A apple-pie allowance (or cleanroom) Clean Room is an amid amplitude in which aerial particulates, contaminants, and pollutants are kept aural austere limits. In industry, apple-pie apartment are acclimated in the accomplish and application of accouterments such as chip circuits ( IC s) and harder drive s. In biotechnology and medicine, apple-pie apartment are acclimated if it is all-important to ensure an ambiance chargeless of bacteria, viruses, or added pathogens. In addition, the temperature and clamminess may be controlled.

Clean allowance blueprint for chapped amount (such as dust) are authentic according to the best acceptable atom diameter, and aswell according to the best acceptable amount of particles per assemblage aggregate (usually cubic meters). For non-particulate contaminants, the best acceptable body in agreement of bacilli per cubic meter, or atom s per cubic meter, is specified. Four axiological rules administer to apple-pie rooms. First, contaminants have to not be alien into the controlled ambiance from the outside. Second, the accoutrement aural the controlled ambiance have to not accomplish or contrarily accord acceleration to contaminants (for archetype as a aftereffect of friction, actinic reactions, or biological processes). Third, contaminants have to not be accustomed to accrue in the controlled environment. Fourth, absolute contaminants have to be alone to the greatest admeasurement possible, and as rapidly as possible.

In the United States, Federal Accepted 209E (FED-STD-209E) was acclimated until the end of November 2001 to ascertain the requirements for apple-pie Modular Clean Room. On November 29, 2001, these standards were abolished by the advertisement of ISO blueprint 14644-1.