CERN building numbers: no rhyme and little reason

Over the years, people at CERN have been trying to develop a single theory to explain CERN’s building numbers. Behind these seemingly random numbers there must surely be an ultimate solution: CERN’s second Standard Model, if you will. The CERN Bulletin finds out more…


Still trying to understand CERN's building numbers? Give up...

There’s no denying it: the CERN site cannot be navigated without professional help. You can walk down a single corridor and pass through Buildings 33, 4, 5 and 53… in that order. Surely there must be a method behind this madness? “Well, if there is one, we’ve yet to find it,” says Youri Robert, who is in charge of geographic information and patrimony data in the GS Department’s Site Engineering group, which is responsible for the classification of CERN’s buildings. “We do have some naming conventions in place, especially for buildings related to the LHC, but most of the older buildings seem to have been numbered without a particular system in mind.”

While Youri and his team are solely responsible for numbering CERN’s newest buildings, they still have firm restrictions on their work. For example, they cannot reuse building numbers, even if the original building has been demolished. “You’d be surprised how few numbers there are left,” says Francois Villagrassa, a technician in charge of patrimony data and plan archiving. “After 50 years, we’ve only got the occasional number left under 1000. Without going too far into the four-digit range, we try to give new buildings similar numbers to other buildings in their area, while also giving some of the more important buildings “round” numbers (i.e. Buildings 80 and 500), and project leaders sometimes request a particular number to reflect the nature of their work. We also try to keep office buildings numbered between 1 and 400, and service buildings numbered between 500 and 600. But ‘try’ is the operative word; it’s really not that easy.”

In an ideal world, the GS Department would just be able to start over, renumbering all of CERN’s buildings (and rooms) using a single policy. Unfortunately, real-life logistics prevent such an overhaul, as many of CERN’s databases rely on the current building numbers. “However, we were able to adopt naming conventions for the SPS and LHC buildings,” says Youri. “As a result, the LHC buildings actually have two names: one (known as a “sigle”) is allocated by the convention and explains the function of the building, while the second is given by the Patrimony service and is used for work by the CERN services.” For example, the magnet testing facility SM18 is considered to be building number “2173”, but its name follows the LHC naming convention: the “S” stands for “Surface Buildings”, the “M” for “Magnets and other machine equipment”, and the “18” comes from its location at Point 1.8.

So it seems that the solution to the building numbers dilemma is less trivial than expected. Let’s all just stick to simpler problems… the Higgs, perhaps?

by Katarina Anthony