Exhaust Risers small sections are usually made of steel no less than 1 mm and supplied with ribs. Air velocity in the riser of the reasons quietness is not taken more than 7 m / sec.
For more reliable obesshumlivaniya recommended cover risers layer of mineral wool thickness 30 -50 mm
Fig. 50. Zadekorirovanie exhaust
1 - pytyazhnye fans, 2 - Flare emissions, 3 - decorating a shield, 4 - mount exhaust pipes
followed by plaster and painting. This event pays off, and from an aesthetic point of view.
Under these buildings in most cases have central corridors, typically used for routing incoming air. Horizontal ducts often form file ceilings in the corridors. In addition to aesthetic aims and objectives of this obesshumlivaniya. The inner surface of the box formed by boarding ceiling is covered with sound-absorbing plaster.
Distribution of fresh air sometimes performed in ventilated rooms. However, the preferred feeding air into the corridors where it drain into the premises through a self-closing of the lattice. Grates should be plastic, since metal grilles rattle when closed.
Feed supply air directly into the ventilated space forced by admissible only at constant volume hoods. When an alternating mode exhaust that is often encountered in the engineering buildings and labs, air flow in ventilated rooms is contraindicated. In such cases, the air must come fully into the corridors, which are like reservoirs of clean air. Need to stipulate that it is absolutely unacceptable to smoke in the hallways. The building should be provided special smoking.
Indoor poluzavodskih installations, workshops, etc., at constant volume hood supply air should be submitted directly to the premises. If there are local pumps n heat low, it is rational to apply the supply air to the upper or middle zones with perforated panels with perforations only at the top or top and side. Is also possible to feed into the upper zone through a perforated ceiling. Such a panel, as shown in Fig. 51, does not take away form the premises provides diffused and Mr. malooschutimy inflow.
The panels preferably arranged with the most advanced surface. On average, we can assume that type 1 m2 of horizontal surface of the panel with the perforated only at the top follow the file from 800 to 1200 m3 / h.
In most of the basic premises of buildings under consideration are local pumps. At the same time is required and general exchange ventilation. The question arises whether it is possible to carry out local and general extract a single system. Such a combination of ventilation systems is possible only if the constant work of local suction and after adjustment carried out by adjusting throttle washers. This, of course, does not apply na suction system.
Some designers having in place a number of local suction, such as fume hoods, provide dampers at the ramifications of this aspiration. These dampers are not intended for primary control, and to turn off the suction na ni moments of inactivity. This decision is wrong: at toxic hazard install dampers in the local suction is unacceptable and may result in poisoning. When the toxic hazards of all available local pumps must operate continuously and consistently. Turn off suction when abeyance equipment is dangerous because of forgetfulness suction may be time not included or not included in the overall productivity and harm will fall into the respiratory organs.
Note that in these buildings, the total air balance must always be positive, ie, the flow dominate hood.