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Key Initiatives

Fault Tree Studies


Have you heard of a fault tree diagram? Commonly used in safety engineering and reliability engineering to provide a visual record that shows the logical relationships between events and causes that lead to failure, fault trees can help people quickly visualize and prioritize issues that need correction, leading to improved safety.

In 2018, we wanted to dig deeper into the four key high risk events we were commonly seeing. We chose the following areas of concern: 

  • ammonia releases;
  • carbon monoxide exposure;
  • electric shock; and
  • escalator brake failures, entrapments and pile-ups. 

We then engaged subject matter experts from each industry — Refrigeration, Gas, Electrical, and Elevating Devices —  to help us look closely at each issue. Fault tree methodology helped us identify the conditions required for a high risk event to occur and all the possible causal factors leading up to that occurrence. By using a top-down, deductive method to analyze the undesired state of a system, we can then use Boolean logic to combine a series of lower-level events.

The Fault Tree reports, shown below, provide a number of recommendations to address causal factors. In 2019, Technical Safety BC will be using this information to help inform decision making around risk, and will focus on those which we believe will have the greatest impact on safety.

These fault trees will be used by Technical Safety BC to enhance our Accident Prevention Model which we use to prioritize assessment, education and outreach, enforcement, and research activities. By using research to enhance our decision making, we can better protect the public harm and work towards our goal of achieving Safe technical systems. Everywhere.

"Our goal is to improve the overall safety performance within targeted industry sectors and, over time reduce the number and impact of high risk events. By using fault trees to help us understand what activities lead to certain events, we are better able to target our efforts to enhance safety."

Alina Urloiu
Programs Manager, Safety Oversight