BS ISO 17359:2011 pdf free download – Condition monitoring and diagnostics of machines – General guidelines.
Typical decisions include:
no action, continue routine monitoring;
reduce the interval to the next required measurement;
change (reduce or increase) the machine load, speed or throughput; shut down the machine;
inspect the machine or bring forward routine planned maintenance; carry out corrective maintenance.
When maintenance actions have been completed, it is recommended that any maintenance activities and changes to the machine be recorded, including details of spares used, skills used, and other faults discovered during the repair/restoration. These should be fed back to form a historical record, which can assist in future diagnosis and prognosis, and which is also useful when the condition monitoring process is reviewed.
When maintenance actions have been carried out, it is useful to inspect components to confirm that the initial diagnosis or prognosis was correct.
Repetitive failures can reduce system reliability and increase operating cost. If the root cause of failures can be identified, the maintenance action can be reviewed and optimized in order to avoid or reduce the impact of the failures. The appropriate maintenance action may include more sophisticated condition monitoring techniques, additional maintenance tasks, discussion with the manufacturer, and modification (design out).
11 Review
Condition monitoring is an ongoing process and techniques that may not have been available, or considered to be too costly at the time, or too complicated, or unfeasible in some other way (lack of access, safety problems, etc.) may, on review, become feasible. It is recommended that the condition monitoring procedure include a review process to allow such re-evaluations to be made. Similarly, the effectiveness of techniques currently being undertaken in the programme should be assessed and any techniques considered no longer necessary removed.
Alert/alarm criteria may also need revision due to changes in the machine such as progressive wear, ageing, modification, operation or duty-cycle changes. Measured values and baselines may also change because of maintenance work, including component change, adjustment or duty change. In certain cases, the baseline may need to be re-established following such changes. It should be noted that changes in measured values may also be due to normal or controlled changes in the operating conditions, and not necessarily indicate a fault condition. Rule-based diagnostics may have to be modified to take these into account.
To ensure effective and sustainable data management, the following items require particular attention:
advisory reports should be issued within an appropriate timescale; all data should be backed up in a secure and regular manner;
databases should be reviewed, updated and refined at regular specified intervals; alarm settings should be reviewed and adjusted at regular specified intervals.
12 Training
Information on the requirements for qualification and assessment of personnel to carry out condition monitoring and diagnostics of machines are given in ISO 18436 (all parts), listed in Annex D.