Mixed media.

Reuse of old buildings is a critical part of an environmentally aware approach to architecture. This former armaments factory has been imaginatively recolonized as a centre for the arts, giving a redundant industrial monument a new lease of life.

As a calculated attempt to establish itself at the leading edge of media technology, Karlsruhe's Zentrum fur Kunst und Medientechnologie (ZKM) has been dubbed the electronic Bauhaus. Unique in Europe, it unites scientists, artists and musicians through a series of exhibition, performance and study facilities. These include media research workshops, recording studios, permanent and temporary exhibitions of modern art and video installations. A collections museum will open in 1999 and a design school in the year 2000. ZKM's initiator and director is Heinrich Klotz, founder and first director of Frankfurt's Deutsches Architekturmuseum.

The container for these experiments is the former Industriewerke Karlsruhe-Augsburg armaments factory designed by Philipp Jakob Manz. Completed in 1918 (too late to contribute to the First World War), it was in full production for the second with East European slave labour. The vast, three-storey factory block is symmetrically arranged around ten inner courtyards. It has a concrete frame structure and a solidly functional external skin of brick and masonry. Abandoned in the seventies and then occupied by artists, it was eventually listed as an industrial monument.

The original intention was to provide the ZKM with two sites, by refurbishing the factory and building a new centre in Karlsruhe (Rem Koolhaas won a competition for the latter). However, faced with the prospect of funding two projects, the city decided to combine them and the Hamburg-based practice of Schweger + Partner won a competition to renovate, service and enlarge the basic factory structure. By roofing over the ten inner courtyards, 31 470sq m has been made available at a cost of 204.3 million DM. The renovated building provides space for contemporary art, video installations and temporary exhibitions, together with a library, theatre, Music Cube, lecture rooms, administration, restaurant and museum shop.

To some extent, this is architecture without architects. Contemporary electronic technologies tend to need little more than black box environments, so industrial-scale halls, with their large, column-free spans, make potentially ideal containers. Yet there is also an inherent contradiction between the light flooded interior- made possible by glazed light wells and generously proportioned facade windows - and the reductive enclosures for various electronic media. Walls and roof for the theatre are formed from steel-framed sound insulation panels which rise like the sloping sides of a pyramid to demonstrate complete independence from the factory frame. Individual video art installations in the Media Museum are housed in black fabric tents, held in tension between steel tubular frames with high tensile cables, and bolted on to the floors. The original industrial window frames and mullions have been restored and backed up by secondary internal windows for insulation purposes.

In orchestrating old and new elements, Schweger + Partner have followed a rigorous approach. The reinforced concrete structure has been stripped and exposed, with all additions, from steel footbridges and stairs to building services, treated as separate elements independently articulated. A workshop atmosphere has been retained. Except for the Music Cube, a glass box extension for performances and recording plugged on to the eastern side, the integrity of the original structure has been protected. (The architects would have liked to attach more cubic volumes to the long east elevation but were forbidden to build any closer to the neighbouring Federal State Prosecution building, a high security establishment.)

Exposed building services called for a high degree of design co-ordination. Without suspended ceilings, raised floors or wall coverings, service runs through the reinforced concrete structure had to be exactly planned to meet up with equipment. Chilled ceiling panels are suspended from the slab, flanked by cable trays, fluorescent tubes, emergency lighting, fire detectors and a dry riser sprinkler system to prevent accidental damage to the art works. Lighting consultant Christian Bartenbach's specially developed system of mirror reflectors, disks suspended at various angles in relation to light sources, increases dispersal of indirect light. In the administration offices at fourth floor level under the eaves, heating radiators are fed from exposed pipes at skirting level and dormer windows, looking out over the lightwell roof glazing, open manually for ventilation. For the exhibition areas there is air-conditioning. The tall volumes and three-storey glazed lightwells consume a lot of energy and although ZKM has a secondary function as a power station, converting solar energy from roof-mounted panels, the electricity produced is not used in the building but instead fed through to the city tram network.

Cutting through exhibiting, research and learning institutions, the long (312m) north-south circulation axis, is an apt device, symbolizing ZKM's chief aim of increased interdisciplinary communication in the exploration, and exploitation, of new media. But where Dessau was the Bauhaus manifesto made concrete, for Karlsruhe's electronic Bauhaus, a recycled, revived post-industrial structure functions as well as any made-to-measure shed.

Architect

Schweger + Partner, Hamburg

Structural engineers

Sobek and Rieger, Janssen + Stocklin, DS-Plan

Services engineer

Jaeger, Mornhinweg + Partner

Lighting consultant

Christian Bartenbach

Acoustic consultants

Muller BBM, Planegg, Institut fur Akustik und Bauphysik

Electrical consultant

b.i.g. bechtold

Stage planners

Walter Huneke + Partner

Photographs

Roland Halbe/CONTOUR