Critical risks are the risks identified in a business where there is the most threat and likelihood of harm. They are where a business’ efforts should be focused to prevent major hazards causing harm, and minimise harm if the inevitable accident happens. However, it is often difficult to easily document the preventative and rescue controls. A practical example is shown here to illustrate a particularly useful method, the bow tie diagram.
I used to work as both a volunteer and paid lifeguard for Surf Life Saving (SLS) – Northern region at lots of different beaches around Northland and Auckland. After becoming an engineer and formally learning about risk and hazards, I realised that the same methods we use to control risks in a machine shop are just as useful to identify risks and controls at my old workplace, the beach. Thinking about it, there are a heap of risks involved at the beach, but unlike a machine shop, it is difficult to guard against swimming and still have fun.
It is not uncommon for people to put themselves in dangerous situations at the beach. Jumping into fast moving currents with little or no experience with the water and, operating marine vehicles, both powered and unpowered, in large swells with little regard for safety are commonplace in New Zealand. However, there are heaps of preventative actions that can be done to prevent people from getting into dangerous situations and then some more in case someone finds themselves in trouble.
As I’ve progressed my career as an engineer, I’ve learnt more about structured methods to control risks. A particularly useful method I’ve found to keep track of risks is a bow tie diagram, which keeps all of the potential hazards associated with a major risk on the left and then controls which are used to block that hazard and turning it into something worse. If that control doesn’t work, it can then turn into a bad situation, which flows through to the right. To stop the risk becoming a bad situation, a reactive control can be put in place. A basic example is shown below in Figure (1), where the proactive measures taken to control hazards leading to the critical risk are coloured green, whereas the reactive measures are identified in yellow on the right.
Figure (1): Basic layout of bowtie diagram
Bowtie diagrams were first used in industry to gain an effective understanding of the risk controls in place associated with oil rigs, led by the Royal Dutch/ Shell group. The spark to cause a flame was the 1988 Piper Alpha platform oil rig disaster, which involved an oil rig catching alight, collapsing into the sea and causing 167 people to lose their lives. After the incident, it was found that it was extremely difficult to track all of the hazards that could lead to a critical risk and even harder to figure out what controls would be useful to prevent the hazards from occurring. They required “assurance that appropriate risk controls are consistently in place throughout all worldwide operations” and found that bowtie diagrams were useful as “a visual tool to keep overview of risk management practices”.
After I had a go at identifying all the risks associated at the beach from swimming, I gave the CEO of SLS NZ, Paul Dalton a ring to see what he thought of it all. He thought that it was a good approach to observing hazards that are present at the beach, but he was also able to immediately able to contribute and expand on what was available. Looking at Figure (2) below, it can be easily seen that preventative actions are important in ensuring the safety of people at the beach when you look at the amount of green controls on the left. SLS focus most of their energy in this area, but have a couple of key rescue techniques or yellow controls to help prevent a dangerous situation getting worse. In my experience, this is very true as I spent a lot more time educating people and preventing them from getting into dangerous situations, rather than rescuing them afterwards.
Figure (2): Application of the Bowtie diagram for swimming at the beach
PDF version of case study: Surf Live Saving and Bowties