Background
Anderson Acoustics was appointed by Make One Group to provide acoustic consultancy services for the redevelopment of 20 Whitfield Street, a multi‑storey CAT A office building in central London. The scope addressed office acoustics, including internal ambient noise, sound insulation and building services noise, to support compliance with BS 8233, BCO guidance and BREEAM Hea 05 and Pol 05 criteria.
The Challenge
The site is located between Tottenham Court Road and Whitfield Street, where external noise levels are influenced by road traffic and surrounding commercial activity. Internally, the building needed to accommodate open plan and cellular office layouts while achieving appropriate internal noise levels once façade sound insulation and mechanical services noise were considered together. Rooftop plant also needed to comply with planning noise limits at nearby residential receptors.
Our Approach
Attended baseline noise surveys were undertaken on both site elevations to establish representative external noise conditions. These data were used to assess internal ambient noise levels and sound insulation requirements in line with BS 8233 design criteria. In parallel, we reviewed the proposed façade construction, glazing, internal partitions and mechanical services strategy, setting defined acoustic performance targets appropriate for a speculative commercial fit‑out.
The Solution
The proposed façade’s glazing and external wall build‑ups were assessed to control external noise ingress and achieve internal ambient noise targets of 35-45 dB LAeq,T, depending on space use. Sound insulation targets were defined for walls and floors separating acoustically sensitive areas, consistent with BREEAM Hea 05 guidance for commercial offices.
For building services, NR design criteria were established for office spaces and applied to the MVHR and rooftop plant. On‑site MVHR testing confirmed that operation at design duty achieved NR35-38 within open plan office areas. Mitigation was recommended to rooftop plant such that plant noise limits were adhered to at nearby residential façades.
The Outcome
The agreed acoustic strategy demonstrated compliance with BS 8233 internal ambient noise criteria and supported the achievement of BREEAM Hea 05 and Pol 05 acoustic performance credits. Verification testing confirmed that building services noise remained within the adopted NR limits, providing suitable workplace acoustic conditions for future tenants. With the identified mitigation in place, predicted external plant noise levels complied with Planning Condition 7 and BREEAM Pol 05 at all assessed receptors.
Conclusion
This project required coordinated consideration of façade sound insulation, building services noise and internal acoustic performance within a constrained urban environment. Through measured assessment, clearly defined criteria and targeted mitigation, the development achieved suitable acoustics for a CAT A office building.
Project Progress
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