Visibility states

The risk of a hazard depends on the operators awareness of it. Accordingly, we need to define two states of the hazard, corresponding to two stages of its development:

• Latent. Initially, at the time of its generation, the operators are still not aware of the hazard.
• Apparent. Normally, after a while, the system generates an alarm and the operators become aware of the hazard.

Case studies

Hazard visibility is a key factor in many celebrated accidents. latent hazards were involved in:

• The state of the steering lever of the Torrey Canyon
• The state of two valves at the TMI accident
• The turning off of the secondary and the auxiliary pumps at the TMI accident.

  If the system does not alarm about the hazard, the operators might not know about it in time.

  The system should detect all hazard s and the operator should be able to cope with the hazard before it threatens.

Related topic

Updated on 28 Oct 2016.