ALD
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Sound attenuating exterior wall grille QUICK FACTS ○○ Excellent noise attenuation ○○ A robust grille that withstands severe climatic conditions ○○ Available in a number of different

Technical description General The ALD grille effectively reduces sound emitted from fan rooms and machine rooms, etc. to the surroundings. The sound is attenuated as the air passes through the attenuator between the sound absorbing vanes. Function Exterior wall grilles normally do not have a sound attenuating function. The unique feature of the ALD is that it is a sound attenuating exterior wall grille. Its main application involves use as an air intake/or exhaust air grille in ventilation systems. Other fields of application can include e.g. use as an airing grille in compressor rooms. The...

General The velocity of the air flowing through the grille should be checked to prevent inherent sound and high pressure drop problems from arising. To obtain the velocity, divide the volume flow through the grille by its net area. The velocity in the net area should not exceed 10 m/s. The net area can be obtained by multiplying the gross area of the grille by the factor obtained from Diagram 1. Diagram 1. The selected grille’s net area can be obtained by multiplying the factor read in the diagram below by the gross area of the grille. Figure 3. ALD – Dimension print Nominal width, supplied...

Sizing / Pressure drop • Calculate the gross face area, B x H (m2). • Find the relevant airflow in Diagram 2 or 3 (depending on type of grille). • Plot vertically upward to the required size of grille (gross). • Read the pressure drop that refers to plenum/duct installation. • Use Diagram 1 to check that the velocity in the net area does not exceed 10 m/s. If there is no risk of rain water being sucked in, then the velocity must not exceed 2 m/s in the net area. Acoustic data For most ventilation systems, Swegon's acoustic external wall grilles meet the requirements on low sound...

ALD Exemple ALD type 2: The distance between the external wall and the ventilation unit is too short to provide space for a traditional sound attenuator. A sound attenuating ALD, type 2 is installed as an air intake grille. The airflow is 0.3 m3 /s and the grille is mounted in a duct having a width of 1000 mm and a height of 500 mm. From Diagram 3 we find that the ALD-1000-500, type 1 has a pressure drop of 24 Pa. The gross face area will be 0.5 m2.  Diagram 1 indicates a net factor of 0.13, which gives us a net area of 0.065 m2. The net velocity will be 4.6 m/s which is too high if there...

Ordering key Specification text Product Example of specification text to VVS AMA. Sound attenuating Model 1 = Single 2 = Double Material 1 = galvanized sheet steel 2 = aluminium Swegon's rectangular sound attenuating external wall grille, type ALD, with the following functions: • Aerodynamically shaped acoustic baffle vanes for the lowest pressure drop/best sound attenuation. • Designed for severe climate conditions. • Type-approved, sound-insulating material, CLEANOLON®-AL. Size ALDa aaaa - bbbb - c - d xx items ALDa aaaa - bbbb - c - d xx items e tc. Wire mesh ALDT 1 Mounting frame...