Background
We were commissioned by VolkerFitzpatrick Ltd in June 2019 to provide acoustic design advice for Gulfstream Aerospace Ltd’s new MRO (maintenance, repair and overhaul) facilities at Farnborough Airport, with a view to achieving the relevant acoustic-related BREEAM New Construction 2018 credits targeted by the design team.
A new 3-storey office facility was proposed for Gulfstream as part of the Farnborough Airport operational premises; comprising general office areas, mechanical equipment rooms, loading bays and hangar bays for aircraft maintenance and storage.
What We Did
BREEAM Acoustic Design Assessment
- Baseline Noise Survey
An unattended noise survey was undertaken at the site to determine the external noise levels incident on the proposed building. Attended measurements were also taken to estimate typical ambient noise levels due to aircraft landings and take-offs on the airport’s runway and at two of the nearest residential receptors to capture typical daytime background levels to be used for the plant noise assessment (Pol 05).
- HEA 05 Assessment
Our assessment was undertaken in order to provide evidence of compliance, at design stage, of the development proposals with regard to BREEAM’s Hea 05 acoustic requirements.
Key areas addressed as illustrated in Figure 1.1 include:
- External envelope design and ventilation strategy to control external environmental noise ingress
- Control of internal airborne sound insulation for walls and floors separating offices and other noise producing spaces
- Control of impact (footsteps) sound via separating floors to offices and other noise sensitive spaces
- Reverberation control within open plan offices, reception, circulation areas
- Control of building services noise to offices and other sensitive spaces
The proposed development was seeking BREEAM “Very Good” rating, therefore three (3) credits for Hea 05 (Acoustic performance) were considered in our assessment (for fully fitted Industrial, Retail, Prisons and Other building types).
The first Hea 05 credit is awarded for achieving sound insulation performance in all relevant spaces in accordance with Section 7 of British Standard 8233:2014 [2].
The second credit pertains to the indoor ambient noise levels throughout the development. In order to achieve the Hea 05 credit, BREEAM states that indoor ambient noise levels must comply with the design ranges set out in section 7 of BS 8233: 2014.
The third credit under is awarded for achieving reverberation times compliant with Section 7 of BS 8233: 2014 in areas used for speech.
Result
- HEA05 Assessment
A programme of sound insulation testing, reverberation time and internal ambient noise level measurements was undertaken in December 2020 in all relevant spaces of the Gulfstream’s new MRO facilities at Farnborough Airport. The purpose of the testing was to determine whether the finished building complied with the design targets and achieved the relevant BREEAM Hea 05 credits.
The results of our testing indicated that all 3 credits available (sound insulation, internal ambient noise levels and reverberation time) should be awarded, given all the measured metrics complied with the target criteria.
- Pol 05
We also undertook commissioning testing to provide evidence, following completion, that the development complied with BREEAM’s Pol 05 acoustic requirements (1 credit available under this subject).
The purpose of BREEAM Pol 05 Reduction of noise pollution assessment is to reduce the likelihood of noise from the new development affecting nearby noise-sensitive receptors.
Attended short-term measurements were undertaken with all fixed plant installations associated with the Gulfstream MRO building operating. We concluded that the installed plant had a negligible impact on the existing ambient noise levels at all the noise-sensitive receptors assessed and is compliant with the Pol 05 criteria and as such, recommended that the credit available for this issue should be awarded.
