It is important that lab work is carefully prepared, with regard to both safety and the end result. A continuously updated lab logbook is an invaluable and indispensable tool in this respect.
An evaluation of the risk and safety precautions is an important part of the preparation for your work. For example, it can be necessary seek information on the properties of a substance: State, reaction with water, combustibility (kindling temperature, explosion limit), caustic and corrosive properties, odour, toxic properties and especially long-term effects, penetration of rubber and plastic (gloves) its possible hygienic threshold.
For many known chemical reactions and products, much of this information is unavailable. Only typical physical and chemical properties are registered. However, various types of literature have articles describing substances that are hazardous to health and the environment.
When preparing for lab work (whether experimental or routine) each person must consider the risk involved.
All work with substances and reactions that give rise to hazardous or malodorous gases or vapours must be carried out in a fume hood. As a general rule, the fume hood should be used for all forms of chemical work whenever possible.
The degree of safety provided by the fume hood depends partly on its technical and construction conditions and partly on personal and actual conditions, namely:
The temperature inside the fume hood.
The Danish Working Environment Authority (”Arbejdstilsynet”) demands that fume cupboards be fitted alarms that are activated when the airflow is inadequate.
Each fume cupboard has its own alarm, which sounds and shows a red light when the airflow falls below a certain level.
When a fume cupboard is closed there is still a slight suction. When the window is opened, the airflow is increased, but when the height of ca. 40 cm is reached, the alarm is activated. Even before this height is reached, air movement around the opening can reduce the effectiveness of the air flow, especially if more than one fume cupboard in a laboratory is open at the same time, as there is a limit to the total capacity for suction.