At least 1 set tertiary air filter. Respectively, the early effect, in effect filter, high efficiency filter.
2 at the beginning of the first level effectively filter should be set in fresh new FengKouChu mouth or close to, and comply with relevant regulations.
3 secondary effectively filter should be set in the system of positive pressure.
4 third class efficient filter should be set in the system of near end or close to an end plenum, shall not be located in air conditioning in the box.
