Former Inmos Microprocessor Factory

Former Inmos Microprocessor Factory

This is a High-Tech factory building from 1982, characterized by advanced materials, highly organized structure, and sophisticated service equipment displayed on the exterior. The building's idiom turns conventional design inside-out, exposing both structure and services to view.

The structural system is formed by a spine of nine H-frame towers, each suspending six very thin suspension rods that hold up primary lattice trusses extending out past the building envelope where they are anchored by return rods. The primary truss arms extend from a third of the way up each tower, with the upper two-thirds cross-braced with a double X. Secondary lattice trusses run between the primary trusses in the same direction as the spine. All structural parts are pin-jointed with a complexly engineered lattice structure. The exterior superstructure is of tubular steel, painted blue, and suspends the building's ceiling while supporting complex rooftop services designed to provide air scrubbed of the smallest particles to the clean rooms where silicon chips are prepared.

North and south entrances are marked by suspended trusses projecting out from the spine ends, with the south entrance now bracketing a later link corridor. Service boxes containing air-filtering equipment were originally placed along the spine between the towers, designed to be easily lifted off by crane for upgrading; none of the original 1982 boxes now remain. Pipework visible over the flat roof has been continuously altered, though the colour scheme has persisted: silver grey for air services, yellow for acidic gas, and blue for structural elements. A steel grid walkway circulates to either side of the spine, below which is a continuous clerestory on either side, sloping down at forty-five degrees from the central spine to the flat roof of the wings.

The curtain walls are an aluminium grid holding removable thin square panels. Originally these were uniformly silver grey on the west production side, with a chequerboard of silver and glazing on the east offices side. With changing use, there is now very little glazing and a chequerboard appearance throughout with lighter and darker panels. The northeast four bays have slightly longer primary truss arms of thirty-five rather than thirty squares as measured by the envelope grid. The southernmost of these was originally left open for a small garden area, since filled in. Small lean-to additions added after construction and a small cube at the southeast corner reproduce the original square grid.

The elaborate roof structure serves the practical purpose of maximizing open internal space uninterrupted by columns or load-bearing walls. To either side of the spine towers is a covered area roughly 106 by 36 metres. At the time of inspection, the west side, originally the production area, was entirely open space used for storage, with steel posts to the north marking the location of the original clean rooms and construction block walls to the south screening off the original loading bays still in use. The east side, originally offices later converted to production, contains modern clean rooms partitioned off in the lower southern third, with open storage space further north. The outward square grid is expressed internally on the curtain wall with vertical bay dividers punched with circular holes, adding to the building's Meccano-like aesthetic.

Originally, the open spaces in the lower thirds of the spine towers formed a continuous seven-metre-wide corridor running the length of the building, bracketed by portal-framed tower bases. These interior portions of the spine towers are tripodal, with two large inner cylindrical columns and a smaller outer column which turns inwards forty-five degrees as it meets the clerestory glazing, connected by zig-zag lattice tubular cross-bracing. This corridor is now interrupted a third of the way north by a changing room and airlock to the current clean rooms, beyond which the sides of the corridor have been opened up. The clerestory remains unaltered structurally, though black-out film has been applied to much of it to block natural light from reaching the later clean rooms. The clerestory consists of slightly wider than square panes vertically divided by steel bracketing punched with circular holes. Overhead services running the length of the spine corridor have been retained and added to; the three large green water pipes are original.