Smoke/Soot Removal
Soot/Smoke is the product of incomplete combustion made visible by the presence of small particles of carbon. Remember, fire is indiscriminatory. Any substance which can burn, will burn! The more substances which burn, the more complex the odor. (See below)
Smoke odors normally may be classified into three categories:
1) Protein Odors: Result from burned meat, flesh, or poultry. The residue is brown/yellow in color. The residues has a greasy texture. Thorough cleaning is often required for complete deodorizing.
2) Natural Substance Odors: Result from burned wood, paper, cotton, wool, jute, cork, feathers, etc. The residue isgray/black in color and of a dry, powdered consistency.
3) Synthetic Substance Odors: Result from burned plastics, synthetic textiles, etc. The residue is black in color and smudges easily. Smoke webs are often visiblein upper corners and smoke “streamers” and are often found hanging from curtain rods, etc.
Smoke is influenced by…
1) Heat: Warmed or heated air rises and migrates to cold areas (outside walls, closets, etc.) Heat causes pores to expand.
2) Pressure: The energy created by the fire produces heat and pressure which enables the smoke to penetrate into minute cracks and crevices.
3) Impingement: Means splatter, when a substance hits a surface with sufficient velocity it will impinge (or splatter) and remain upon that surface.
4) Magnetism: Attraction of smoke to metal surfaces. (Plumbing pipes, nail heads, metal coat hangers).
5) Ionization: Opposite charges attract, forming smoke webs on structural surfaces. Plastic bags originating at the dry-cleaner’s retain static electrical charges which attract smoke. In fact, in many fire situations, more smoke residues will be found on garments protected by plastic bags, than found on unprotected garments.
We utilize two adjectives when we refer to smoke:
Driven-smoke and free-floating smoke.
Driven Smoke, also known as hot smoke, is pressurized and has energy or force behind it. The smoke residue found on vertical surfaces results from driven smoke.
Free Floating Smoke, also known as cold smoke, originated as pressurized smoke but has lost the energy and velocity behind it. Because free floating smoke is heavier than air it normally will settle out on horizontal surfaces. Horizontal surfaces are the single biggest source of smoke odor.
Smoke is aided by both natural and man-made air currents. Natural convention currents of air rise when heated and fall as they cool. Forced air heating and cooling systems if in operation at the time of the loss can spread smoke odor over a wide area.
The relative size of the smoke particles we are dealing with is .1-4 microns (1 micron = 1 thousandth of 1 millimeter; 1 millionth of 1 meter, or 1 twenty-five thousandth of 1 inch).
Combustion or burning is the chemical process transforming a solid into a gas via heat. Because water vapor is formed during combustion, it may be assumed that when a smoke particle is generated it comes off the source as a tear shaped, damp droplet. The exterior of the smoke droplet dries before the interior.
Smoke dissipates rapidly after the fire and we clean up the leftovers or residue. The rapid cooling particles of incomplete combustion by-products may form a difficult to remove film on surfaces, known as vapor plating. The combination of acidic smoke residues and heat may cause plastic and other vulnerable materials to quickly discolor.
Low Oxygen Fires:
Are smoldering type long duration fires which produce a difficult to remove wet smoke residue.
High Oxygen Fires:
Burn more efficiently and produce an easier to remove dry residue.
Corrosive Nature
Smoke residues are generally acidic in nature and often cause corrosive damage to metal surfaces. To prevent corrosion to metals, smoke residues should be removed as quickly as possible. PVC plastic when burned produces highly corrosive PIC’s (particles of incomplete combustion), which combine with atmosphere moisture to form hydrochloric acid.
Substances which burned influence the difficulty of the Clean-Up.
Smoke residues from fires of natural origin are generally easier to clean up than fires of synthetic or protein origin. For example, it would be easier to clean up the residue from a wood or paper fire than it would to clean up the residue from a fire of synthetic or protein origin.
Factors effecting the degree and amount of smoke residue deposits
1) Substance burning
2) Amount of available oxygen i.e., type of fire smoldering versus well oxygenated
3) Duration of the fire
4) Temperature and penetration potential of the fire
5) Air currents
6) Method of extinguishment
7) Type of HVAC system
8) Building layout and design
Smoke odors are most apparent when both temperature and relative humidity are high.
“Puff-Back” is a malfunction of an oil fueled heating system with attached ductwork. The malfunction which can be caused by a cracked heat exchanger, component failure, improper venting, etc., causes the sudden and accidental release the combination of pre-existing dust particles (which were in the ductwork and droplets of improperly burned fuel oil.
Testing for Smoke residues
Smoke residues may vary in color from white to yellowish to brown to black. Smoke residues differ from dust in that smoke residues are thin and dust may be thick and billowy. Smoke residues may be greasy and odorous.
Folding a white paper towel in half and then in half again will provide 8 test surfaces. Smoke residue is most likely to be found on windows and outside walls. Testing should begin in the source area, (check windows and outside walls when first looking for telltale residue).
Our normal business hours are Monday through Friday from 7am to 5pm. After hours our lines are handled by an answering service that will page our emergency crews 24 hours per day, 7 days a week, weekends and holidays.
Downers Grove:
1.630.512.9690 |
Freeport:
1.815.235.9690 |
Madison:
1.608.819.0130 |
Rockford:
1.815.962.7200 |
Fax:
1.815.235.8814 |
