in manufacturing and research, dust-free working area with strict temperature and humidity control that is of vital importance in the manufacture of equipment sensitive to environmental contamination, such as components for electronic and aerospace systems. Seamless plastic walls and ceilings, rounded corners, external lighting and wiring, a continuous influx of dust-free air, and daily cleaning are characteristic features. Clean-room workers wear special clothing, including head coverings, and, on entering, pass through an air blast, or air shower, to remove particles. Workpieces for assembly enter through an airlock.