Highly effective products for sound insulation and sound absorption
Sound insulation and sound absorption in vehicles, machinery and buildings ensures that sound cannot spread unchecked and cause noise pollution or impact indoor acoustics. Highly-effective products are used to absorb, dampen or insulate noise. Hanno offers a wide range of products for sound insulation and sound absorption that fulfil the requirements of many different applications.
What is sound protection?
Sound protection includes many different methods used to reduce sound transmission from a source to a recipient. Materials and sound protection systems are used to absorb, dampen or insulate the sound. In general, we can differentiate between structural and added sound protection. Structural sound protection methods are included during the planning phase and installed when a building is constructed. Added sound protection ensures the desired acoustic properties in existing buildings. Structural and added sound protection help minimise transmission of structure-borne sound from one room to another, or sound transmission from a source to a recipient inside a room.
What is sound insulation?
Sound insulation prevents the spread of structure-borne or airborne sound by reflecting the sound at defined points. Rooms, building sections, vehicle sections or machine components are separated acoustically from one another. Sound insulating partitions prevent sound from passing through from one room or component to another. Typical applications for sound insulation methods include, for instance, sound studios that need to block all external sound, or footfall sound insulation in buildings. Both structure-borne and airborne sound insulating materials are used.
What are sound dampening and sound absorption?
Sound dampening and sound absorption are different from sound insulation. While sound insulation reflects structure-borne or airborne sound via partitions, sound dampening and sound absorption convert sound energy to heat. Specialised materials absorb the sound energy and translate it into thermal energy. Noise and sounds are essentially destroyed, rather than reflected. Sound dampening and sound absorption are typical indoor sound protection measures. They can be used to influence room acoustics in a targeted manner. Sound dampening and sound absorbing materials or components are used, for example, on the ceiling, walls, floors or on objects in concert halls.
Differentiation between structure-borne sound and airborne sound
To understand sound protection and sound insulation, it is important to differentiate between structure-borne sound and airborne sound. Sound generally spreads in the form of pressure fluctuations and mechanical waves. In the air, it is spread as longitudinal waves of air pressure with a speed of approx. 340 meters per second. Above a certain sound pressure level, the human ear can perceive airborne sound in a frequency range of between 20 and 20,000 Hertz. Sound is perceived as painful above a sound pressure level of approx. 100 dB(B).
Sound spreads in solid materials depending on their density and the sound frequency. It does so at different speeds, depending on the material. Humans perceive structure-borne sound as vibration at very low frequencies. The structure-borne sound is only audible when it transitions into airborne sound at the end of the solid material.
Product requirements for sound protection and sound insulation
Products used for sound protection and sound insulation must fulfil a variety of requirements. In addition to sound insulating, sound absorbing or sound dampening properties, other properties may be needed depending on the application. These include, for instance:
- Thermal insulation
- Cold insulation
- Fire retardant
- Temperature-resistant
- Permanently elastic
- Resistant to ageing
- Hydrolysis-resistant
- Good resiliency
- Hydrophobic / oleophobic customisable
- Fibre-free
- UV resistant
- Low specific weight
- Free from chemicals
- Properly hygienic
Applications for sound protection and sound insulation products
Sound protection and sound insulation products are used in many different areas. The following section provides a brief overview of typical applications.
In cars and commercial vehicles
Cars pose a variety of challenges in terms of sound protection and sound insulation. Highly-effective solutions reduce noise pollution inside the vehicle as well as noise transmission outside, minimise the spread of structure-borne sound or create the desired acoustics for multimedia technology. Commercial vehicles benefit from sound absorbing and sound insulating products at different critical structural points.
In energy technology
Wind turbines, heating pumps, generators and aggregates should be constructed so as to minimise noise. They are designed or covered with sound-insulating materials that reduce sound transmission to the ambient air or adjacent solid objects. Sound protection products must also fulfil thermal insulation or cold insulation requirements.
In household appliances
Appliances like vacuum cleaners, washing machines, dryers, dishwashers, range hoods or coffee makers should work efficiently and produce as little noise as possible. Sound insulating and sound absorbing materials are used to cover critical areas of these appliances and help them produce less noise.
In railway vehicles
For a comfortable journey, noise pollution in train cars should be kept to a minimum. Passengers should not be exposed to wind, rail or engine noise, even at high speeds. Structure-borne sound and vibrations should also be minimised. Products with sound absorbing and sound insulating properties offer the desired noise insulation inside railway vehicles. The materials are fire retardant, in order to comply with specific fire protection requirements.
In HVAC equipment
HVAC equipment needs to do its job every day without creating a stir, by generating a low level of sound radiation. Unavoidable airborne sound, for instance from fans, should always remain at a comfortable, low level. Products used should minimise emissions of airborne sound and insulate transmission of structure-borne sound.
In room acoustics
Work rooms, concert halls or sound studios have different room acoustic requirements. Products made of materials with sound-absorbing properties installed on floors, walls or ceilings help reduce noise levels, improve speech clarity and minimise echoes. They can also be retrofitted as needed.
In mechanical engineering
When designing machinery, mechanical engineers work to avoid sound bridges and include sound protection measures in their designs. It is critical to avoid combinations of materials and components that transfer distant sound to the surface. Products with sound dampening properties break this link and reduce clapping or vibration noise. Encapsulating the machines makes it possible to minimise the external transfer of airborne sound and avoid noise emissions. The materials used may need to have special properties like resistance to lubricants or acids, depending on the application.
Hanno products for sound insulation and sound absorption
Hanno offers a large portfolio of products for sound protection and sound insulation. They can be made of very lightweight material or heavy-duty film or have highly absorbent qualities depending on requirements. The Hanno product groups are:
- Hanno Protecto
- Hanno Redusoft
- Hanno Tect
- Hanno Fibre
- Hanno roller blind box insulation
Hanno Protecto products are made of highly absorbent speciality foams that can be finished with different surfaces. They may be laminated with aluminium foil, for instance, to withstand temperatures of over 100 °C. Waterproof coverings and surface sealing are also available.
Hanno Redusoft products stand out for their outstanding hydrolysis resistance. They remain permanently elastic for years even when compressed, and can be used to seal out dust and moisture in addition to sound. The properties of the PU foam are improved through impregnation with modified acrylate dispersions.
The very lightweight material used in Hanno Tect products offers good sound absorbing and thermal insulation properties. Thanks to their fire retardant properties, the products are very safe and can be used in applications with specific fire protection requirements. The material can be hydrophobic or oleophobic if desired, as well as UV-resistant and fibre free.
Hanno Fibre sound and insulation products are an excellent choice for industrial applications. They are made from a polyester fibre weave with different densities, and can be laminated to a coarse-grain aluminium foil. Product variants fulfil the fire protection requirements of EN 45545, and can be used in railway vehicles.
Hanno roller blind box insulation is a combination of open-cell melamine resin foam with bendable heavy-duty film and an absorption layer. The foam layer offers outstanding thermal insulation and airborne sound absorption. The heavy-duty film stabilises the roller blind box. Thanks to its self-adhesive properties, the material can be installed in mounted roller blind boxes quickly and easily.
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