Vacuum Cleaner Info
A trade group representing vacuum cleaner manufacturers requires that all vacuums pass standard soil removal tests that only remove 36% of all dry soil/PM with 4 passes. That means that a vacuum cleaner that leaves 64% of the soil behind is “OK” for sale to consumers.
Advertisements for vacuum cleaners say they have a 99.97% efficiency rating seem impressive but mean very little. The vast majority of homes don’t vacuum often enough to effectively remove soils specific to that home and even if they did, most of those homes have vacuum cleaners (even HEPA) that only remove a third or a half of the soil that they should remove…even with multiple passes. So what if they are 99.97% effective with the soil they do remove when 60% of the soil is still there?
(For more information about vacuum cleaner effectiveness and efficiency, go to http://www.ristenbatt.com/filt_eff.mv where this established vacuum retailer discusses vacuums, vacuum efficiency, HEPA filters, etc.)
Truly, dry soil is abrasive and can harm carpet fibers if not removed. Under the weight and movement of foot traffic, these particulate soils can scratch and cut carpet fibers, dulling the appearance of the carpet. Abrasive soil is the major cause of carpet wear.
However efficient the vacuuming, various sources who have measured the actual composition of soil say that from 5% to 23% is made up of oils, waxes, clays and other “sticky” binding agents that do not vacuum away. And Hoover says that vacuuming leaves the smallest (.03 - .4) micron materials of particulate matter (PM) still in the fabric or carpet.
Various studies state that PM of less than 2.5 microns but larger than 1 micron in size are the most problematic for humans. They penetrate and then lodge deeply in the alveoli of the lungs and are not coughed up. Larger particles do not make it past the natural protective systems in the body. Some research says smaller particles of less than .03 microns either cause greater damage because they lodge more easily or less damage because they are exhaled. What’s the truth? HEPA filters (are supposed to) stop particles of .03 microns or greater. That is not always so, since most HEPA filters are not replaced often enough and, within only a few months become compromised and ineffective.
NOTE: HEPA is an acronym for "High Efficiency Particulate Air" or "High Efficiency Particulate Arrestance." Laser particle counter measurements typically show that more than 99% of the particles suspended in indoor air are one micron (1/1,000,000 of a meter) or smaller in size. EPA calls these “lung-damaging” particles, because they can lodge deep in the lungs when inhaled. The ability of HEPA filters to capture particles this small is what sets them apart from other types of filters. Regulations developed by EPA, OSHA, CDC and other federal, state and local government agencies responsible for human health and IAQ issues specify HEPA filters for asbestos, lead and mold abatement, TB and SARS isolation rooms and healthcare renovation projects. To qualify as a Type A HEPA filter, the filter must capture at least 99.97% (9,997 out of 10,000) of particles 0.3 microns in size–about 300 times smaller than the diameter of a human hair, and 25 to 50 times smaller than we can see.
You will conclude that dry vacuuming is effective at removing “some” unknown percentage of soil from your carpet. However, dry vacuuming is the only reasonably effective method available and MUST be performed just to keep some control on dry soil that, at most, is 90% removed with each vacuuming. That means that 10% of soil is ALWAYS left behind…then add in the sticky soils and the PM that is imbedded
You can see the acceleration of heavy soil and deterioration of appearance of carpet that is not vacuumed frequently. However, it is a known fact among professionals that dry extraction, vacuuming and solvent extraction are neither as effective or as safe as corrective or restorative cleaning methods as wet extraction is.
Professional Testing Labs, an independent laboratory in Dalton, Ga. is used by the Carpet and Rug Institute for CRI Green Label certification. Vacuum cleaners must pass standards of criteria in soil removal, dust containment and carpet appearance retention. Strict protocols are observed in each area of testing. For “successful” soil removal, the vacuum cleaner must be able to remove 36 percent of the sandy soil being tested within four passes, moving at a computer-controlled rate of 1.8 feet per second, from a 400-square-foot strip of carpet. Yet because there are a wide variety of fabrics and carpets in a home, and the industry has no incentive to endorse one specific method, there is still no industry accepted method of rating a dry vacuum for effectiveness that assists consumers to make good purchasing decisions. (Do your OWN soil testing after vacuuming!)