Translate the sentences from english into russian. 1. for hazardous areas flameproof enclosures alone are recommended, except in areas with moderate intensity of contamination and where such assemblies are located away from the affected area and in a separate well- ventilated room, when pressurized enclosures may also be safe. 2. the reason for this precaution is that frequent arcing takes place within the enclosure on each switching of a contactor, switch, breaker or an ocr etc. and also during operation of power and auxiliary contactors. 3. the classification of gases, vapour and volatile liquids according to their ignition temperatures has been given. 4. as a switch, a contactor or a breaker produces an arc during a switching operation, an explosion may occur within the enclosure on a re-switching. 5. it is also possible that when the enclosure door is opened to check, test or replace a component, contaminants may have entered the enclosure. 6. it is also likely that on a re-closing of the feeder door, the closure is not perfect due to human error and contaminants have leaked into the enclosure. 7. all this may lead to an explosion on a re-switching. 8. since it is not practical to manufacture a flameproof enclosure due to its size and bulk and the number of knockouts and openings on the doors for switches, metering, indicators, and pushbuttons (pbs) etc., it is common practice to locate these assemblies some distance from the affected area in a separate well-ventilated room. 9. depending upon the location and intensity of contamination, it may be permissible to meet the requirement by using a pressurized enclosure by maintaining a positive pressure inside the enclosure similar to that for motors. 10. when there are many switchgear assemblies, the room itself can be pressurized, which is safer and easier.