Colt Acoustic Louvre Module - CALM C

Plant rooms, factory machinery and power generation sites will often produce sound pressure levels which may exceed noise criteria at building boundaries so risking complaints from neighbours.

Colt has a range of acoustic panels which are design to integrate with the Universal Louvre range, to provide sound attenuation to meet the most stringent reduction needs.

If a single bank of acoustic louvre does not provide the required noise reduction, a double bank may be specified.

To ensure the most economic solution, noise control must be considered at the earliest possible design stage. Retrofit installations of acoustic louvres can be significantly more expensive. If in doubt, please contact Colt for assistance.

Features and Benefits

There are three versions of CALM

  • S20-300 : Standard rectangular blade profile
  • S20-300-H : rectangular bade profile with higher sound reduction
  • C30-300* : curved blade to provide lower pressure drop

All versions are 300mm deep

* C30 – 300 only available for large projects. Please contact us for more details.


The CALM range does not come within a harmonised standard and as such CE marking isn't required and so cannot be applied.


  • S20-300 :
    • 200mm blade pitch
    • Rw = 15 dB
  • S20-300-H :
    • 160mm blade pitch
    • Rw = 19 dB
  • C30-300* :
    • 305mm blade pitch
    • Rw = 13 dB

All sound reduction test data to BS EN ISO 717-1 : 2013

Acoustic modules are constructed from galvanised steel with a mineral wool fill.

* C30 – 300 only available for large projects. Please contact us for more details.


Units have been independently tested in accordance with BS EN 717-1 : 2013

The standard range

There are two standard acoustic louvre models:

  • CALM-S - rectangular acoustic blade array for optimum sound reduction.
  • CALM-C - aerodynamic blade sections for improved airflow / reduced pressure drop

The outer casings are 1.2mm galvanised mild steel sheet, with the acoustic louvre blades of aerofoil configuration formed from 0.7mm perforated galvanised mild steel sheet on the inner surface and 0.7mm galvanised mild steel sheet externally.

The infill is of organic mineral wool or glass fibre of 47kg/m³ density and packed under not less than 5% compression to eliminate voids due to settlement.

Acoustic louvre banks over 1220mm wide and/or 3660mm high will normally be supplied as two or more modules for site assembly.