For a fume cupboard to perform satisfactorily it must be connected to an appropriate ventilation system which extract fumes efficiently from the fume cupboard and discharges them outside the building in such a manner that they are adequately dispersed and do not re-enter the buildings or otherwise present a potential hazard or nuisance.

The air extracted through a fume cupboard is far greater than the normal extract rate of a room or laboratory and to prevent excessive build up of negative pressure within the laboratory which often reduces the performance of the fume cupboard then  a balanced make up air system should be introduced. This should be designed in such a way that the make-up air introduced into the laboratory should not interfere with the air movement and patterns around the fume cupboard and should still maintain a small negative pressure within the laboratory.

Holliday Fielding Hocking Fume Cupboards Ltd. have a design team with many years experience in designing and specifying fume extraction and make up air systems and would be happy to discuss your requirements.