Condition Monitoring- A Case Study
Being currently involved in a research project on Asset Management practice in Construction industries, I have been interacting with folks within the industry to understand the peculiarities involved in their Asset Management practices. One such interaction I think is worth mentioning here and this relates to a sparingly or partially used maintenance practice- The Predictive maintenance in the construction industry. The projects awarded to the construction companies depends largely upon their ability to deliver quality projects in a time effective manner requiring them to rely heavily on the maintenance functions which drives the reliability parameters and hence governing the upkeep of the equipment. While the industry does reasonably well with the traditional kind of maintenance like preventive and corrective maintenance (CM), the proactive maintenance still lacks the charm. What do we need for a successful condition monitoring, heaps of operational data? A high profile instrumentation infrastructure? Knowhow of slice and dice data analysis, possibly true but in my opinion these are not comprehensive enough. I think while these are some good enablers, the most important factor for a successful CM is the understanding of reasons behind the every actions which are being performed in the exercise, be it gathering or analyzing a specific set of data or performing a certain set of corrective actions to evade a failure and more importantly spreading this understanding to each and every stake holder involved in the CM exercise. You can witness several CM programs failing because of the limited understanding of holistic program goals. Here's presenting the case study of how a seemingly workable condition monitoring exercise can possibly go wrong.
The case company had procured a fleet of excavators and pipe layer equipment for their interstate gas pipeline project. Being critical equipment, it was a mandate to practice detailed documentation of operational and condition monitoring data for these equipment's. These information were being relayed directly to the company's headquarter on a regular basis. The maintenance team did that religiously, capturing the hours run, the Sequential Oil Sampling (SOS) results etc. and sharing it with the concerned team.
Why? - Because "someone" is asking for it
Does that "someone" know what is destiny of these information? - May or may not be!
How is the information which we are sending being used? - Who cares, we have better work to do than worrying about other's Job!
Now taking you to the real problem. The excavators which were deployed to rip through the right of way (RoW) for seating the gas pipeline had a target of clearing about a minimum stretch of 1 KM) per day. They were the heroes braving the tough terrains and also were the favorites among the operations team for this reason. Any breakdown would mean an overall impact to the project timeline. You know how the constructions company contract and their penalty clauses are, it's tough to miss even a single milestone. Everyone were on their toes and watching the equipment performance closely. While all equipment followed a comprehensive preventive maintenance schedule, one of them received a special attention. The reason was a perennial hydraulic leakage being reported. The field engineers while engaging the vendors with whom the responsibility of the equipment under warranty resided, also ensured that they double up the PM schedules to ensure that they make up for the dropping oil levels. As a maintenance engineer, it was natural to equate an oil leakage to an O-Ring or a hydraulic seal issue and the maintenance team exactly did this. A day or two down, the leakage would resume and the frustration cycle continued. As the situation worsened, the team decided to look deeper into the problems. It was definitely not an inferior quality of seals. The team could have easily concluded this because they were sourcing the original spares from the OEM. What was it then?
Detailed inspection revealed scoring of the cylinder piston rods which created an abrasive surface for the seals thereby naturally wearing them. The equipment was brand new, for the given life of the hydraulic cylinders which runs into years of operations, this early failure of the piston rod was unusual and left the maintenance team baffled. Though late, but when they decided to run through past condition data they found a substantial evidence- A high copper concentration in the hydraulic oil. The oil sampling results had been showing increased copper levels but neither the field engineer who were reporting the data nor the bosses sitting in the head office caught the spike. Having done some quick primary root cause analysis it was concluded that the increased metal level was the prime reason contributing to the failure. The metal increased the abrasion thereby resulting into cylinder piston and a subsequent seal damage. The field engineers concluded that the origin of the rising metal level was a result of worn out copper bushing of the gear pump supplying hydraulic oil with residual metal directly into the hydraulic circuit. Replacing of the copper bush was a cheap one but replacing the complete hydraulic cylinder was not. The field engineers claim- We gave all the necessary information for the analysis, were not aware how to decipher the readings against the reference values so could contribute very little. For the bosses in the head office, again, the data collection had been one of the rituals which they performed religiously on all new equipment to be supplied to the equipment vendor. Actually, the goals were never associated to do a proactive monitoring but some reporting which they themselves were not sure about. In summary, the information on an imminent failure was broadcasted all over the place but still remained invisible to the key stakeholders. The team did their hard work but an action of simple copper bush replacement did not preceded a costly cylinder replacement!
The proactive nature of the CM emphasizes on the Root Cause Analysis element of the maintenance. To support this, CM feeds in with all critical information required for a continuous analysis and drawing of meaningful conclusions from a consolidated-comprehensive Asset view with relations and dependencies factors accounted. It is then just a matter of converting them into meaningful action items for the stakeholders to take up. The case discussed here is not a unique but one of countless cases where heaps of information gets wasted after being collected. The purpose is sometimes not known well, as in this case where the maintenance teams were completely cutoff from the mainstream use of the Asset data. None of the fleet engineers understood the actual intent of the data collection, neither did they appreciate the whole exercise, actually none of the stake holders did! They considered the whole activity as a complete non-value because the entire fleet of equipment's were anyways covered under preventive Maintenance. Anything over and above this and which did not contribute directly to the improvement of such PM programs were deemed as wasteful exercise. At the same time, the crucial condition data were disregarded by the folks who actually ordered this information. Had the intent been known or responsibility assigned correctly on who's expected to do what, the exercise could have be a more meaningful helping one to perform what was needed to be done when and how. All this even without getting entangled into complex statistics and science of probability. An equipment delivering reliable service has direct implication on the overall productivity of the firm while significantly improving the parameters such as timeliness of the project, cost effectiveness, utilization of manpower and improving the quality of work. This is the reason heavy investments are being made in the area of Asset Management to ensure the Asset reliability but while we are investing our energies towards a cause which is so critical let us also ensure that we have the knowledge and the accountability to fend for it and more importantly making the most of what we already have!