The Iris damper permits airflow to be adjusted to within ±5%, resulting in reduced field time and improved air balancing accuracy, states the manufacturer. It is permanently installed, permitting future airflow verification and adjustment, and retracts fully for duct cleaning. The unit uses interlocking blades, which are positioned by a calibrated positioning system to form a circular aperture. By measuring differential pressure across the damper blades, airflow can be precisely determined, states the company. It is available in 10 sizes, from 4 to 32 inches, with various CFM capacities. They are fitted with a neoprene gasket. A low-voltage motorized version is also available in galvanized steel for duct diameters up to 12 inches.
Continental Fan Manufacturing Inc., 203 Eggert Rd., Buffalo, NY 14215; 800-779-4021; 716-842-0611 (fax); firstname.lastname@example.org (e-mail); www.continentalfan.com (website).