Wednesday, 16 January 2013

Managing the depth of RCM

RCM stands for Reliability Centred Maintenance. It is a process whereby a series of questions are structurally raised to conclude a maintenance requirement. It can be as tedious as a full blown RCM where you are moving on average about 3-4 Failure Modes an hour in a RCM workshop to a quick straight forward 30-50 Failure Modes an hour in a peer review workshop.

How deep to go for the RCM analysis? There're a few things to consider when making this call.

  1. How skilled are your maintenance team in addressing the Failure Modes? There is no point going into too detail if your trades does not share the understanding and knowledge. For example, carrying out vibration analysis on an equipment without a skilled person is useless. No one will be able to interpret the data and put it to good use. Your strategy would then have to be fine tuned to fixed-time replacement on an optimized shutdown interval.
  2. How critical is the equipment? The more critical it is, the more time should be invested towards making it performing reliably.
  3. What is the current state of the maintenance strategy? Is it running reliably? If it is, are we seeing potential Failure Modes that we are not addressing? A peer review to close the gap in the strategy is sufficient in this case. If the equipment is not reliable to start with, it may require a full blown RCM from scratch.
  4. There will be times where you run into a highly critical equipment but yet the Failure Modes are highly unlikely. The facilitator or reliability engineer would have to make the call whether a full blown RCM is worthwhile or manage the risk with a peer review process to ensure all gaps in strategies are covered. This require local plant experience that none of your external consultants have. Re-emphasize, invest in your reliability team!
  5. ???

A note to reliability managers out there, if a person pitch you they can deliver RCM workshop at 15 Failure Modes an hour, be very wary about it. You get what you pay for. Quality takes time and it is inevitable in RCM! Again, your best value is through having invest in a very good reliability engineer on your side. After all, the RCM databases will still require maintenance and update in-house, unless you are ready to pay the continual work from the consultancy.

Post-Operational Readiness Project (Continuous Improvement)

With the growing world, the mega projects keep coming. With mega projects comes the need for certainty to the investor. In the world of plant maintenance, the certainty comes from Operational Readiness Project. To some, it is a common phase of a project, to some parts of the world, it is an alien that they have never heard before, that includes experienced multinational EPCM contractors.

If you are deciding on the OPEX of a project, and your EPC or EPCM contractor gives you a cost projection that says, oh, it's 3-5% of capital cost. Ask them where that figure comes from, chances are they'll say it's an estimates from historical data. I can also tell you the figure is INCORRECT. Why? It is because your operating cost depends on the quality of your equipment too! Not in linear, or able to be defined by any mathematical algorithm model! It has to be painstakingly compiled, equipment by equipment, building up to the complete plant! A simplified example, a Japanese car OPEX will be very different from a German car OPEX. They have different service intervals, differing coping ability in operating bandwidth & context, difference in material cost, different in complexity. In some cases, higher capital upfront is justifiable! This has to be evaluated on a case by case basis in details.

Planning and budgeting an Operational Readiness to get your master data up to standard, and having all your equipment registered is essential to every process plant. Once up and running, the OEM recommended maintenance plan has to be put in. No, the process does not end here. You need your reliability team to continually manage the plant changes, and it has to update the master data to reflect the changes occur over-time. As the equipment fails in service, reliability engineers need to assess and evaluate your maintenance task to optimize the time and cost for improvement in reliability, increase in production and reduction in cost. This is an on-going task that cannot be neglected.

From experience, a neglected Master Data can cost upwards of $10 million dollars or more to clean up in a brownfield project and a trailing $1 million dollars a year of labour to keep it clean as they go. If a dedicated person acting as the gate-keeper since day 1 at a price of $150,000 a year, imagine how much less money needs to be re-invested to maintain the original business case projected reliability figures!

A lesson for the Executives out there, Operational Readiness does not guarantee you the reliability outcome. Reliability is a culture and an on-going continuous process. Invest in your reliability team!

Reliability Modelling

I have been working full on until New Year building component library for a consultancy and running reliability modelling. I have run into a lot of issues with the model and would like to share them to promote an understanding.

The very first thing you do as an engineer is always question the validity of those data you acquire. In summary, I would not recommend doing reliability modelling. My personal opinion is, it is a waste of time, effort and money. If you are looking at doing reliability modelling, chances are, your existing plant reliability is not great and your reliability knowledge is not comprehensive. For the accuracy you get, you are better off with a 0.9 factor of industry average reliability figure. No modelling out there I have seen is accurate enough for any good use. If you are doubtful on the quality of people you are able to hire into the maintenance team, use a factor of 0.7 and you should have a somewhat conservative availability figure. Yes it looks ugly, yes it looks unrealistically low, but I'm sorry to say, that is reality of the availability and reliability figure you should expect for saving cost hiring cheap people. I could not emphasize enough, good asset management and reliability starts with good people.

Back onto the topic I was suppose to be writing about - Limitations of reliability model. Firstly, ALL reliability model I have seen is designed in series. It is all well and good if your process is in series like a simple production line of a simple mine site, if you have a complicated processing plant, your reliability model will not do. In fact, there's so much work trying to design the model to fit your plant, it is just not worth the effort. Unless there's a free template already setup similar to your plant and takes just a little bit of effort to patch up, there's no point going down this path.

Secondly, in a complex process plant, you will have varying equipment MTBF and MTTR. Every plant's figure is unique. For the model to be accurate enough to be of any use, it has to be from your plant, your production forecast, you historical availability, and reliability. This is because as the errors build up in the reliability model, the final result is again of not much use to you as the owner.

Thirdly, a complex equipment in a complex plant will have a long list of failure modes to prevent. Some of these failure modes will be attended to in one work task and reset their likelihood of occurrence and budgeted life. None of the reliability model I seen cater for this.

With this three fundamental issues in modelling unresolved, I would not recommend any company looking at carrying out the modelling without understanding the limitations of it.