Sanjay Labroo executive cabin, Global Business Park

Mr Sanjay Labroo, Managing Director of Asahi India Glass Ltd., needed his executive cabin at Global Business Park to stop leaking sound. The target was an internal ambient of 38–42 dB(A), comparable to NC-25 to NC-30 Room Criteria benchmarks. The constraints were as firm as the number: a three-week execution window, night-shift-only site access, and direct competitive benchmarking against India's largest engineering and infrastructure consultancies, including L&T and Bosch.

The enclosure had failed comprehensively rather than at a single point. Uncontrolled airborne leakage ran through the door seals. The air-handling ductwork was shared with adjoining spaces and carried speech between them. The glazing system was under-specified and offered negligible STC performance. Any one of those sets a ceiling on what the cabin can achieve, and the ceiling here sat well above the target.

The turnkey solution was a complete envelope reconstruction rather than a patch.

• Full-height wall systems rebuilt as mass-loaded, decoupled partition assemblies.
• A bespoke Jumbo-format switchable acoustic glass wall in place of the original fenestration, giving privacy-glass function and high STC-rated sound isolation in one element.
• Comprehensive treatment of the shared air-handling ducts — historically the weakest flanking link in any executive-cabin isolation strategy.
• Door assemblies rebuilt and sealed, the other habitual point of failure.

Every surface was afterwards restored to its original decor, finish and colour specification, so that the retrofit reads as no change at all. The whole of the work was executed within nocturnal working hours to keep daytime corporate operations running — which is a sequencing problem as much as an acoustic one, since each night's work had to be left safe and presentable by morning. This is standard acoustic construction practice pushed into an unusually short programme.

An aggressive dB(A) target met in three weeks of night shifts, with the design integrity of the cabin and the working day of the building both left intact.

Executive cabins are a particular acoustic problem, because the value of the room is the confidentiality of what is said inside it, and confidentiality is decided by the leakiest detail rather than the best one. Mass in the walls is the straightforward part. The doors, the glazed wall and the duct crossing two rooms are where the cabin is won or lost, and all three had to be resolved together for the number to hold.