Includes series of installation processes ranging from fitting devices and accessories to air-conditions, ventilators, air-purifiers , to reconditioning and maintaining the old units, cleaning air ducts, fixing fans, fabric filters, sound dampers... etc. It also involves installing air-sterilizers in foodstuff cold stores, kitchens, hospitals, laboratories, animal breeding and husbandry rooms, electronic plants, any facility that requires highly purified air or air with specific gas concentration.