With "VDA19.2 - Technical Cleanliness in Assembly", the German Association of the Automotive Industry published a guideline in 2010 that classifies different levels of cleanliness. The aim of this guide is to provide users with assistance on how to avoid critical particle contamination at sensitive points.
Clean rooms and clean spaces differ primarily in the definition of the permitted particle sizes. The construction effort of a clean room is significantly smaller and the operation cheaper than that of a clean room due to the less complex filter and ventilation technology.