51 Harley Street

Harley Haddow was appointed by a private cosmetic surgery provider to survey the existing basement, which previously housed only a minor treatment room. The review found that the existing M&E systems did not meet the required HTM or HSE standards for ventilation, air change rates or the safe administration of anaesthetic gases. A full feasibility study was undertaken, involving close engagement with clinical leads, users, the Care Quality Commission and the Conservation Officer. This study explored whether a compliant theatre could be achieved within the very restricted footprint and limited headroom of the listed building.

Given the constraints, Harley Haddow developed a series of bespoke engineering solutions to achieve compliance. These included a modular non-HTM air handling approach to minimise plant space, high-pressure ductwork to reduce duct sizes, and the development of a dedicated services corridor to avoid ceiling-mounted distribution. A hybrid ventilation strategy was created to meet HTM and HSE requirements while working within the limits of the existing building, supported by VRF heat pump systems and heat-recovery solutions to reduce energy use. Throughout the process, key derogations from standard HTM maintenance requirements were discussed and agreed with the CQC to ensure full acceptance at commissioning.

Following the successful feasibility stage, Harley Haddow was appointed to deliver the RIBA Stage 3 design and produce the performance specification for the design and build team. This included preparing the employer’s requirements for commissioning, validation and verification to achieve CQC approval. The completed facility meets all clinical standards, has passed all testing, and now operates as a fully approved theatre. The project has become a benchmark for delivering high-quality clinical environments within highly constrained and historic building settings.