Table 5. Position of the preventive maintenance.

Recommended practice	Maintenance operations that have an impact on practice are identified. IQCs (or other means) are used before and after maintenance. Quality indicators are set up to control risk management.
Acceptable practice	Concepts are known and used, but not formalized in regular documentation (documents found but not included in the guidelines). Risk controlled by IQC test or other appropriate means.
Unacceptable practice	No knowledge of the nature of maintenance or its impact. No IQC used (or other means) before and after an impacting interview.
IQC – internal quality control.