The building takes the form of a square engine house, with extensions north and south rising five double-height storeys containing offices.

Above the engine house is the air shaft, a square column rising to the height of the neighbouring Port of Liverpool building.

Above the door is the figure of 'Speed, the Modern Mercury', carved in high relief and standing approximately 23 feet from base to top.

[4] Along the top of the engine house runs the decorative frieze, comprising a repeated geometric pattern flanked at each end by a winged horse.

[5] On the central tower is a large relief design, repeated each face, comprising a panel depicting Ventilation flanked by two columns capped with a Liver Bird.