Acoustic absorption measured and /or expressed as Noise Reduction Coefficient refers to the absorption of sound waves by a material. The absorption is the "missing waves", when comparing the total reflected and transmitted energy with the incident energy. LAF’s basic component of vermiculite has the inherent property of being able to transform acoustic energy into other forms of energy (e.g. heat). In our case a vermiculite ceiling or acoustic coating will absorb a substantial part of any sound waves without reflecting them. A given acoustic absorption of our vermiculite ceiling will be frequency-dependent and is affected by the size, shape, location, and mounting method used for the overall sound absorptive membrane.
Our noise abatement systems are porous by nature hence their ability to be considered excellent sound absorbers. Other materials which may successfully be combined with any of LAF’s acoustic coating include mineral or glass wool, as well as micro perforated plates.
Vermitex® Acustico is primarily used for its acoustic absorption properties. However, its low cost decorative finish and speed of application when applied by means of mechanical spray equipment plays a large role in its use over walls and ceilings of sport and transport hubs. The thickness of the coating applied normally improves the level of acoustic absorption. Vermitex® Acustico is a lightweight sound absorptive coating manufactured from expanded vermiculite of appropriate sizing, and inorganic binders. During the mixing process, air-entraining additives generate copious amounts of micro-dispersed air bubbles. This increases the ‘porosity’ of the mix and reduces the reflection of sound waves off the Vermitex® Acustico spray. Vermitex® Acustico cement and plaster-based formulations have been successfully tested at VIPAC and Engineers & Scientists Ltd and the CSIRO in accordance with: AS 1045-1985; ASTM C-423-02; ASTM E 1050-98; BS EN 20354:1993.
Typically 26 mm of Vermitex® Acustico will achieve a Noise Reduction Coefficient (NRC) of 0.62.
In large volume buildings, or undercover transport hubs, sound reflections are considered noise, especially in a hard surfaced enclosed area where a multitude of reflected sounds can collect. This collection of reflected sounds is called ‘reverberation’.
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