Ultraviolet disinfection facilities should not be used unless specifically required for experimental work.
While the rays are undoubtedly bactericidal on unprotected moist microbes, they are ineffective on dry organisms and in the presence of dirt, e.g. would be useless for inactivating tubercle bacilli in dried sputum on the cabinet floor.
It is essential that little or no objects are stored inside the Safety Cabinet because the germicidal effect of the lamp in shadowed areas is lost.
Furthermore the lamp has to be kept clean and its bacterial ultraviolet output should be frequently tested due of the loss of the germicidal power over the time period used, although the visible rays remains unchanged. The typical expected life of a germicidal lamp is about 3000 hours.

recommend that if the ultraviolet light is regularly used, then the lamp should be replaced at six monthly intervals or if used occasionally used replaced once every twelve months, as part of the service visit.

Warning ! The lamp should not be switched on whilst the laboratory is occupied by people working, the light emitted by the lamp is harmful to the eyes and continual exposure can lead to permanent eye damage.