The safety of process automation

The effect of automation on process safety is not clear. On the one hand, automation is blamed for posing risk and for increasing the chance of human error in situations involving disturbances; on the other hand, it is admitted that automation enables sophisticated process control and handling of disturbance situations without human interference. The methods of safety analysis can be applied during the designing stages of safe process automation. The hazard and operability study makes it possible to take into account the potential process disturbances and to develop countermeasures for them. Action error analysis studies the consequences of potential human errors in task execution. Fault tree analysis can be used to study the causes of potential accidents and to examine the control actions suitable for providing protection against them thereby reducing the probability of accidents. Event tree analysis is a method for considering the consequences of potential hazardous situations and for developing countermeasures to reduce such consequences. Failure mode and effect analysis is a method for checking that the potential failures of the control and automation system are not overlooked. Reliability assessment can be used with safety analysis methods to study the bottlenecks in the design and to prioritize the countermeasures whereby the risk can be reduced to attain an acceptable level