4. High jeopardy risk
5. Inconsistent cueing
6. Monotonous, degrading, or meaningless work
7. Reinforcement absent or negative
8. Sensory deprivation
9. Suddenness of onset
10. Task load
11. Task speed
12. Threats of failure, loss of job
No two persons are similar, and perform differently even at the same level of
stress. However, many stress factors influence many people in similar ways. Therefore, to decrease human failures, the factors conducive to stress, need to be
addressed, thereby producing the right environment for everybody. In most cases,
it will be difficult to address stress arising from domestic trouble.
Control room operators not only work under critical conditions, but also perform
critical functions. When the plant starts, shuts down or suffers an upset, their skills
are under stress. When things go wrong, alarms usually trip up to catch the operators’
attention. Thus, control room designers need to minimize the number of alarms
required: if too many alarms get triggered too quickly during a plant upset, operators
may get disturbed and react incorrectly, thereby deteriorating the situation.
Weariness, often due sleep deprivation, is an important cause of human failure.
As the human body functions with the assistance of a biological clock, work shifts
can disturb the daily (or circadian) sleep cycles, entailing slow reactions to stimuli.
Thus, the response ability of the operator, to a rapidly developing scenario, may be
affected. In particular, night shift workers are more vulnerable to this problem given
the disruption of their circadian rhythm. Without stating any correlation, it is
significant to note that some of the worst industrial disasters including Piper
Alpha, Bhopal, Chernobyl, Three-mile Island, and Exxon Valdez occurred during
the silent hours. This does not imply that it is unsafe to work at night, but the
contextual combination of circumstances that matter, must be understood. It is
impossible to eliminate night shift work, particularly in continuous processing
plants. Thus, the risks must be understood, so that suitable steps can be taken to
minimize them. Apparently, some shift patterns (thus affecting sleep cycles) are
superior to others from an ergonomic point of view.
Apart from stress generated by circumstances, some work situations can entail
human errors (Lorenzo 2001). These should, of course, be avoided or remedied. A
non exhaustive list is:
1. faults arising from control hardware or software
2. high demand on operator attentiveness
3. improper housekeeping
4. improper tools and test equipment
5. inadequate ergonomics
6. inadequate, unsuitable or unclear communications
7. incompatible priorities, particularly between safety and production
20.2 Infrastructure and its Operation Requirements
577
5. Inconsistent cueing
6. Monotonous, degrading, or meaningless work
7. Reinforcement absent or negative
8. Sensory deprivation
9. Suddenness of onset
10. Task load
11. Task speed
12. Threats of failure, loss of job
No two persons are similar, and perform differently even at the same level of
stress. However, many stress factors influence many people in similar ways. Therefore, to decrease human failures, the factors conducive to stress, need to be
addressed, thereby producing the right environment for everybody. In most cases,
it will be difficult to address stress arising from domestic trouble.
Control room operators not only work under critical conditions, but also perform
critical functions. When the plant starts, shuts down or suffers an upset, their skills
are under stress. When things go wrong, alarms usually trip up to catch the operators’
attention. Thus, control room designers need to minimize the number of alarms
required: if too many alarms get triggered too quickly during a plant upset, operators
may get disturbed and react incorrectly, thereby deteriorating the situation.
Weariness, often due sleep deprivation, is an important cause of human failure.
As the human body functions with the assistance of a biological clock, work shifts
can disturb the daily (or circadian) sleep cycles, entailing slow reactions to stimuli.
Thus, the response ability of the operator, to a rapidly developing scenario, may be
affected. In particular, night shift workers are more vulnerable to this problem given
the disruption of their circadian rhythm. Without stating any correlation, it is
significant to note that some of the worst industrial disasters including Piper
Alpha, Bhopal, Chernobyl, Three-mile Island, and Exxon Valdez occurred during
the silent hours. This does not imply that it is unsafe to work at night, but the
contextual combination of circumstances that matter, must be understood. It is
impossible to eliminate night shift work, particularly in continuous processing
plants. Thus, the risks must be understood, so that suitable steps can be taken to
minimize them. Apparently, some shift patterns (thus affecting sleep cycles) are
superior to others from an ergonomic point of view.
Apart from stress generated by circumstances, some work situations can entail
human errors (Lorenzo 2001). These should, of course, be avoided or remedied. A
non exhaustive list is:
1. faults arising from control hardware or software
2. high demand on operator attentiveness
3. improper housekeeping
4. improper tools and test equipment
5. inadequate ergonomics
6. inadequate, unsuitable or unclear communications
7. incompatible priorities, particularly between safety and production
20.2 Infrastructure and its Operation Requirements
577