Fume Cupboards for Special Applications

The fume cupboards detailed in this catalogue are general purpose. The Conditionaire “Safe-Tee” range can be adapted for special applications provided additional considerations are taken into account to address the special hazards.

Radioactive Materials:
The quantity of radioactive material that can be safely handled in a fume cupboard is limited by the radiotoxicity and the physical state of the nuclide. Fume cupboards for use with radioactive materials shall have smooth and crevice free interiors with radiused corners for ease of cleaning and decontamination. Lead shielding, filtered exhausts, special glass sash and strengthened bases may all be considerations.

Perchloric Acid:
The use of concentrated perchloric acid in the laboratory gives rise to special hazards as almost all metal or organic perchlorates are explosive and some are extremely shock sensitive.

Materials of construction for the fume cupboards, supporting framework, ducting, exhaust fan, adjacent cupboards and flooring are of critical importance. Baffle wash-down systems, scrubbing of exhaust fumes and neutralising of waste are all special requirements.

Hydrofluoric Acid:
Many of the features that apply to perchloric acid fume cupboards also apply to hydrofluoric acid use, except that the hazard arises from skin contamination rather than explosion. Materials of construction, hand-held showers, safety charts and neutralising agents must all be incorporated with hydrofluoric systems.

High Temperature Work:
If a fume cupboard is to be used for high temperature work, selection of materials for construction shall be determined by the time/temperature response to the heat source. Plastic materials may withstand high temperatures for short periods but fail at lower temperatures if subjected to prolonged heating. If necessary, interior surfaces should be protected by shields of heat resisting materials.

Flammable Reagents & Distillation:
These processes may be hazardous to different degrees, depending on the flammability of the liquid and the volumes involved. A risk assessment is required to determine the level of hazard a particular set of circumstances may create. Crevices on sink/sump bases should be avoided to eliminate areas where flammable or explosive fume or liquid can accumulate. Special attention should be given to waste and drainage to prevent
liquid solvents being trapped.

Heavy Vapour Work:
Where heavy vapours are generated such as Tetrabromoethene and Diiodomethane, a specially designed down-draft fume cupboard should be used. The exhaust fumes are usually exhausted downwards through a perforated work base.

Conditionaire “ASAH®” with a high density and superior fire properties is a suitable material for all these applications and our sales engineering department can assist you with your special purpose systems to ensure a safe working environment.

Maintenance of these types of systems also requires some special processes and caution, our service department should be contacted before carrying out maintenance or service on these systems.

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