School of Chemistry

Search site

Overnight Experiments, Out of Hours Working and Working Alone

Anyone working outside of normal working hours (6pm-8am during the week, at any time over the weekend or during University holidays) must sign the ‘out of hours book’, which is kept at the front (Woodhouse Lane) entrance to the building. This record is required by the fire service. University Security are authorised to evict persons whose names are not entered in the book. This also applies to people already in the building. Thus if late working is anticipated beyond 6 pm the late working book must be signed. The electronic access system to the School outside of working hours is able to log the identity of all persons entering and leaving the School, and periodic checks of these records against the late working book are made and persistent offenders will be reported to the Head of School. The 'out of hours' book should always be used, even if only popping into the School for a brief period, for example, to top up Dewars.

The rules for out of hours working depend upon the risk associated with the activity.  Note that if a reaction is to be left running out of hours then an unattended reaction form that has been signed must be placed in front of the reaction.

Low risk activities are classed as:  Computer and other office based work; The use of low risk analytical equipment such as NMR machines, HPLC equipment etc. 

Low Risk Out of Hours Work

Hazard

(1,2,3)

Likelihood (1,2,3)

Risk (H,M,L)

Actions to minimise risk and notes

Operation or Hazard

Slips, Tips and Falls.  Simple slips trips and falls around the department could be more serious out of hours as the casualty could remain undiscovered for several hours. 

2

3

LOW

If possible inform a colleague, friend or family member that you are working out of hours and inform them when you leave the building.

In the event of fire out of hours a lone worker could become trapped without the knowledge of the emergency services

1

3

Medium

All workers must sign in and out of the out of hours working book situated at the main entrance to the building.

 

Medium Risk Activities are classified as:

General laboratory work including the manipulation of simple reactions and performing post reaction manipulations and purifications.  These procedures are permitted providing you have a LAB BUDDY. If you wish to perform medium risk activities then another person – your lab buddy- must be in the building, ideally in a near by lab, to check on your well being.  Lab buddies must contact each other ever 30 minutes to check that all is well.

Medium Risk Out of Hours Work

Hazard

(1,2,3)

Likelihood (1,2,3)

Risk (H,M,L)

Actions to minimise risk and notes

Operation or Hazard

The risks associated with low risk activities also apply. 

 

 

 

 

Problem during reaction leading to incident – chemical spillage, fire, chemical burn or irritation

1

3

Medium

All workers must have a laboratory 'Buddy' who checks that all is well every 30 minutes.

High Risk Activities are classified as:

Some work with class 3 lasers and above (e.g. high risk activities such as cavity alignment, work on power supply - see laser safety officer for guidance), work with cyanide, pyrophoric reagents, flammable gases and reactions with any risk of explosion.  These activities are not permitted out of normal working hours.  In some cases it may be possible to leave reactions containing these types of reagent etc running out of hours as long as there is no risk of exposure to others. 

Reaction Assessment

The suitability of a reaction to be conducted out of hours should be indicated on the individual reaction assessment (See later). Specifically by ticking the box marked 'All' the assessment shows that a reaction could be set up, worked up and generally manipulated at any time (subject to the above rules).  The box 'WU' indicates that a reaction can be allowed to proceed outside normal hours and be 'worked up' but should not be set up 'out of normal hours' times.  The box 'RUN' indicates that the reaction can be allowed to proceed outside normal hours (e.g. stirred or heated) but should not be interacted with by the researcher outside normal hours- a reduction with LiAlH4 would fall in this class as both the set up, handling the pyrophoric reagent and the work up which generates hydrogen are both too hazardous to perform outside normal hours. 'No' Indicates the reaction is not suitable for out of hours work, these types of reaction may pose a specific hazard by for example venting a toxic gas or requiring very close temperature control. 

Overnight Experiments

Minimise overnight running of experiments. If any experiment or equipment is left on overnight it is your responsibility to make sure that it is safe and ‘fail-safe’ (ie. that it will still be safe if the thermostat, electricity or water supply fails). Plastic tubing must be ‘tied’ on and water flow reduced to a steady minimum and sinks checked for blockages to reduce the risk of flooding. Heated systems need thermal cut-offs (for example a contact thermometer in an oil bath). An "Unattended Reaction" form must be displayed near the reaction which must include details of chemical hazards, your name and emergency contact details and a shut-down procedure. An example is shown on the following page. Solvent drying stills are especially hazardous and a common source of serious fires and therefore should not be left on overnight. In general they must be comprehensively protected with cut-off devices and not left running longer than is absolutely necessary.