HD Grant 24X24 Perforated Return PPDDR122424TB

The HD Grant PPDDR122424TB is a 24 by 24 inch perforated return air grille with a 12 inch round duct collar, the largest in this group, for T-bar ceiling installation.

A 12 inch collar carries considerably more return air than the smaller sizes, suiting spaces with higher airflow requirements served from a limited number of ceiling positions: conference rooms, open plan areas, laboratories, and healthcare spaces with elevated air change rates.

At this size two constraints deserve checking against manufacturer data rather than estimation. The first is the relationship between the perforated face and the collar. A 12 inch collar can deliver more airflow than the perforated face of a 24 by 24 inch grille will pass at an acceptable face velocity, in which case the face becomes the limiting restriction and the noise source. The second is duct velocity in the collar itself and the connected duct, which generates noise that carries through the grille into the space.

Where the required return airflow exceeds what one grille will pass quietly, distributing it across additional return positions gives a better result than driving a single grille beyond its comfortable range.

Ducted returns are specified where the ceiling void may not be used as a plenum, or where a space requires separate return for pressure control.

Applications include commercial offices, healthcare, laboratories, and buildings with ducted return systems.

Brand

HD Grant

SKU

PPDDR122424TB

Category

Return Air Grilles

Weight

7.6 lbs

Dimensions

24.00" x 24.00" x 3.50"

Price

$133.00

Availability

In stock

Rating

0 / 5.0