Yvette Volschenk 083 658 8373

1. Yvette Volschenk 083 658 8373 Technology Solutions Environmental Measurement Laboratory

2. THE IMPORTANCE OF ANEMOMETER CALIBRATION Technology Solutions Environmental Measurement Laboratory

3. The Importance of Anemometer Calibration WHAT IS AN ANEMOMETER? An anemometer is a device that is used for measuring wind speed. The term is derived from the Greek word anemos, meaning wind. The first known description of an anemometer was given by Leon Battista Alberti in around 1450. Technology Solutions Environmental Measurement Laboratory

4. The Importance of Anemometer Calibration WHAT IS AN ANEMOMETER? Anemometers can be divided into two classes: • those that measure the wind's velocity, • and those that measure the wind's pressure but as there is a close connection between the pressure and the velocity, an anemometer designed for one will give information about both. Technology Solutions Environmental Measurement Laboratory

5. The Importance of Anemometer Calibration WHAT IS AN ANEMOMETER? There are 3 types of measuring equipment : • Hotwire Anemometer • Pitot Tube • Vane Anemometer Technology Solutions Environmental Measurement Laboratory

6. The Importance of Anemometer Calibration HOTWIRE ANEMOMETER Technology Solutions Environmental Measurement Laboratory

7. The Importance of Anemometer Calibration HOTWIRE ANEMOMETER Hot wire anemometers use a very fine wire (on the order of several micrometers) heated up to some temperature above the ambient. Air flowing past the wire has a cooling effect on the wire. Technology Solutions Environmental Measurement Laboratory

8. The Importance of Anemometer Calibration HOTWIRE ANEMOMETER As the electrical resistance of most metals is dependent upon the temperature of the metal (tungsten is a popular choice for hot-wires), a relationship can be obtained between the resistance of the wire and the flow velocity. Technology Solutions Environmental Measurement Laboratory

9. The Importance of Anemometer Calibration HOTWIRE ANEMOMETER Hot-wire anemometers, while extremely delicate, have extremely high frequency-response and fine spatial resolution compared to other measurement methods, and as such are almost universally employed for the detailed study of turbulent flows, or any flow in which rapid velocity fluctuations are of interest. Technology Solutions Environmental Measurement Laboratory

10. The Importance of Anemometer Calibration PITOT TUBE A pitot (pronounced /pi-to-/) tube is a pressure measurement instrument used to measure fluid flow velocity. Technology Solutions Environmental Measurement Laboratory

11. The Importance of Anemometer Calibration PITOT TUBE The pitot tube was invented by the French engineer Henri Pitot in the early 1700s [and was modified to its modern form in the mid 1800s by French scientist Henry Darcy]. It is widely used to determine the airspeed of an aircraft and to measure air and gas velocities in industrial applications. Technology Solutions Environmental Measurement Laboratory

12. The Importance of Anemometer Calibration PITOT TUBE The basic pitot tube consists of a tube pointing directly into the fluid flow. As this tube contains fluid, a pressure can be measured; the moving fluid is brought to rest (stagnates) as there is no outlet to allow flow to continue. Technology Solutions Environmental Measurement Laboratory

13. The Importance of Anemometer Calibration PITOT TUBE This pressure is the stagnation pressure of the fluid, also known as the total pressure or (particularly in aviation) the pitot pressure. Technology Solutions Environmental Measurement Laboratory

14. The Importance of Anemometer Calibration PITOT TUBE The measured stagnation pressure cannot of itself be used to determine the fluid velocity (airspeed in aviation). However, Bernoulli's equation states: Technology Solutions Environmental Measurement Laboratory

15. The Importance of Anemometer Calibration PITOT TUBE Stagnation Pressure = Static Pressure + Dynamic Pressure Technology Solutions Environmental Measurement Laboratory

16. The Importance of Anemometer Calibration VANE ANEMOMETER Technology Solutions Environmental Measurement Laboratory

17. The Importance of Anemometer Calibration VANE ANEMOMETER A vane anemometer is a portable instrument used to measure low wind speeds and airspeeds in large ducts; consists of a number of vanes radiating from a common shaft and set to rotate when facing the wind. Technology Solutions Environmental Measurement Laboratory

18. The Importance of Anemometer Calibration VANE ANEMOMETER A small fan is turned by air flowing over the vanes. The speed of the fan is measured by a rev counter and converted to a wind speed by an electronic chip. Technology Solutions Environmental Measurement Laboratory

19. The Importance of Anemometer Calibration WHAT IS VELOCITY? In physics, velocity is the rate of change of displacement (position). It is a vector physical quantity; both magnitude and direction are required to define it. The scalar absolute value (magnitude) of velocity is speed, a quantity that is measured in meters per second (m/s or ms−1) when using the SI (metric) system. Technology Solutions Environmental Measurement Laboratory

20. The Importance of Anemometer Calibration WHAT IS VELOCITY? Technology Solutions Environmental Measurement Laboratory

21. The Importance of Anemometer Calibration WHAT IS VELOCITY? An airflow that enters a channel undergoes quite a change on its way downstream. It is evident that the only exact way to characterise such a flow is as velocity field. That type of specification is of course complex but computers can easily manage this problem. Technology Solutions Environmental Measurement Laboratory

22. The Importance of Anemometer Calibration AIR VELOCITY MEASUREMENTS • Aircrafts • Mines • Fume cabinets • Cranes Technology Solutions Environmental Measurement Laboratory

23. The Importance of Anemometer Calibration • Aircrafts Pitot tubes on aircraft commonly have heating elements called pitot heat to prevent the tube from becoming clogged with ice. The failure of these systems can have catastrophic consequences, as in the case of Austral LíneasAéreas Flight 2553, Northwest Orient Airlines Flight 6231, AeroPeru Flight 603 (blocked static port), and of one X-31. Technology Solutions Environmental Measurement Laboratory

24. The Importance of Anemometer Calibration • Mines Chile’s Mine, San José, disaster! On 5 August 2010, 33 people were trapped underground, because the roof of the copper mine collapsed. These men are trapped 700 meter underground, and 5 kilometres from the mine entrance. Technology Solutions Environmental Measurement Laboratory

25. The Importance of Anemometer Calibration San Josè Mine in Chille Technology Solutions Environmental Measurement Laboratory

26. The Importance of Anemometer Calibration Mines in Cille Technology Solutions Environmental Measurement Laboratory

27. The Importance of Anemometer Calibration • Mines • Temperature • Humidity • Fresh Air Technology Solutions Environmental Measurement Laboratory

28. The Importance of Anemometer Calibration The basic requirement for the mine ventilation system is to provide air for people to breath and in a state that will not cause any immediate or future ill effects. Technology Solutions Environmental Measurement Laboratory

29. The Importance of Anemometer Calibration The ventilation system must therefore be sufficient to deal with the contaminants released during mining. If they are not adequately dealt with, as they are identified, they may become at best a discomfort to mine workers, and at worst cause serious or even fatal illness. Technology Solutions Environmental Measurement Laboratory

30. The Importance of Anemometer Calibration The prime contaminants produced during mining are • dust • heat • gases (including water vapour i.e. Humidity) Technology Solutions Environmental Measurement Laboratory

31. The Importance of Anemometer Calibration and the prime method for dealing with these is an effective ventilation system that • supplies oxygen and cools • dilutes dust and gases and • removes the contaminants from the workplace. Technology Solutions Environmental Measurement Laboratory

32. The Importance of Anemometer Calibration It is possible that any known substance will be identified, in either the air we breathe or the food we eat. Although the human body is equipped to reject or absorb these substances this can only be done providing the quantities involved are not excessive. Technology Solutions Environmental Measurement Laboratory

33. The Importance of Anemometer Calibration “Heavy or strenuous work increases lung ventilation, thereby increasing the uptake of airborne contaminants. Similarly, heavy physical work under adverse climatic conditions, such as excessive humidity or heat, or work at high altitudes, may lead to an increased uptake of contaminants. Technology Solutions Environmental Measurement Laboratory

34. The Importance of Anemometer Calibration It is therefore of particular importance that any evaluation of the working environment considers the lung ventilation rate where there is a significant airborne concentration of contaminant.” Technology Solutions Environmental Measurement Laboratory

35. The Importance of Anemometer Calibration A Comparison of some Atmospheric Exposure Standards Adjusted for Shift Duration Technology Solutions Environmental Measurement Laboratory

36. The Importance of Anemometer Calibration A Comparison of some Atmospheric Exposure Standards Adjusted for Shift Duration NOTES: * = ppm # = mg/m3 UR = Under Review NA = Not Applicable TWA = Time Weighted Average STEL = Short Term Exposure Limit Technology Solutions Environmental Measurement Laboratory

37. The Importance of Anemometer Calibration • Short-term exposure limits (STELs) provide guidelines for the control of short-term exposure. • These are important supplements to the eight-hour TWA exposure standards that are more concerned with the total intake over long periods of time. Generally, STELs are established to minimise the risk of the occurrence in nearly all workers of: • intolerable irritation • chronic or irreversible tissue change, and • narcosis to an extent that could precipitate industrial accidents. Technology Solutions Environmental Measurement Laboratory

38. The Importance of Anemometer Calibration A significant number of these hazards can result in serious health problems, ranging from long-term physical impairment (e.g. lung disease) to immediate death (e.g. carbon monoxide poisoning, or heat stroke). It is the role of a mine’s ventilation systems to control these hazards, but before any ventilation engineering design work is carried out, it is vital that the hazards are well understood. Technology Solutions Environmental Measurement Laboratory

39. The Importance of Anemometer Calibration It should be noted that the human body is very resilient and well equipped to deal with nature’s climatic and atmospheric extremes. However, some processes involved in activities such as mining produce contaminant levels and environmental conditions which are beyond those with which the body’s natural defence systems can cope. Technology Solutions Environmental Measurement Laboratory

40. The Importance of Anemometer Calibration The human capacity to function at the maximum potential will reduce rapidly in atmospheres contaminated with dust, gases, heat and humidity and the long term effects of exposure to contaminants may have serious impact on general medical health. Technology Solutions Environmental Measurement Laboratory

41. The Importance of Anemometer Calibration Respitory System Technology Solutions Environmental Measurement Laboratory

42. The Importance of Anemometer Calibration • Gases, vapours and dusts may enter the human body in three ways • Inhaled into the respiratory system • Ingested with food and saliva into the digestive system • Absorbed through the skin Technology Solutions Environmental Measurement Laboratory

43. The Importance of Anemometer Calibration The danger posed by fire is another aspect of large-scale mechanization in mining operations. Fire is a constant hazard wherever large sources of energy are stored and used, as is the case in mining machinery. The outbreak of a sudden, highly intense fire underground has the potential for catastrophic outcomes and must be avoided at all costs. Technology Solutions Environmental Measurement Laboratory

44. The Importance of Anemometer Calibration The combination of combustible materials such as hydraulic oils and rubber tyres in the vicinity of hot surfaces has to be managed continuously and safely wherever vehicles operate. The fire risk posed by diesel powered machinery is further intensified by the presence of diesel fuel, which may participate in the combustion process and increase the intensity of the heat, smoke and gas emissions in the event of a fire. Technology Solutions Environmental Measurement Laboratory

45. The Importance of Anemometer Calibration A further dimension to the risk in terms of using diesel power underground is found in the large-scale transport and distribution of the fuel as part of routine operations. The storage of fuel underground requires awareness in terms of a thorough risk assessment and the adoption of protective and preventative measures to limit the fire risk. Technology Solutions Environmental Measurement Laboratory

46. The Importance of Anemometer Calibration The large-scale use of conveyor belts also presents a significant risk for the rapid development of underground fires. The flow of fresh air over conveyor belts provides a continuous source of oxygen that may cause the fire to become self-sustaining under certain circumstances. In addition, the location of conveyor belts in intake airways provides the potential for large-scale contamination of the mine’s atmosphere. Technology Solutions Environmental Measurement Laboratory

47. The Importance of Anemometer Calibration These hazards are managed effectively by the analysis of various risk scenarios and the implementation of protective and preventative measures devised in accordance with such analyses: Technology Solutions Environmental Measurement Laboratory

48. The Importance of Anemometer Calibration • Routing of fresh air away from high risk areas (conveyor belts, underground rubber tyre, fuel and oil storage areas, etc.) will limit air contamination during a fire. Technology Solutions Environmental Measurement Laboratory

49. The Importance of Anemometer Calibration • The provision of early detection systems, action protocols and fire fighting procedures is essential in limiting the spread of a fire. This includes the remote monitoring of the air flowing through high risk areas, the provision of adequate and back-up communication systems and protocols, the provision of effective fire fighting equipment Technology Solutions Environmental Measurement Laboratory

50. The Importance of Anemometer Calibration • The timely provision of protective measures and the training of workers in the use of protective equipment is the last component of the strategy. Of particular importance are systems designed to provide respirable atmosphere to workers who are affected by the smoke and gases emanating from the fire and who may not be able to reach a point in fresh air. Technology Solutions Environmental Measurement Laboratory