflow through the supply ducts can pull contaminants from the basement, attic or crawlspace into the ducts. Quite often I see HEPA bypass systems and no duct sealing – what a waste this is. > > > > Regarding filters on return grilles, I have not seen this. What type of product do you recommend? Is there any concern regarding obstructed airflow with certain types of filtration devices on grilles? > > > > Connie Morbach > > > Quote Link to comment Share on other sites More sharing options...
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