19th INTERNATIONAL CONGRESS ON ACOUSTICS
MADRID, 2-7 SEPTEMBER 2007
ALTERNATIVE ROOM ACOUSTIC DESCRIPTORS FOR OPEN OFFICES –
PROGRESSES IN STANDARDIZATION
Chigot, Pierre
Saint-Gobain Ecophon SA, 19 rue Emile Zola, BP 30030, 60 291 RANTIGNY, France
pierre.chigot@saint-gobain.com
ABSTRACT
Limitations regarding the use of Reverberation Time for acoustical assessment of open plan
offices are known: large variance between measurement positions at low frequencies, poor
reactivity to changes in the acoustics due to the lack of diffusivity of the room. In order to mirror
the acoustical issue in open offices, i.e. the sound propagation from workstation to workstation,
rate of spatial decay per doubling of distance (DL2) is proposed. Originally been applied to
workrooms (as defined in EN ISO 14257), DL2 seems to be a consistent and reliable descriptor
of open plan office acoustics and is now included in sound quality standards for buildings. A
standard for field measurements of DL2 is needed, taking into consideration the physical
specificities of open plan offices (geometric proportions, presence of screens and furniture, etc),
available equipment for acoustic consultants, as well as speech characteristics (increased
energy contents at low frequencies, voice levels, raised hearing sensitivity at high frequencies,
etc).