Comfortable acoustics can make a working environment more effective and play an important role in employee well-being and efficiency. Effective design and installation of acoustic glazed partitioning has proved key to many successful projects.
In order to understand how best to specify glass partitions, it’s good to start with an introduction to the decibel scale. This then provides a basis for where on that scale your specification should be. The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. Here are some common sounds and their decibel ratings:
- Near total silence – 0 dB
- A whisper – 15 dB
- Normal conversation – 60 dB
- A lawnmower – 90 dB
- A car horn – 110 dB
- A jet engine – 120 dB
- A gunshot – 140 dB
How do Acoustic Glass Partitions work?
A thin, clear PVB membrane is bonded to the glass panes. This clever, acoustic membrane absorbs sound energy, preventing the sound vibrations from penetrating the glass, resulting in a significant noise reduction. Glass partitions are acoustically rated according to their performance in laboratory acoustic tests. The resulting figures give an index of performance, which enables one form of a partition to be compared with another, and a particular type of partition to be assessed for a specific application.
Laboratory tests are carried out under acoustically optimised conditions. The conditions on-site are very different, and most buildings possess a number of acoustic pathways, or flanking transmissions, which will greatly reduce the sound insulation. Areas of glazing and the insertion of door openings will also reduce the overall performance of the partitions. Typical sources of sound leakage are:
Trunking passing through walls, floors, and ceilings
When installed, the nominal acoustic performance of a glass partition can reduce by 12-15%, even though the installation detailing can be optimised to reduce losses to a minimum. Example: acoustic mastic to abutments, acoustic foam to tracks, thresholds to doors. There are generally accepted acoustic insulation values which when achieved in laboratory test conditions will provide, with appropriate care in installation, acceptable values on site.
The following table provides some general guidance on acoustic privacy in relation to sound reduction:
- 25 Normal speech easily overheard
- 30 Loud speech clearly overheard
- 35 Loud speech can be distinguished
- 40 Loud speech heard but not intelligible
- 45 Loud speech heard faintly
- 50 Loud speech and shouting can be heard with difficulty
BS 5234: 1992: Glass Partitions suggests sound insulation performance levels for privacy in some occupational conditions. These are given in the following table:-
- General offices Rw38dB
- Private offices Rw44dB
Achieve the best sound quality glass meeting room
Whilst you will not be able to achieve 100% sound insulation there are features that can help you achieve the very best acoustic performance:
- Double glazed acoustic glass – on top of the acoustic membrane, the double glazing provides an extra layer of glass to help block sound.
- No door – perhaps you already have another entrance to the room? Choosing not to install a door in will help keep sound within the room, however we appreciate that you need to get in and out somewhere!
- Seals and frames – if you do need a door, opt for seals and frames to help contain the sound.