LINEAR GRILLES / DIFFUSERS

EX-AL LD Linear grille with fixed blades at 12.5mm pitch centres. EX-AL LD/OBD Linear diffuser with fixed blades at 12.5mm pitch centres, complete with opposed blade damper.

Sizing Nomogram for Linear Grilles & Registers

To achieve good a continuous live length of grille from wall to wall should be avoided. It is preferable to divide the total length into suitable lengths of live and dummy sections. No live sections should exceed 10ft in length.

The ratio of live length of grille to overall length of wall may be up to 80%.

Example Problem:

To size a grille to deliver 600 cfm to a room 21ft long x 16ft wide.

Solution:

Assume the grille is to be along the short wall then:- Throw = 0.75 x length of room = 16ft. In the nomogram join 16ft Throw to 600 cfm Air Flow Rate and extend to pivot line. Select a grille of suitable proportions by pivoting about this point e.g. 9ft long x 3" high.

If it is desired to use a greater length of the available wall then consider the room in two halves i.e. 300 cfm into a room 21ft x 8ft wide. The Throw remains at 16ft and joining 16ft Throw to 300 cfm gives a new pivot point from which a new grille 6ft long x 2" high may be read off. Thus for the full room the selection becomes a grille 12ft long x 2" high.

Check from the respective scales that the noise level and total pressure are acceptable.