Extraction of air via fume hoods uses up large amounts of energy, but there are measures in building 30 to minimise this usage. All the fumes hoods in the building are of the variable air volume (VAV) type. These extract air at a constant velocity, but the volume being pumped out through the hood in a given time depends on how far open the sash is. When the sash is lowered, a lower volume of air is be extracted in a given time.
The air is then pumped out through chimneys on the roof. Building 30 was recently fitted with a wind modulated extraction system, that pumps out air at the most efficient rate based on the weather condition and surroundings. In the first year, this wind-modulated system prevented 180 Tonnes of Carbon Dioxide emissions!
Installation of VAV fume hoods and a wind-modulated extraction system is planned for building 29 – the second chemistry building – in the future.