have you been told that duct board used for an air plenum for your hvac system is dangerous to your health that flakes of insulation are falling off every day entering the air stream that you breathe in your house does duct board cause cancer how long does duct board last before i need to change it [Music] well i'll tell you what every time that i dive into a blog i like to use my personal experience as an hvac tech and relate it to common questions that customers ask me but i love getting into the real facts i love talking to people in the industry who make the product and contemplate what the epa acca or ashrae has to say about it too the type of duck board that i find in a lot of systems is similar to john's manville matte-faced microair 5-ish duck board we see duck boards so much because neighborhoods bill around 2000 and even earlier have gone through their share of service calls several of those homes have changed their ac system out completely but the plenums used for those systems have typically been duckboard plenums but even if those homes had sheet metal plenums they'd still have fibrous duct insulation inside of them if they didn't the metal plenum or distribution box would get hot in the heating season and start to sweat in the cooling season on a side note there is another type of insulation that we line sheet metal with and it's called astrofoil or bubble wrap and it's pretty good stuff too guess how many parts of your hvac system have this fibrous glass insulation as part of its construction at the very least three not one you have the furnace the evaporator coil and the air plenum i don't understand why hvac salesmen tell folks who are buying a new system that they should have a new plenum installed specifically to prevent the use of duct board are they just trying to pad the commission they get after selling you a system because again there's really no getting around it all manufacturers have it in their equipment super salesy type companies create fiber phobia in a customer's mind either because they heard it from their trainer or just randomly finding things on the internet to scare you into spending more money here's a couple samples of opinions that i've read from so many hvac and green energy websites after the primary seal has fully deteriorated it allows raw fiberglass fibers to be exposed to the airstream turbulent air streams wick the raw fiberglass through the ventilation system creating additional deposits within the hvac components and exposing building occupants to raw fiberglass fibers companies also show those terrible pictures of mold and dust buildup inside ducts to convince you to change your ducts or to clean them i see mold and spores in just as many vinyl line ducts as i see in duct board if the system is regularly maintained like something as simple as changing your air filter every 90 days how will dirt and debris find their way into the duct system anyways but let's look at some facts manufacturers like johns manville and owens corning test their products they use isokinetic sampling method as well as long duration testing the manufacturers rate their product for use up to 6000 feet per minute way more than your typical residential hvac system to pass the test on complying with ul 181 section 17 the materials used in the fabrication of air ducts shall not break away flake off or show evidence of delamination or continued erosion when the air is passed through typical sections at a velocity of two and a half times the manufacturer's rated velocity i found another snippet of research that says the potential for shedding of glass fibers from the duct surface was evaluated at the maximum recommended velocity of 6000 feet per minute testing was conducted using an air duct fabricated into an l shape as described in section 17.2 and 17.3 of the ul 181 procedure sampling the airstream at the same velocity as the air test velocity conducted near the outlet of the duct and examined by phase contract microscopy following niosh method 7400 demonstrated no detectable glass fibers in the seven hour test the sampling detection limit for this test is 0.01 fibers per centimeter cube of air test samples contained fewer fibers than values reported for ambient air reviewing several major studies the world health organization's international program on chemical safety concluded the contribution of fiberglass lined air transmission systems to the fiber content of indoor air is insignificant complying with astm c1071 the following test methods have been performed corrosiveness water vapor absorption fungi resistance temperature resistance erosion resistance odor emission surface burning characteristics apparent thermal conductivity sound absorption coefficients bacteria resistance and combustion characteristics there is no causal association between cancer or non-malignant pulmonary disease and human exposure to glass fibers that biosoluble wool fibers are thin enough that fibers disappear from the lung at the same rate as dust in the air we breathe every day that levels of glass fibers in most settings are less than one fiber per centimeter cube and that airborne levels and insulated buildings are not significantly different than levels outside or in uninsulated buildings the following bodies which are well-known industry names can be used as reference when making your assessment of whether duckboard plenums are dangerous nema which is the north american insulation manufacturers association ashrae the american society of heating refrigeration and air conditioning engineers astm american society for testing materials the epa the nfpa national fire protection agency smackna sheet metal and air conditioning contractors national association the icc international code council aia american institute of architects aiha american industrial hygiene association and the ama which is the american medical association does duck board need to be changed out at some point in the life cycle of your home yes most likely whether it be flexible vinyl ducting or duct board and if for no other reason than when you move into a recently purchased home i personally don't want to be breathing in the air dead skin hair mites and other disgusting deposits that may have made it into the ductwork from the last people who lived there having provided the service myself for customers i don't believe that duct cleaning works as well as people say it does it might knock the dust off but it doesn't disinfect or make it like new home inspectors take a look at the exterior of the ducts and determine the shape they're in with a brief glance in the attic but they don't look inside of them so the duffs will pass the inspection but for me as a new home buyer i'd want to change them out another reason you change out ductwork regardless of the type of material it's made of is if the vapor barrier surrounding the ducts if it's shredded or falling apart does your home have hot or cold spots uneven airflow smashed ducts from a serviceman who needed access to the space these are all reasons to change or upgrade your ducting regardless today i wanted to clear the air about yet another way the hvac companies send their guys out into the field with bad information i couldn't find any facts as to why using duckboard would be a poor choice or that you should change your duckboard plenum because it flakes off and enters your airstream they were all fluff written by blog writers or companies talking about stuff they really don't know about my company doesn't install duckboard when we change duct systems out we typically use flexible ductwork but we do install plenums that are lined with fiberglass that we've discussed today and remember it's already in your new hvac system anyways for insulation and sound attenuation so i hope this hasn't come across as a sales presentation i just like to know the facts and i thought you would too that's why we've cited specific standards made by the industry's major players and told you their observations so hopefully this has helped with any questions you have about fibrous glass duct board if this is your first time watching our channel please click subscribe down here on the bottom right and if you click that little bell next to it you'll be notified of all of our videos as they come out thanks so much for watching and we'll see you on the next video you're watching fox family heating and air don't forget to subscribe and check out more of our videos by clicking on the right side of the screen [Music]
