Safety Services


Overnight, long term experiments and continuous running of equipment

Not all experiments will fit into core hours and may run overnight, over a weekend or even longer. The same is true for certain equipment or instruments that need to be kept on for long periods.

Long running experiments

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If your experiment is running for a long period you must ensure that your risk assessment covers the following additional hazards:

Loss of utility supply

  • Does the experiment require power, running water, temperature control?
  • If so, what happens if there is a power cut?
  • Do you have alarms, automatic shut off devices?
  • What will happen if the power switches off the moment you leave the experiment alone?

Loss of reactants

  • If a boiler runs out of water, an explosion may happen. Is it possible for your experiment to run out of one or more reactant?
  • If the proportions change will that change the reaction?
  • If a gas cylinder empties, what would be the impact?

Accidental or unknowing tampering

  • Could someone disturb the experiment, is it in a shared fume cupboard or other shared space?
  • Will they know who to contact to ensure that your work is not lost?

What happens in an emergency

  • If there is a fire or flood in the building, how will this affect the experiment? 

Who else might be affected

Emergency services

  • What information may personnel need to know e.g. do not wear breathing apparatus if entering a working NMR room?


  • The expectation is that cleaners will not move equipment and researchers will work where possible to a clean work area.

New users of the space

  • You have included the current laboratory users in your distribution list of the original risk assessment, but how do you inform new people to the shared space of the risks?

Maintenance contractors

  • Although contractors should have been cleared to enter an experimental area, mistakes are made.
  • Do they know the hazards in your work area?
  • Do they understand if their planned work may cause a risk to themselves or other people?


  • Safety Services and external regulators have a duty to carry out inspections without prior approval.
  • Would they have the information needed to make a suitable and sufficient risk assessment before entering the space?

What you need to do

Complete a specific risk assessment 

  • Unattended experiments or equipment are a separate situation to the experiment alone and this should be assessed in addition to the risk associated with the experiment. Control measures described must be specific to the circumstances.

Ensure capacity for all substances produced, including waste, to be captured or removed 

  • Although the containers may have to be replaced, they should be sufficient in size for at least 110% of the amount produced in the longest period the experiment is left alone.

Ensure all extraction systems fail to safe 

  • If gases need to be removed to stop a dangerous atmosphere from being produced, the system should contain the gases even if the forced ventilation fails. This is true for any mechanical control measure.

Check the emergency alarms

  • If you rely on gas monitors, temperature alerts or another form of monitoring as a control measure, it is your responsibility to check they are working and will be working for the entire period the experiment will be running, even if they are part of general lab equipment
  • If there is a problem do not begin the experiment, report the fault to your local safety officer or lab manager

Ensure there is clear communication with all interested parties on the following details

  • What the experiment is (including labelling all samples, reagents and reaction vessels).
  • Who is responsible of the experiment (including contact details for non-UCL personnel, not just the extension number).
  • The start date and end date (including time if relevant).
  • Emergency contacts including Security (extension 222).
  • Information for what must be done and what must not be done.
  • Where to find the relevant risk assessment(s) and safe systems of work.

Get written acknowledgement that the work has been authorised

  • For students, this is signed permission from the appropriate supervisor.
  • For other researchers, it could be the Lab Manager or Head of Department.
  • How to do this will be detailed in your departments’ Arrangements for Safety document.

File documents on riskNET

  • The full information (including the authorisation trail) must be available in an emergency.
  • Keeping documents only in personal email, lab books or on the desktop of a personal computer limits the access to this information.
  • Hard copies must be kept outside labs and other arrangements may be set up by departments if riskNET is not suitable. 

Do not assume permission is granted

  • If the experiment runs over the expected time or an identical one needs repeating, the environment may have changed. For example, maintenance may be planned or a non-compatible experiment may be running in the same area.
  • Do not change the location after permission has been granted. One location is not the same as another. 

Do not by-pass any systems

  • UCL requires the ability to make safe any area without warning. Experiments and equipment that by-pass these systems will put people at risk. If using these emergency systems will create a greater risk. This must be discussed and approved with your department head and communicated to UCL Estates before work begins.

Do not become complacent of the risk

  • Everyday exposure to a hazard, without any near misses or injuries, can cause individuals to become complacent about the risk leading to bad practice such as PPE not being worn, eating or drinking in the work area or failure to label samples or other items.
  • It is often found that a serious accident was not caused by one mistake, but a pathway of small errors that when put together resulted in the system failing to danger rather than to safe.

Last updated: Tuesday, July 21, 2020