... not decay, mildew, durability.Fire---resistance.Practicality: suitable for the densely-populated area (such as school, supermarket, ... high requietment of the enviroment area, such as hospital, laboratory, howff, bus, train, broadcasting studio.PROPERTIESVALUEDiameter Range75-750mm ... usage and low wind resistance, and specifically produced for low and medium pressure heating, cooling, ventilation, air ...