I took the NEBOSH National General Certificate a few years back. The course was a comprehensive overview of health and safety in a work environment.
One of the mnemonics provided by my lecturer for the course was “Eric, P.D.”, as a way to remember the Hierarchy of Control. The Hierarchy of Control is the order in which controls should be implemented to best protect the people doing their jobs.
Eric PD can be written out like so:
- E – Eliminate. Eliminate the danger by removing the hazard completely.
- R – Reduce. Limiting the exposure to the danger or substitute it with something less dangerous.
- I – Isolate. Isolate or segregate the people from the hazard.
- C – Control. Put engineering controls and systems of work in place to protect people.
- P – Personal Protective Equipment (PPE). Provide safety gear to the workers.
- D – Discipline. Rules of behavior for workers to keep them safe.
To apply the Hierarchy of Control, you work down the ERIC PD list. Everything is done to remove hazards but, given that some hazards cannot be removed completely, it's important to reduce the dangers as much as possible. Measures that are most effective at reducing risk are considered before less effective ones. Safety isn't restricted to industrial situations – it's applied to our all aspects of our lives.
Lets consider each of the aspects of the hierarchy of control and how it relates to safety on the roads. I'll describe them in reverse order, starting with the least effective and work up to the more reliable, and intrinsically safer, controls.
In the factory, discipline is the basic rules, like always follow the procedures, don't open a valve unless you are authorised to do so, don't use equipment you have not been trained to use, etc. In the factory, these rules ensure that all the rest of the safety process works correctly and any failure to abide by these rules results in an investigation and willfully ignoring the rules results in instant dismissal and possible prosecution.
Personal Protective Equipment usually goes hand-and-hand with Discipline. It requires workers to follow the rule that the appropriate PPE should be worn (and worn correctly) in the appropriate locations. PPE is not perfect and should be considered a last line of defense. A hard hat won't help if a 10-foot scaffolding bar falls from 30 meters overhead, for example – but it might help if I stand up fast and hit my head on an overhead pipe. Welders in the factory wear a welders mask and gloves, because this PPE is the final remaining option to protect their body from radiation and sparks.
PPE for cyclists consists primarily of helmets and high-vis. For many cyclists, it also includes gloves and goggles to protect against wind and bugs.
Control is procedures and systems of work. Systems of work include
things like the permit to work system and risk assessments. These
provide checklists to ensure that the work will be done safely.
There's also engineering controls. Engineering controls are better because they're automatic, but they could fail. Engineering controls include things like Local Exhaust Ventilation (extractor fans), Emergency Shutdown Systems, and relief valves.
Systems of work would include things like the highway code rules - Drive on the left. Overtake on the right. Stop at a red light. Everyday on the roads, you see this. It includes painted cycle lanes saying “this space is dedicated to cycling”. It's a system of work. If you cross this line as a motorised vehicle driver, then you are in the wrong space. Drivers licenses also come into it because, to gain a license, a driver has to prove a level of competence with a vehicle by taking a test.
The engineering controls include things like the air bag in a car, and anti-lock brakes. If you had self-driving cars that stop automatically if they detect a pedestrian in the road, this would count. There aren't many engineering controls that would help with cycling so we mostly rely on systems of work.
Even with signs, lines, and reminders, though, there is still the possibility of human error (or mechanical failure of the engineering control) which could lead to an accident. A worker may miss a crossover line on their isolation list which means workers further down the line might be exposed to hazardous chemicals, or driver may have a heart attack and cross into a cycle lane.
When working upwards through the ERIC PD list, this in the first step
which protects people from hazards without relying on perfect behaviour
at all times and is inherently safe or safe by default.
In the factory, isolation means separating people from the danger. This may involve installing guard railings along high platforms, installing protective guards in front of spinning rotors, using metal spades to block pipes to stop the flow of materials towards pipes that will be worked on.
On our roads, this would be separated cycling lanes with barriers between fast moving vehicles and cyclists. This wouldn't rely on drivers providing sufficient passing distance, because there would already be a barrier preventing them from deviating onto the path of a cyclist or pedestrian. This would also be separation between slower-moving pedestrians and cyclists.
In the factory, hazard reduction refers to things like reducing the volumes of hazardous chemicals stored on site or by changing the chemicals used to be less dangerous ones. Reduction could even mean using newer, better-maintained, or quieter equipment to reduce noise levels.
On the roads, the obvious way to reduce the hazard is to reduce the speed of vehicles by introducing 20MPH limit zones. This not only reduces the likelihood of a collision but also the consequence of a collision with a vulnerable road user such as pedestrians or cyclists (injury rather than death).
Likewise, reducing the number of vehicles on the road would also reduce the risk of a collision. This could be achieved by introduction of a congestion charge in certain locations to reduce the appeal of driving in the area.
The only certain way to reduce risk associated with a hazard is to remove the hazard completely. This is not always possible because, for example, we can't stop working with a particular carcinogenic chemical that is essential to the process.
Similarly, it is not always possible to completely eliminate the hazard of vehicles. However, in some cases you can and should. Town centres often have pedestrianised zones which disallow vehicles altogether. Similarly there are routes completely separate from any vehicle, such as a cycling and pedestrian route along a waterfront or through a park. In this case, not only are vulnerable road users protected from collisions but they will not be exposed to noise or air pollution from vehicles.
Hierarchy of Control on the Roads
The safest measures for road users are those at the top of the Hierarchy of Control – Eliminating the hazards, Reducing the hazards, and Isolating the hazards. These are the only levels of safety that remove the dependence on human judgement and protect against human error (and mechanical failure). Greater emphasis should be places on elimination and reduction and less on PPE and discipline.Go Top