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close this bookAsbestos Overview and Handling Recommendations (GTZ, 1996)
close this folderPart II. Asbestos
close this folder5. Occupational safety measures in handling Asbestos
View the document(introduction...)
View the document5.1 Suitable fiber binding
View the document5.2 Wet operations
View the document5.3 Enclosure
View the document5.4 Vacuuming of dust near the point of origin
View the document5.5 Limiting the areas in which Asbestos dust may arise
View the document5.6 Personal respiratory protection
View the document5.7 Regular and thorough cleaning of workplaces
View the document5.8 Dust-free waste collection and landfill disposal

5.3 Enclosure

The best control of fine Asbestos dust exposure is achieved through enclosure of the working area. This prevents people from direct contact with Asbestos fibers and prevents fibers from reaching areas where people are situated. Enclosure is primarily used in the feeding of raw Asbestos to mixing and stirring plants for the manufacturing of materials. This process can be described as follows:

1. Asbestos fibers are brought in air-tight plastic sacks to the feeder.

2. The closed sacks are opened automatically in special facilities.

3. The Asbestos fibers are transported from the feeding point in closed conveyor systems to the processing point.

4. After the mixing process, the Asbestos fibers are embedded in moist binding agents, and additives and are brought in this state to the manufacturing station.

These process methods are state of the art for nearly all areas, such as production of Asbestos cement, friction linings, yarns, gaskets, and filters, as well as manufacturing of intermediate materials (mixtures, nonwoven, formed fabric, etc.).

In addition to the use of closed circuits, the avoidance of the generation of fine Asbestos dust in the processing of Asbestos containing materials is also possible through enclosure for discontinuous systems, e.g. automatic stamping, pressing and other mechancical processing operations in the manufacturing of e.g. gaskets and friction linings at stations with tool feeding and retrieval equipment. These processes can be characterized as follows:

1. The processing stations at which Asbestos dust arises are encapsulated dust-tight.
2. The operating personnel stand outside of the capsule.
3. The arising Asbestos dust from the processing is vacuumed up by an air exhaust cleaning unit.

A regular and careful cleaning of the processing station within the enclosure is important in order to prevent an accumulation of easily releasable fibers.