1960 · Laminar Flow Clean Room · Work 845 of 1,871
A steel workbench in a workshop in Albuquerque in winter, dry desert light falling through a tall window in a sharp shaft with fine drifting dust, on the bench a closed bound notebook with a plain dark green cloth cover lying flat, its cover smooth and unmarked, a ballpoint pen on top, a hand in a light shirt sleeve resting on the closed book, beyond the bench the open doorway of a small new room with bare stainless steel walls, its far wall a grid of pale filter panels glowing softly, inside it the air perfectly clear against the dusty light outside.
What it was used for
The laminar-flow clean room came out of Sandia: the nuclear weapon components built there, mainly mechanical switching parts, kept getting smaller; from 1959 dust particles were preventing the required quality, and Willis Whitfield's group was told to fix it. By the end of 1960 he had first drawings for a 10-by-6-foot room. Air flowed evenly through filters that held back 99.97 per cent of particles larger than 0.3 microns, about 10 air changes a minute and slightly over 1 mph - barely perceptible to the people working there. The work area averaged 750 particles per cubic foot at one-third of a micron or larger; one of the best conventional clean rooms of the time averaged more than 1 million. Whitfield gave his first paper on what was then called the "ultra-cleanroom" in Chicago in 1962.
What was new
What marked it out was the direction of the air. In conventional clean rooms the airflow was turbulent; Whitfield's room pushed the air through the work area as an even stream and carried particles out instead of mixing them in. By Sandia's account the result was more than 1,000 times cleaner. The figure itself was the problem: about 1 year after the 1962 paper, at a talk in Boston, manufacturers accused Whitfield of perpetuating a hoax, according to Sandia historian Rebecca Ullrich. The turn came from outside: Whitfield's son Jim recounts that a Bell Labs colleague said Whitfield's numbers were "10 times too conservative". Within a few years, Sandia reports, $50 billion worth of clean rooms of this design were built.
What the sources leave open: All figures from the operator's own release, Sandia National Laboratories, for the fiftieth anniversary. It gives no construction or commissioning date for the first room, only the drawings of late 1960 and the 1962 paper. Cost per room, funding source and the basis of the $50 billion figure are not stated there.