We constantly get calls from the disaster restoration companies in our area wanting to hire us to clean and sanitize the duct systems in homes and businesses following a fire, flood or other catastrophe.
I always recommend networking with entities such as building contractors, property management companies, real-estate agents and HVAC installers, as long as the companies with whom you’re networking are upstanding representations of their industry.
Remember: You’re a reflection of them, as they are of you.
Disaster restoration companies are some of my favorites, as they constantly stimulate us with something different from the norm, and the revenue generated by performing work for them is usually maximized.
So when our phone rang one recent morning and we were asked to perform a duct cleaning and sanitizing in a home, it started out pretty routinely.
After the address of the residence was given and a cleaning date selected, our receptionist asked for the nature of the disaster.
The restoration representative paused, lowered her voice and replied, “A human corpse was discovered in the home two weeks after expiring.”
Now, we’ve handled duct cleaning in homes where people have died before, but this was a little different. Usually when a person expires in their home, the body is quickly removed, and it’s not too difficult to clean.
In this case, not only had two weeks passed before the body was removed, but the weather had been in the mid-90s, and there was no air conditioning in the home.
Fortunately for us, duct cleaners are usually one of the last ones to perform our services in disaster cleanup situations, so the rest of the home had already been cleaned and was in pretty good shape when we got there.
Although there still was an unmistakable odor present — an odor which is difficult to describe. If you’ve experienced this odor before, you know what I mean, and you’ll never forget it.
Just to be on the safe side, wanting to be sure everything was done “to code,” I called and spoke with a representative with the Environmental Protection Agency (EPA). Additionally, being a member of the National Air Duct Cleaner’s Association (NADCA), I called and spoke with one of their experts.
In a nutshell, it was basically a matter of making sure every bit of the ductwork was cleaned and sanitized using equipment and antimicrobials that met the standards for such a level of restoration.
The first step was to take a look at the duct system to see with what we were dealing with:
- What type of ducting was it, and how porous was it?
- What was the inside the furnace — i.e., did it have fiberglass lining?
Cleaning the ducts
By removing the register covers and looking and feeling down the ducts, we could tell they were made of typical plastic flex, so the porosity was not a factor; however, they still needed to be deep-cleaned and sanitized.
We performed a thorough cleaning with an air whip and skipper ball, removing all the dust and debris adhering to the sides of the ducts.
As with nearly all homes that have not had their ducts cleaned recently, copious amounts of sheetrock dust, sawdust and household dust came pouring out into our vacuum box and HEPA vacuum unit. We cleaned the ducts one at a time, first agitating the duct walls with the air whip, then blasting them with the compressed, air-powered skipper ball, scouring the sides with 100+ psi of targeted air.
Construction debris in the form of chunks of wood, sheetrock, nails and discarded sandpaper were then vacuumed out by running the vacuum hose through each duct.
There’s nearly always some “interesting items” removed during this part of the process. In this case: An empty yogurt container (probably discarded by a construction worker 23 years prior); a McDonald’s Big Mac container, which still had some cheese stuck to the inside that was now dehydrated and petrified by two decades’ worth of warm-air movement over it; some marbles and loose change; a tennis ball that likely fell in and rolled down during a game of “fetch” and a handful of toys ranging from Barbie accessories to tabletop game pieces.
Cleaning the furnace
Once we were sure the return and supply ducts were cleaned, we moved our attention to the furnace.
Removing the access doors, we found that indeed there was a fiberglass lining, as is the case for most furnaces, which is quite porous and very successful at trapping odors. We needed to be especially effective at removing the dust and debris from the furnace and fiberglass lining, as the dust itself works like an “odor sponge” and can be very odoriferous.
The thin layer of dust covering the furnace interior was proportionate to that which was on the duct walls, and was blown off rather easily.
Sanitizing the system
After making sure the furnace was completely devoid of all dust and debris, we applied an antimicrobial/ odor- neutralizing sanitizer to it by removing the application hose from the SaniJet and fogging the furnace interior directly.
We then disinfected the ducts themselves, fogging the sanitizer directly to the duct walls by running the SaniJet hose through each duct via each duct opening and blasting them with the sanitizing fog.
I believe it’s very poor practice to treat odors with other aromas, such as “spring fresh this” or “flowery that.”
Covering odors is not getting rid of the problem; it’s just adding pleasant odor on top of an unpleasant one. To me, this is tantamount to, rather than taking a shower, simply slathering oneself with deodorant and body spray every day.
Proper duct sanitizing is a good follow-up to every duct cleaning, but in a restoration situation such as this, it’s absolutely crucial.
Finishing with ozone
As the final step to ensure that any and all odor-producing molecules had been completely eradicated, we turned the furnace system on and placed an industrial-grade ozone generator on an intermittent 48 hour setting at the entrance of the return duct.
While the ozone generator is operating, each entrance to the dwelling must be clearly marked with “Ozone — Do Not Enter” signs, as it’s a biologically hazardous gas while in its active form.
The beauty of ozone is two-fold:
- It is a very powerful sanitizer and odor neutralizer, which destroys fungus, bacteria, mold, etc.
- After it’s generated, its half-life is very short, converting back to oxygen in a short amount of time and leaving no residue or toxic trace.
I was eager to return to the job site after the ozone generators had completed their cycle and all the ozone had a chance to form back into oxygen. I wanted to give the home a “sniff test” to see for myself how effective our process was at ridding the building of odors.
As I walked through, it was very satisfying to smell absolutely nothing.
The restoration company was thrilled with the results, even going so far as to write us a thank you letter for our efforts.
David W. Hart, founder and CEO of RamAir International, is a 24-year veteran in the carpet and duct cleaning industry. He invented the RamAir ClearView Duct Cleaning System, which is now available for purchase in more than 500 locations in five countries. He also owns and runs Guarantee Cleaning Services Inc. in Bend, OR.