Noise control in ventilation
Why is it such an issue? In 1999 the WHO (World Health Organisation)…
Type DDOV
The DDOV series grilles are designed to be used in air conditioning, ventilation and heating systems. They are suitable for side wall mounting or for mounting in false ceilings.
The adjustable blades can be set to provide either narrow, normal or widespread distribution of the air and can be graduated both in width and height to give the desired discharge angle and direction.
SDO-DDO Selection Data
Air Volume m3/sec | Spigot Velocity m/sec | Grille Size width x height | Throw m | Pressure Drop n/m2 | Sound Rating nc |
0.5 | 1.4 1.66 1.66 | 350x100 300x100 200x150 | 2.5-4.0 3.5-5.5 3.7-5.7 | 2 3 3 | - - - |
0.075 | 1.25 1.87 1.66 2.5 | 600x100 400x100 300x150 200x150 | 3.0-5.0 3.8-5.3 4.0-5.6 6.0-7.5 | 2 5 4 6 | - - - 20 |
0.10 | 1.33 1.60 1.66 2.22 | 600x125 500x125 400x150 300x150 | 3.7-5.0 4.5-5.5 5.2-7.0 5.6-7.6 | 2 4 4 6 | - - - 16 |
0.125 | 1.38 1.66 2.08 2.50 2.77 3.33 | 600x150 600x125 400x150 400x125 300x150 300x125 | 4.3-6.0 5.0-6.8 5.5-7.5 6.1-8.6 7.5-10.0 8.5-11.4 | 2 3 4 6 9 12 | - - 20 20 28 35 |
0.150 | 1.5 2 2.14 2.5 2.85 3.33 | 500x200 500x150 350x200 300x200 350x150 300x150 | 5.5-7.5 6.6-8.6 8.0-10.5 8.3-10.8 8.5-12.5 9.1-13.1 | 2 4 5 7 10 13 | - - 20 25 28 35 |
0.20 | 2 2.66 2.5 3.33 3.33 4.44 | 500x200 500x150 400x200 400x150 300x200 300x150 | 8.0-11.0 9.3-12.6 9.5-13.0 11.2-14.5 12.0-16.0 13.5-17.2 | 5 7 7 11 12 22 | 20 23 25 26 35 39 |
0.25 | 1.8 2.38 2.08 2.77 2.5 3.33 | 700x200 700x150 600x200 600x150 500x200 500x150 | 8.5-11.5 8.9-11.8 9.0-12.0 9.7-12.7 10.0-13.0 11.3-14.3 | 4 5 5 7 7 11 | - 20 20 25 25 36 |
0.30 | 1.8 2.50 2.2 2.5 3.75 | 800x200 800x150 700x200 600x200 500x200 400x200 | 7.5-10.5 8.8-12.3 9.0-12.5 10.5-14.5 11.0-15.0 12.0-16.5 | 4 7 6 8 12 17 | - 21 22 25 30 35 |
0.40 | 2 2.22 3 3.8 | 700x300 600x300 450x300 350x300 | 10.0-14.0 11.1-14.1 14.5-18.0 17.0-25.0 | 3 6 8 14 | - 25 27 36 |
0.50 | 2 2.77 3.33 4.16 | 850x300 600x300 500x300 400x300 | 11.0-15.0 12.1-16.0 13.0-17.5 17.0-23.0 | 4 4 5 0 | 20 24 25 33 |
The frame and blades are made from extruded aluminium HE9TF, the blades from HE30. The same grille is available manufactured from galvanised steel sheet which makes them suitable for car park areas and areas requiring a greater degree of strength.
The smallest grille produced is 200mm x 100mm and rises up to 1200mm x 1200mm2.
In epoxy powder coating or polyester paints from the BS4800 or RAL range of colours. Alternative anodised finish available on request.
Fixing through the frame into a fascia or secret fixing from the sides into the plenum box or ductwork. These grilles can be supplied complete with a deflectrol which is hinged off the rear of the grille, where a number of grilles are run in one single duct.
– DDOV grilles with moveable blades parallel to the longer side and opposed to the shorter rear side.
– DDOSV grilles with moveable blades parallel to the shorter side and opposed to the longer rear side.
– DDOV Extruded aluminium grilles. Galvanised steel grilles.
All the grilles are provided with a seal on the back of the frame.
V = Opposed blades damper to regulate the air flow.
The damper is operated by an easily accessible key inside the grille. It is entirely constructed from milled
aluminium. The damper is held in place by “S” springs.
Correction Factor for Ceiling Effect Layout:
Ceiling distance < 0.8m
The factors of Al0.2 (m) are multiplied by 1.33.
The figures indicated refer to 0°position blades.
α = 0° α = 22° α = 45°
bh = 0.4 . L0.2 bh = 0.53 . L0.2 bh = 0.8 . L0.2
Lb = 0.66 . L0.2 Lb = 0.66 . L0.2 Lb = 0.66 . L0.2
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