“If you know the enemy and know yourself you need not fear the results of a hundred battles.”
“Everything must be made as simple as possible. But not simpler.”
Making the health and safety battle simple
“There has been an increasing realisation that safety cannot be achieved through technical means only. There is also the acceptance that absolute safety is impossible and, in fact, no design strategy can eliminate all risks particularly because of the many uncertainties involved.”
I ended the previous article by introducing the concept of ‘shared responsibility’ for safety. In an ideal world everyone would feel responsible for the health, safety, welfare and security for all people. Everyone would find their work meaningful; they would be empowered to make necessary changes for the better and they would have healthy attachments to their colleagues. Without trying to sound like a finalist in a beauty contest, the result would be a safer and healthier environment.
In exploring how we are going to achieve this utopia we will look at two ideas:
- Systems approach
- Cognitive ergonomics
Although neither of these sound like anything you would want to impress someone on a first date with, they are actually quite interesting.
Systems thinking and safe design
A systems approach to safe design develops the concept of designing for responsibility. One of these assumptions is that safety is produced by reliability. A system can, in fact, be both reliable and unsafe and vice versa. In complex systems, accidents can occur from interactions among components that are satisfying their individual requirements (so not failing). This is described in Nancy G Levenson’s book “Engineering a Safer World” (2016). Professor Levenson is Professor of Aeronautics and Astronautics and also Professor of Engineering Systems at MIT. She is an elected member of the National Academy of Engineering (NAE).
Prof Levenson describes the tragic example of the Herald of Free Enterprise disaster, which was a ferry that capsized in 1987, killing 193 people. This diagram shows each component that interacted to the back doors being left open when the ferry put to sea, resulting in it capsizing:
Below is a diagram that shows how the different components of the system the Herald operated within worked together (or not, as the case may be):
(Leveson, 2016, p13)
- Each component worked within its parameters
- All those who made decisions about the vessel design, harbour design, cargo management, passenger management, traffic scheduling and vessel operation were unaware of the impact of their decisions on the others and the overall impact on the process leading to the ferry accident
- Each person involved followed the procedures within their area of responsibility but did not share the overall responsibility for the whole system. Their ‘local’ decision making interacted in a dysfunctional way.
It was normal practice for the assistant boatswain to close the ferry doors but on this day he did not. The first officer, who would normally have remained on deck to make sure that the doors were closed, returned to the wheelhouse instead to make sure the ship kept on schedule. It was never ascertained why nobody else closed the doors.
The systems approach to health and safety changes the emphasis from preventing failures to enforcing behaviours that increase safety. Safety is seen as an ‘emergent’ property that arises when the system components interact with the environment. It is not going to increase safety if only one part of the system is made safer. Something that is perfectly safe in one environment can become lethal in another (certain medications are good examples of this). There was anecdotal evidence of a reduction in back strain among women in the UK in the 1960s. A factor that might have contributed to this was the fashion for wearing mini skirts. If any of you have ever tried picking up a heavy bag or wriggling child wearing one, you will understand that you keep your rear end down and your back straight in an effort not to show your underwear – an example of a component interacting with the environment creating ‘emergent’ safety!
The mini skirt is a good example of an item someone uses that forces them to behave in a safer manner. Child-proof bottles, speed restrictors on vehicles and two hand control devices are also examples.
The Human System
Engineering clever devices that keep us safe is straightforward, but how do you create a system which motivates people to keep themselves and other people safe? How do we create a system where people want to and are able to reduce harm in a volatile, uncertain and chaotic environment? The answer is to let the human to use the one attribute they have that no machine, computer, robot or artificial intelligence has – their humanity. That, and the role of cognitive ergonomics, will be explored in the next article.
Leveson, N. (2016). Engineering a Safer World. Cambridge: The MIT Press.