interiorsandsources.com october2018 interiors+sources 21
echoes, reverberation, poor intelligibility and auditory fatigue. In stations
where the trains and people are all in one space, there is an even greater
need for a good acoustical design since the largest noise creator is the train.
To be fair, new trains are quieter than ever with maglev and electric trains.
Yet our aim is to design transportation hubs that are quiet, comfortable and
The solution? The same as airports only more so, with a focused eye on
performance and ease of cleaning. As the mechanical transportation device is
in the same space with the travelers, the noise floor is higher than in airports.
Also, any emissions created or dirt encountered on its travels might be brought
into the station with the train. With a higher noise floor, a higher degree of
surface area must be acoustically controlled. This means a more complex
design with more devices and panels. In this environment, a thermodynamic/
HVAC solution would not be the best solution as the improvement of the solution might be less than the already higher levels of noise. However, greater use
of artwork-wrapped quantum devices as information kiosks between tracks
would help mitigate cross track acoustical noise.
Creating a sense of division at specific places would serve to disseminate
information as well as steer travelers to their correct location. Again, cleanliness over time is of concern and will affect acoustical devices. Like an HVAC
air filter, acoustical devices can become blocked or clogged by the dirt which
builds up on the textile wrapping, limiting effectiveness dramatically by not
allowing air to pass through.
Bogota, Colombia had a city-wide transportation issue. The population
outgrew the myriad of small bus lines, which worked poorly and took over two
hours to travel only 30 km. In addition, the city did not want to spend large
amounts of money for a light-rail/subway mass transit system. In 2000, the
TransMilenio BRT, or Bus Rapid Transit system, was launched. This govern-ment-operated system uses interconnected lines of buses with bus stops on
raised platforms down the middle of the road and exclusive bus lanes adjacent
on both sides. Travelers reach the BRT stops via bridges and overpasses.
Like subways, there are local and express buses.
This new style of rapid transit does not have large stations or terminals,
but rather many small steel and glass shelters down the middle of the road
where the buses stop. As they are smaller spaces made completely of hard
reflective surfaces, they are loud and filled with echoes and reverberation. As
many of these are open-air and not acoustically sealed from street noise or
bus noise, the average noise floor will be higher than an airport to start with.
The BRT is an effective and economical system, the acoustic solution should
be as well.
In these small metal glass enclosures, quantum devices would be wasted
and the spaces are not tall, so acoustical devices above head height would be
useless (except for the ceiling). The best solution for assuming limited effectiveness and a budget scaled to match the system would be traditional acoustical
treatment or to use the CAT System for more elegant and artistic thin panels to
control the hard reflections in these narrow, short spaces. Again, if the space
is open to the street noise, one can only hope to control the sound once it’s in
the bus stop, not to isolate it. The BRT is an unusual acoustical circumstance,
so the higher ambient noise is simply part of the environment.
By using intelligent design and a blend of new technology, high performance
can be achieved by integrating dual-purpose acoustical materials and devices
into the architectural and interior design process at an early stage.
See an expanded version of this article in our
digital edition at interiorsandsources.com.