Learn Hazard and Risk basics with The Safety Artisan.
So what is this risk analysis stuff all about? What is ‘risk’? How do you define or describe it? How do you measure it?
In this free session, I explain the basic terms and show how they link together, and how we can break them down to perform risk analysis. I understand risk and that allows me to explain it in simple terms. I’ve used all my 20+ years in the business to help me unpack the jargon and focus on what’s really important.
You Will Learn to:
- Describe fundamental risk concepts.
Topics: Hazard and Risk Basics
- Risk & Mishap;
- Probability & Severity;
- Hazard & Causal Factor;
- Mishap (accident) sequence; and
- Hazards: Tests & Example
Transcript: Hazard and Risk Basics
Click here for the Transcript on Risk Basics
Let’s get started with Module One. We’re going to recap on some Risk basics to make sure that we have a common understanding of risk. And that’s important because risk analysis is something that we do every day. Every time you cross the road. Every time you buy something expensive. Every time you decide whether you’re going to travel to something, or look it up online, instead. You’re making risk analysis decisions all the time without even realizing it. But we need something a little bit more formal than the instinctive thinking of our risk that we do all the time. And to help us do that, we need a couple of definitions to get us started.
What is Risk?
First of all, what is Risk? It’s a combination of two things. First, the severity of a mishap or accident. Second, the probability that that mishap will occur. So it’s a combination of severity and probability. We will see that illustrated in the next slide.
We’ll begin by talking about ‘mishap’. Well, what is a mishap? A mishap is an event – or a series of events -resulting in unintentional harm. This harm could be death, injury, occupational illness, damage to or loss of equipment or property, or damage to the environment.
The particular standard we’re looking at today is covering a range of different harms. That’s why we’re focused on safety. And the term ‘mishap’ will also include negative environmental impacts from planned events. So, even if the cause is a deliberate event, we will include that as a mishap.
Probability and Severity
I said that the definition of risk was a combination of probability and severity. Here we got a little illustration of that.
Probability is; how likely is this thing to go wrong? How likely is this thing to happen?
And severity is; How significant is this event? This can vary in seriousness. From death to injury, illness, property damage or equipment loss, damage to the environment, or monetary loss.
And to be honest, we can apply or define risk any way we want. It doesn’t have to be a Safety Risk. We could be thinking about Financial Risk, Reputational Risk, whatever it might be. But what you see there with the little matrix is we measure risk. And whether we say the risk is high, medium or low, or whatever scheme we use. A combination of high severity and high likelihood is going to result in high risk. At the opposite end of the scale, the low probability that a low impact event is going to happen, we would call a low risk.
That’s what we mean by this combination of probability and severity. We put them together and we can measure risk in, to be honest, whatever way we choose to do so. This is a very simple example.
Safety Risks: Hazards
In safety, we have another concept. One that gives us a much finer degree of control over how we’re thinking about risk. We have this concept of hazards. As it says, a hazard is a real or potential condition that could lead to a mishap. It’s not the mishap, it’s a sort of an intermediate stage, as we will see. And the mishap can result in death, injury, property damage, damage to the environment.
Then there’s also this thing called causal factors, or causes. It might be one or several mechanisms that could trigger the hazard. Or they could lead to the hazard, which in turn can lead to a mishap. So the causal factor or the cause can trigger the hazard and then the hazard can lead to the mishap.
(Mishap) Accident Sequence
Here we have an illustration of an accident sequence or a mishap sequence if you prefer. Let’s not get hung up on terminology. So, we may have many causal factors on the left-hand side of this bow tie diagram. Any one of these factors may lead to a particular hazard. A single hazard we’re looking at here. And then that hazard may lead to a range of different consequences.
Not all these consequences are going to be bad. Not all the consequences are going to result in a mishap. There may be lots of consequences where there is no mishap, no accident, no harm whatsoever. There’s going to be a range of possible consequences. What I would like to take away from this diagram is one thought. That thought is ‘Yes, we can have causes leading to a hazard’ – this sort of pinch point in the middle. And from that hazard and number of consequences can arise.
Now that thought is important. It’s a very powerful concept because it helps us to reason about accident sequences. Also, it helps us to do some much more sophisticated work that would otherwise be possible.
Tests for a Hazard
There are three tests, that I know of, for a hazard. The first two are saying the same thing in different ways. We can think of a hazard as being both necessary and enough for harm to occur. We need the hazard to be present before harm can occur, but the hazard is enough for harm to occur. In other words, once the hazard is present, nothing else unusual needs to happen for harm to occur. Once the hazard is there, nothing else needs to go wrong for somebody to get hurt. Normal events can lead to a mishap once the hazard is present. Another helpful way of thinking about it is ‘hazard is an accident waiting to happen’.
Then the third on this list, we can think of a hazard at the point at which we lose control of something. It might be an energy source that we lose control of. It might be something toxic. It might be a physical piece of equipment that we’ve lost control of or a vehicle. It might be a substance. Whatever it might be, we’ve lost control and now somebody could get hurt.
So, those are some tests for a hazard and some different ways of thinking about hazards.
Example of a Hazard
But I always think it’s helpful to have an example. Let’s imagine we’ve got a causal factor. We’ve got some oil that is leaking from its container.
And we can imagine the hazard. The oil has got onto a walkway. Or pavement or a sidewalk or whatever you want to call it. It gets on to an area that human beings would walk on, as the name implies. It’s normal. So once the oil is on the walkway, nothing else unusual needs to happen for there to be an accident. But it doesn’t make the accident inevitable. Because if nobody comes along, there can be no accident. If somebody comes along, but they see the oil and they step over it and avoid it. Or even better, they warn other people about it and tear it up – but that’s another story. But the accident, the mishap is not inevitable.
One of the combinations that is possible is that we get a mishap. A person comes along, doesn’t see the oil, steps on it, slips, and hurts themselves. All these things have to happen in a sequence in this accident sequence for the mishap to occur. For people to get hurt. So there we have a little summary of those risk concepts that we need to get a hold of.
Summary of Module
We’ve covered risk and mishap, probability and severity, hazards, and causal factors. We’ve looked at the mishap or accident sequence, looked at hazards, and at some tests for what makes up a hazard. Including how we tell where the hazard is in the sequence? Where is it between cause, hazard, and consequence, the hazard is? We looked to an example of this in the module.
From this module, we have a common understanding of risk. This will form the foundation for everything that we’re going to do with risk from now on.
This is Module 1 of SSRAP
This is Module 1 from the System Safety Risk Assessment Program (SSRAP) Course. Risk Analysis Programs – Design a System Safety Program for any system in any application. You can access the full course here.
You can find more introductory lessons at Start Here.