At Al Muayed, we manufacture Sound Attenuators which are designed using authentic computer selection software with ASHRAE standard. Casings are formed with Pittsburgh longitudinal joints conforming to DW 144 Class B ductwork code. Splitters are in compliance with Class O building regulations. The infill material is inert, non-hygroscopic, non-combustible, vermin and rot proof the Sound Attenuators have been successfully tested and certified by an authorized test laboratory.