lifting height of exhaust pipes
Lifting height of exhaust pipes on the building ridge sometimes limited by aesthetic considerations. Indeed, the beam pipe above the roof - it is ugly. For such cases it is recommended to display the pipe through the roof of the concentration and decorate them by constructing a common box, the circuit is shown in Fig. 50.
When placing the air intake above the roof of the building with only obscheobyennoy hood (with the release of air, free from dust) according to the instructions SNIP may have air intake on a par with hood, subject to rupture, the horizontal equivalent of more than 10 square diameter of the exhaust pipe, but not less than 10 m.
It seems that such interposition at intake and exhaust air is acceptable at best, only for ancillary buildings and industrial plants for non-industrial buildings. When you remove the same stretch of the general exchange of toxic or odorous substances should raise the exhaust air is not less than 3 m above the air intake, and the horizontal break to take at least 12 m.
Have air inlets on the roof of the building in the presence of air emissions over it, remove local suction, is generally not recommended. II absolutely unacceptable to have the air intake above the roof of the building in the presence of exhaust air silnotoksicheskih hazards. As an exception to this is possible only with a favorable wind direction gospodstvuyushego, with flare emission and the location of the mouth of the exhaust pipe above the air inlet at 6.8 m by Breaking horizontally not less than 15 m.
In SNIP II-F. 7-62, 1!. 4.50 contains the following statement: "If over the top! An emission of air, remove local suction contaminated with noxious gases and dust in the hole for a fence outside air may be placed above the roof where the calculation or data analysis will be shown that the concentration of harmful substances at intake does not exceed 30% of the maximum allowable in the working zone air space. "
Over the cited should be noted that, unfortunately, PA level of our current knowledge, we can not any accurate calculation of pollutant concentrations in outdoor air na small distance from the exhaust pipes. Hence, given an indication of SNIP is purely formal and essentially prohibits the suction device over the roofs of industrial buildings.
In confirmation of this, building codes and regulations recommend to arrange air inlets to air handling systems with mechanical drive inside buildings or in a special stand-alone air inlet.
The air holes in the walls should be located not less than 2 l / from ground level to the bottom of the hole, and at the air intake of the green zone - not less than 1 m. The correct positioning air inlets in the area from 3 to 6 m from ground level. Have air inlet at a height of 1 m from the ground even in the Green Zone only if the air is filtered.
Speaking of the fan installation, you need to recall the often overlooked requirement SNIP II-F. 7-62, namely the set out in paragraph 4.62. It speaks of the need to take into account the loss or air leak in determining the performance of the fan. Loss of PLI air intake recorded in 10% of the system performance of steel, plastic and asbestos cement ducts up to 50l / and the rate of 15% in all other cases.