Background
VolkerFitzpatrick Ltd commissioned us to provide acoustic design advice for the proposed QinetiQ Battery Test Facility, A7, to be housed within an existing airport hangar at Farnborough Airport. Additionally, we were tasked with conducting acoustic commissioning testing post-construction to ensure the facility met the proposed acoustic performance standards.
What We Did
Acoustic Design Assessment
To develop noise transfer criteria for the new test facility, we visited the existing Fort Halstead battery testing facility, from where most of the equipment would be relocated. We measured noise levels and reverberant conditions in rooms containing high-noise generating equipment.
- Structureborne Noise Transfer
Considering the potential for structureborne noise from equipment with moving parts, we recommended isolating such equipment from the floor using suitable Anti-Vibration Mounts (AVMs) provided by the manufacturers. We advised against directly fixing equipment or associated pipework to partitions.
- In-Situ Sound Insulation
Given the facility’s single ground-bearing floor plate, we set targets for in-situ sound insulation against airborne sound across walls. These targets considered the noise sensitivity of spaces and the activity noise levels in adjacent areas, aiming to minimize disturbance when adjacent spaces were used simultaneously.
- Reverberation Noise
In typical test rooms, we aimed to control excessive reverberant noise by providing suitable reverberation times. As these spaces were not intended for critical listening, the recommended reverberation times were guidelines, ensuring usability even if criteria were not strictly met.
- Plant Noise Assessment
For the fully mechanically ventilated and cooled facility, we conducted a detailed plant noise assessment. We recommended placing all equipment on suitable anti-vibration mounts with inertia bases where necessary (e.g., rooftop AHUs and extract fans) to control noise and vibration transmission. We also assessed airborne noise transfer from the rooftop plant area, ensuring no key noise-generating items were located above noise-sensitive areas like the Customer Presentation Suite and Data Analysis & Prep rooms. Our assessment confirmed that no further mitigation was needed as the targeted building services noise criteria were met.
Commissioning Testing
Post-construction, we conducted commissioning testing to verify the acoustic design targets. Testing included:
- Noise generated by building services
- Reverberation times of rooms
- Airborne noise transfer between test rooms
We performed airborne sound insulation testing of walls separating high-noise areas from noise-sensitive rooms. A desktop noise-transfer assessment determined the resultant noise levels in receiving rooms using previously measured source noise data.
Internal ambient noise level measurements followed the methodology in the “Measurement of Sound Levels In Buildings” document by the Association of Noise Consultants (June 2020).
Result
The testing results indicated that the measured noise transfer, internal ambient noise levels of ventilation building services, and reverberation times were acceptable for the intended use of the spaces.
