UNIVERSITY BANNER ID:
PROGRAMME OF STUDY:
M. Sc. Safety, Health and Environment/Occupational Hygiene COURSE:
The Chemical Environment
Carbon fibre is a strong, yet light, reinforced polymer. Carbon fibres are used in applications where high strength and light weight are required. Carbon fibres can also be easily moulded into the desired shape. They are also chemically inert, resistant to heat, and do not expand under changing temperatures.
Machining of carbon fibre materials can generate airborne particles. The potential health effects of these particles have been widely debated. To date, there has been no report of occupational illness directly related to carbon fibres. Its chemical properties and toxicity have been researched and analysed to determine if it is safe for human contact.
Carbon fibres are widely used in industrial and strenuous applications. Because of its desirable strength and light weight, carbon fibres can be expensive. It is used in the following applications: * Automotive (including Formula One racing);
* Rowing boats;
* Fishing rods;
* Hockey sticks;
* Archery equipment;
* Tent poles;
* Racquet frames;
Picture 1: Sanding a carbon fibre surface
When analyzing dust-related occupational diseases, both chemical and physical factors must be taken into account. Carbon fibres can cause discomfort to employees if the fibres make contact with an employee’s eyes, skin, nose or throat. Carbon fibres are not a known carcinogen (see appendix A – MSDS). The health effects of carbon fibres depend on three factors (Seibert, 1990): 1. The quantity of fibre that is deposited in the lungs;
2. The dimension of the carbon fibres;
3. The amount of time that the carbon fibres spend in the lungs. Not all carbon fibres that enter an employee’s breathing passage will enter the lung. Some fibres will become trapped in the nose and throat, and will eventually be exhaled by the employee. Such fibres are classified as non-respirable fibres. These fibres are short and thick, with a diameter greater than six micron (Christensson, et al., 1999). No non-respirable fibres are known to pose a health risk to an employee’s respiratory system. According to the European Union, man-made vitreous fibres are not carcinogenic if the diameter of the fibre is greater than 6 µm (European Commission, 1997). The exhaled fibres would not have any effect on the employee’s health. Conversely, respirable fibres can enter an employee’s respiratory system (Christensson, et al., 1999). Long fibres are more than 8 µm long, and thin carbon fibres are less than 0.25 µm thick. Carbon fibres of this size will pass through the nasal passage; they can enter and remain in the alveoli of the lungs. Carbon fibres that reach the lung may not harm the employee. The body fluids may dissolve the carbon fibre without generating any poisonous substances, or the fibres may change dimensions such that the body will use normal mechanisms to remove it. Contact with carbon fibres can also cause skin irritation (Seibert, 1990). The degree of irritation is proportional to the diameter of the carbon fibre. A bigger diameter allows more surface area of the carbon fibre to come into contact with the skin. Contact with carbon fibre can cause red rashes to appear on the skin. Also, pieces of carbon fibre can form splinters similar to glass, and cut into the skin. These cuts would not cause any long term health effects if the splinters are removed from the wound immediately. Carbon fibres can cause irritation to the employees’ eyes. Dust from machining, grinding and sawing can enter the eyes and cause immediate bother to the employee. This can cause the worker to rub his eyes, thus pushing the carbon fibre...
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