The building’s original air conditioning design specified four downflow units per floor: two supplying the rear zone of the building and two for the front zone. Each zone was split into two further zones: one supplying cool air towards the perimeter of the building to combat solar gain, and the other providing warmer air to the central areas of the office space, where there is less heat generated by the sun.

With One Benjamin, the contractor decided to implement an underfloor air conditioning solution by AET Flexible Space, where its highly flexible system would be well suited to cope with the variations in temperature across the building caused by increased or decreased sunlight. An underfloor air conditioning system uses the few inches of space beneath a raised access floor to create the air ventilation path, eliminating the need for ducting and pipework. In new build construction, it can free up additional lettable space or reduce overall building height. Notably for this project, it allows for more room overhead: an average usable space saving of 15 percent.

One Benjamin selected AET’s most flexible system, the CAM-V, which makes use of the raised floor void as a plenum for the distribution of supply air, while receiving return air back to the CAM unit near the ceiling level. The contractors were able to eliminate much of the ceiling-based services and ductwork, and the project was awarded an “Excellent” rating through the Building Research Establishment Environmental Assessment Method.