Trinath Sahoo - Root Cause Failure Analysis

feedback system: feedback is poor, ambiguous, or inappropriate,

conformation: no clear conformation is available from the system of the action that is required to control it,

inexperience: the circumstance present requires experience, to understand and control the situation, beyond that of the person involved,

information quality: specified procedures, or instructions from other humans, are of poor quality such that they are inappropriate to the situation present when followed,

diversity: the system has no diversity to allow checking of information presented,

physical ability: the person does not have the physical ability to perform the required tasks,

mental stimulation: the person is required to spend a lot of time either inactive or involved in highly repetitive, menial tasks,

disruption: work patterns cause disruption to normal sleep and rest cycles,

pacing: other people influence the pace at which tasks can be performed,

over manning: more people present than required to do the job satisfactorily.

Human performance depends on a lot of factors which means they perform differently in different situations. Below are list of factors that affects people performance.

reaction to stress,

fatigue,

supervisor's expectations,

social interaction,

social pressure,

group interaction and identification,

crew efficiency,

morale,

time at work,

idle time, and

repetition of work.

These factors should be taken into account for considering reliable system. What is the possibility that good engineering practice will not be followed? It is also important to consider these factors when selecting personnel or setting up teams.

If we eliminate human error or at least reduce the consequences, we will have gone a long way to preventing failures. To improve human reliability, we need to understand what affects it. Human's will always make errors, the reason that failure happen because of latent errors that are present in the systems which do not give the operator a chance. These latent errors are the root cause of most failures. The way to reduce human error through effective management such that reliability is considered important by everyone involved.

Procedures are very important and should be well thought out.

They should be clear, precise, and easy to read.

They should be easily understood by those who will use them. The best way to achieve this is to write procedures with close participation with those people.

They should be easily accessible.

Checklists should be provided, to be followed for unusual circumstances. The system should be checked for any shortcuts that may be easy to take and that will cause risk.

These will generally be regular checks made by independent assessors covering a wide range of features like whether maintenance procedures are followed or not, whether equipments are running within operating window or not etc. They provide a good indication of the obvious problem areas.

Here people are punished for the failures they are involved in. Once again, this is more likely to reduce reporting of errors rather than necessarily the number of failures. It also requires placing the blame on certain people. Although an operator might have been directly involved, the failure is more likely to have been caused by latent human errors which may not be so obvious and are out of their control. Of course, it is usually the management of a company that would decide who to punish, blaming an operator is a lot easier than blaming a manager who is really more responsible by allowing latent errors to be present in the system.

Here human manual control is replaced by automatic controls, generally electronic devices. These devices will do as instructed without the problems of human variability and unpredictabilty. With a high amount of automation, the human has different tasks to perform. They are basically there to deal with unforeseen circumstances or to perform tasks that the designer cannot automate. This generally means that during normal operation there is less to be done. Automation can be useful but must be designed correctly. The information should match the operators own mental idea of what is happening. The information should be useful. Important information should be given priority, cross checking should be possible to validate information, alarm analysis and decision aids should be included. Operators probably need more training to operate automated plant although it would appear they have less to do than on a manually operated plant.

Automation can be useful but must be designed correctly. The information should match the operators own mental idea of what is happening. The information should be useful. Important information should be given priority, cross‐checking should be possible to validate information, alarm analysis and decision aids should be included.

Training is very important in the effort to reduce human errors and hence accidents. Safety training is vital for everybody involved in the system. Operator training will not, however, improve reliability when the root cause is bad design or poor management. Training given should be well planned and appropriate to the job. Realistic simulation and role‐play exercises are some of the best ways to train people. Everybody must be familiar with the system and made aware of the risks involved and how their actions effect reliability. Training should cover the use of all job aids including procedures, and other ancillary and emergency equipment. Recovery procedures should be explained for use after errors have been made. Personnel performance checks and evaluations should be used and good, constructive feedback given at regular intervals. Refresher training should also be used to prevent behavior patterns building up such that variations of equipment and procedures can not be handled.

This is a system where some sort of reward is offered for operating in a reliable manner. This usually involves analyzing failure rates. There’s little doubt that advertising and campaigns can significantly affect how people think and act. It is not a set offixed rules; it is purely a collection of recommendations. Pick and choose what you want, adapt them to your individual circumstances. People are in undated with information every day. To grab their attention, your message must be short, simple and relevant to your target audience. They must immediately understand its importance and what you are asking them to do and why. Try to distil your main message down to a jargon‐free statement, ideally no longer than two sentences. One way to do this is to think in terms of ‘problem and solution’. Other method for campaign areRaise awareness of reliability problems, including their causes, amongst managers, employees and people who advise them on these issues. Provide practical solutions through ‘good practice models’. Alert people to new risks and possible solutions.

Human error does account for a large number of accidents, however, it is the latent errors that are the real root cause. It is far too easy to blame operators for causing accidents but it must be appreciated that all humans will make errors. It is the job of the management to ensure that system and procedures are in place to avoid such incidents. The responsibility starts at the very top, with the managing director, and must work its way to all levels in the company. That way the company culture will improve to support reliability first.