The NRC's aircraft noise reduction facility in Ottawa is composed of a reverberation chamber adjacent to an anechoic chamber operated separately or jointly to evaluate and improve the performance of aircraft noise reduction solutions.
When used jointly, the reverberation chamber and the anechoic chamber form a sound transmission loss capability operated in accordance with the ISO 15186‑1 and ISO 5186‑3 standard procedures using a sound intensity technique.
When used separately, the 2 chambers of the aircraft noise reduction facility operate as a complete technological research and development capability based on modelling tools and measurement methods allowing the accurate evaluation and improvement of the performances of hearing protectors (HP).
The reverberation room is constructed of 30‑cm‑thick reinforced concrete walls. The internal surfaces of the ceiling, walls and floor are coated with epoxy resin paint. The reverberant room has a non‑regular shape with 5 walls, a ceiling and a floor. The cut‑off frequency of the anechoic room is 200Hz. The anechoic room dimensions are 7 m (W) x 3 m (L) x 5 m (H).
Why work with us
Our acoustic facilities are registered to the ISO 9001:2000 quality management system and produce quality test results that continually exceed clients' expectations. Our experienced, professional and dedicated research staff is on hand to support clients' testing requirements from start to finish, from design of experiments to the creation of reports. Testing is tailored to clients' projects, and we customize testing approaches and assist clients in interpreting results.
- Measurement of sound insulation: The sound transmission loss capability has a very large test window opening of 2.56 m by 2.23 m. Quoting from ISO 15186‑1: "The method can be used as an alternative to ISO 10140‑3 and ISO 10140‑10 respectively. One important use is when the traditional ISO 10140‑3 method fails because of high flanking transmission. The reproducibility of the sound intensity method is estimated to be equal to or better than that of ISO 10140‑3." The major advantage with using a sound intensity probe technique is that it allows for a more detailed measurement and analysis of the sound radiated from complex structures. Highly radiating areas on a complex structure are easily detected using sound intensity mapping.
- Hearing protectors performance evaluation: The acoustic test fixture (ATF) manikin G.R.A.S. 45 CB is operated in accordance with Standard ANSI/ASA S12.42 under a wide range of noise levels, continuous and impulsive, for testing active and passive earplugs; active and passive ear muffs; circumaural ear muffs integrated in work and safety helmets or designed for use under helmets.
Areas of expertise
- Hearing protection: ANSI/ASA S12.42 "Methods For The Measurement Of Insertion Loss Of Hearing Protection Devices In Continuous Or Impulsive Noise Using Microphone‑In‑Real‑Ear Or Acoustic Test Fixture Procedures."
- Sound transmission loss:
- ISO 15186‑1:2000 "Acoustics — Measurement of sound insulation in buildings and of building elements using sound intensity — Part 1: Laboratory measurements."
- ISO 15186‑3:2002 "Acoustics — Measurement of sound insulation in buildings and of building elements using sound intensity — Part 3: Laboratory measurements at low frequencies."
- Sound absorption measurements in reverberation rooms:
- ASTM C423 – 17 and ISO 354 for Measurement of sound absorption in a reverberation room.
- Sound power levels measurement:
- ISO 3745:2012 "Acoustics — Determination of sound power levels and sound energy levels of noise sources using sound pressure — Precision methods for anechoic rooms and hemi‑anechoic rooms."
- ISO 3744:2010 "Acoustics — Determination of sound power levels and sound energy levels of noise sources using sound pressure — Engineering methods for an essentially free field over a reflecting plane."
- ISO 7779:2018 "Acoustics — Measurement of airborne noise emitted by information technology and telecommunications equipment."