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Sonic Series acoustic louvre SL4-30

The Sonic Series acoustic louvre SL4-30 is a 300mm deep acoustic louvre designed to provide controlled airborne sound reduction while maintaining airflow performance. Use it where increased acoustic attenuation is required and available installation depth allows for a deeper louvre configuration.

Engineered to balance acoustic attenuation, airflow performance and weather protection, the SL4-30 provides increased airborne sound reduction compared with shallower Sonic Series acoustic louvre configurations while maintaining efficient airflow through a 35% free open area.

Product Properties Test Data Technical Information

  • Product name:

    AcousTech Sonic Series acoustic louvre SL4-30

  • Weighted Sound Reduction Index (Rw):

    Rw 27 (C −2, Ctr −5) assessed to AS 1191-2002, rated to AS/NZS ISO 717.1

  • Insertion loss:

    21dB (C −2, Ctr −5)

  • Free open area (FOA):

    35%

  • Effective flow area (EFA):

    0.29m² (1000 × 1000mm reference specimen)

  • Discharge coefficient (Cd):

    0.82

  • Airflow classification:

    Class 1 to AS 4740

  • Rain penetration class:

    Class C (overall) / Class B (0–0.5 m/s)

  • Fire rating:

    Manufactured from non-combustible materials

  • Test standards:

    AS/NZS ISO 717.1 | AS 4740

  • Typical test specimen:

    1000 × 1000mm

  • Customisation:

    Available in standard module sizes or engineered to project-specific dimensions.

Noise reduction
Frequency (Hz)-1/3 Octave Noise Reduction
1/3 Octave 1/1 Octave
100 10 11
125 11
160 12
200 18 19
250 20
315 21
400 23 24
500 24
630 26
800 27 27
1000 27
1250 28
1600 28 28
2000 29
2500 29
3150 29 28
4000 28
5000 28
Pressure drop
Face Velocity
(m/s)		 Throat Velocity
(m/s)		 Pressure Drop (Pa) Cd (-)
0.5 2 3.5 0.83
1 4 15 0.80
1.5 6 32 0.82
2 8 57 0.82
2.5 10 90 0.81
3 12 128 0.82
Free open area (FOA):
FOA Cd EFA Performance Level
35% 0.82 0.29 Class 1
  • Weather performance
    Core Velocity
    (m/s)    		 Penetration
    Rate (L/h.m2)    		 Effectiveness Rain Penetration Class
    0 3.1 0.958 B
    0.5 3.6 0.951 B
    1 8.9 0.882 C
    1.5 9.4 0.875 C
    2 10.4 0.861 C
    2.5 10.9 0.854 C
    3 12.0 0.840 C
    3.5 13.0 0.826 C
  • Sonic Series acoustic louvre SL4-30 datasheet PDF
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  • AcousTech Sonic Series acoustic louvre SL4-30 line drawing PDF
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  • AcousTech Sonic Series acoustic louvre SL4-30 - DWG DWG
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  • AcousTech Sonic Series acoustic louvre SL4-30 - RFA RFA
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