In a new series exploring core OSH topics and your role in ensuring their risks are well managed, we look at working at height.
1. Define it
Drawing on the GB Health and Safety Executive’s definition, IOSH defines work at height as follows: Working in any place where a person could fall a distance liable to cause personal injury. This can be above or below ground level. Work at height also covers places where objects could be dropped onto and injure a person (or persons) below.
Examples include working:
- On a flat roof
- From a ladder
- Near or adjacent to fragile materials
- At ground level, adjacent to an open excavation
- From scaffolding
- From access equipment
- Anywhere else where there is a risk of falling.
2. Identify physical hazards
The main hazards in working at height are either workers or objects falling from height. Identifying these hazards is key to correctly assessing the risks of working at height. There are many causes of these hazards, including:
- Unsafe, faulty or poor design of access equipment, including harnesses and lanyards
- Unprotected edges of roofs and services, including fragile roofs, unprotected openings and excavations
- Siting of access equipment: for example, unstable surfaces and covers of sewer access points not able to support the weight of access equipment
- Weather conditions that relate to hazards, such as lightning (to which people working at height can be more exposed), or that contribute to a person or objects falling from height
- Thermal effects: for example, embrittlement of metal ladders in very cold weather
- Unintended use of access equipment
- Carrying or moving heavy loads at height
- Zoonoses and animal interaction
- Geological activity: earthquakes, landslides, floods
- Interaction with other machinery
- Workplace transport
- Poor planning and organising of work-at-height activities
- Not providing a safe system of work and ensuring it is followed.
3. Identify personal hazards
- Workers’ attitudes and behaviours
- Medical conditions and disabilities
- Young workers
- Lone workers
- Workers with insufficient or inadequate information, training, instruction or supervision.
4. Conduct risk assessment
As with any risk assessment, those for working at height are usually undertaken using this five-step process:
Hazards can be identified by workplace inspections or by methods such as ‘what if’ or task analysis.
Any existing control measures should be considered. Risk assessments can be either qualitative (an educated opinion) or quantitative (using measurement and calculations).
A risk assessment can be used to estimate the impact of the risk, based on its likelihood and consequence (risk = likelihood × consequence). An example is shown below.
5. Implement controls
Once work-at-height hazards are identified and assessed, they need to be eliminated or controlled. Good practice within OSH is to use a hierarchy of control (HOC) to choose the appropriate control measures for each hazard.
HOC is a method of prioritising controls to reduce risks – from most effective to least (this might be a result of a risk-cost analysis).
The diagram to the right, from Workplace New Zealand, highlights the different control measures for working at height, linked to the corresponding hierarchy of control category.