Mechanical Technology may 2015

⎪ Proactive maintenance, lubrication and contamination management ⎪

reactive and preventative maintenance strategies alone. What about predictive maintenance methods? Not very long ago the choice in technology was both very limited and costly (vibration, oil analysis and infra-red thermography) and so too the applicability. It also made selection easy. Now there is very little that cannot be done and costs have tumbled. Not only in choice of method, but often also in terms of whether conducted in-house or outsourced, on or off-line, periodic or continuous, local or remote, manual or

definition of predictive maintenance is understood to include all forms of condi- tion assessment or condition monitoring that is conducted with the asset in situ in the assembled state. A condition assessment is a ‘snapshot’ of asset condition determined at a single point in time. Condition monitoring in- volves either continuous on-line or regular trending of periodic assessments. In predictive maintenance, the insight into asset condition may be used to trigger an intervention, but this is not a given because, in many circumstances, run- to-failure is a good option. The predictive maintenance benefit is that there is no longer an unplanned outage – unless the prediction is ignored! A degree of maturity must first be achieved to bring the concept of pre- dictive maintenance into reality, for its acceptance and practical application to the benefit of the organisation. Only then can the question of which assets to consider for predictive maintenance be properly answered. This should not be surprising, as there is a necessary period of learning required. Not only in how to use the technology, but also in the nature and extent of knowledge obtained that was hitherto unseen and unavailable. It takes time to build confidence in this new business tool. It is quite normal to have initial responses such as: “I don’t know if I can believe there really is something wrong with my machine, so why take it down? I will wait and see. If it fails I will believe it next time”. Acceptance takes time. The danger is that this period of learn-

ing and confidence building can become extended. When the smart young guy with the fancy gadget is proven correct, the old hands often feel threatened and defensive instead of embracing it as an aid to better business. In the meantime, the predictive maintenance team becomes somewhat alienated and protective of their new-found skill. So silo building begins. There is a natural tendency for this to occur when predic- tive maintenance is first introduced into an established organisation. If the two components of proactive maintenance – preventative and predic- tive maintenance – are confined to silos, the path is easier, but significantly less rewarding. First prize is to have the predictive and preventative teams work- ing together very closely – this is the essence of proactive maintenance and essential for fully realising its benefits. What it also means is that an effective and comprehensive proactive mainte- nance strategy cannot be introduced into an existing organisation without passing through the predictive mainte- nance phase. As with many things in life, learning to walk is essential before we can learn to run. When the opportunities afforded by a mature and effective predictive main- tenance programme are fully realised, prior thought processes on preventative and even reactive maintenance must be revisited. When taken to their con- clusion, it should be realised that the investment in predictive maintenance is more than offset by the reduced costs and risks associated with traditional

Safety, environmental, reputational and other consequential risks asso­ ciated with failure are also increasingly important. If these outweigh the costs of conducting reactive maintenance, then it is an appropriate strategy for the asset in question.

automatic defect detection, manual or inclusive diagnostics, manual or inclusive prognostics, etc. On the surface it would appear to be simply a question of eco- nomics, but this is deceptive and is best left as a topic for a separate discussion. In order to realise the cost and reli- ability benefits of a full proactive main- tenance strategy, it is important take a progressive approach. It is only when an asset has already been categorised and successfully managed, based on preventative maintenance strategies, that predictive maintenance strategies and tools can be added to further reduce failure risks and their consequences. q

"Training is the cornerstone of an effective ultrasound inspection program." Allan Rienstra, SDT North America

Our Level 1 & 2 Airborne and Structure Borne Ultrasound Inspector's courses are a 3-day comprehensive mix of theory and practical experience and provide maximum transfer of knowledge, skills, and abilities. User Group discussions for CBM Ultrasound users and Underground Tank Testing. Don’t miss this opportunity to work one-on-one with the worlds most experienced ultrasound trainers and inspectors.

COURSE DATES UAS Software Training 31 st August & 1 st September Level 1 2 – 4 September 2015 Level 2 7 – 9 September 2015 Tank Test Training 7 – 9 September 2015 User Group 10 th September 2015

Tom Murphy

For further information and registration: www.martec.co.za• Tel.: +27 11 326 2708 • Cell: +27 76 903 7235 • Email: matthew@martec.co.za

Mechanical Technology — May 2015

13