Pressure Relief Horizontal Air Up 3520-20X25 Smoke-Fire Damper Front blades parallel to shortest

Front blades parallel to shortest dimension

Standard Features * 1/2" spaced vision-proof dual angular louvers for strength and maximum free area * Margin edges are 7/8" projection for baseboard installation * Soft White with color matching screws Options * 1133 - 1/3" spaced dual angular louvers * 1175 - added mullion stiffeners for greater strength * Standard Color

3 cone steel diffuser with hinged core for easy duct access

22 gauge galvanized steel roll formed frame

2750 Install Instructions

Pressure Relief Horizontal Air Up 3520-20X25 Smoke-Fire Damper Front blades parallel to shortesth3. Standard Features * 3510 Vertical mount * 3520 Horizontal mount air up * 3530 Horizontal mount air down * Designed to open with negative or positive pressures for intake or exhaust air * Felt edge blades to hold noise to a minimum * Aluminum construction * Blade to blade linkage * 1 4" pivot pins in nylon busings * Maximum size 24 x 24 * Mill finish h3. Options * Sleeve variations * Mounting flange * Adjustable counter balance to adjust various