Duplication exhaust fans
Duplication of exhaust fans are often used in ventilation plants with toxic hazards. If the exhaust system removes a significant amount of gases, vapors, aerosols, PLI, and if you can not immediately stop the process and stop the allocation of pollutant, the duplication of exhaust fans required. With highly toxic gases may have to duplicate the fans and the general exchange ventilation hoods, supplemental to the local, especially when undesirable stop shop for fans of the accident.
Consider the cover specific to particular harmful plants. It is intended for pressure pipelines delivering highly toxic substances or working under great pressure. Shelter is depicted schematically in Fig. 12 and is called "pipe in pipe". It is used in the trace of pressure pipelines outside the cabin - in a clean room or yard.
Umbrellas and curtains can be used as auxiliary shelters that remove periodically evolved hazard.
Umbrellas are set, for example, working windows with low-emission furnaces secretions and a short stay of people near these windows. Turning, lifting and rolling umbrellas are used for catching updrafts, but subject to non-occurrence of people below them.
Of toxic vapors and gases sometimes give good results suction panels placed near the source of hazards. Particularly widely used are rotary and rotary-sliding panel, and battery.
Gases and smoke during spot welding, brazing, tint, molding is well removed slotted suction and craters, but always provided the location of the receiver hazard near the source of its release (preferably from 100 to 200 mm).
Slotted pumps - ring and semiring - can be successfully used to remove harmful substances ejected from working windows furnaces and dried, a rotary kiln at the junction of the mobile and stationary parts, near the cap apparatus operating under pressure, and in other similar cases.
If not possible with local suction ventilation, but such cases are not excluded, have yet to allow extraction of general exchange and struggle with toxic hazard. The main task of the general exchange extraction in this case - to prevent the formation of indoor areas of high concentration, so in all cases, the hood should be zonal. Should explore and identify particularly dangerous for the release of harmful substances zones, and areas of possible air stagnation. Hood should be made from these zones.
When general ventilation plants with heat and gas hazard play the role of such seemingly extraneous factors as the construction and insulation of the roof. The latter is particularly significant. When too "cold" roof of the inevitable return currents of cool gas in the work zone. This should be considered when designing.