Behind the scenes of GS: keeping CERN clean

More than 350,000 square metres to be maintained, two different cleaning companies due to CERN’s sites being in two different countries, underground installations where cleanliness is a question of safety… the CERN team in charge of supervising cleaning services overcomes all these challenges to ensure that our workplace remains clean and pleasant every day.


Ensuring the cleanliness of sites containing a huge variety of buildings is an enormous challenge for the two experts in the GS Department in charge of cleaning services. Alain Bertrand has been at CERN for 29 years and knows all there is to know about the Organization’s buildings and what they are used for, the condition of their toilet facilities and, of course, the location of the border between France and Switzerland which, in terms of cleaning services, denotes the transition point between the two companies used.

David Chameaux has been doing the same job as Alain for two years, working with him to ensure that the services provided correspond to the specifications, managing tickets received via the 77777 helpdesk and finding more efficient solutions to pass on to the contractors. “The CERN site is very complex to maintain,” confirms Alain. “Often, alongside normal offices, there are clean rooms, chemical laboratories and radiation protection laboratories. As well as the usual meeting rooms, there are workshops housing delicate equipment, electricity substations, tunnels where it is vitally important that no metallic waste is left behind and even offices where people are working very late!"

Mechanised cleaning of the LHC tunnel (apron and vault).

For the companies involved, all of this requires specialised work protocols, a variety of cleaning products and machines adapted to the huge range of types of flooring at CERN. “All of these details are included in the contracts that CERN has drawn up with the companies,” explains Alain. In addition to regular cleaning, which for offices takes place once per week, the contract with the outside companies also includes standby cleaners, a schedule for deep cleaning every eight weeks and annual polishing of the floors. “The specific frequencies depend on the type of premises,” explains David. “Overall, the cleaning services are improving, even if sometimes it can be a bit tricky to keep some of the older installations clean.” He has a point – just as some of CERN’s buildings are celebrating their 60th anniversary this year, the same is true for some of the toilet facilities!

Sometimes the cleaning service is called upon to deal with unusual situations. “From rodents hiding inside the walls of the ATLAS cavern to cleaning the gutters of the LHC, the problems are varied, but the technicians always handle them in a professional way," confirms Alain. “The work often has to be done manually and be carefully adapted to specific situations. No machine can replace our experts when, for example, an electricity substation needs cleaning and the concrete is waterlogged and slippery!" 

For Alain and David, the most important thing is the satisfaction of the personnel and the thousands of users at CERN. “They should be concentrating on physics and they should be able to do so in a clean and pleasant environment. That’s what we’re here for!” concludes David.

If you have any comments or you are not satisfied with the cleanliness of your environment, do not hesitate to contact the cleaning service by sending an e-mail to or by calling 77777. Satisfaction surveys are also carried out to monitor quality and identify locations where improvements could be made.

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by Antonella Del Rosso