HIRA HIERARCHIES OF CONTROL
The health and safety “hierarchy of hazard controls” is a widely accepted system that is promoted by numerous safety organizations all over the world to eliminate or minimize worker’s exposure to hazards. For the sake of this blog, let’s refer to this hierarchy as the “general hierarchy of hazard controls”.
The “general hierarchy of hazard controls” is however not the only hierarchy that organizations use to eliminate or minimize worker’s exposure to hazards. The American National Standards Institute or ANSI as they are commonly known developed the ANSI Z359.1 and ANSI Z359.2 fall protection standards to enable employers in the US to identify, evaluate, eliminate, or control fall hazards in their workplaces. Through these standards, ANSI promotes the use of the “hierarchy of fall protection controls” which differs from the “general hierarchy of hazard controls” on some levels.
As a health and safety risk assessor, do you know what the differences are between these two hierarchies and do you know how to apply these two hierarchies to your own work at height risk assessments?
Both of these hierarchies are often used by many risk assessors all over the world when doing their work at height risk assessments. After reading this article, you should hopefully be able to incorporate both of these hierarchies into your work at height risk assessments. So let’s begin.
Both hierarchies ranks the controls from highest to lowest based on their effectiveness and/or desirability.
The “general hierarchy of hazard controls” ranks the controls as follows:
- Elimination controls: These controls physically remove one or more of the hazards from the work situation.
- Substitution controls: These controls attempt to replace hazards with something that is less hazardous.
- Engineering controls: Engineering controls involve isolating employees from work-related hazards. This is often achieved by re-designing workplaces and/or processes. In workplaces where they are appropriate, these types of controls reduce exposure to hazards without relying solely on worker behavior. When considering “engineering controls” for work at height, one must first determine if the control will be used to try and “prevent” a fall from happening or if the control will be used to try and “lessen the impact” of a fall as “fall prevention” controls are always more effective and more desirable compared to “fall arrest” control measures.
- Administrative controls: Administrative controls do not remove, replace or isolate hazards but instead attempt to limit worker’s exposure to hazards by adjusting their work tasks or schedules.
- PPE controls: Personal protective equipment is generally considered to be the last line of defense against worker injury and/or illness and its use only becomes acceptable when other controls, higher up on the hierarchy, don’t eliminate or control the hazards sufficiently.
The “hierarchy of fall protection controls” on the other hand, ranks the controls as follows:
- Hazard elimination: The underlying principle here is that working at height should be avoided wherever possible. What is of concern is the fact that “hazard elimination” and “hazard substitution” are often grouped together by individuals that are promoting this hierarchy whilst they are clearly not the same thing.
- Passive fall protection: Passive control measures such as handrails, guardrails and safety netting are collective constraints that protects more than one person and that often doesn’t require any action from our workers. Many safety practitioners assume that they will eliminate the risk of a fall all together when they install things such as handrails. Collective constraints like handrails for example, are engineered solutions at best. They isolate our workers from work-related hazards but they do not physically remove the hazards all together.
- Active fall restraint: A personal work restraint system prevents the user from falling by holding him back. The idea is to keep the worker away from an unprotected edge or an opening. Personal work restraint systems that require our workers to wear safety harnesses are PPE controls at best.
- Active fall arrest: Fall prevention is always preferred to fall arrest. Fall arrest is a form of “fall protection” which involves the safe stopping of a person that’s already falling. Fall arrest is the only category that physically allows the worker to fall from an elevated position. The fall arrest system takes over during the fall by activating and arresting the fall in a controlled manner before the worker hits the ground. Just like with “active fall restraint”, personal fall arrest systems that require our workers to wear safety harnesses are PPE controls at best.
- Administrative controls: According to this hierarchy, the least preferred control measure is work practices or procedures that increase worker’s awareness of fall hazards. Administrative controls such as “safety training” for example are thereby ranked below PPE controls in terms of their effectiveness or desirability.
- PPE controls: Personal protective equipment is generally considered to be the last line of defense against worker injury and/or illness and its use only becomes acceptable when other controls, higher up on the hierarchy, don’t eliminate or control the hazards sufficiently.
So which hierarchy should you use?
What is important to note here is that “work at height” risk assessments are “issue-based” risk assessments. The need for them is usually identified via “baseline” risk assessments. So if your company’s risk assessment methodology requires you to apply the “general hierarchy of hazard controls” to your risk assessments, it makes no sense to revert to the “hierarchy of fall protection controls” during an issue-based risk assessment. As long as you understand that “fall prevention” is always preferred to “fall arrest” and that “personal fall restraint” and “personal fall arrest” are PPE controls at best, you should be able to incorporate these principles into any methodology.
Further to this, based on ISO 31000 principles, ISO 45001 suggest a step-by-step approach using the “general hierarchy of hazard controls” to enhance occupational health and safety and to reduce or control workplace risk. Irrespective of where you are based, I therefore recommend you apply the “general hierarchy of hazard controls” to all your risk assessments, including your “work at height” risk assessments.
SAPERE AUDE by Andreo du Preez
