toxicity of the dust
In the fight against dust often ignored one of its essential properties - toxicity. In modern industries, in addition to silikoznoy dust, which can also be attributed to the toxic, there are dust with a distinct virulence, such as lead and lead oxides, mercury compounds, arsenic anhydride, and so and. Fighting like dust much more complicated; become actual specific conditions of struggle with toxic gases, and particularly aerosols. Sometimes it is difficult to draw a clear distinction between dust and aerosols.
Consider the problem of feeding the supply air with toxic dusts.
The first rule - deliver air to the area of least contamination can be observed with the release of fresh air in the upper and the working area. It is important to establish a zone in which dust anymore. At first glance it seems that at the bottom, because the dust settles. However, if the premises are rising thermal currents, dust, particularly fine-the most active and dangerous for a person - shall be made up and creates an upper zone of greatest concentration.
The second rule-feeding clean air in the breathing zone - too much of toxic dusts. But the breathing zone is the working area. This should be remembered and for ventilation of dusty rooms.
You can not use the mechanical guidance of sanitary norms for ventilation with toxic dust emission. Place of filing the supply air must be chosen with this in mind, a thorough analysis of the phenomena occurring in the air. As a rule, part of the supply air must be made in the work zone, in place of the least pollution. In these areas the floors should be kept moist. When the toxic dust emission and the presence of permanent jobs may be appropriate to supply fresh air from the air showers.
Design of dust extraction ventilation and extraction should be based primarily on knowledge of the designer of the process. Where, why, under what conditions there is dust, and what its quality (particle size, wettability, chemical composition) - these issues must be addressed by the designer in the first place. The designer must be aware of the phenomena occurring in this dust-raising process: zones of high pressure in the shelter, the direction of the dust plume, the air currents near the source of dust. Only in this case, you can create a rational design pylepriemnika or shelter. Give any specific advice is impossible. Therefore, we state only some basic considerations related to aspiration of the most frequent and most studied of technological equipment.