Filtration Soiling is dark staining near baseboards, air registers, under doorways and in other areas where moving air may filter throughout rug fibers. Builders and new home warranty groups are finding that streaking caused by carbon soot or nicotine often cannot be removed.
Where Does It Happen?
Soot deposits are usually seen in more recently built homes, but it has also been seen in older homes. There have even been cases of staining in newly built, unoccupied residences. Most filtration soiling has been reported in metropolitan areas
What Causes filtration soiling ?
Dust or dirt causes most marks on carpets, and will wash out quite easily. Filtration Soiling is caused by carbon soot or nicotine and can come from inside or outside the house and often permanently marks the carpet. Two factors cause filtration soiling: a source of carbon soot plus Air movement causing carbon particles to move through the carpet.
Carbon Soot Sources
Carbon or tobacco smoke is particulate matter - it is made up of very small particles.
Research shows that houses near exhaust from vehicles, trains or airplanes can be affected by carbon soot stains. Leaky furnaces, gas ranges, fireplaces, and cigarette smoke can also cause carbon soot stains.
However, recent studies show that a common cause of carbon soot stains is the use of candles in the house. Some candles - particularly those made of low-quality paraffin wax, those using oils for scent produce more soot than others. Wick length and the amount of oxygen a candle gets can also cause overproduction of carbon soot.
For example:
* Candles inside jars produce more soot because less oxygen reaches the wick
* Incorrectly designed candles will burn the wax too quickly, leaving more of the wick exposed
* Oversized wicks cause the flame to burn too high
* Any draft passing over the flame will cause the candle to smoke.
To find out if a candle produces carbon soot, burn it on top of a turned-on television. After several hours, wipe the screen with a clean, white cloth or tissue. If there is soot on the cloth, switch to another make of candle. Several candle manufacturers print warning labels about carbon soot on their packages.
Air Movement
Carpets act as filters for airborne particles. For example, if a bedroom door is usually kept closed, positive pressure caused by the supply register blowing air into the room will force the air underneath the door. As the air moves underneath the door, the carbon fibers trap the particles. Over time, the carpeting begins to darken. Another cause is a furnace intake vent that is sized for the furnace but is not large enough to replace air being exhausted from the clothes dryer or the bathroom. Filtration soiling can become quite noticeable, especially in light-colored carpeting. It can also be seen on drapes, furniture and around light switches, on brass door hinges and even inside your furniture.
How To Avoid the Problem
Prevention is the best way to reduce or avoid carpet streaking.
* Avoid light colored carpet
* Keep soot sources out of the house-choose your candles wisely
* Prevent pollutants from entering the house
* Prevent air from passing through the carpet. You can find out where this occurs by watching the smoke from a stick of incense held near the baseboards.
Keeping soot from entering your house requires a fairly complicated ventilation system. Preventing air from moving in your carpet requires some thought, good design and quality construction.
Air movement in a house requires a pressure difference & an opening like along the floor-wall junction or stairs, near registers or where the sub-floor panels join. Air cannot pass through a carpet if the floor underneath is sealed between the floor & wall.
A tightly built house, with few or no air leaks, will not have air leaking into the house through exterior walls. But rooms with supply ducts and no returns could have a problem if the doors are kept closed. Unsealed duct runs, or return air ducts that use the floor joists, are apt to cause pressure differences.
In a New Home Or After Renovation.
There are several ways to reduce the risk of filtration soiling. Most do cost more, but some will actually save money by improving energy efficiency. Others can make your house healthier by reducing dust.
Recommended System
To avoid carpet staining, remember that a house with a very tight envelope will not have wall leaks that drive the dust through the edge of carpet. This type of house must also have a Heat Recovery Ventilator (HRV) to provide all the house’s ventilation. Air entering the HRV can be passed through a high efficiency filter. This treats almost all the air coming into the house and keeps airborne particles out. It is still good practice to ensure that all forced air ducting has well-sealed metal ducts and a balance of supply and return air.
Other Solutions
* Caulk or seal all baseboards before applying trim and installing carpeting
* Use a high efficiency filter on the furnace or an electrostatic precipitator to reduce staining at the registers and improve air quality
* Use area rugs instead of wall-to- wall carpets
* Have your home and stove, furnace and fireplace performance tested to ensure they meet all recommendations and specifications.
If you have this problem now…
Filtration soiling may not be caused by carbon soot. Dirt and dust stains are usually gray.
To clean the stains use a Professional carpet cleaning service.
Unfortunately, black carbon soot stains are often permanent. For streaking along the baseboards, cut off the stained edges, put plastic sheeting over the floor-wall joint (or caulk) to stop air movement, and re-stretch the carpet to fit.
Is There a Health Risk?
Concentrations of particles that cause streaking are likely to be quite low. It is not yet clear if low concentrations of carbon soot particles inside a house are a health threat.
I hope this information was helpfull. Feel free to contact me with any carpet concerns or questions.
David Gargan
David’s Eco Clean
