A

PARTS AND COMPONENTS OF ENVIRONMENTAL CONTROL SYSTEMS-NAMELY, HEATERS, AIR CONDITIONERS, AIR WASHERS FOR VENTILATING, AIR HUMIDIFIERS AND DEHUMIDIFIERS, WASTE DISPOSAL SYSTEMS COMPRISING INCINERATORS, AIR DIFFUSERS AND MIXERS, SOUND TRAPS, STRUCTURAL OR BUILDING PANELS AND DUAL OR SINGLE DUCT SYSTEMS