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THE ROLE OF HUMAN ERROR IN ACCIDENTS
INTRODUCTION
After many years of improvements in the technical security methods in the design process
many organizations they have found that the frequency rate and the severity rate of accidents /
incidents have reached a Palteau that seems difficult to reduce. Another fact is that even in
organizations with a good trend in the accident occur occasionally of large-scale disasters that
reduce public confidence in chemical companies. The common factor for these phenomena is
human error. This is probably the biggest contributor to accidents-accidents. Human error also
has a significant impact on the quality, production and ultimately profit.
Thus the priorities of the organizations influence the resources made available for safety
compared to that for the production dates. Factors such as the degree of participation that is
encouraged by the organizations, the quality of communication at all levels have the greatest
impact on safety. The existence of clear policies that ensure good procedures and training
also impact on the probability of occurrence of human errors.
Inappropriate policies at the corporate level or inadequate implementation of the line
management policies create conditions at the operational level, which results in "latent errors"
that do not cause damage themselves, but in combination with other conditions (such as noise
levels at plant) give rise to operational errors (eg "unsafe acts" as incorrect operation of valves
or inadequate maintenance) then .If your systems (hardware and software) are also
considered inappropriate then it can rise to a negative effect (result catastrophic).
A CASE OF ERROR
A major cause of failure is the imbalance between demand from the process system and the
human capacity to meet that demand. One aspect of the application is the call for human
capabilities that arise from the nature of work, as well as physical capacities (solder a pipe,
tightening a flange), mental ones (diagnosing a problem, trend interpretation) and the sensory
(be skilled to identify changes in the process) are more or less all requests from different jobs.
On the side of the capacity (resources) we can say that these will be developed when the jobs
and tasks are designed to use these skills effectively if the teams are made strictly in terms of
roles, if the staff is properly trained and formed .In addition to these resources will be more
effective if there is an appropriate culture within the company that makes sure that there is the
right to personal commitment. An important aspect of optimization is make sure there is a
proper allocation of functions to which they are assigned problem-solving functions and
diagnosis to men where they excel, while features such as long-term monitoring are entrusted
to machines / computers.
A CASE STUDY
In a batch system in an exothermic reaction in a cstr reactor it was controlled by circulating
cooling water in the jacket. The circulation pump broke and there was a run -away reaction
resulting in violent explosion .A low flow alarm was present but not he was operating. A
bearing of the pump was not lubricated during the maintenance and the bearing collapse had
led to the stop of the pump. The accident report reported that the cause of the accident was
human error. Although there were maintenance procedures were not used.
Conditions that led to the error
1) (design factors and culture)
There were several reasons why the maintenance procedures regarding the bearings were not
used .They had been provided by the pump supplier and were written on a highly technical
language format and layout of the process made it difficult to find information. The nature of
the maintenance that had changed it since the maintenance procedures had been written, but
there had been updated. The general culture in the workshop was that only young people
would read procedures. Since the technicians had not been involved in the development of
not it was believed their procedures. The training was done "On the Job" and there was no
competency testing system.
2) (Factors Organization due to politics)
There was a lot of distraction in the workshop: maintenance technicians working under
considerable pressure on many pumps .The situation had arisen because there was no
effective political scheduling. there were no policies to update the procedures or training .
Furthermore, maintenance of the bearings had been omitted on several occasions but had not
been noticed as it lacked an effective management of accident reports and were not discussed
near misses.Il fact that the plant was working with a low flow alarm inoperative was an
indication of deficiencies in the management of safety.
An opportunity for error recovery might have been the implementation of a review by a
supervisor or by the safety manager since the pump was a critical item. The fact that the
critical cooling of a reactor depended on a single pump and 'symptom of a poor design that
would be able to emerge if it was done a HAZOP.
EXAMPLES OF ERROR
The following is a list of errors of process:
1) errors in the system changes and stressful situations
2) Inadequate interface Man -Machine
3) not suitable for the display of process information
4) poor way to label equipment and process lines
5) not appropriate scale on instruments
6) errors due to false assumptions
7) bad operating procedures framed
8) violation of the routine
9) ineffective organization of work
10) error in the allocation of operational responsibilities
Some examples of errors:
1) an operator is wrong to close a valve due to spatial confusion with other valves
2) an operator assumes that the reactor is OK on the indication of the temperature, which was
proved to be wrong
3) operate a mistake in the diagnosis of the causes of severe abnormalities under
considerable psychological pressure
4) an operator does not follow the procedure because he considered no longer relevant for the
task to be performed
5) the safety devices are reset by a supervisor in order to perform quickly the orders
STRATEGIES FOR REDUCING ERRORS
Examples of strategies to reduce errors:
1) physical training (repeated practices of operations of equipment)
2) checklist with BEGINNING and end points
3) Labelling of lines and valves
4) ensure that operators receive extensive hands-on training on the rules
5)) explanation of exceptions and possible errors
6) which can provide simulations of complex events and encouraging development of
intervention strategies
7) provide training on the dynamics of the process
8) provide data as a P & I in an easily accessible format
9) provide problem-solving patterns and make sure all information is taken into account
10) make sure that they are given appropriate information so that workers do not use
inappropriate rules similar symptoms but have different causes.
11) provide feedback
ALFREDO RUGGIERO
Reference: Guidelines for preventing human error in process safety –CCPS-Aiche

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THE ROLE OF HUMAN ERROR IN ACCIDENTS

  • 1. THE ROLE OF HUMAN ERROR IN ACCIDENTS INTRODUCTION After many years of improvements in the technical security methods in the design process many organizations they have found that the frequency rate and the severity rate of accidents / incidents have reached a Palteau that seems difficult to reduce. Another fact is that even in organizations with a good trend in the accident occur occasionally of large-scale disasters that reduce public confidence in chemical companies. The common factor for these phenomena is human error. This is probably the biggest contributor to accidents-accidents. Human error also has a significant impact on the quality, production and ultimately profit. Thus the priorities of the organizations influence the resources made available for safety compared to that for the production dates. Factors such as the degree of participation that is encouraged by the organizations, the quality of communication at all levels have the greatest impact on safety. The existence of clear policies that ensure good procedures and training also impact on the probability of occurrence of human errors. Inappropriate policies at the corporate level or inadequate implementation of the line management policies create conditions at the operational level, which results in "latent errors" that do not cause damage themselves, but in combination with other conditions (such as noise levels at plant) give rise to operational errors (eg "unsafe acts" as incorrect operation of valves or inadequate maintenance) then .If your systems (hardware and software) are also considered inappropriate then it can rise to a negative effect (result catastrophic). A CASE OF ERROR A major cause of failure is the imbalance between demand from the process system and the human capacity to meet that demand. One aspect of the application is the call for human capabilities that arise from the nature of work, as well as physical capacities (solder a pipe, tightening a flange), mental ones (diagnosing a problem, trend interpretation) and the sensory (be skilled to identify changes in the process) are more or less all requests from different jobs. On the side of the capacity (resources) we can say that these will be developed when the jobs and tasks are designed to use these skills effectively if the teams are made strictly in terms of roles, if the staff is properly trained and formed .In addition to these resources will be more effective if there is an appropriate culture within the company that makes sure that there is the right to personal commitment. An important aspect of optimization is make sure there is a proper allocation of functions to which they are assigned problem-solving functions and diagnosis to men where they excel, while features such as long-term monitoring are entrusted to machines / computers. A CASE STUDY In a batch system in an exothermic reaction in a cstr reactor it was controlled by circulating cooling water in the jacket. The circulation pump broke and there was a run -away reaction resulting in violent explosion .A low flow alarm was present but not he was operating. A bearing of the pump was not lubricated during the maintenance and the bearing collapse had led to the stop of the pump. The accident report reported that the cause of the accident was human error. Although there were maintenance procedures were not used. Conditions that led to the error
  • 2. 1) (design factors and culture) There were several reasons why the maintenance procedures regarding the bearings were not used .They had been provided by the pump supplier and were written on a highly technical language format and layout of the process made it difficult to find information. The nature of the maintenance that had changed it since the maintenance procedures had been written, but there had been updated. The general culture in the workshop was that only young people would read procedures. Since the technicians had not been involved in the development of not it was believed their procedures. The training was done "On the Job" and there was no competency testing system. 2) (Factors Organization due to politics) There was a lot of distraction in the workshop: maintenance technicians working under considerable pressure on many pumps .The situation had arisen because there was no effective political scheduling. there were no policies to update the procedures or training . Furthermore, maintenance of the bearings had been omitted on several occasions but had not been noticed as it lacked an effective management of accident reports and were not discussed near misses.Il fact that the plant was working with a low flow alarm inoperative was an indication of deficiencies in the management of safety. An opportunity for error recovery might have been the implementation of a review by a supervisor or by the safety manager since the pump was a critical item. The fact that the critical cooling of a reactor depended on a single pump and 'symptom of a poor design that would be able to emerge if it was done a HAZOP. EXAMPLES OF ERROR The following is a list of errors of process: 1) errors in the system changes and stressful situations 2) Inadequate interface Man -Machine 3) not suitable for the display of process information 4) poor way to label equipment and process lines 5) not appropriate scale on instruments 6) errors due to false assumptions 7) bad operating procedures framed 8) violation of the routine 9) ineffective organization of work 10) error in the allocation of operational responsibilities Some examples of errors: 1) an operator is wrong to close a valve due to spatial confusion with other valves 2) an operator assumes that the reactor is OK on the indication of the temperature, which was proved to be wrong 3) operate a mistake in the diagnosis of the causes of severe abnormalities under considerable psychological pressure 4) an operator does not follow the procedure because he considered no longer relevant for the task to be performed 5) the safety devices are reset by a supervisor in order to perform quickly the orders
  • 3. STRATEGIES FOR REDUCING ERRORS Examples of strategies to reduce errors: 1) physical training (repeated practices of operations of equipment) 2) checklist with BEGINNING and end points 3) Labelling of lines and valves 4) ensure that operators receive extensive hands-on training on the rules 5)) explanation of exceptions and possible errors 6) which can provide simulations of complex events and encouraging development of intervention strategies 7) provide training on the dynamics of the process 8) provide data as a P & I in an easily accessible format 9) provide problem-solving patterns and make sure all information is taken into account 10) make sure that they are given appropriate information so that workers do not use inappropriate rules similar symptoms but have different causes. 11) provide feedback ALFREDO RUGGIERO Reference: Guidelines for preventing human error in process safety –CCPS-Aiche