With over 17 years experience in business management and extensive experience in the building industry, specifically with building improvements, restoration and design in the greater Seattle market. Lorin Emtage is an entrepreneurial minded thinker with skillful coordination skills, creativity and an excellent ability to build long-term client trust and relationships.
1. ACOUSTICS by LORIN EMTAGE
1. Why acoustic performance matters
The way a space sounds, though invisible, is just as important as the way it looks and feels.
However, we tend to notice acoustics either when they are articularly good, in a concert hall for
example, or particularly bad, say in a restaurant when we cannot hold a conversation.
In the best offices, acoustics will have been thought about from the outset and the way a space
needs to work acoustically will have influenced the space planning as well as the choice of
fixtures, finishes and furniture. It can be five to ten times as expensive to address acoustic
problems at a later date rather than dealing with them during a fit out project – prevention is
definitely better than cure.
The part acoustics plays in creating a successful working environment is recognised by the Fact
that it is included in most environmental assessment schemes.
2. New ways of working and sustainability
The trend to “new ways of working” and the drive for improved sustainability have both
affected the acoustic profile of office space. The move away from redominantly cellular offices
towards more collaborative working has seen an increase in open plan workstations, breakout
2. areas and partially enclosed space for impromptu meetings. These all present challenges in
terms of acoustics.
Leaving the structural slab exposed, to control internal temperature and reduce energy use, is
becoming more popular along with the use of chilled beams. However, these hard surfaces can
reflect sound and may require the use of additional elements to improve acoustic performance.
3. Basic acoustics
Acoustics is a specialist field but it is useful to know some of the principles and terminology.
Sound emanates from the source as a series of waves or pressure fluctuations moving in all
directions at the speed of sound – about 340 metres per second or 760 mph.Sound pressure
level is generally measured in decibels (dB). Frequency, measured in hertz (Hz), is also
important. Although humans can hear frequencies between 20Hz and 20,000Hz we hear best at
between 500Hz and 4,000Hz and acousticians weight calculations accordingly, with levels
expressed in dBA.
Our hearing range is affected as we age so it’s important to think about the fact that most office
populations will have a good proportion of older people. The human response to a noisy
environment is another important factor. People will often respond by raising their voice, as
typically happens in a busy staff restaurant.
Sound in an office building can be both airborne and structure-borne and each of these
methods of transmission needs to be treated and controlled differently. There are many ways
in which sound can travel from one part of an office floor to another or even between floors.
Sound can be transmitted through ductwork, pipes, cladding and columns but perhaps the most
common route is via voids, particularly over and under demountable partitions.
4. Building and fit-out elements – compromising and enhancing good acoustics
For most fit out projects it will be the specification of ceilings and partitions that will have the
greatest influence on acoustics.
Ceilings
Suspended ceilings have the greatest impact on sound absorption in a space. Acoustic ceilings
of all types (mineral fibre and metal, tiles and planks) have a pattern of holes or fissures that
soak up sound. Some products with additional layers offer higher levels of absorption. Ceilings
also offer a level of sound attenuation.
Partitions
3. The most effective way to ensure sound insulation between areas of an office is to create full
height partitions between the structural slabs of the building.
However, in most fit-out situations this will not be an option because a raised floor and/or
suspended ceiling will already be in place.Office partitions to create cellular offices, meeting
rooms and other enclosed or semi-enclosed spaces will generally be constructed on site from
plasterboard (on a metal or timber framework) or assembled using a modular system of
manufactured panels.
Floors and floor covering
Raised floors need to be carpeted to reduce impact from footfall. Although standard
commercial carpets do not provide much absorption a very thick carpet, laid over a very thick
underlay can reduce ambient sound by as much as 70 per cent.
Furniture/ screens
Furniture and other fittings such as storage, bookshelves, screens and even planting should be
considered as part of the whole acoustic picture. All will absorb or reflect sound to some
extent.
Fans, boilers, pumps, chillers, air handling units – they are all sources of noise. Think carefully
about the location of external and internal plant rooms and individual items. Acoustic
enclosures, screens, louvres and baffles can be used to attenuate noise from air handling
equipment without affecting airflow or performance significantly.
5. Getting the brief right
Clients should work with their fit-out company to ensure that the brief includes acoustics.
Activity-based planning of offices – where zones are designed to support different activities –
should incorporate acoustic characteristics which enhance these spaces.
Reception areas, particularly those in atria, tend to have hard surfaces. Reception staff may
have difficulty handling calls and conversations with visitors if there is too much reverberation.
It is fair to say that achieving a high level of acoustic insulation and attenuation requires a lot of
thought and will certainly add to the cost of a project. So, as well as the physical aspects of the
office be sure to consider questions of planning and behaviour. Open plan space in particular
requires some guidelines around acceptable noise levels so that everyone can work effectively.
6. Conclusions
4. Prevention is better than cure. If acoustic barriers need to be fitted after a client has moved
into their new building it costs five to ten times more.Consult the leaders of the business early
on the requirements for boardroom, private offices, meeting rooms and any others areas which
will have a particular need for privacy.