Sawdust

Industrially, the correct term is wood dust . In everyday language, it is known as sawdust . Sawdust or wood dust is a by-product or waste product of woodworking operations such as sawing, milling, planing, routing, drilling and sanding. It is composed of fine particles of wood. 

These operations can be performed by woodworking machinery, portable power tools or by use of hand tools. Wood dust is also the byproduct of certain animals, birds and insects which live in wood, such as the woodpecker and carpenter ant . It can present a hazard in manufacturing industries, especially in terms of its flammability. Sawdust is the main component of particleboard. Wood dust is a form of particulate matter, or particulates . Research on wood dust health hazards within the field of occupational health science, and study of wood dust control within the field of indoor air quality engineering.

How wood dust is formed

Two waste products, dust and chips, form at the working surface during woodworking operations, sawing, milling and sanding. These operations are both lignified wood cells and whole cells and groups of cells. Shattering of wood cells creates dust, while breaking up of whole groups of wood chips. The more cell-shattering that occurs, the finer the dust particles that are produced. For example, and more often than not, this is a combination of shattering and chip forming processes. [1]

Uses

A major use of sawdust is for particleboard; coarse sawdust may be used for wood pulp . Sawdust has a variety of other practical uses, including serving as a mulch , as an alternative to clay cat litter , or as a fuel . Until the advent of refrigeration, it was often used in icehouses during the summer. It has been used in artistic displays , and as scattered in miniature railroad and other models. It is also sometimes used to soak up liquid spills, allowing the spill to be easily collected or swept aside. As such, it was formerly common on barroom floors. [2] It is used to makeCutler’s resin . Mixed with water and frozen, it forms pykrete , a slow-melting, much stronger form of ice .

Sawdust is used in the manufacture of charcoal briquettes . The claim for the invention of the first commercial charcoal briquettes goes to Henry Ford who created them from the wood scraps and sawdust produced by his automotive factory. [3]

Use in food

Cellulose, fiber starch that is indigestible to humans, and a filler in some low calorie foods, can be made from other sources. [4] While there is no documentation [5] for the persistent rumor, based on Upton Sinclair’s novel The Jungle , which was used as a filler in its use, cellulose derived from sawdust was used for sausage casings. [6] Sawdust-derived cellulose has also been used as a filler in bread. [7]

Auschwitz camp concentration survivor, Dr. Miklós Nyiszli , reports in Auschwitz: A Doctor’s Eyewitness Account that the subaltern medical staff, who served Dr. Josef Mengele , subsisted on “bread made from wild chestnutssprinkled with sawdust.” [8]

Health hazards of wood dust

Airborne sawdust and sawdust accumulations present a number of health and safety hazards. [9] Wood dust becomes a potential health problem when, for example, the wood particles, from processes such as sanding, become airborne and are inhaled. Wood dust is a known human carcinogen . [10] [11] Certain woods and their dust contain toxins that can produce severe allergic reactions. [12]

Breathing airborne wood can cause allergic symptoms, and mucosal and non-allergic respiratory symptoms. [13] In the USA, ACGIH, the Occupational Safety and Health Administration (OSHA), and the National Institute for Occupational Safety and Health (NIOSH), are published by the American Conference of Governmental Industrial Hygienists (ACGIH). All these organizations recognize wood as carcinogenic in relation to the nasal cavities and paranasal sinuses. [14]

People can be exposed to the skin by the skin of the skin, contact, or contact. The Occupational Safety and Health Administration (OSHA) HAS set the legal limit ( permissible exposure limit ) for wood dust exposure in the workplace as 15 mg / m 3 total exposure and 5 mg / m 3 respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has a recommended exposure limit (REL) of 1 mg / m 3 over an 8-hour workday. [15]

Wood dust breathable particulates

As with all airborne particles, wood dust particles are classified with a view to the human respiratory system. For this classification, the unit for measurement of particle size is micron or micron micrometer (μm), where 1 micrometer = 1 micron. Particles below 50 μm are not normally visible to the naked human eye. [16] . Particles of concern for human respiratory health are those <100 μm (where the symbol <means ‘less than’).

Zhang (2004) [17] has defined the size of inner particles according to

Respiratory fraction Size range
inhalable ≤ 100 μm
Thoracic ≤10 μm
breathable ≤4 μm
diminutive ≤0.5 μm

Particles which precipitate in the vicinity of the mouth and eyes, and get into the organism, are defined as the inhalable fraction, that is total dust. Smaller fractions, penetrating into the non-cartilage respiratory tract, are defined as breathable dust. [18] Dust emitted in the wood industry is characterized by dimensional disintegration of particles up to 5 μm, and that is why they precipitate mostly in the nasal cavity, increasing the risk of cancer of the upper respiratory tract. [19]

Exposure

The parameter most commonly used to characterize exposures to wood dust in the air is total wood dust concentration, in mass per unit volume. In countries that use the metric system, this is usually measured in mg / m³ (milligram per cubic meter) [20]

A study to estimate occupational exposure to inhalable wood dust by country, industry, the level of exposure and 25% states of the European Union (EU-25) found that in 2000-2003, about 3.6 million workers (2.0 % of the employed EU-25 population) were occupationally exposed to inhalable wood dust. The highest exposure levels are estimated to occur in the construction sector and furniture industry. [21]

Cancer

Wood dust is known to be a human carcinogen, based on sufficient evidence of carcinogenicity from studies in humans. It has been demonstrated that the occurrence of cancer of the nose (nasal cavities and paranasal sinuses). An association of wood dust exposure and cancers of the nose has been observed in numerous cases reports, cohorts studies, and case control studies. [22]

Other safety hazards of wood dust

Water-borne bacteria digest organic material in leachate, but use up much of the oxygen available. This high “biological oxygen demand” can suffocate fish and other organisms. There is no doubt that it is an effective detrimental effect on the beneficial bacteria, so it is not advisable to use it as a tool in your home.

Explosions and fire

Main articles: Combustibility § Combustible dust , and Dust explosion

Sawdust is flammable and accumulations provide a ready source of fuel. Airborne sawdust can be ignited by sparks or even heat accumulation and result in explosions.

Environmental effects

At sawmills , unless reprocessed in particleboard, burned in a sawdust burner or used to make heat for other milling operations, sawdust may collect in batteries and add harmful leachates to local water systems, creating an environmental hazard . This has been placed in a deadlock.

Questions about the science behind the determination of environmental hazards (see page 3), who compares wood residuals to dead trees in a forest. Technical advisors-have reviewed Reviews some of the environmental studies, say MOST goal Lack standardized methodology or evidence of a direct impact is wildlife . They do not take into account large drainage areas , so the amount of material that is getting into the total area of ​​drainage is tiny. quote needed ]

Other scientists have a different view, saying the “dilution is the solution to pollution” argument is no longer accepted in environmental science. The decomposition of a tree is similar to the impact of a sawdust, but the difference is of scale. Sawmills can be storing thousands of cubic meters of wood residues in one place, so the issue becomes one of concentration. quote needed ]

But they are more important than lignins and fatty acids that protect them from predators while they are alive. Those types of things remain in the tree and, as the tree decays, they slowly are broken down. Purpose When sawyers are processing a large volume of wood and wide concentrations of These materials permeate into the runoff, the toxicity They question is harmful to a broad ranks of organisms. [23]

Wood dust control

Concentrations during woodworking, dust extraction systems are used. These can be divided into two types. The first are local exhaust ventilation systems. Use of personal respirators , a form of personal protective equipment , can aussi isolate workers from dust.

Local exhaust ventilation (LEV) systems

These rely on a suction force through piping systems from the point of view of training to a waste disposal unit. LEV systems consist of four elements: dust hoods at the point of dust training, ventilation ducts, an air cleaning device (a fan, a known as an impeller). [24] . The air, containing dust and chips from the woodworking operation, is sucked by an impeller. The impeller is usually built into, or placed close to, the waste disposal unit, or dust collector.

Guidelines for performance for woodworking LEV systems exist, and these tie in occupational air quality regulations that exist in many countries. The LEV guidelines are often referred to by the ACIAH.

Low Volume High Velocity (LVHV) systems

Low-volume / high-velocity capture systems are a specialized type of LEV that is used to extract the engine from the tool or the tool. The cap is designed to provide high velocity capture, often greater than 50 m / s (10,000 fpm) at the contaminant release point. This high velocity is often less than 0.02m3 / s (50 cfm) due to the fact that it is used. [25] These systems have been adopted for portable power tools, although adoption of the technology is not widespread. Festool is a manufacturer of portable power tools using LVHV integrated ventilation into the design tool.

Room ventilation systems

If suitably designed, general ventilation can also be used as a control of airborne dust. General ventilation can often help reduce skin and clothing contamination, and dust deposition on surfaces. [26]

Air quality standards for breathable wood dust

Within industry, many countries have air quality regulations. This is to help ensure that the dust is extracted to a maximum level of concentration.

References

  1. Jump up^ IARC 1995.Wood Dust. InIARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 62: Wood Dust and Formaldehyde. Lyon, France: World Health Orgaization International Agency for Research on Cancer, p.70. http://monographs.iarc.fr/ENG/Monographs/vol62/mono62-6.pdf
  2. Jump up^ Felman, David (2005) “Why Did not They Have to Put on the Sawdust on the Floor? Why Do not They Anymore?” Why Do Elephant’s Jump? HarperCollins, New York,page 118,ISBN 978-0-06-053914-6, quoting Christopher Halleron, bartender and beer columnist.
  3. Jump up^ Green, Harvey (2006)Wood: Craft, Culture,Penguin Books, New York,page 403,ISBN 978-1-1012-0185-5
  4. Jump up^ Nassauer, Sarah (May 4, 2011). “Why Wood Pulp Makes Ice Cream Creamer” . The Wall Street Journal .
  5. Jump up^ Packing houses formerly purchased this wide quantities of sawdust for the cutting room floors, and still purchase sawdust for use as a fuel and flavoring in the smoking process.
  6. Jump up^ Savic, IV (1985). “Small-scale sausage production: Sausage Casings”. Rome: Food and Agriculture Organization of the United Nations (FAO).
  7. Jump up^ “Bread Labels on Wood Fiber Draw Attack” . Los Angeles Times . 9 October 1985. Archived from the original on 16 September 2010.
  8. Jump up^ Nyiszli, Miklos (2011). “3”. Auschwitz: A Doctor’s Eyewitness Account . New York: Arcade Publishing. p. 34.
  9. Jump up^ “Wood Dust Exposure” . State Compensation Insurance Fund . Retrieved April 30, 2012 .
  10. Jump up^ “Report on Carcinogens, Twelfth Edition, Wood Dust” (PDF) . Retrieved July 12, 2014 .
  11. Jump up^ “FINAL Report on Carcinogens Background Document for Wood Dust”(PDF) . Retrieved July 12, 2014 .
  12. Jump up^ Meier, Eric. “Wood Allergies and Toxicity” . The Wood Database.
  13. Jump up^ United Startes Department of Labor: Occupational Safety and Health Administration. Wood Dust. http://www.osha.gov/SLTC/wooddust/index.html
  14. Jump up^ Baran, S., & Teul, I. 2007. Wood Dust: An Occupational Hazard Which Increases the Risk of Respiratory Disease. Journal of Physiology and Pharmacology 58, Suppl. 5, pp. 43-50. http://www.jpp.krakow.pl/journal/archive/11_07_s5/pdf/43_11_07_s5_article.pdf
  15. Jump up^ “CDC – NIOSH Pocket Guide to Chemical Hazards – Wood dust” . www.cdc.gov . Retrieved 2015-11-28 .
  16. Jump up^ Zhang Yuanhui, 2004.Indoor Air Quality Engineering. Boca Raton, Florida: CRC Press, p.14
  17. Jump up^ Zhang Yuanhui, 2004.Indoor Air Quality Engineering. Boca Raton, Florida: CRC Press, p.18
  18. Jump up^ Baran, S., & Teul, I. 2007. Wood Dust: An Occupational Hazard Which Increases the Risk of Respiratory Disease. Journal of Physiology and Pharmacology 58, Suppl. 5, pp. 43-50. http://www.jpp.krakow.pl/journal/archive/11_07_s5/pdf/43_11_07_s5_article.pdf
  19. Jump up^ Baran, S., & Teul, I. 2007. Wood Dust: An Occupational Hazard Which Increases the Risk of Respiratory Disease. Journal of Physiology and Pharmacology 58, Suppl. 5, pp. 43-50. http://www.jpp.krakow.pl/journal/archive/11_07_s5/pdf/43_11_07_s5_article.pdf
  20. Jump up^ IARC 1995. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 62: Wood Dust and Formaldehyde. Lyon, France: World Health Orgaization International Agency for Research on Cancer, p.66. http://monographs.iarc.fr/ENG/Monographs/vol62/mono62-6.pdf
  21. Jump up^ Kaupinnen, T., et.al. 2006 Occupational Exposure to Inhalable Wood Dust in the Member States of the European Union. Ann Occup Hyg (2006) 50 (6): 549-561.
  22. Jump up^ Final Report on Carcinogens. Background Document for Wood Dust. Meeting of the NTP Board of Scientific Counselors, December 13-14, 2000. Research Triangle Park, NC: US ​​Department of Health and Human Services Public Health Service National Toxicology Program / Durham, NC: Technology Planning and Management Corporation. http://ntp.niehs.nih.gov/ntp/newhomeroc/roc10/wd.pdf
  23. Jump up^ Canadian Geographic Online
  24. Jump up^ Mutchler, JE, 1973.Chapter 41: Local Exhaust Systems. In:The Industrial Environment: its Evaluation and Control. Washington: US Dept. of Health and Human Services, National Institute for Occupational Health and Safety (NOISH). www.cdc.gov/niosh/pdfs/74-177-w.pdf
  25. Jump up^ Burgess, WA, and. al., 2004.Ventilation for Control of the Work Environment, 2nd ed. Hoboken, NJ: John Wiley & Sons, p.192
  26. Jump up^ WHO, 1999. Hazard Prevention and Control in the Environment: Airborne Dust. WHO / SDE / OEH / 99.14. Geneva: World Health Organization, Department of Protection of the Human Environment, Occupational and Environmental Health. p.98. http://www.who.int/occupational_health/publications/en/oehairbornedust.pdf