Explicit rules

The explicit rules define the design scope .

Definition

An explicit rule is specified in the system documents, and thereof implemented in the system design.

Rule design

The applicability of operational rules depends on modes, and is subject to the scenario thereof.

  Scenario-based rules prohibit latent failure, such as those performing normal maintenance when the system operates in normal functional mode.

Examples

• The TMI accident due to disabling of the backup cooling system  ( Perrow ) could be avoided, as this activity is not permitted in normal functional operation
• The Torrey Canyon accident due to disconnecting the rudder from the wheel ( Casey ) could be prevented, as this action is not permitted in normal navigation.

Related topic

Updated on 17 Apr 2016.