Controlling Risks
How to bring a risk down: change the likelihood, the consequence or both, choose controls with the hierarchy of risk control, and decide when you have done enough.
Pages in this chapter (1 of 4)
3.1 How Do We Reduce Risk?
You now know how to assess risk. The next question is what to do about it. Knowing that a risk exists is not enough.
Risk is affected by several factors. The risk of falling from a ladder depends on how stable the ladder is, how well you can use it and how you work. Think of learning to drive again. A learner on the road is a hazard to themselves and to others. A qualified instructor and dual controls in the car do not remove the hazard, but they control the risk.
Risk control means changing the way we work in order to lower the risk. Whatever you plan, estimate what it will do to the likelihood and to the consequence. Remember that risk = likelihood × consequence. So to reduce risk you can:
- reduce the likelihood of the hazardous event
- reduce the consequence of the event
- reduce both
The examples below use the five point scales from Module 2. Imagine that you manage a woodworking shop with several cabinet makers, and your assessment shows that some risks must come down.
Reduce the likelihood
The likelihood that someone touches the saw blade is 4, and the consequence is 5, so the risk rating is 20. Immediate action is needed. A guard reduces the likelihood of contact. If the guard is used most of the time but not always, the likelihood falls to 1 and the rating to 5.
Reduce the consequence
A paint sprayer faces a harmful substance in the paint. The likelihood of exposure is 3 and the consequence is 4, so the rating is 12. If the paint is replaced with one that contains less harmful substances, the likelihood stays at 3 but the consequence drops to 2, and the rating falls to 6.
Reduce both
Use the less harmful paint, so the consequence is 2. Replace the manual sprayer with a robot and enclose the process, so that the worker controls the spraying from outside and enters only to place and remove items. The likelihood falls to 2, and the rating falls to 4.
Residual risk
The risk that is left after you add controls is called the residual risk. Before a holiday you set the alarm, close the windows, lock the doors and ask the neighbours to keep watch. Your home is as secure as you can make it, but the controls could still fail. In the same way, controls at work lower the risk but never remove it altogether.
A study aid, not published or endorsed by IOSH or OSHA. Laws and limits differ between countries.