Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/1179928
Healthy Indoors | 17 mixing/VAV boxes, etc.), and the ductwork. I regularly get RFPs that only call for cleaning small portions of an HVAC system during commercial renova- tion projects, as if the debris intentionally confines itself to specific sections of ductwork (the same physics principals that used to keep cigarette smoke out of a restaurant's non-smoking section?). Partial cleaning (i.e. leaving out portions of the work) generally only yields partial benefits of having the service performed. Does Size Matter? With some things, perhaps, but not necessarily with duct clean- ing. I became involved in the industry back in the late 1980s, when truck-mounted vacuums were pretty much the way things were done. Equipment manufacturers touted their massive CFM vacuum airflow specs. Of course, bragging about the size of your tool was nothing new in the duct cleaning industry. Vacuum capabilities are certainly a factor for effective cleaning, but those alone do not ensure thorough contami- nant removal. You see, HVAC ductwork, despite what you might have heard, is not really cleaned by sucking the dirt out! Vacuum equipment serves as the collection device for debris, once it has been dislodged via mechanical and/or pneumatic means. In lay terms, you gotta knock the junk loose so it can get vacuumed up. We'll talk more about those methods later in the article. Now don't get me wrong, size does matter--a bit. You need enough flow and static pressure to control, contain and capture debris, otherwise the duct in question won't get cleaned and unwanted contaminants may be spread throughout the rest of the system and building. As I mentioned earlier, truck-mounted and other large por- table gas or diesel engine-type vacuums used to be the only option for duct cleaning purposes. These are still extensively used for residential and light commercial service work today. In the early 1990s, a new wave of portable electric duct cleaning vacuums were introduced. Unlike the earlier vacs that were located outdoors, these new portable units are exhausted indoors. As such, they utilize HEPA, otherwise known as High Efficiency Particulate Air filtration (99.97% efficient at 0.3 micron particle size) to minimize the possi- cooling coils and drain pans), as well as a deterioration of internal insulation, gasketing, and metal components. The presence of corrosive chemicals, biological contaminants, or other adverse environmental conditions can further serve to affect the hygiene of a building's HVAC system(s) and contribute to degraded indoor air quality (IAQ). The bottom line is: For an assortment of reasons, HVAC systems become contaminated over time, leading to poten- tially compromised IAQ and increased energy consump- tion. That said, duct cleaning represents only one piece of the indoor environmental management puzzle. The Solution to Indoor Air Pollution? Before he took to speaking to empty chairs, Clint Eastwood nailed it with his quote in the movie Magnum Force back in the 1970s when he said, "A man's got to know his limitations..." An industry's got to know its limitations, too. Air duct cleaning will not solve all the IAQ problems in a building, despite the claims from some practitioners. It's only one piece in the puzzle...perhaps an important one, but none-the-less, just a piece. I see this card played all the time in both the com- mercial and residential markets by duct cleaning service providers that are over-selling their service. Responsible, knowledgeable firms don't make excessive benefits claims, period. Run Away —Part 1 While I'm on that rant, if I see one more residential duct cleaning promotional piece with a picture of a dust mite in it, I'm going to lose it...seriously. It's like another bad Kev- in Bacon movie, only with the tremors in your HVAC and wallet. Cleaning your ductwork doesn't rid your building of dust mites, since they don't live in your ductwork! As a con- sumer, when you see dust mites in duct cleaning market- ing--RUN AWAY! Also, when you see group-on-dupe-on ads for $49, $99, $149 or similar duct cleaning "specials" --RUN FASTER. There's no way you can get even margin- al quality service work done for these bait prices. What Duct Cleaning Does (or at least should) Entail Duct cleaning is somewhat of a misnomer. Unlike the term says, duct cleaning should include the entire system: Grills/ diffusers, air handling unit (including fans, coils, and filter compartments), control devices (dampers, turning vanes,