Appendix F - Barrier Analysis

There are many things that should be addressed during the performance of a Barrier Analysis. NOTE: In

this usage, a barrier is from Management Oversight and Risk Tree (MORT) terminology and is something

that separates an affected component from an undesirable condition/situation. Figure F-l provides an

example of Barrier Analysis. The questions listed below are designed to aid in determining what barrier

failed, thus resulting in the occurrence.

What barriers existed between the second, third, etc. condition/situation and the second, third, etc.

problems?

If there were barriers, did they perform their functions? Why?

Did the presence of any barriers mitigate or increase the occurrence severity? Why?

Were any barriers not functioning as designed? Why?

Was the barrier design adequate? Why?

Were there any barriers in the condition/situation source(s)? Did they fail? Why?

Were there any barriers on the affected component(s)? Did they fail? Why?

Were the barriers adequately maintained?

Were the barriers inspected prior to expected use?

Why were any unwanted energies present?

Is the affected system/component designed to withstand the condition/situation without the barriers?

Why?

What design changes could have prevented the unwanted flow of energy? Why?

What operating changes could have prevented the unwanted flow of energy? Why?

What maintenance changes could have prevented the unwanted flow of energy? Why?

Could the unwanted energy have been deflected or evaded? Why?

What other controls are the barriers subject to? Why?

Was this event foreseen by the designers, operators, maintainers, anyone?

Is it possible to have foreseen the occurrence? Why?

Is it practical to have taken further steps to have reduced the risk of the occurrence?

Can this reasoning be extended to other similar systems/components?

Were adequate human factors considered in the design of the equipment?

What additional human factors could be added? Should be added?

F-1