The risks associated with CERN’s activities are many and varied, as in any
large industrial establishment. As indicated in the introduction, the safety
rules to be observed are described in documents like SAPOCO/42,
notes and safety
bulletins (see the list of safety documents issued by Safety Commission
The Safety Vade-mecum sets out a few elementary safety rules.
A number of specific potential dangers are listed below, together with some simple rules for preventing them.
Road accidents on and outside the CERN site, particularly those occurring on journeys to and from work, are responsible for many days of absence every year. The traffic regulations in force are those of the French and Swiss highway codes, which are not reproduced here. All drivers of vehicles entering the CERN site must observe the traffic regulations (Safety Code A7, "Road Traffic at CERN"), in particular the speed limits.
Over half the cases of occupational illness recognised by CERN are attributable to hearing impairments caused by noise in the workplace. The most common causes are cryogenic installations, water pumps and piping and sheet metal shops. Appropriate noise protection devices (e.g. sound-insulating casings, non-reverberating walls, dampers to prevent noise propagation along pipes, etc.) must be incorporated in new installations from the outset, i.e. at the design stage and when the specifications are being drawn up.
In addition, since its installations are almost all located close to residential areas, CERN is obliged to comply with the Host States’ environmental legislation concerning permissible noise levels on the boundaries of its site. These levels are particularly low, especially at night.
The associated requirements are set out in Safety Code A8, "Protection against Noise".
The Chemical Safety Code (Code B) sets out the rules concerning the purchase and disposal of chemicals.
A chemical safety manual has been drawn up to help CERN users to apply the Chemical Safety Code in specific situations:
Everyone is required to obtain the correct information before using toxic and/or corrosive materials. In the case of ingestion or contact with the skin or eyes, contact the medical service and, in the two latter cases, rinse with copious amounts of water (for 10 minutes).
Never dispose of chemicals or other waste by throwing them down sinks or drains. For their safe disposal, call the Special Waste Collection service of GS-SEM-LS.
Electrical hazards are to be encountered almost everywhere; all persons working at CERN must be made aware of them. In particular, persons carrying out work on electrical installations must have the necessary qualifications.
With a view to ensuring the safety of people and property, Safety
Code C1, "Electrical Safety Code", lays down the regulations concerning
electrical construction work and for the installation and use of electrical
Safety Instruction IS 5 Rev. describes the three kinds of emergency stop (general, local or individual), defines the areas to be equipped and explains the effects of the emergency stop systems.
Safety Instruction IS 24, "Regulations applicable to Electrical Installations", specifies the standards in force on the CERN site.
Safety Code E, "Fire Protection", lays down the regulations concerning fire protection and prevention. It is particularly important that everyone should be familiar with the location of the alarm systems and fire-fighting equipment in the vicinity of their workplace and know how to use them.
Many fires have been caused by activities involving tools or equipment creating "hot spots", such as welding equipment, cutting torches, grinding machines, etc. All persons carrying out this type of work outside a workshop specially fitted out for this purpose must hold a "fire permit" issued by the person requesting the work and countersigned by the TSO responsible for the area where the work is to be done (see Annex V of Safety Code E).
The combustion of plastics containing halogens, phosphorous or sulphur releases corrosive gases that often cause more damage than the fire itself. To minimise this risk, the rules for the selection of plastics to be used at CERN and those for the selection of the appropriate electric cables are laid down in Safety Instructions IS 41 and IS 23 respectively.
To facilitate the evacuation of personnel in the event of fire, the emergency routes and exits must be clearly indicated with the appropriate signs (see Safety Code A3, "Safety Colours and Safety Signs").
Procedure to be followed in the event of fire in an underground area
Since the new agreement between CERN and France came into force in September
2000, the LHC and SPS have been classed as Basic Nuclear Installations (INB).
The INB perimeter comprises the LHC and SPS tunnels and their transfer lines to the targets (including the CNGS), as well as a number of surface buildings and areas of land on the various CERN sites.
By virtue of this agreement, the safety of these installations - and that of the LEP dismantling activities - is ensured under terms and conditions that are subject to the approval and monitoring of the competent French authorities.
In particular, CERN has defined "nuclear" and "conventional" zones in the INB area. The "nuclear" zone is defined from the outset as one that will contain radioactive elements or elements that are likely to be radioactive. The "conventional" zone is similarly defined beforehand and contains only conventional elements, i.e. non-activated material.
CERN has also established precise traceability procedures for all material entering or leaving these areas.
In general, it is everyone’s duty to avoid, both for themselves and for others,
any unnecessary exposure to ionising radiation and to comply with the rules
laid down in Safety
Code F (Radiation Protection Manual). This requires activities to be carefully
planned and workers, including contractors’ personnel, must be given the appropriate
information and training.
For work in radiation-controlled areas, indicated by yellow panels, the following instructions must be complied with:
Any material leaving an accelerator area may have been activated. It must therefore
be checked and, even if it is only slightly radioactive, it must be marked as
such with an adhesive strip bearing the usual yellow warning sign for radiation.
The repair, maintenance, etc., of radioactive components is authorised at CERN but they are not allowed to be machined there. As a general rule, such equipment, even if it has a very low level of radioactivity, must not remain in the workshops or halls for any longer than absolutely required by the work to be done and it must then be stored in one of the areas specially set aside for this purpose. Material leaving an accelerator may be eliminated as ordinary waste only if the DGS-RP Group has confirmed that it falls into the conventional category.
The DGS-RP Group is responsible for the elimination of all radioactive waste.
Radioactive sources, even those with low levels of activity, must be registered with the DGS-RP Group. The Radioactive Sources service of the DGS-RP Group must be notified in advance of any intended movement or use of these sources, which shall be subject to its approval. The DGS-RP Group provides advice on the purchase of radioactive sources and, in many cases, may lend such sources to users. Film-badges must be worn at all times when working with or in the vicinity of radioactive sources. Radioactive sources must be properly stored and shielded when not in use.
Safety Code G, the "Flammable Gas Safety Manual", and Safety Note 23 both contain safety rules, recommended practices and technical information concerning the design and operation of flammable gas systems.
In particular, systems using flammable gases, whether or not in liquid form, for combustion (e.g. fixed or mobile welding apparatus) must meet the requirements of Swiss legislation as laid down in Order No. 3 relating to labour law (OLT3). Safety Commission implements this Order at CERN in lieu of the Swiss national authorities.
Instruction IS 47, "The Use of Cryogenic Fluids", contains information on
the systems which use cryogenic fluids, the risks they present and the safety
rules to be applied.
In places where large quantities of cryogenic fluids such as liquid helium, nitrogen or argon are stored, the appropriate safety requirements must be displayed by the person in charge of the equipment, in agreement with the CSO.
A leak of cryogenic gas appears as a thick cold cloud, which diffuses upwards
in the case of helium and downwards in the case of nitrogen or argon.
In such an event, keep as far away as possible from the leak and follow the instructions of IS 47.
In addition to the dangers mentioned above, all gases constitute a potential hazard to some extent, including:
The aim of the provisions laid down in Safety Code A4, "Confined Spaces", is to prevent the latter two risks.
Safety Instruction IS 22 Rev., "Rules for the Safe Use of Lasers at CERN", describes the risks associated with the use of lasers. All lasers entering the CERN site must be registered with the Laser Safety Service, which will recommend the appropriate safety measures to be implemented.
Precautions must also be observed when working near magnetic fields (see IS 36/Rev.) and sources of microwave radiation (see NS 9/Rev.). In particular, these areas are out of bounds to all persons wearing a ferromagnetic implant or pacemaker.
Areas associated with specific risks include confined spaces, which are covered by Safety Code A4.
In agreement with Safety Commission, certain areas where access is difficult or
where oxygen may be lacking or toxic gases present are declared as "confined
A list of the areas presenting specific risks in your department is given in Annex I.
Access to confined spaces, which is strictly regulated, is subject to the provisions of Safety Code A4, "Confined Spaces".
Access permits for carrying out work in confined spaces are issued subject to a favourable recommendation following a joint safety inspection carried out by the person in charge of the work and a representative of the CERN's Fire Brigade immediately prior to entry. The oxygen concentration in the confined space must be controlled at all times while the work is being carried out. The detailed provisions relating to this subject are given in Safety Code A4.
The General Safety Instruction "GSI-M2 - Standard Pressure Equipement" covers the design, manufacture, testing, installation and use on the CERN site of all pressure vessels, except those that contain only cold water at domestic supply pressure or cooling water.
All equipment for lifting shall be in conformity with the General Safety Instruction "GSI-M1 - Standard Lifting Equipement", and the operators shall hold the relevant authorization to use lifting equipment at CERN delivered by the Safety Commission. During transport a safety perimeter where the presence of persons is not allowed shall be clearly defined and human presence under suspended loads is forbidden.
In the halls equipped with a crane loading and unloading areas as well as transport corridors of appropriate dimensions, must be defined and clearly marked. No material may be permanently stored in those areas reserved to the movement of suspended loads.
The installation of barracks used as laboratories or offices should be avoided. In case the installation of a barrack is mandatory, its position in the hall should be agreed by the services in charge of the handling.
No high item must prevent an overhead traveling crane from passing empty over it with its hook. The crane driver shall always be able to see the crane hook(s). If not, safety measures (like the definition of safe areas) shall be implemented.
All heavy transport must be planned in advance, referring to a written operating mode and risk analysis. Other services in the same area must be informed of the forthcoming transport. This information must be sent to persons having a permanent activity in the area indicating that the transport has priority over other activities in the area, and that the instructions given by the crane operator must be followed.
|Created 21.05.1997 - modified 12.07.2010 - Author: DSOC -|