Smoke is basically fuel that didn't burn, made visible by the
presence of small particles of carbon and other material. Complete combustion
gives off light, heat, the gas carbon dioxide, and water vapor. Smoke contains
these gases and the tiny particles known as PM10. PM10 stands for "Particulate
Matter less than 10 microns in diameter". They include small droplets of wood
tars (if originating from a wood fire), gases, soot, and ash. In fact, most
smoke particles are less than one micron in diameter.
Wood smoke has been studies by the EPA and found to contain carbon monoxide,
methane, VOCs, formaldehyde, benzene, acetic acid, formic acid, toluene, oxides
of nitrogen, sulfur dioxide, organic carbon, and even traces of heavy metals.
This may help you understand why smoke is not only so dangerous to people, but
Of course, in most situations smoke comes not just from burning wood, but a
whole host of other materials — plastics, fabrics, foods, and other construction
materials. These produce a range of toxic off-gases, as well as complex odors.
Synthetic odors are generated by burning plastics and synthetic textiles. This
form of residue is typically black in color and smudges easily. Burnt wood,
cotton, or paper products produce natural odors and the residues are typically
gray to black and usually powdery. Protein odors result from burning meat,
flesh, or grease and the residue is greasy and yellowish to brown in color.
Smoke may seem to dissipate quickly after a fire, but the rapid cooling of the
particles of incomplete combustion leave a film and odor that penetrates
throughout buildings and collections. The acidic nature of the film causes
discoloration, corrosion, and overall damage.
Smoke can be classified as either driven or free floating. Driven smoke is
energized and pressurized — it has force behind it. Vertical surfaces are the
most common places where driven smoke will be found. For examples, walls catch
driven smoke as it is being pushed through the building. In contrast, free
floating smoke, which originated as driven smoke, has lost its energy and is
typically found on horizontal surfaces where it has settled.
Fires may also be classified as having either low or high oxygen content and
each produces different types of damage. For example, a low oxygen fire is a
smoldering type and it will leave a wet, smoky residue. A high oxygen fire
produces a dry residue that is often easier to remove.
You should also understand a little about the nature of fire. Fires produce
intense dry heat. As the flames are extinguished, a hot, humid, smoldering fire
is created. It is not uncommon to see relative humidities range from as low as
2% in a fire to upwards of 100% as water is applied. This high relative humidity
can cause extensive problems, especially among wood objects. Their pores open
and the wood absorbs various odors which are often very difficult to remove.
As mentioned earlier, smoke is corrosive and can easily damage a wide range
of collections. This damage is usually exacerbated if you touch the item with
your bare hands — the combination of finger oils and the acidic by-products can
etch into finishes and metals. As a result, it is critical that you always
wear gloves during fire recovery efforts. Often the most suitable will be
After a fire you will likely have several types of damage.
Some collections or parts of your building will be water damaged. We don't
discuss water damage here, although there are a variety of excellent sources for
additional assistance. Some items will be heavily damaged by the fire —
exhibiting ashing, charring, melting, or other distortion from the heat. Much of
this material is likely not salvageable. The remainder may be lightly scorched,
covered in soot, and have a strong odor of the fire. It is these materials that
we will focus on this discussion.
fire department will have equipment to help pump water out of the building and
vent much of the smoke outside. You should ask them for their assistance and
advice — they have a lot of experience dealing with different types of buildings
and different conditions of fire damage.
After this you should immediately contact your insurance carrier and notify them
of the fire and/or smoke damage. You should ask for immediate assistance from a
senior adjuster, explaining the unique nature of your collections and that
salvage is time sensitive. A study after the 1985 Huntington Art Gallery fire
found that some soot materials became harder to remove from collections through
No matter how bad the fire or smoke damage, remember that life safety must
always be the first concern. Fires can release a number of hazardous materials —
PCBs from transformers, toxic chemicals from labs, asbestos from insulation of
pipes. Even after a fire electrical lines can still be energized — and deadly.
The building should be carefully examined by your engineer to ensure that it is
safe to enter.
If recovering yourself, it will help to prioritize collection damage. After the
1995 Contra Costa County (California) Courthouse fire, documents were classed as
level 1 or 2, depending on the heaviness of the soot. Such records needed
cleaning, but little else. Level 3 records were scorched, but not burned. These
required cleaning, but brittleness became a major issue in handling and
cleaning. Often such materials need support during handling (you can use heavy
paper or cardboard, which should be in your recovery supplies). Level 4
documents were burned, but had little or no information loss. After cleaning
they could be trimmed to remove the burnt areas. Or they could be immediately
copied. Level 5 documents had lost all or nearly all of their information
Keep in mind that even seemingly unaffected items may have suffered damage in a
fire. For example, the high temperatures of fires can melt adhesives or plastics
and distort textblocks. Films and tapes inside containers can be much more
damaged than it appears from a cursory glance of the container itself.
You may also discover that much of your institution's floor is covered in a mass
of charred timbers, broken materials and glass, and a soup of soot and water.
Consequently, you must begin by sorting through this slush so that additional
damage isn't done by walking on collections. Since these materials will likely
already be waterlogged, you will probably do well to rinse them off — they will
be easier to treat if they are recognizable as collection objects. You will also
want a large number of trays (disposable aluminum baking pans work well) in
which you can begin the process of sorting out different materials.
of the Building
Use HEPA vacuums to remove the dry soot and any chemical
residue left by extinguishers. If possible (without endangering collections)
open the building and use fans to ventilate, helping to remove the smoke smell.
Staff undertaking recovery will want to wear gloves. Often goggles and boots
will be appropriate. Likewise, HEPA respirators may be necessary. Remember that
throughout recovery, personal safety must be the major consideration. This means
complying with all applicable OSHA requirements.
Because of their soft surface, dry cleaning sponges are ideal for removing loose
soot and smoke from latex paint, blown ceilings, and acoustic tiles. The sponges
are used dry and you should begin on the ceiling, since debris will drop down.
Then move to the walls, again beginning at the top and working to the bottom
using straight, parallel strokes that overlap a little. When the surface of the
sponge becomes clogged with soot, simply skim it off with a knife to reveal a
new cleaning surface.
Made from vulcanized natural rubber, these sponges leave behind a large quantity
of particles or crumbs embedded with soot. These should be vacuumed up since
they are not only dirty, but the rubber will become gummy through time.
Dry cleaning sponges are not recommended for oil-based paint, acrylic paint, or
vinyl wallpaper. Nor are they recommended for the greasy soot resulting from
kitchen fires or the burning of meat or flesh. For these surfaces, and this type
of soot, your best approach is to use a regular sponge and a strong detergent
capable of cutting through grease. Pine cleaners are often recommended, although
there are a variety of "kitchen" detergents and you should probably try several
to see which works best in your particular situation. There are also a variety
of industrial products made for the removal of soot — contact your local
janitorial supply company. But be aware that many of these commercial products
are much harsher (for example, one product, SuperKleen, has a pH of 12) than
those used by homeowners. It's best to test first and also wear protective
Be sure to clean Formica and chrome fixtures in kitchens and bathrooms to
prevent permanent staining (the acidic soot will etch these materials).
Likewise, quickly wipe down porcelain fixtures.
It is essential, however, that you remove all of the soot — the sooner it is
gone the sooner you will begin to get some control over the fire smell. If
structural framing is damaged, some portions may need to be replaced. But even
scorched timber should be cleaned to remove the smoke smell. This is typically
accomplished by using a sealant. Another approach, however, is the use of a
"soda blaster" — which uses baking soda (sodium carbonate) as the blasting media
to remove the charred wood.
Historic buildings present a range of additional, and difficult, recovery
situations. All architectural remains should be collected — nothing should be
thrown out. Many items can be cleaned and re-installed. Others, such as plaster
ornaments, may have portions still intact that can be used for molding
replacements. Tiles and flooring, while perhaps not recoverable, may be
sufficiently intact to guide replacement efforts. Even burned or scorched
paneling or wall coverings should be retained since they may serve as models for
replacements or may actually be salvageable. If a historic building has been
involved, it is essential that you bring in an architectural conservator who can
work with you to sort out the lost from the salvageable.
It is almost always important to call in preservation and
conservation experts to assist in the salvage of collections. The suggestions
offered here are not intended to be a replacement for the advice of individuals
who have the opportunity to examine the damaged or affected collections and
develop treatments specifically for those items. This information, however, may
be of assistance when preservation/conservation assistance is not immediately
Many items can be cleaned by simply vacuuming — using a HEPA filter. Also be
sure that the floors of areas which are not heavily involved are protected from
soot, drips, and stains — cover them with plastic (but be aware of the slip
hazard) or towels. Also understand that the smoke odor, often overpowering, will
be transferred with the soot and smoke damaged collections.
You should inventory, photograph, and note the treatment that each object
— If covered with water and other debris, carefully sweep the debris off, roll
them up, and remove them to a safe spot where they can be unrolled and rinsed
off with low pressure water, such as from a garden hose. Be very careful in
the transfer, since the fabric will almost certainly be weakened by the weight
of the water. Most will require additional cleaning, using a product such as
Triton-X, with repeated rinses. They will then likely require drying on
non-rusting metal or plastic racks with about a 2-inch mesh.|
— Separate costumes into two groups: those which can be safely cleaned
commercially and those which cannot. Tests on modern materials reveal that a
combination of liquid and dry detergents with bleach were most effective at
removing smoke damage — although such harsh treatments should only be used on
modern materials and not collections. A safer approach, suitable for cottons
and polyesters is the use of a warm water wash with liquid detergent. Up to
five washings may be necessary to remove the visible smoke and the smell.
Typically dry cleaning is less effective at removing the smoke odor than
detergents. Some dry cleaners use ozone to remove smoke odors and this should
be avoided (see discussion below). More delicate textiles should be vacuumed,
being sure to use a screen to prevent small, fragile items from being sucked
into the vacuum tube.|
— Most furniture can be cleaned using cotton swabs wetted with mineral
spirits. Afterwards the wood should be buffed with diapers or other soft,
lint-free cloth. You should be careful to avoid damaging loose veneer (which
will require reattachment) or gilt bronze mounts (which may be cleaned with
— These can be cleaned with cotton swabs using a mild soap (Orvus Wa Paste)
and distilled water solution. They should be immediately buffed dry with
— Typically paintings will need to be unframed so they can be cleaned
separately from the frames themselves. Be careful, however, to inspect each
painting for loose or flaking paint. If stable, most paintings can be cleaned
with mild solvents (such as water, Orvus Wa Paste and water, or VMP naphtha)
that will remove the soot without affecting the varnish layer. Gilt frames
will most likely require cleaning with mineral spirits, but again it is
essential that care be taken not to remove fragments of the gesso on the
furniture and other textiles — conservators have developed a range
of techniques to clean these materials. One approach used in the Huntington
Art Gallery fire was a solvent activated poultice, when objects couldn't be
washed with water. The treatment used a rice hull ash poultice and a type of
freon as a solvent. The ingredients were mixed, spread on the textile, and
covered with plastic. After about 45 minutes to an hour the plastic would be
removed, the poultice was allowed to dry, and them vacuumed off the textile.|
paper — Paper materials may be treated by either vacuuming (using a
HEPA vacuum) or wiping down with a dry cleaning sponge. Special attention
should be paid to the headcap, where soot may have settled. Be sure to keep
the book closed tightly, to prevent the soot from being forced into the text
block. Individual paper documents will likely require individual cleaning of
both sides of the document using dry cleaning sponges. Afterwards be sure to
vacuum up all particles of the sponge, using if necessary a screen to prevent
damage to the document.|
glass objects — These may be washed in a warm water and Orvus Wa
Paste solution. Silver should be thoroughly rinsed, first with water and then
with ethyl alcohol. The alcohol will allow faster drying, ensuring that no
moisture is trapped in crevices. For silver be certain that the piece isn't
weighted with plaster — such items should never be wetted. And for glass be
careful not to loosen previous repairs.|
There are a number of companies that offer fire restoration
service. These services typically include board-up (of windows and doors) and
cover-up (of roofs) service, moving out collections, cleaning, smoke odor
removal, cleaning and restoration of electronics, structural repair, and control
of corrosion. Before jumping at such services, however, be sure you understand
what will done — and how.
Several issues require your attention. First, how well trained are the
individuals who work for the restoration company?
Many restoration companies send a manager and a couple of key team members, but
hire the remainder of their labor from the local market. This means that many,
perhaps the majority, of the individuals working in your institution may have
absolutely no disaster recovery experience. Consequently, you should insist on
having a clear, and detailed, account of how these individuals will be trained —
not only to perform recovery operations, but also on how they will treat your
collections. You should also insist on appropriate insurance coverage protecting
your building and collections. You may also want to insist that individual
workers are bonded.
The second question you should consider is whether the techniques they propose
are appropriate for your collection? What is typically used, and is perhaps
appropriate, in a household setting may not be acceptable for your collections.
For example, most commercial restoration companies like to use a variety of
chemicals — chemicals to seal in soot, chemicals to treat for mold, chemicals to
reduce the smell, chemicals to clean items, and even chemicals to "eliminate"
the smoke odor. What are these chemicals and are they appropriate? Without
insisting on step-by-step explanations and doing research yourself, you may wind
up causing more harm than good.
Realize also that restoration companies have relatively few opportunities to
work with collections. Even fewer have trained conservators on-staff. So be wary
of claims for services such as "fine art cleaning and restoration" or
"restoration of books and documents." Remember, it is up to you to ensure that
the techniques are appropriate and are being done by individuals with
appropriate training and expertise.
There are a range of professional restoration organizations. Examples include
the Restoration Industry
Association (formerly the Association of Specialists in Cleaning and
Restoration or ASCR) and the Institute of
Inspection, Cleaning, and Restoration Certification (IICRC).
Some of these organizations have very specific training requirements.
For example, the RIA Certified Restorer is required to take
training in both buildings and personal property and have prior experience on
restoration projects. The IICRC offers two-day training classes in smoke damage
and three-day classes in restoring water damage. While none of this
guarantees competency, it does indicate that an individual is willing to invest
considerable effort, time, and money in attaining their certification.
You should ask what organizations a company belongs to and whether individuals
in those organizations are certified. But remember, there is a big difference
between a "restorer" and a "conservator." Carefully consider the value of your
collection and determine the minimum qualifications of the individuals you want
handling and treating your objects.
the Smoke Smell
One of the biggest concerns among most institutions is getting
rid of the odor of a fire. Unfortunately, this is also among the most difficult
activities. Records which survived the 1906 San Francisco fire and are today in
the National Archives still smell strongly of smoke — over 90 years latter.
Besides the use of chemicals to mask the smell, there are two general approaches
used commercially. One is called Thermal Deodorization and the other is Ozone
Treatment. Neither are acceptable for valuable museum, library, or archive
Thermal deodorization uses high temperatures to drive off the smell. Having
survived the fire, and suffered the resulting damage such as premature aging and
increased brittleness, you should not subject collections to yet additional
stress. Thermal deodorization is unacceptable and should be avoided.
Ozone treatments use ozone generators to create large quantities of ozone (O3)
— a very powerful oxidizer that attacks virtually all organic materials. When
humans are exposed to ozone it causes irritation of lungs, eyes, and skin. When
collections are exposed to ozone it will deteriorate leather, alter dyes,
embrittle paper, and fade inks. In other words, it prematurely ages virtually
everything in collections. Consequently, it, too, should never be used as a
means of eliminating the smoke odor.
Unfortunately, this just about eliminates the arsenal of the professional
restoration company. You do have some options — although none are "silver
bullets." As explained earlier, you should clean everything — floors, walls,
ceilings, carpets, drapes, furnishings. Structural damage should be sealed or
replaced. By getting rid of as many odor sources as possible you will minimize
You should also flush the building with large volumes of fresh, clean air. If it
is impossible, or impractical to open the building to gain fresh air, then use
HEPA filters to capture the fine smoke particles. Just remember to change
For a small number of relatively small objects, you can seal the items in a
plastic bag with baking soda, clay cat litter, or activated charcoal — all will,
over time, absorb much of the offending odor.
Remember, too, that the source of the odor can be very complex. For example,
with furniture, the smell may be literally on the surface in the soot; or it may
in impregnated into the finish, which perhaps softened during the fire; or it
may actually be in the pores of the wood, especially if the furniture was
exposed to high humidity levels during the fire. Consequently, there will likely
be some objects that retain the fire smell for very long periods of time.
However objectionable this smell may be, you will do your collection far more
harm by subjecting it to either thermal or ozone treatments.
If you would like more information about fire salvage, check
out these sources:
Hall, Richard and Barbara Adams, editors. 1998. Essentials of Fire Fighting,
Fourth Edition. Stillwater, Oklahoma: Oklahoma State University Press.
National Fire Protection Association. 1997. NFPA 909: Standards for the
Protection of Cultural Resources Including Museums, Libraries, Places of
Worship, and Historic Properties. Quincy, Massachusetts: National Fire
National Institute of Disaster Restoration. 1997. NIDR Guidelines for Fire and
Smoke Damage Repair. Annapolis Junction, Maryland: Association of Specialists in
Cleaning and Restoration.