This part of the ISO 14644 standards gives guidance on the interpretation and application of the results of the measurement of Particle Deposition Rate (PDR) on one, or more vulnerable surfaces in a cleanroom as part of a contamination control programme. It provides some guidance on how to influence the PDR and reduce the risk of particle contamination on vulnerable surfaces.

This standard gives information on how a cleanroom user can use the PDR measurements to determine limits that can be set for macroparticles on vulnerable surfaces. It also gives a risk assessment method by which an acceptable risk of deposition of particles onto vulnerable surfaces in a cleanroom can be established and, when this is not achieved, methods that can be used to reduce the PDR.

Note to entry: An alternative to the PDR is the particle obscuration rate which determines the rate of increase of coverage of particles onto an area of surface over time. The POR can be used in an analogous way to the PDR and the required POR for a specified surface can be calculated and the risk from deposited particles reduced.

This standard does not:

• provide a method to classify a cleanroom with respect to PDR or POR,
• directly consider the deposition of microbe-carrying particles (MCPs), although MCPs can be treated as particles,
• give any consideration to surface deposition by contact as, for example, when personnel touch a product and contamination is transferred.