A. Validation Concept
To prove the performance, one must demonstrate (document) that the processes or systems consistently produce the specified quantity and quality of water and/or air when operated and maintained according to specific written operating and maintenance procedures. In other words, validation involves proving
1. Engineering design
2. Operating procedures and acceptable ranges for control parameters
3. Maintenance procedures
To accomplish this, the system must be carefully designed, installed, and tested during and after construction, and therefore for a prolonged period of time under all operating conditions.
Variations in daily, weekly, and annual system usage patterns must be validated. For example, water may be drawn from the system for manufacturing use only during normal working hours; there may be no demands on the system at other times during the 24-hr cycle. The system may be idle on weekends and on holidays, which could extend for as long as 4 days or more.
In addition, many firms have annual plant maintenance shutdowns, typically in the summer, and systems must be sanitized and restarted prior to use, and of course emergency shutdowns can occur at any time and the system must be brought back online.
Systems with ion exchange resins (deionizers) must be at least partially shut down to regenerate the resins when the chemical quality of the treated water drops below a specified level. (This could be a matter of a few days or even a few months, depending on the quantity of water processed through the system and other factors).
For the air handling system, the same kinds of issues exist. Clean rooms should be maintained at their required cleanliness level, even during the time of no manufacturing operation. If the cleanliness is broken or the air handling system stops, the whole clean area has to be made clean according to the initial validation procedure and assessment. Water treatment and/or air handling systems must be validated under all of these normal operating conditions in order to prove the adequacy of the engineering design and the effectiveness of the operating, control, and maintenance procedures.