Hierarchy of control – how it applies to Arc Flash incidents

The hierarchy of control is a critical process in preventing health and safety incidents. Think of it as a strategy for safety. The Health and Safety Executive (HSE) says that risks should be reduced to the lowest level practical, but also that not every step will be relevant to every project.

The standard hierarchy of control is:

1. Elimination – removes the cause of danger completely
2. Substitution – controls the hazard by replacing it with a less risky way to achieve the same outcome
3. Isolation – separates the hazard from the people at risk by isolating it
4. Engineering – using engineering controls, i.e. making physical changes, to lessen any remaining risk, e.g. redesign a machine by adding safeguards
5. Administration – use administrative controls to lessen the risk, e.g. install signs, rotate jobs
6. Personal Protective Equipment (PPE) – require your employees to wear PPE, e.g. provide gloves, earplugs, and/or goggles

So the first question to ask is, do we have to do this task at all? Because not doing the task immediately eliminates any Arc Flash hazard.

Why is Personal Protective Equipment at the bottom?

The list is deliberately ordered with PPE the final consideration because it should be the last line of defence when everything else has been done to make the situation safe. PPE exists not instead of effective elimination, substitution or isolation of hazards, but in case those previous steps fail.

As Arc Flash incidents – along with many other types of electrical incident – are likely to be life-ending or life-changing, it’s critical that your hierarchy of control is well-understood not just by the people doing the assessment, but by all of the team who could be exposed to danger.

When it comes to electrical safety, after training, safe signage, and comprehensive risk assessments are completed to reduce the risks, the working environment is still far from risk-free.

When an electric luminous bridge in a gap between two electrodes (an arc) forms, the result can be devastating. An Arc Flash occurs during a fault, or short circuit condition, which passes through an arc gap. An Arc Flash expels large amounts of deadly energy, potentially causing severe burns or even death. Even when electrical equipment is properly maintained to avoid corrosion or deterioration and when the possibility of accidental contact is minimised, the risk remains.

A last line of defence

In these cases, PPE comes into its own as the last line of defence. Arc Flash protective clothing is flame resistant, helping protect the wearer against the most severe burns. Conversely, flame resistant-only clothing isn’t guaranteed to protect the wearer from an Arc Flash incident.

The key difference between Arc Flash clothing and flame resistant clothing is that while all arc-rated apparel is also flame-resistant, not all FR clothing is arc-rated.

Depending on the level of protection, Arc Flash clothing will resist ignition, offer heat resistance, or self-extinguish.

For help on which Arc Flash protective garments you need for your particular circumstances, call one of our sector experts on 01482 679600.