Global – Four Millbank, Westminster Studios

The chilled water fan coil system at Four Millbank presented a number of challenges for a broadcast environment. Because the water coil operates at a higher temperature than traditional DX systems, the units require a greater volume of air to achieve the same cooling effect. This increases fan size, airflow and the potential for noise, which needed careful management to ensure the studios and control rooms remained quiet in operation.

Space for mechanical equipment was extremely limited, and coordinating chilled water pipework and acoustic ductwork through the structure required precise setting out. To address the higher airflow, custom acoustic plenums were developed to slow and diffuse the air before it reached the discreet shadow gap outlets, removing the need for visible grilles and maintaining clean sightlines throughout the studios.

Airflow calculations helped ensure velocities remained low, avoiding turbulence or drafts within the technical spaces. Each unit was positioned accurately within the restricted mechanical zones, allowing correct operation, access and integration with surrounding services.

The installed system provides stable cooling across all rooms, with airflow controlled to deliver even, draft free distribution. Custom acoustic plenums maintain low noise levels, and chilled water pipework, acoustic ductwork and equipment were integrated within the available space without compromising acoustic performance.

The brief was to deliver broadcast grade acoustic performance across a suite of TV, radio and podcast spaces while avoiding unnecessary over specification. Global arrived with a clear concept based on previous projects. Our task was to test that strategy against the realities of this particular building, refine it where needed and maintain agility within a compressed programme.

An initial noise survey was undertaken pre strip out to benchmark existing conditions. As parts of the structure and services were only confirmed during strip out, elements of the design were refined as site conditions became clear. The building’s varied floor build ups, from early hollowpot assemblies to later precast systems, influenced the isolation strategy and required careful verification of potential flanking paths.

Strip out revealed lower than expected isolation between the demise and the pavement lights and lightwell, and a drainage pipe running above one studio that required careful consideration. Designs around these areas were refined to ensure they did not compromise performance in critical spaces while working within the constraints of the site and available headroom.

Below the studios, the basement houses several items of plant. Their contribution to overall noise could only be meaningfully assessed as surrounding works progressed. Staged assessments allowed plant noise to be quantified accurately and informed the level of mitigation required. Where aspects of performance were influenced by areas outside the demise, solutions were developed in coordination with the landlord and building management.

Because all production in this facility is voice based rather than music based, the acoustic requirements differ from a typical music studio. This made a non fully floating solution technically appropriate, but it also meant every potential noise path required careful assessment. Our strategy focused on how adjacent rooms interact, and how each studio relates to the surrounding building, using higher spec constructions only where they delivered measurable benefit.

Acoustic data was presented in clear, colour coded diagrams, with priority given to studios located against more exposed parts of the building envelope. This supported fast, informed decisions while keeping the approach proportionate to the brief.”

Two areas were identified where a proportionate level of risk was acceptable: footfall noise from the pavement lights and lightwell, and noise transmission from basement plant. These decisions were based on clear technical evidence, with acoustic impact and cost implications set out to guide the level of mitigation required. The studios were designed to meet the requirements for voice based broadcasting, and the technical approach gives the client confidence in how the rooms will operate in use.