Subway station “Rotes Rathaus” in Berlin

Trans­porta­tion projects require stay­ing pow­er and reli­able part­ners: More than ten years passed from the plan­ning to the open­ing of the exten­sion of Berlin’s sub­way line 5. The fact that the under­ground plat­form hall at the Red City Hall now looks even more impres­sive in real­i­ty than the plans promised — is not least due to the light­ing with WE-EF.

At the Red City Hall, the seat of Berlin’s state gov­ern­ment, archi­tect Oliv­er Col­lignon cre­at­ed an under­ground sta­tion that under­scores and cel­e­brates the impor­tance of the site for the city’s cit­i­zens — with a design that is as clear in form as it is gen­er­ous and rep­re­sen­ta­tive. The 140-meter-long plat­form hall, with its radi­ant­ly light floors and ceil­ings, dark, sub­tly glit­ter­ing walls of pol­ished con­crete cast stone, and strik­ing mush­room sup­ports, is a sight worth paus­ing for: For exam­ple, on the con­nect­ing gallery between the two plat­forms, which is ful­ly glazed towards the con­course. The short esca­la­tor ride through the all-anthracite stair­well then height­ens the dra­mat­ic effect of step­ping back into the light of the hall and being able to expe­ri­ence its spa­tial feel­ing directly.

Accom­pa­nied by the light­ing design­ers from Licht Kun­st Licht, the archi­tect eschewed the com­plex­i­ty of addi­tion­al light­ing struc­tures in favor of pure down­light­ing inte­grat­ed into the con­crete ceil­ings. The cal­cu­lat­ed inter­play with the reflec­tion of the white floors and ceil­ings pro­duced the desired, pure light­ing effect — with a high lev­el of visu­al com­fort for the sta­tion’s users. The design­ers respond­ed to the dif­fer­ent ceil­ing heights of the hall and inter­me­di­ate lev­els with appro­pri­ate­ly adapt­ed lumi­naire wattages and beam angles in order to achieve suf­fi­cient ver­ti­cal illu­mi­nance on the side wall in the con­nect­ing bridge, for exam­ple. The ends of the plat­forms, where ceil­ing pro­jec­tions pre­vent the use of down­lights, are each marked by pairs of recessed floor luminaires.

Impressively elegant: the ceiling-integrated lighting solution

The ele­gance of this light­ing solu­tion lies in the cap­ti­vat­ing sim­plic­i­ty of its appear­ance: the WE-EF recessed lumi­naires are lined up like a string of pearls, with a pre­cise recessed detail that recess­es a few cen­time­ters into the ceil­ing sur­face. A con­vinc­ing result that does not show its long and not at all sim­ple his­to­ry of cre­ation. After all, the usu­al process­es in build­ing con­struc­tion were lit­er­al­ly turned upside down here — with a mas­sive impact on the plan­ning, logis­tics and instal­la­tion of the light­ing. The sta­tion, which is locat­ed direct­ly below street lev­el, was built using the so-called “wall-base-cov­er” con­struc­tion method.

This involved first con­cret­ing lat­er­al diaphragm walls and then a water­tight base as the low­er con­struc­tion pit bound­ary. The exca­va­tion pit was then giv­en a “lid”, which at the same time already formed the lat­er sta­tion ceil­ing. Accord­ing­ly, the heads of the mush­room-shaped columns were also com­plet­ed ear­ly in the struc­tur­al work — the columns them­selves, on the oth­er hand, did not grow upwards from below until lat­er, while the soil for the hall was being exca­vat­ed. This had con­se­quences for the ceil­ing-inte­grat­ed light­ing con­cept: The first step for instal­la­tion, name­ly the assem­bly of con­crete recessed hous­ings, took place very ear­ly in the project. As ear­ly as 2013, WE-EF sup­plied the cus­tomized mod­i­fied hous­ings, which, in addi­tion to a form­work ele­ment for the recessed instal­la­tion detail, also had addi­tion­al entries for redun­dant wiring. In terms of fail-safe­ty, the lat­er oper­a­tor, Berlin­er Verkehrs­be­triebe (BVG), did not want to take any risks.

Setting the course for LED at an early stage

No risk — this also applies to the choice of WE-EF as a man­u­fac­tur­er that was trust­ed to be able to sup­ply the pre­cise­ly match­ing recessed lumi­naires even sev­er­al years after the instal­la­tion of the con­crete hous­ings. Already in the plan­ning phase at the begin­ning of the 2010s, it became appar­ent that LEDs would replace the HIT dis­charge lamps com­mon­ly used at that time. Togeth­er with WE-EF, the archi­tect and light­ing design­er opt­ed for the future-proof tech­nol­o­gy. This also allowed the safe­ty light­ing to be seam­less­ly inte­grat­ed into the con­cept, and the free­dom from main­te­nance was anoth­er argu­ment in favor of LEDs in view of the con­tin­u­ous oper­a­tion of the light­ing under­ground. When the lumi­naires were final­ly deliv­ered and installed in 2017 as part of the expan­sion of the hall, their effi­cien­cy and light­ing qual­i­ty exceed­ed all expec­ta­tions of those involved — that’s how pos­i­tive­ly LED tech­nol­o­gy had devel­oped with­in just a few years.

When the new U5 line was cer­e­mo­ni­ous­ly opened in Decem­ber 2020, the light­ing of the Rotes Rathaus sub­way sta­tion had already been doing its job com­plete­ly unob­tru­sive­ly for sev­er­al years. A total of 70 lumi­naires of the type WE-EF DOC240 are mount­ed above the plat­forms. With 24 LEDs in warm white (3000 K) and a con­nect­ed load of max. 48 W, they pro­duce a sym­met­ri­cal medi­um-beam light dis­tri­b­u­tion. In addi­tion, more than 100 DOC220 recessed lumi­naires with 12 LEDs and like­wise sym­met­ri­cal medi­um-beam optics are installed in the areas with low­er ceil­ing heights. At the ends of the plat­forms, ETC140 recessed floor lumi­naires with 24 LEDs in 3000 K are installed and pro­vid­ed with slip-resis­tant ceram­ic coat­ing “ASC” accord­ing to DIN 51130. Con­ti­nu­ity both in the prod­uct struc­ture and in the project sup­port — how impor­tant such aspects are for clients like BVG is shown by the fact that WE-EF also sup­plied light­ing sys­tems for the two oth­er new sta­tions of the U5 line, which were also indi­vid­u­al­ly designed by renowned architects.