Acoustic Ceiling Tiles

This is the time, in seconds, required for reflecting or reverberant sound in an enclosed space to decay to one-millionth (equivalent to a drop of 60 dB) of its original energy level after the cessation of the sound source.

It is the most common, and easily obtained, measurement or predictor of a room’s potential sound quality. The reverberation time (RT) for any enclosed space will be influenced by the room's volume and how much sound absorption (which controls the reflection of sound) is present. Increasing the volume will increase the RT while increasing the amount of sound absorption will lower the RT. Because Zentia suspended ceilings can provide a substantial surface area and can provide more or less sound absorption depending upon the product chosen, they can significantly influence the RT of a space. However any room will have an optimum reverberation time (RT) requirement depending upon its use and size and whether the main activity is speech or music based. Providing too much sound absorption, and hence having a very low reverberation time (RT), can be just as acoustically damaging and undesirable as having insufficient sound absorption when an excessively long reverberation time (RT) will result.

Rooms with reasonable amounts of sound absorptive finishes appear quieter and less frenetic than those with little or no sound absorptive treatment. If the amount of effective sound absorption in a room is doubled (or halved), the noise level will be reduced (or increased) by 3dB (Decibels). However, it should be considered that a change of 3dB will only just be detected by the human ear, while a difference of 5dB is necessary to be really noticeable. In addition, sound absorptive treatments that are applied to the boundary elements (walls, ceilings, floors etc.) of a room, do not have any significant effect at enhancing the element’s sound reduction properties, ie when sound transmits through it from one adjacent room to another.

By using a mathematical model based upon the 'Sabine' formula which takes into account the significant surfaces of a room, their respective sound absorption coefficients and the room dimensions. Get in touch for a more detailed calculation which also considers specific user criteria.

A sabine (also known as the equivalent absorption area) is a measure of sound absorption afforded by a material which is defined as the product of its exposed surface area S (m2), multiplied by its random incident sound absorption coefficient alpha s. However the sabine is also specifically used to describe the total absorption provided by individual discrete objects, such as an acoustic canopy, where all of its surfaces may be influentially providing sound absorption and the use of as would not be sensible or realistic.

Once the total sound absorption present in a room (from both planar surfaces and objects) has been calculated, an estimate can be made of the room's probable reverberation time. The installation of canopies in a reverberant space can significantly reduce the reverberation time and contribute to the reduction in background noise.

Some trends in modern building technology, such as the use of concrete thermal slabs as heat-sinks, requires that the slab be exposed to the occupied space. In these designs, a continuous (wall to wall) ceiling is not permissible because it could interfere with the airflow pattern around the room. But the downside of not having an acoustic ceiling will probably result in higher reverberation times and increased noise levels above those which would be acceptable to the users. Also in many existing spaces, even though a continuous ceiling is present and has to remain in place for various technical reasons, it may provide insufficient sound absorption than is suitable for the activities being carried out in the room. The installation of canopies in a reverberant space, in sufficient numbers and in a layout to satisfy both technical and aesthetic considerations, can significantly reduce the reverberation time and contribute to the reduction in background noise and improvement of aural comfort.

The speech frequency range is generally described as being between about 500Hz and 4000Hz. However it is not defined in any known national or international standard.

Sound absorption relates to the control of sound reflections within a room while sound attenuation is associated with the control of sound transmission between adjacent rooms via a continuous suspended ceiling.

Probably not. Materials that provide high levels of sound absorption are generally lightweight and porous which is the direct opposite of the qualities required for sound reduction ie massive and impervious.

In terms of sound absorption there may be a small loss, depending upon the tile face pattern (fissures, perforations, scrim, etc), the paint type used and the thickness of the paint coating. It is unlikely that the ceiling's sound reduction or attenuation performance will be adversely affected but if the spaces where the ceiling has to be repainted are acoustically critical, then laboratory testing to assess any possible differences in acoustic performance should be conducted on repainted samples.

It should be noted that the repainting of ceiling tiles could also adversely affect their other technical performance factors such as fire reaction, sag, light reflectance, among others, and the implication of such possible changes needs to be considered. Finally, it should be appreciated that the repainting of any tiles supplied by Zentia will invalidate any warranty that was provided when the tiles were new.

Zentia suspended ceilings are one of few building products with sound reduction performance that can be measured in two entirely different ways. These are sound reduction index (R or SRI = vertical or single pass), which is measured in accordance with EN ISO 140 Part 3, and Normalised Level Difference for Ceilings (Dnc = horizontal or double pass) which is measured in accordance with EN ISO 140 Part 9.

No. Although there are some empirically derived relationships between the two different values for the same product, there are no theoretically based methods for deriving one value from the other.

The decibel is a unit used in acoustics to describe the magnitude of sound levels. These levels can either describe how loud something is (eg 85 dB due to a passing bus), or they can describe the ability of a product or system to reduce sound. For example, a 35 dB suspended ceiling will reduce a sound level of 75 dB in one room down to 40 dB in an adjacent room. The bigger the number, the greater is the sound energy level or sound difference involved.

The terms 'reduction' and 'attenuation' both mean a decrease or lessening of something. These expressions describe the same process and are usually interchangeable. In relation to the acoustics of suspended ceilings, 'sound reduction' is generally used to describe the 'single or vertical pass' decrease (typically from a ceiling cavity to a room below) while 'sound attenuation' is reserved for the 'double or horizontal pass' lessening in transmitted sound energy where the ceiling is continuous above two adjacent rooms.

The Rw of the total construction is unlikely to be more than about 40 dB – an increase of up to only 5 dB on the floor construction. This is because the two separate elements are very close to each other and are rigidly connected together and therefore the sum of their two individual reductions cannot practicably be achieved.

This is not a problem that can be easily or simply solved by installing a further suspended ceiling below. It all depends upon the level of disturbance that is occurring and the type and construction of the existing floor and surrounding walls. Further advice should be sought from an acoustic consultant or specialist supplier of noise insulation materials.

Echoes are discrete sound reflections from a distant surface which, if they are of sufficient intensity and time delay, can be heard distinctly from the direct sound, ie you hear the same sound twice in quick succession. The expression 'echoey' is often used to describe the sound heard in an enclosed space which is particularly reverberant or 'lively'. This is actually the wrong use of the term as, perhaps surprisingly, echoes are a rare phenomenon in most normal sized and occupied enclosed spaces. However excessive reverberation and noise can be controlled by the introduction of sound absorptive treatments, such as suspended acoustic ceilings.

Sound absorptive materials make a space seem less ‘echoey’ or ‘lively’ by reducing the amount of sound reflected back into a room. The room becomes less reverberant. In a commercial environment, the ceiling is often the most substantial and unobstructed area where sound absorptive materials (like ceiling tiles) can be introduced.

Whatever kind of project you're working on, Zentia can provide a ceiling solution to match. Zentia ceilings can provide acoustic control with absorption values from 0.10 to 1.00 Alpha w, and attenuation values of up to Dnfw 44dB. So whether sound absorption or sound attenuation is your main priority, we can help. Get in touch with our experts if you aren’t sure which option is the right ceiling solution for your project.