ACOUSTIC APPLICATIONS

Tel 0870 803 2271

• Lafarge Acoustic Floor

1. Acoustic Performance Partitions
2. Sound insulation

Sound insulation
Sound insulation prevents two kinds of sound transmission: airborne sound and impact sound.

The conventional rule for reducing sound transmission is the mass law. This says that the heavier the structure, the less sound it will transmit. However, other factors, such as discontinuous construction and stiffness, mean it is possible to achieve good sound insulation levels with lightweight construction, making the most of the drywall advantage.

One of the most important features of sound insulating structures is that they should be imperforate. Even the smallest of cracks, say only 0.4mm wide, has a significant area along the length of a wall, and could halve the effectiveness of a 50dB partition.

Sound frequency
Structures have variable sound insulation values depending on the frequency of the sound. With Lafarge’s twin frame partitions significant improvements can be made, especially in insulating against higher frequencies.

Acoustics
In domestic buildings, acoustic factors are not very critical. Most of the necessary sound absorption will be provided by the furnishings and occupants. However, with auditoria of all types the design problems are complex, and acoustic specialists should be consulted. Despite the complexity of acoustic science, some basic principles are universal:
• Provide direct sound paths between sound sources and listeners – consider raking floors and try to avoid columns.
• Beware of curved surfaces – convex shapes scatter sound and concave shapes focus it, often with disastrous results!
• Optimum reverberation times will depend on the use of the space and will be longer for music than for speech. With unwanted sounds, for example the noise of machinery, it is best to shorten the reverberation time as much as possible.

Acoustic Performance Partitions

Leisure is one of the fastest growing sectors in the construction industry. Large leisure centres often include several cinemas, an ice rink, swimming pool or bowling alley, a gymnasium and possibly night clubs as well, besides the usual ancillary accommodation. They therefore have extremely demanding performance standards when it comes to acoustic separation and fire resistance. Lafarge drywall systems, with the drywall advantage, have the capability to satisfy these exacting needs, on time and within budget.

Lafarge partitions will meet various acoustic insulation standards up to 65dB and at the same time achieve up to 240 minutes fire resistance. A range of different specifications is available, using either single or twin frames, and including insulation and a choice of wallboard, to meet specific technical requirements at minimum cost, and achieve fast-track completion targets.

Exceptionally high standards of sound insulation can be achieved using specially developed acoustic designs. 300mm thick twin-wall Lafarge partitions can be provide separation between auditoria, rise to 10.5m high and provide proven sound insulation levels of 65dB.

To ensure the highest acoustic performance standards, partitions must be installed strictly in accordance with our recommendations including the use of Lafarge acoustic seals around perimeters, and acoustic brackets.

Lafarge Acoustic Floor

Converting existing buildings calls for great care, particularly when upgrading floors to achieve sound insulation between compartments. Complications with historic buildings can include the need to retain original plaster ceilings. Lafarge Acoustic Floor, which is equally applicable for new projects, is a ready-made solution for the task because of its high performance technical specification and its ease of installation directly over delicate original ceilings.

A very high standard of sound insulation can be achieved between storeys and added fire performance may be built-in, using 15mm Megadeco or Firecheck wallboard.

Effective sound insulation requires very close attention. It is the careful and correct detailing of perimeters and junctions that determines success. Lafarge drywall systems provide the perfect solution to challenging problems in acoustic design. They have a proven track record in buildings where high acoustic subdivision is absolutely essential – for example between dwellings or between auditoria in multiplex cinemas.

Lafarge Acoustic Floor is one of the simplest high-performance sound insulating floor systems available. It has wide applications in new-build, conversion, and particularly remedial work, where an improved sound rating is required. Lafarge Acoustic Floor adds only 6mm to the overall floor thickness, so it can be accommodated in existing buildings without expensive alterations to internal joinery.

It is a free-floating system and adds both mass and sound absorption to achieve exceptional airborne and impact sound insulation. Lafarge Acoustic Floor is suitable as a separating floor between dwellings and can provide 60 minutes fire resistance, in addition to sound insulation of between 62dB and 65dB.

Comprising special Acoustic Floor Clips, Resilient Tape and Resilient Bars, together with Lafarge Standard wallboard and metal angle products, Lafarge Acoustic Floor forms a highly effective system which is simple, easy to use and cost-effective.