Background noise level to determine the speech privacy in open plan offices
Regular paper
Peutz bv
Tuesday 2 june, 2015, 14:40 - 15:00
0.9 Athens (118)
Abstract:
The importance of a high acoustic quality for open plan offices is clear to
(acoustic) designers of these offices. The optimal acoustic requirements that
can be used as guideline are however subject of discussion. The ISO 3382-3
standard describes several acoustic parameters like the spacial decay rate of
speech D2,S and the distraction and privacy distance rD and rP . The ISO
desribes how tot determine these single number quantities by measurements and
gives examples (Annex A) of what target values can be used.
Measurements according to the ISO are in basis done in empty offices. For the
STI the background noise from mechanical services is included. In practice
however the background noise in open plan offices is also determined by the
people in the office. The background sound level (L95) in everyday use caused by
people can easily be 10 dB higher than the sound levels due to mechanical
services. A measurement of the STI in an occupied office is however not
feasible. As desribed in the ISO the STI can be determined by using a simulated
background noise from human activities.
It is clear that it is important to study on the background noise levels caused
by people to determine speech privacy in open plan offices. This level is
determined by number of workplaces, the office layout, the occupation rate of
the workplaces and the type of work in the office. A study of the activities of
the users is required to determine background levels. The percentage of time
that a person is typing, walking, talking should be the basis for this
calculation. This paper describes how to determine the background noise caused
by people and how it influences the speech privacy (STI) values.