Reliability Assessment: A Guide to Aligning Expectations, Practices, and Performance. Daniel Daley
anyone,” said Joe. “I am just trying to describe some of the things that affect the reliability of this machine. It really doesn’t matter to this machine if it was slugged with liquid due to operator oversight or a malfunctioning suction drum level instrument.”
About this time, several of the people in the meeting began to glaze over. Apparently the meeting was not going as they had expected. They wished they were elsewhere.
Joe again reached into his file and pulled out two documents. He was sensing that his air time was running out and, if he wanted to make a point, he would need to do so quickly. “This first document is a record of predictive and preventive maintenance,” started Joe. “it shows that roughly fifty percent of the time the recommended PM is not being done.”
Joe flipped to the second document, saying, “This is a record of the work that was recommended for the last turnaround and the work that was actually completed. Our analysis showed that several components were at the end of their life and several other components would not survive another run. You can see that the decision was made to defer the overhaul from the turnaround. Here you see that when the bearings failed, the other components with limited life were not changed because of the desire to get the machine back as quickly as possible. The decision to defer the overhaul from the turnaround caused the first shutdown. In turn, the decision to make only a partial repair caused the second.”
By this time, the Plant Manager had seen enough. He said, “I will have to take responsibility for those decisions. I made those choices.”
Again sensing that his audience was running out of patience, Joe pulled out the last two documents from the folder. The first was a document from a recent project and the second was a copy of a recent budget detail.
Pointing to the project document, Joe began by saying, “The first of these documents describes some communications that occurred during the recent capacity expansion project. You may or may not be aware that the corporate project management process does not include any design-for-reliability or reliability analysis steps. As a result, we in the plant reliability department performed a comparison of the pre-project reliability and compared it to the reliability of the proposed post-project configuration. Our calculations showed that the proposed post-project configuration would be less reliable. This is the result of the redundant electrical feeder to this machine being used to supply a new load. We made a recommendation to the project manager that the redundancy be maintained, but was told that was beyond the project scope.”
Once again, the Assistant Plant Manager interjected, “That was analyzed and viewed as an acceptable risk.”
Joe responded, “One problem is that risk is really a measure of hidden cost. In some cases, the costs appear later; in other cases, the costs appear sooner. In this case, we have already experienced a failure associated with this choice. Although the failure was charged to this machine, it was really a failure of the electrical system that supplies the motor — and the decision making process”
Joe continued, referring to the final document, “This final document is a copy of the budget detail for last year. I have highlighted a line item that proposes replacement of several outdated controls on the machine. Also some of the instrument wiring shows deterioration and should be replaced as a part of our plant renewal initiative. As you can see, the line item was struck from the budget and will need to be proposed for some later time.”
“Is that all” said the Plant Manager, “or is there anything else?”
“That’s about it,” answered Joe.
“Well, I can see how some of these things might have an effect, but I guess I don’t completely follow what you are saying,” said the Plant Manager.
Sensing that several of the participants were becoming defensive, Joe started slowly to explain, “At the beginning of the meeting, you said that this machine was not meeting expectations. For reliability, realistic expectations should be based on an assessment of risk. Risk is a measure of the likelihood that an undesired event will occur. In this case, the undesired event is a shutdown of this machine. Each choice and action during the life of the machine will affect the risk of failure. In some cases, choices will improve reliability, some choices will maintain the same level of risk, and some choices will deteriorate reliability and increase the risk of failure. Each of the choices I have mentioned today tended to increase the risk of failure and reduce reliability. Thinking in terms of ‘what we have a right to expect,’ we should think of reducing our expectations or investing in efforts that will enhance reliability.”
“Well, Joe, I think I speak for everyone here when I say that we appreciate your efforts in assembling the information you shared with us today. I am sure you have other things you need to do and we have taken enough of your time,” said the Plant Manager, looking around the room. “If everyone else would hang around a few minutes, Joe, you can get back to work.”
Joe left the file with the Plant Manager and departed his office, closing the door behind him. The room was silent for a few minutes. Finally, the Plant Manager broke the silence asking, “Are there any comments?”
The Manager of Reliability and Maintenance (to whom Joe reported) started with, “Joe is a very conscientious employee. He takes his job seriously and works a lot of long hours.”
After another few moments of silence, the Plant Manager began, “I guess I have two observations. The first has to do with the information in this file. From my viewpoint, it is too late to bring these things up at this time. If they were as critical as Joe contends, he should have brought them up earlier.”
The good-hearted but naïve Operations Manager responded, “I think he did bring them up, but no one listened.”
His face reddening, the Plant Manager responded, ignoring the Operations Manager and speaking directly to the Assistant Plant Manager (to whom the Operations Manager reported), “You miss my point entirely. It is his job to get our attention. He needs to get our attention when there is a problem. He needs to be more persistent. That is his job.”
By this time, the room was completely silent. No one but the Plant Manager spoke. “I said there were two things. The second is the defeatist attitude I heard. What I heard in the tone of what he said, if not the words, was that he was giving up on this machine. We just cannot afford that kind of attitude.”
The meeting was over. Ignoring the others in his office, the Plant Manager looked down on his desk and began working on something else. One by one, the other members of the audience got up and left the office.
Some months later Joe was given his annual appraisal. Although there was nothing specific, his supervisor mentioned that he was not viewed as a “team player.” Several months later, Joe parted and joined another company.
Joe’s new employer thought he walked on water. Joe’s old company continued to suffer along with frequent failures of the recycle compressor and poor reliability in general.
Although this story is only fictional, it is a compilation of a variety of real-life experiences. It is intended to impart several messages to the reader:
1.Each of the papers Joe extracted from his folder represents one of the elements that contribute to the overall reliability of any system or piece of equipment.
2.The composite reliability or “what you have a right to expect” is a combination of all the items mentioned.
3.Unless the impact of each choice is clearly quantified, it is impossible to have an accurate understanding of reasonable expectations. Most people like to recall only the good things.
4.People can become defensive when their decisions are shown to be faulty.
5.It may be better to have a third