Fire Smoke Odor Removal


According to the National Fire Protection Association, there is a call for help to fire departments across the U.S. every 24 seconds.

In 2017, almost 500,000 of those calls were for structure fires; 72 percent of which were in homes.

On average, between 2012 and 2016, structure fires – both residential and commercial – resulted in more than $9 billion in property losses.

For restoration contractors, this means there is a lot of work up for grabs. It also means handling some of the trickiest, most subjective jobs the property loss restoration industry faces. This is largely because of the odor that accompanies fire, smoke, and soot damage. Odors can infiltrate deep into any porous surface, and unless properly remediated from the start, smells can reappear weeks or even months after the loss, leading to very unhappy clients.

Fire Smoke Odor Removal Process

It’s critical to follow a step-by-step process to effectively and fully remove smoke odors from any structure after a fire.

Step #1: Create a Scope of Work & Setting Equipment

When you initially arrive on the scene of a structure fire, meeting with the property owner is likely your first step. This is a very good opportunity to get to know them and create a rapport, as well as hear their story about the loss. The details they recount about the source of the fire, the damage, health issues, and so on, can be vital to creating a full, effective scope of work for the project. You should also determine the type of fire, which we address below. As you walk the property, be sure to note square footage and severity of damage from space to space.

Hydroxyl generators can begin running on site immediately to help knock down odors even before any structural work begins. In addition to removing odors, the hydroxyl radicals blast away harmful VOCs, making the environment safer for your crew (although proper PPE should always be worn, of course). And remember, hydroxyl generators are safe to run in occupied spaces, so crews can be working and items can be present the entire time.

While every project is different, and there are various techniques for dispersing hydroxyl radicals throughout a loss, the general rule of thumb is that one machine will cover 1,000 to 1,500 square feet, depending on ceiling height, layout, odor severity, etc.

Remember with fire losses, time is of the essence. Here is what the Institute of Inspection Cleaning and Restoration Certification (IICRC) says about fire damage:

  • Within Minutes: Acid soot residues cause plastics to yellow; small appliances located close to the source of combustion discolor; highly porous materials (marble, alabaster) discolor permanently.
  • Within Hours: Acid residues stain grout in bathrooms; fiberglass bath fixtures may yellow; uncoated metals tarnish; counter tops may yellow; finishes on appliances, particularly refrigerators, may yellow; furniture finishes may discolor.
  • Within Days: In time, acid residues cause painted walls to yellow permanently; metal corrodes, pits and rusts; wood furniture requires refinishing; vinyl flooring requires refinishing or replacement; clothing becomes soot-stained; upholstery stains permanently.
  • Within Weeks: Restoration costs escalate tremendously. Synthetic carpet fibers may yellow or discolor permanently; silver plate is corroded permanently; glass, crystal, china may require replacement due to severe etching and pitting caused by prolonged exposure to acid soot residues.

The quicker you and your team get to work, the better!

Step #2: Source Removal

While you were creating your scope of work, you were likely also evaluating what needs to be removed, replaced, or cleaned. Be sure to start by identifying the source of the fire and contain this until it can be cleaned or removed. Also, carefully evaluate porous materials, like carpet, to see if it can be cleaned and deodorized on site, or if it needs to be removed and/or replaced. Some fire projects require a focus primarily on odor removal, while others also leave behind significant amounts of soot and ash that need to be cleaned.

Anything in the structure that has visible smoke and/or fire damage should be packed up and transported for the contents restoration process, if applicable. The more items you can remove that have absorbed noxious fire odors, the quicker the odors will be eliminated on site. However, it’s important to note that hydroxyl generators not only address the odors in the structure itself, but also those that are absorbed into the contents. So, contents left within the structure during the restoration and cleanup process can be deodorized on site, thanks to the use of hydroxyl generators.

Step #3: Clean & Restore

Once all non-salvageable items are removed from the property, along with items sent to your facility to go through your contents restoration line, it’s time to clean everything left behind. Any visible soot and fire damage needs to be cleaned, restored, or replaced. Soot and ash have the ability to travel into tiny crevices, and unless wiped away properly, can lead to odors creeping back into a structure after your crew believes the job is complete.

Hydroxyl radicals, by nature, are able to penetrate porous surfaces including wood and textiles and eliminate odors. However, any parts of the structure truly damaged by the fire should be removed and replaced.

Step #4: Sealing

Sealing is a popular protocol in the smoke odor removal process, however, it becomes unnecessary when using hydroxyl generators properly. Sealers only need to be used to address the visual aspect of fire damage – i.e., to make things look better. The hydroxyl generators should have already done the job of eradicating all fire odors.

Step #5: Odor Check

How do you know if the odor is truly gone? It’s probably simpler than you realize – just follow your nose! Do you and your crew detect any lingering smoke odors? Be sure to especially do smell tests on porous items where odors may have settled; not just the air. If some odor lingers, repeat the necessary steps above. If there’s no odor detected by you, your team, or the property owner, then your job is done!

Types of Fire Smoke Odor Removal Scenarios

No two fires are the same, and therefore, can cause different kinds of damage. For example, high-oxygen fires will create dry soot, meaning odors don’t become so deeply embedded in contents. This makes it a bit easier for odors to be destroyed by the hydroxyl radicals produced from your strategically placed generators. Low-oxygen fires produce greasy, wet soot that will require more cleaning, and likely a longer deodorization process because of how much the soot and ash set into materials.

Protein fires are perhaps the most challenging when it comes to odor removal because they produce more severe odors than other fires. These types of fires generally start in a kitchen area as the result of burnt food. They do not create a whole lot of visible damage, but the lingering noxious odors can easily fill an entire structure. The use of hydroxyl generators for protein fires is highly effective.

Aside from the various types of fires, you’ll likely encounter fires of different scales that require different odor removal techniques.


Fire smoke odor from wildfires can be addressed using hydroxyl generatorsMillions of homes were affected by the California wildfires in 2018. Even communities far from the actual fires experienced smoke odor and air quality issues. Hydroxyl generators were the perfect solution in both scenarios. During the 2018 wildfires, countless hydroxyl generators were used in all different types of properties to effectively and permanently get rid of these odors.

In these large-scale loss situations, it’s critical to have relationships established with your local equipment providers and/or the manufacturer itself, like Odorox. That way, when you see the need for equipment on the horizon, you can be first in line to get what you need before supplies inevitably dwindle due to high demand.


Large Loss

Hydroxyl generators have been used with great efficacy in hundreds of large losses across the U.S., including at major retailers.Hydroxyl generators have been used with great efficacy in hundreds of large losses across the U.S., including at major retailers like Costco and Ikea. One major value to using hydroxyl generators for odor removal is businesses that mainly suffered smoke damage, and therefore don’t require much structural repair or cleaning, can remain open throughout the odor removal process.

Understanding the square footage, ceiling height, layout, and severity of the odor will help you determine just how many hydroxyl generators you’ll need to effectively handle the loss. There’s no need to worry if you don’t have enough generators on hand; they can be rented, and the cost reimbursed through the property owner’s insurance policy by putting CLNDODHY> into Xactimate. This adds the cost of the air mover as well since it is required to operate the hydroxyl generator.

With large losses, it’s wise to think about how best to aim and disburse the hydroxyl radicals throughout the space. Can you create a vortex of radicals around the affected area using additional air movers? Can you aim them toward the original source? How can you get creative to get those radicals right where they need to go to eliminate odors quickly and effectively? See Chapter 3, "Using a Hydroxyl Generator to Remove Fire Smoke Odor", for some tips and tricks to maximize efficacy!



Residential fires are the most common type of fire restoration contractors face.This is obviously the most common type of fire restoration contractors face. Remember, as a general rule of thumb, one hydroxyl generator (and its accompanying air mover) will typically address odors in 1,000 to 1,500 square feet. Keep in mind that if more contents are left on site for treatment deodorization could take longer.

Using a Hydroxyl Generator to Remove Fire Smoke Odor

Using a hydroxyl generator to remove fire smoke odor is nearly as simple as plugging it in, attaching it to the necessary air mover to disburse the hydroxyl radicals, and letting the machine do its job. These generators produce oxidizing gasses that break apart odor molecules and eliminate a very broad range of odors and VOCs.

It’s important to understand hydroxyl generators stand alone when it comes to odor removal. There is no need for additional chemicals, oils, masking agents, charcoal filters, sealers, and so on. Hydroxyl radicals have the ability to get into the smallest nooks and crannies and densely porous materials to eliminate odor.

Going back through previous chapters, there are five variables to consider when using hydroxyl radicals to remove smoke odor:

  1. The layout of the structure.
  2. Contents on site.
  3. Severity of the odor.
  4. Time needed, or available, to complete the project.
  5. Source removal/containment options.

Here are some tips and tricks to maximize efficacy:

  1. Use additional air movers to distribute hydroxyl radicals throughout the structure, especially if the space is broken up.
  2. Consider containing items with heavy odors in storage containers or within plastic sheeting, and blast them with hydroxyl radicals. Likewise, consider ducting or injecting hydroxyls into hard-to-reach areas and crevices, like wall cavities, school lockers, etc.
  3. If needed, use air scrubbers to capture any solid particulates in the air. While the air scrubbers do their job, the hydroxyls will disassemble the odor molecules. They work great together!
  4. Don’t be afraid to move the machines around as the job progresses to target the most problematic areas.

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