The Fume Cupboard : If a reaction uses or produces harmful gases, dusts or vapours, it poses a risk of inhalation. Such reactions should be carried out not on an open bench but in a fume cupboard. You would have read briefly about the designing part of fume cupboard in Unit 1 of this coarse. You may know that many laboratory operations need to be carried out in fume cupboard, e.g. working I with nitrating mixtures, benzoyl chloride etc. A demonstration activity will enable you to understand the importance and use of a fume cupboard. A typical laboratory fume cupboard is shown in Figure.

'Figure: A typical laboratory fume cupboard.

A fume cupboard is constructed to allow the normal laboratory services of gas, water and electricity to be utilised. In addition, an air extraction system i.e. an exhaust fan, with a minimum statutory air flow, ensures that dangerous vapours are vented to the atmosphere.

Access to the fume cupboard is via sliding panels of safety glass. It is important to note the maximum height to which these panels can be safely raised before the air flow into the fume cupboard drops below the required rate.