Procedure for Chemical Reactions Left Unattended
Not all chemical reactions reach completion within regular working hours. It is sometimes necessary to leave reactions overnight or longer due to the nature of the reaction.
If you need to leave a reaction unattended for longer than 3 hours you must complete and display an Unattended Chemical Reaction form. These can be found here. An example of a completed form can be found here.
If you are unsure how to complete the form after consulting your COSHH assessment please contact the Chemical Safety Technician.
Before leaving the reaction, check that:
- Reaction vessel is secure
- Any heating apparatus is at a stable temperature or that heating equipment is functioning correctly for reactions where there is planned temperature variation
- All electrical leads are away from heating elements
- Any cooling systems will be able to function for the period the reaction is left
- Any water lines are secure
- Any gas cylinders are off, or that a pressure release system (safety valve) is in place
- Fumehood sashes are fully closed
- Stock bottles and any chemicals are put away
- All equipment is in a safe state
Information in an emergency
Make sure there is a printed copy of the overnight reaction form easily available in the lab as well as outside of the lab at the nearest suitable space. This can be on or near the door into the lab, or another clearly labelled location close to the lab entrance.