MASTERING LITERACY OF SAFETY USE CASES- HOW TO TAME THEM, HOW TO MAKE THEM EFFICIENT, HOW TO RE-VALUE THEM

A safety use case describes in Romania the development and consequences of an unpredicted work event, a near-miss situation and things like this. Traditionally, use cases are having an educational purpose. Safety use cases are narrations of real unexpected events- that were recorded using the recollection of survivors together with the expertise of safety inspectors. Sometimes, even the use case is very interesting; it is not recorded because it is considered as not significant.

Our approach is oriented towards the improvement of the development process of safety cases- not just around safety training but also focusing on the optimal decisions that should be taken by the top management connected with the safety and well being of the workers.

We have started with the improvement of classic use cases – UML style. Here beyond the traditional components we have introduced two distinct classes- ”Safety affected”- that is leading to the unexpected event- and could be further developed using the 5 Why method – and ”Safety mitigated” including mitigation solutions.

Our further developments have established a cognitive framework for the safety use cases- with three main parts:

-the description (in natural terms) of the unexpected event start-up- having attached the results of the 5 Why analysis and also a taxonomy that is revealing the exact role of the Human Failure, Safety Failure and Machine Failure in the birth of the unexpected event.

-the happening of the unexpected event;

-the resulting consequences and the possible scenarios that could happen or that could be developed in the making of an optimal decision;

The safety use case framework is boosted by two expert mechanisms- an use case constructor- that is performing the most  routine operations regarding the optimized building of the use case (the use case constructor-UCC- could be goal oriented considering simultaneously 3 different goals) and an use case destructor-UCD- that is ”killing” the non-interesting or non-significant parts. 

UCC is completing/tailoring the terms from the narration with terms found in a specific ontology developed for this instrument.

A special accent is put on the so called “transition areas” when the use case is performing its main developments towards the nefarious event.

Having a draft use case developed by UCC and not destroyed by UCD- the case is tested against uncertainty factors that are specific to the industrial domain of development. An old use-case could be”refurbished” and re-used.

 The obtained results have been integrated into a primary list of safety use cases. The use cases will not cover all existing problems but will focus on the most important ones which most likely will have a big impact on the decision making process.

We considered interesting to share this experience with other interested parties at the Hazards conference- hoping eventually to establish a cooperation regarding the development and usage of safety use cases.