There are many different sources
of odor,
and they often require more than
one method of deodorization. However, no
matter what the cause, the same fundamental
principles apply in order to deodorize:
• Remove the odor source and debris;
• Clean surfaces that have odor-causing
residues on them; and
• Seal surfaces exposed to malodors.
After a fire or smoke damage occurs,
the odor will linger in the affected areas
unless treated, and water damage may
also leave a musty odor. No matter the
cause, these odors need to be neutralized.
According to the University of Florida’s
Institute of Food and Agricultural Sciences’
“Disaster Handbook,” the first step
is to get the air moving. Open windows to
ventilate areas, and install a fan to circulate
air. If there has been substantial water
damage and the weather is warm, you will
probably need to keep the windows shut
and run a dehumidifier.
Dry wet items as soon as possible. Use
fans and dehumidifiers to dry carpets and
draperies. If not thoroughly dried, carpets
and floors underneath may quickly be damaged
beyond repair by mold and mildew.
Removing Soot
Soot is oily and easily stains carpets,
draperies and other textiles. For this reason
it must be removed before you attempt
to clean or deodorize items. If
possible, hire a professional restorer to remove
soot with a heavy-duty vacuum. If
you don’t plan to hire a professional, you
can remove some soot by holding a vacuum
cleaner nozzle slightly off the surface
of the item. Do not use vacuum attachments
or an upright vacuum because the
brushes tend to force soot into fabrics.
Cover carpets after removing the soot
to keep other soil from being tracked in
during clean-up.
Removing Smoke
Odor from Textiles
Smoke odor may remain in upholstered
furniture, carpets and draperies unless
they are properly deodorized before
cleaning. Consult professional fire restorers
about using “counteractants,” chemicals
or additives that break up smoke molecules to eliminate odors. The type of
counteractant used will vary with the type
of material burned in the fire.
Cleaning Furnishings
and Clothing
After deodorizing, it’s time to clean
textiles. Take non-washable clothing and
draperies to a dry cleaner for traditional
dry cleaning or a special cleaning process.
Have carpets cleaned twice—both before
and after repairs. Wet carpets must be
dried before cleaning. In some cases, removal
of carpet is necessary for complete
drying and to save the wood floor beneath.
During a fire, smoke can permeate
walls and other surfaces and drift through
ducts, where it becomes trapped. If not
properly removed, smoke odor reoccurs
from time to time, especially during warm
or damp weather.
During a fire, the heat will expand
pores in the walls and fill the pores with
smoke. After the fire, the structure cools,
the pores close and trap the smoke odor.
On warm days the pores will open and release
the trapped smoke odor, which
could settle on furnishings. Professional fire restorers can eliminate the smoke odor
with a process called thermal fogging,
which opens the pores in the walls and
neutralizes the smoke odor.
Consult restorers about smoke removal
from ducts. They may use a chemical
sealer to secure smoke permanently to the
sides of ducts since these areas, with their
joints and crevices, may be difficult to
clean with conventional vacuum-andbrush
methods.
Consider replacement of attic insulation,
which may retain odors.
There are several processes that will remove
mal-odors. According to RESTORx,
a Northern Illinois loss reduction specialist,
these include: adsorbents, neutralization,
oxidation and counteractants.
Adsorbents
Adsorbent refers to the property of a
substance to absorb something on its surface
by chemical attraction, instead of
throughout its interior. This is analogous
to baking soda vs. a sponge. Adsorbents
are very effective in the odor removal industry,
especially the commercially available
product activated carbon.
Activated carbon is a substance created
by a controlled process of heating and
cooling wood. Activated carbon has many
pores on its surface which are able to adsorb
large quantities of mal-odor compounds.
Indeed, 1 pound of activated
carbon has 5,000,000 million square feet
of adsorption area.
Activated carbon is good at trapping other
carbon-based impurities (“organic” chemicals).
However, many other chemicals are
not attracted to carbon at all, like sodium
and nitrates, so they pass right through the
carbon. This means that an activated charcoal
filter will remove certain impurities, but
will be highly ineffective with others.
This also means that, once all of the
bonding sites are filled, an activated charcoal
filter stops working. At that point, the
filter must be replaced.
Neutralization
Neutralization refers to the chemical property
of pH, the characteristic of compounds
to have an acidic or alkaline composition.
pH actually refers to the relative concentration of hydrogen ions in distilled water.
Low pH corresponds to high hydrogen ion
concentration and vice versa. A substance
that when added to water increases the concentration
of hydrogen ions (lowers the
pH) is called an acid. A substance that reduces
the concentration of hydrogen ions
(raises the pH) is called a base.
Compounds may be neutralized by first
analyzing the compound’s pH, and then
applying a chemical with the opposite
value pH to make the overall pH 7. Thus,
if you were trying to neutralize urine (an
acid with the pH of 6), you would need to
apply an equal amount of a base chemical
with a pH value of 8 (such as seawater).
Also, the application of sodium
bicarbonate will effectively neutralize the
odor liberated from an acid spill.
However, neutralization is only effective
when the compound is accessible and
has a pH. Many times a mal-odor producing
compound is neither accessible or
has a pH, and therefore this technique
cannot be used.
Oxidation
Oxidation is what happens when a substance
combines with oxygen. Nowadays
this has a broader meaning and
includes reactions not involving oxygen.
Most compounds are susceptible to oxidation,
according to their oxidation number,
which leads to a chemical change.
In many materials, this can lead to a decomposition
of the mal-odor creating
substance, removing the odor.
Biocides
Biocides are materials which kill or inhibit
the growth of micro-organisms.
Most molds, mildews and yeasts create
their own odor (actually technically a myco-toxin). When the mold is killed, it
will stop producing these myco-toxins.
However, it is important that when dealing
with mold, dead mold spores are just
as dangerous as live ones. So just killing
the mold isn’t all that is required.
Bio-enzymatic Digestion
This is a process where genetically engineered
bacteria and enzymes consume
the mal-odor producing material. These
can only be used on organic matter, such
as animal feces and fuel oil. Bio-enzymes
are used throughout the human body to
facilitate digestion, especially in the
upper and lower intestines.
In order for something to be smelled, it
must meet the following criteria:
1) It must be a highly volatile material,
such as something being cooked.
This increases the rate of which the vapor
is given off by the substance.
2) The odor bearing molecules must be
soluble in water, even to a miniscule degree.
If it is not water soluble, it will
never reach the smell receptors in the nose
as they are covered in a watery film.
3) The odor bearing molecules must be
usually absent from the nasal tissue. If
they weren’t, the person would soon “get used” to them, and they wouldn’t smell
them anymore.
Counteraction
To work against, it is most often used
when there are combinations of offensive
odors, referred to as complex odors.
Odors caused by decomposition and other
biological processes, and also smoke
odor, can be highly complex and require
two or more of the above techniques for
effective odor removal. ❑
