Partial reverberation room (PRR)
Research activities undertaken by LCPC's ESAR Division in the field of road acoustics have been extended over the past few years to include "urban" settings. Controlling noise levels in the environment has become a major issue for city planners and engineers. While this field of investigation remains focused primarily on outdoor acoustic propagation (see page on LCPC's Long-Term Monitoring Site), the study of noise propagation and diffusion in urban settings, along streets and thoroughfares makes use of highly-specialized models. The development of such modelling tools definitely requires experimentation either on actual sites or in the laboratory on mock-ups. In situ testing introduces considerable constraints: temporary closing of urban arterials, dissemination of information to road users and neighbouring residents, deployment of police/security services, etc. After conducting several experiments under such conditions, the ESAR Division began looking to laboratory testing, performed in a partial reverberation room.
Presentation of this facility
The partial reverberation room (PRR) measures nearly 8 m wide, 12 m long and 5 m high, which makes for a total volume of 240 m3 available for tests (due to the thickness of the insulation material). The cut-off frequency, as determined according to the ISO 3745 Standard, is 100 Hz, with a background noise level of less than 17.5 dBA (air conditioning running at maximum). The PRR is complemented by a multi-channel, high-frequency acoustic recording instrument (Plateforme Pulse by Brüel & Kjaer, set up in a control room), associated with an automated system for moving the measurement microphone. Another room with a volume of over 250 m3, adjoins the PRR and serves to assemble and prepare the experimental set-ups.
The partial reverberation room (PRR) measures nearly
8 m wide, 12 m long and 5 m high
Research conducted using the PRR
For the most part, the research undertaken using this facility lies within two of LCPC's priority orientations:
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Mitigating impacts caused by infrastructure on the environment throughout the infrastructure life cycle - Enhancing structural and site safety by means of improved risk knowledge;
- Optimizing the quality of civil engineering structures within urban settings by focusing on characteristics.
More specifically, the PRR is currently used to carry out some of the experiments scheduled as part of the laboratory's Research Project 11M061: "Predicting noise in an urban environment", with emphasis on two of this project's main topics:
- Development of a "sound particle transport/diffusion model" to describe noise propagation on a dense urban site: Model validation using measurements on acoustic mock-ups.
- Study of sound reflection off of building facades (to improve existing noise prediction software programs): measurements recorded on building facades and streets.
Acoustic absorption measurements of a wall facing the front
In conjunction with these efforts, the room is also used as an accessory to other ESAR Division activities (acoustic absorption measurements of pavement surfacing, characterization of noise barriers, etc.).
This room and the accompanying set of equipment are also available upon request for industrial applications. |
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