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Basic Department Safety Rules

A printable version of this page is here.

This is a summary of the general safety rules of the Laboratory. More detailed information and guidance is available for several of the topic areas. These are linked where appropriate.

1. Department Rules
  • Joining the department
  • Normal hours
  • Out-of-hours
  • Unattended operation of equipment

2. Short-Term Visitors to the Department
  • Persons of restricted mobility
  • Children
  • Conferences and public meetings
  • Individual visitors
  • Equipment service personnel

3. Building Maintenance and Alterations

4. Security Arrangements
  • Access to buildings
  • Identity badges
  • Avoidance of theft from the Department
5. Management of Hazards and Risks 

6. Specific Items of Importance
  • Ionising radiation
  • Chemical hazards and substances hazardous to health
  • Disposal of chemical waste
  • Biological projects
  • Electrical hazards
  • Lasers
  • Cryogens
  • Compressed gases and high pressure systems
  • Vacuum systems
  • Lifting and manual handling
  • Display screen equipment
  • Personal protective equipment
  • Ladders

1. The Department Rules

Joining the Department

All new entrants to the laboratory (other than Undergraduates and first year Postgraduates), who are expected to stay for more than one month, are required to attend an Induction course in the Department. These are organised by the Department Safety Officer, and take place each month. Click here for the course schedules.The Department reserves the right to withdraw access card privileges from those who fail to undertake Induction training within three months of arrival, pending completion of the course.

New Postgraduates should attend the two-day course schedule laid on by Health and Safety Division. If there is some reason why this is not possible (e.g. arriving at another time of year) they are integrated into the normal staff induction progress.

Training is an essential part of maintaining a healthy and safe environment. It is required at all levels of the organisation. For instance Senior management and Supervisory staff need to know:

  • The legal framework that governs what we can and cannot do;
  • Their responsibilities;
  • How to do risk assessment and how to judge the quality of the risk assessments in their area;
  • The importance of pro-active management of safety.

The Department provides courses, tailored to the needs of the staff, visitors and students, on subjects relevant to the Department. Attendance is recorded.

Access in Normal Hours

Normal working hours are from 0830 to 1700, Monday to Friday. During these hours there is someone on duty at reception and there are first aiders on the premises. This enables a rapid response in the event that something goes wrong.

Access Out of Hours

For people wishing to work outside normal working hours, the following are requirements:

  • Signing-in using the Department system is compulsory
  •  A person may work alone in an office, on paperwork, without special permission of any kind.
  • All those working out of hours are expected to have a good working knowledge of the emergency procedures, since they may be the first to discover something that requires action.
  • The risk assessment for any work other than office work must have taken account of the increased risk of working out of hours. ONLY those with the requisite skills may work out-of-hours. ONLY those who have secured the agreement of their Research Group may work out of hours.
  • No-one may work alone in a laboratory area - there must always be someone within calling distance who would know what to do in the event of an emergency.
  • Work on high risk experiments, such as work with hydrofluoric acid is FORBIDDEN

Please note that the heating is switched off outside working hours. Only heaters issued by the Department may be used.

Unattended Operation of Equipment

Much equipment in the laboratory runs continuously, and there is always the possibility of something going wrong with it while the owner is away. Each laboratory that contains equipment or items that could pose a serious risk to a person going in to investigate, must have a notice fixed to the door outlining the risks, and what should be done if a fault develops. Typical information would include the presence of:

  • Gas bottles in the room
  • High magnetic fields
  • Alarms in the room, and what should be done about them (especially if there is a reasonably foreseeable risk of asphyxiation); and
  • The location of the main electricity switch in the room
  • The location of any other services that may need to be shut down (e.g. gas lines, water)
  • A contact name and telephone number of someone with detailed understanding of the equipment in the room, who can be called in an emergency.

A template for the door labels is available here.

If your equipment is running outside of normal hours, fix a label to the apparatus with emergency out of hours contact names and phone numbers, so that security personnel and others can contact you if the system visibly fails.


2. Short-term Visitors to the Department

Persons of Restricted Mobility

Any visitor who has restricted mobility, to the extent of not being able to use the stairs, must have a personal evacuation plan before going above the ground floor, since the lifts must not be used if the fire alarm is sounded. In the simplest cases this may be evacuation to an adjacent building across the bridge and down in the lift in the unaffected building. The Department also has a number of 'Evac Chairs' and a list of those trained to operate them is kept in Reception. The information document is here.


The buildings were not designed with children in mind, and therefore even the stairs and landings are dangerous. Obviously laboratory areas are even more dangerous. For this reason, children are allowed into only a few areas of the Department. Please see the formal policy here.

Conferences and Public Meetings

Those organising conferences, public meetings and larger scale visits should do a risk assessment relating to the safety and welfare of their guests. This risk assessment will determine the arrangements to be made and the information that the guests should be given about access, first aid, safety, fire and other arrangements related to their welfare. It will also define the means for delivery of the information. Further advice is available in the Department Code of Practice for Ensuring the Safety of Visitors. See 'visitors and events'.

Individual Visitors

All temporary visitors to the department arriving in smaller numbers must sign for a visitors badge from reception, where they will be given a leaflet giving key safety information (a copy of which can be seen in the Department Code of Practice for Fire). Visitors should be accompanied at all times when on site, or given enough information to ensure their safety. Staff receiving visitors are responsible for those visitors while they are on site. Visitor's badges must be returned to reception when the visitor leaves the department.

Equipment Service Personnel/Contractors

Visiting service personnel must report to reception for issue with a visitor's badge, and be accompanied by a staff member to the equipment. Wherever possible, appointments should be made, but in any case the person who has responsibility for the equipment must ensure that it is safe to work on.

Whenever work is required on the buildings or plant by outside personnel, arrangements must be made with the Lab Superintendent (or in his absence, his deputy). We need to liaise with them in order to ensure that they do not pose a risk to us, and vice versa. If the area is particularly hazardous, or their work poses a serious risk to the Department (e.g. fire) the Laboratory Superintendent or Head of Maintenance may require the person(s) entering the area to comply with a Permit to Work system. Contractors who come to the laboratory for extended projects are given an induction course, with a booklet.


3. Building Maintenance and Alterations

Estate Management (EM) is responsible for the care and maintenance of all University sites, buildings and grounds. However, in the Physics Department rather more self-help for maintenance is provided by the Departmental staff than is normal in other Departments. Building services, such as heating, ventilating and compressed air plant are regularly serviced by the Departmental maintenance team.

All requests for building and maintenance work must be routed via the Laboratory Superintendent or the Head of Maintenance who will act as liaison with EM where necessary. In general, Departmental staff should not contact EM directly except in cases of emergency.

The Laboratory Superintendent (or in his absence, his deputy, or the Safety Officer) must be notified of any defects which might cause a hazard together.

All modifications to the building require authorisation. Note that, due to the presence of asbestos throughout much of the site, even simple operations such as drilling holes in walls will require explicit authorisation.


4. Security Arrangements

Access to Buildings

For reasons of safety and security outside doors to the buildings are locked at night and at weekends (normal open hours are 0730 to 1800 hours, weekdays). The University Security Service patrols outside normal working hours.

Staff members, research associates and research students are issued with programmed cards to external doors on application to the Secretary of the Department. Those with cards must not allow others in when entering building unless that person can be positively identified and is known to have permission to enter the building out of hours. Abuse may result in the withdrawal of cards.

Entry to the Mullard Radio Astronomy Observatory, Barton Road (Lord's Bridge) is only by prior arrangement via the Astrophysics research Group. Casual visits are NOT permitted.

Entry to the Battcock Centre and Physics of Medicine is always via access card.

Identity Badges

All staff and research students are issued with identity badges bearing their name and photograph, which double as their access card. If you see any person on site without a badge, and about whom you have suspicions, ask politely 'How can I help you?' The response will generally enable you to decide whether they are a legitimate visitor or not. Do not put yourself in danger, but if you are suspicious about the credentials of anyone, call 37499 to alert the Emergency Team, and attempt to keep the person under observation. Out of normal working hours, the University Security Service will remove from the site any person who is unable to prove their identity. Security can be contacted by calling 37499.

Avoidance of Theft from the Department

It is the responsibility of all working in the Department to reduce to a minimum the likelihood of theft, and reduce to a practical minimum the loss should a break-in occur. There have been numerous break-ins within the University, several accompanied by acts of considerable violence against university staff. By making the department less attractive to criminals or by making their 'job' more difficult, the risk to department and person can be minimised. This can be done by:

  • Ensuring that all doors and windows are locked securely whenever rooms are unoccupied, and especially out of normal working hours.
  • Marking all expensive items such as computers, printers, etc. in an indelible way to reduce their saleable value.
  • Keeping valuables out of sight and locked away whenever possible. Don't hang coats and jackets, place handbags near doors where wallets, etc. can be easily seen. Personal property is NOT covered by University insurance, and there have sadly been cases of people losing very large sums of money in this way.
  • Reporting sightings of any stranger/furtive behaviour/suspicious activities to the Lab Superintendent or Deputy Lab Superintendent via reception (37499) during normal working hours, or to the university security control out of hours (37499), immediately.

5. Management of Hazards and Risks

Click here for a simple guide to risk assessment.

All work activity that carries anything more than a trivial risk must be assessed.The primary purpose of risk assessment is the establishment of a safe system of work. The law requires that it must be done before work begins, but it must be reviewed if it turns out that the initial predictions were not valid.

Any Statutory requirements must be met first. Once these are satisfied it should be assessed to identify the hazards that it presents, the harm that might result, who could be affected and the risk or likelihood that it might happen. Risk that is significant (either in terms of the severity of the outcome, or the frequency with which it occurs, or both) must then be controlled, preferably by elimination of the risk altogether or by engineering control measures.

Risk assessment is an essential part of the design, construction and assembly of any research rig or apparatus, or the introduction of any laboratory or workshop equipment. Risk assessment is of particular importance where equipment is designed and built in-house, where commercial equipment is modified, or where commercial equipment is used for a purpose not envisaged by the manufacturer. It is unwise to leave the risk assessment until after the apparatus is built, as it is likely that many of the hazards can be removed more easily and cheaply at the earlier stages. Risk assessment shall be applied retrospectively to existing plant, machinery, workshops and research environments, and routine activities within them.

Risk assessment is also a Statutory requirement in setting up work experience arrangements, and must be undertaken for school visits to the laboratory, public open days, conferences, etc.

Risk assessment for postgraduate research work should be initiated by the postgraduate student, and developed under the guidance of his/her supervisor or person delegated to undertake that task. Post-doctoral staff, Lecturers and others should carry out their own risk assessments. Advice on the legal constraints may be gained from the Safety Officer or the appropriate specialist.

Risk assessment for support services (e.g. workshops) should be carried out by their manager.

The results of the risk assessment must be recorded in writing. It is recommended that this is done either in a laboratory notebook, or on the Department form. Other formats are acceptable provided that the key points addressed by the headings in the risk assessment form are all covered, the activity to which it relates can be easily identified, and the assessment is dated. The results of the risk assessment must be shared with those that are affected - in particular, those expected to follow the system of work that has been devised.

Risk assessment should be reviewed at regular intervals (not usually exceeding one year) and when circumstances change or evidence comes to light suggesting that the assessment was inaccurate.


6. Specific Items of Importance

Ionising Radiation

There is a Department Code of Practice here.

Radioactive sources and X-ray machines must be registered with the departmental Radiation Protection Supervisors (RPS), Bart Hommels and Saba Alai, who will check the risk assessment and the local rules for the use of the equipment/sources.

Bringing a radioactive source on site without ensuring that the legal requirements have been met can result in expensive and unwanted action from the authorities, up to and including appearance in Crown Court. Please help the RPS avoid this eventuality by keeping them well informed.

The RPS is available for advice, and must be consulted before purchasing, using or disposing of any radioactive material or x-ray generating equipment.

Chemical Hazards and Substances Hazardous to Health

The use of chemicals and chemical preparations needs to be addressed explicitly in the risk assessment for the work. Chemicals should be stored and used only in areas that are suitable, e.g. flammable liquids must be stored in the designated cabinets.

Advice on chemical matters may be obtained from the specialist adviser Suresh Mistry and further information can be found in the Department Code of Practice, here. There is a risk assessment form specifically for projects with a significant chemical hazard linked from that page.

Certain hazardous substances, notably nanoparticles, or those which are known to be sensitizers, carcinogens, mutagens or  toxic to reproduction, are subject to strict requirements for control of exposure. To further protect users, they must also fill in a 'COSHH Health Record Form' annually in October. 

Maintenance of the hardware for the fume cupboards, i.e. fans and filters, is undertaken by the Cavendish Maintenance team. The performance checks, such as measurements of face velocity, are undertaken by the Chemical Safety Officer. Faults in fume cupboards should be reported immediately to Maintenance, the Chemical Safety Officer or the Safety Officer.

Disposal of Chemical Waste

Chemical waste should not be poured down the sink unless it is with the explicit approval of the Chemical Safety Officer. Solid hazardous waste must not be placed in the normal skip.

There is a facility within the department for the storage of waste chemicals awaiting disposal. This facility is managed by the Department Chemical Officer, who should be contacted before anything other than routine waste is deposited in the store. The key is available from stores, who keep a stock of the forms that must be filled out to accompany the waste. Additional copies of the form are to be found on the website here. Please observe the instructions in the waste facility regarding the segregation of waste.

In the event of an emergency contact Mr Suresh Mistry, tel 37010, and/or the Department Safety Officer.

Biological Projects

Before such projects begin, it is essential to assess the risk, and ensure that the right level of containment and the right handling protocols are arranged for the materials. Certain projects will require prior notice (minimum one month lead time) to be given to the Health and Safety Executive, and it is essential to plan for the disposal of any wastes. A Departmental Biological Safety Officer has been appointed, Dr Sarah Bohndiek (seb53), who should be consulted at the earliest opportunity. The Biological safety page is here.

Electrical Hazards

All work in the department involving electrical systems shall be conducted in accordance with the Electricity at Work Regulations 1989, and with the Department Code of Practice. Faults that become apparent in the Laboratory supply network must be reported as soon as possible to the Safety Officer or the Laboratory Superintendent, so that repair can be arranged. No-one, other than the authorised persons in Maintenance, is permitted to work on the mains supply to the Laboratory.

It is essential that at all times, access to the 'off' switch for apparatus is unobstructed, and that it is obvious to anyone (such as a first aider) which switches are relevant to the apparatus. Electrical leads must be placed carefully, to avoid them becoming trip hazards, or being damaged on the floor by abrasion, liquid nitrogen, water, etc.

Electrical apparatus built in-house, or commercial equipment adapted in-house, must be designed and constructed in accordance with good engineering practices. Advice should be sought from the Electronics Workshop before building the equipment, to avoid time consuming and possibly costly modifications later. When the equipment has been built or modified it must be inspected for safety by one of the persons nominated to do so (the list of names will be maintained by the Electronics Workshop). The equipment will be given a Cavendish Laboratory identity number, and placed on the electrical test (PAT test) register.

Access to live electrical parts, at voltages/energies that are dangerous, must be prevented by insulation and/or covers. It is, in general, illegal to work 'live', where the live conductors present a danger. Please see the guidance in the Department Code of Practice for further details

In general within the Department the permanent wiring will be inspected by the Maintenance Staff or EM on a regular basis. Portable and transportable electrical appliances should be tested by the Research group concerned using their local arrangements unless they have chosen to 'opt in' to the Department contract. Advice and equipment may be obtained from the Maintenance Workshop or Electronics Group.


Formal training for the use of lasers is mandatory BEFORE an individual is permitted to start work on lasers.

Consult the Department Laser Safety Officer (Richard Gymer, rwg11@cam) BEFORE installing or altering a laser experiment. It is essential that he is notified of all new lasers of classes 3 or 4 coming into the Department, whether they are new or have been acquired from elsewhere. He must also be informed of any significant change in laser use, and of any changes in personnel authorised to use lasers.

Safety precautions that are addressed properly at the design stage are almost certainly cheaper and more effective that those that are tagged on later. All lasers within the department must be sited and operated in accordance with current statutory, university and departmental rules. An outline of these rules may found in The University code of Practice, which is at All users must read the University code of practice and abide by the advice. Note in particular that beam enclosure is the default condition required by law for class 3B and class 4 lasers.

The Department Laser Supervisor keeps a register of all Class 3R, 3B and Class 4 lasers, their local rules and laser users. Before working with Classes 3B or 4 lasers, prospective users should therefore register with the Department Laser Safety Officer.

Cryogens/piped nitrogen supplies

The Department code is here.


Liquid nitrogen and Helium do not support life. Small volumes of liquid will evaporate into large volumes of gas that displaces oxygen, and death can result without warning.

Where there is a reasonably foreseeable risk that a room may become depleted in oxygen due to escape of gas either from Dewars or the network of gas supply and recovery pipes, at least one, and preferably two oxygen monitors should be placed in the affected area. Another monitor must be available outside in case those in the room go off. Note that monitors need to be looked after, and training is needed to ensure that people follow the correct procedure when the monitor alarms. Note also that not all monitors are linear in different gas mixtures. In particular an asphyxiating atmosphere with an excess of helium may cause monitors to give an artificially high oxygen reading. It is therefore essential that monitors are not used to enter rooms below 19.5% reading on the meter without knowing the calibration curve of the meter.

Cryogenic equipment must have up to date pressure reliefs, safety valves and vent lines maintained to prevent the build up of pressure and possible explosion or uncontrolled gas release.

Cryogenic liquefied gases can cause severe cold burns if allowed to come into contact with the skin or other delicate tissues such as eyes.


Compressed Gases and High Pressure Systems

The code of practice is here, relating to compressed gases. The code for pressure vessels is here.

Gas bottles are pressure vessels, and it is essential that people intending to use them, fit regulators, transport them, etc. are given training in the correct methods.

Regulations exist to guard against the unintended release of stored energy, and the injuries that may arise from high pressure systems. Experience has shown that these accidents can be very serious. Systems must be properly designed, properly constructed, tested and provided with protective devices as necessary. Competence in this speciality will arise from adequate academic training, knowledge of the design standards and experience. Refer to the department code of practice, linked above.

All pressure systems which contain steam, and those which contain gases or liquid gases and have a product of pressure and volume that exceeds 250 bar litres must be notified to the Safety Officer. These will require formal inspection by the insurers.

Vacuum Systems

Containers maintained at reduced pressure and made from brittle materials, such as glass, pose a significant risk of injury if they should implode. Suitable guarding should be fitted to items such as desiccators and glass cryostats.

It is not uncommon for vacuum systems to be connected to compressed gases, and the possibility that the gas supply can pressurise the vacuum system must be assessed and prevented.

Lifting and Manual Handling

All manual handling tasks that have the potential to cause injury should be the subject of a risk assessment, and some guidance on both manual handling and the use of lifting equipment is given in the department code of practice.

Mechanical lifting aids, such as lifting bars, chains, cranes and slings are preferred where the load is heavy and/or awkward to handle. The choice of lifting aid should be the subject of risk assessment and the person(s) using it should be given adequate training.

Lifting equipment such as genie lifts, hoists, slings, chains etc must be on the department register, kept by the Safety Officer, so that it is insured. ALL new lifting equipment, shackles, chains, slings, etc. MUST be accompanied by a manufacturer's test certificate, which must be passed on to the Department Safety Officer on delivery. A six monthly inspection is carried out by the Insurers. Any lifting tackle failing these inspections must be replaced, or repaired promptly as specified by the Inspector.

The University Lift Team, based in Estates Management, attends to the passenger lifts, which are inspected every six months by an approved testing company. Any faults noticed by lift users should be reported to the Laboratory Superintendent.

Display Screen Equipment

Display Screen Equipment (which includes computers) carries a risk of injury to the upper limbs and the back, mainly from poor work station layout or work practices. For useful advice see the Department Code of Practice. There is a department code of practice.

Please read the advice, and follow the instructions. Fill in the questionnaire and discuss it with your supervisor/manager. If there are any problem, report them to the Safety Officer.

Personal Protective Equipment

Personal Protective Equipment (face masks, goggles, glove) is the last resort for controlling risks, because it only protects the wearer and is easy to use incorrectly, thereby providing no protection. Its use, where appropriate, will be specified by the Risk Assessment for the activity. Consult the Department Code of Practice for the choice of suitable equipment.


A register of all ladders and steps at the Cavendish Lab is kept by the Maintenance section who will inspect all items once a year. Any defects will be dealt with immediately. Senior Assistants should notify the Head of Maintenance of any defects noticed on ladders and steps, also of any new ladders and steps purchased. Purchasers are reminded of the need to buy of approved quality (BS EN 131 or BS2307, Light Trade minimum, or Class 1 or 2). Steps that are of 'Domestic' grade will fail their inspection and will have to be disposed of.


This page was last updated 21 December 2015 (updated name of Safety Officer/basic arrangements for oxygen monitoring)