FIT FOR PURPOSE

As safety professional, we are tasked with making people, equipment and places Safe by reducing the risks to harm and damage.?When we are using the term “Safe” (and by relation “Unsafe”) we are trying to determine if we are at Risk, which is the probability that a Consequence occurs (harm, injury, damage or unacceptable outcome).

We cannot have zero risk. As long as we are exposed to a Hazard (an uncontrolled substance, energy or situation) there is potential for a Consequence (harm, injury, damage or unacceptable outcome).

So, if cannot have zero Risk, then we can only reduce our exposure to that Risk – the probability of a Consequence.?To do so, we employ a number of risk reduction items, such as safeguards, safety controls, Independent Protection Layers, safety procedures, safety equipment, safe design, etc. etc.?The degree and/or number of risk reduction items that are employed determine how much we have reduced the Risk – but remember, cannot have zero Risk.?

So, how much or what risk reduction items, such as safeguards, safety controls, etc. do we engage??Industry standard says to as low as reasonably practicable – note, not as low as possible.?It is when the cost and energy of additional safeguards and safety controls is disproportionate to the amount of risk being reduced.

Part of making that determination involves the concept of Fit-For-Purpose - allocating appropriate resources proportionate to the risk. We must balance the potential for under-design exposing to higher risk versus over-designed wasting organizational resources (time, money, people).

To illustrate this let’s look at stopping a vehicle – probably most important if you want to avoid a dangerous collision.

The brakes on a fictional vehicle called the A Model are mechanical brakes (single circuit, pads/drums, lever actuated) and they can get the car to stop.

Another fictional car, the B Model, is outfitted with power brakes (hydraulic, expanding internal shoe, dual circuit, with a Master Booster/Cylinder). This has a greater degree of reliability and integrity of stopping power. This B Model would be considered “Safe” as well and cause us to think of the previous car (the A Model, with mechanical brakes) as not being “Safe”.

Another car, the C Model, uses anti-lock, disc brakes with 2 piston calipers for its braking system. Obviously, another improvement and more stopping power. So, the C Model is “Safe”. But the other cars (A Model and B Model) do not appear “Safe” with their seemingly lesser braking systems – even though those braking systems will stop the car.

Going further with another car, the Z Model, uses carbon-fiber discs, ventilated, anti-lock, 6 piston brake system. Again, further improvement and more stopping power. So, the Z Model is “Safe”. But the other cars, A Model, B Model and C Models were considered “Safe”.

We cannot have zero risk. As long as we are exposed to a Hazard (collision) there is a Risk for a Consequence (damage and injury from collision). So, if cannot have zero Risk, then we can only reduce our exposure to that Risk – probability of the Consequence to as low as practicable.

Notice that all the cars have a braking system that can stop the car. They just differ on the design and equipment used. The differences involve a degree of performance that can be delivered – disc having more grabbing power than pad/drums and 6 piston calipers more powerful than 2 piston calipers.

When deciding on what is “Safe”, the parameters of how you are using the vehicle determines what braking system is needed for you to consider the vehicle to be “Safe”.

For basic general vehicle use, commuting to work, running errands, grocery shopping, transporting kids to soccer practice, a vehicle with basic power brakes, dual system, anti-lock, disc brakes with 2 piston calipers are “Safe” to drive around and manage the Risks (ability to stop to avoid collision and avoid potential for damage and injury).

Carbon-fiber discs, ventilated, 6 piston brake system, while a real stopper, affords no real larger benefit for basic general vehicle use.?The extreme extra costs of that high end braking system are grossly disproportionate to the nominal amount of risk reduction realized.

Basically, for basic general vehicle use, the power brakes, dual system, anti-lock, disc brakes with 2 piston calipers brake system are Fit-For-Purpose.?

But then, if the use of the vehicle is different – say it is used in racing – then carbon-fiber discs, ventilated, 6 piston brake system is Fit-For-Purpose.

Fit-For-Purpose - allocating appropriate resources proportionate to the risk.