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Safety beyond boundaries – Embracing all flavours

Many terms are used to describe different types of safety in energy transition projects, whether “personal safety” or “technical safety”, and several flavours in between. Sometimes these terms are described accurately, other times they are used loosely or mistakenly. To non-safety professionals this is at best confusing and at worst can lead to poor project outcomes. So, what are these different types of safety and how do they relate to each other? And does it really matter?


The flavours of safety include (but are not limited to) occupational safety, personal safety, behavioural safety, system safety, technical safety, process safety, and functional safety.

Despite decades of experience across all these types of safety and their application in different industrial sectors, it can be difficult to specify them precisely. There is a great deal of overlap, and some terms are more commonly used in specific industries than others. Unfortunately, there is no single, authoritative source that explains all. It is no surprise that confusion can arise. Nevertheless, in this brief article we attempt to shed some light.

A reasonable place to start is with “safety” itself, which may be defined as the state of being free from harm. There is always a residual safety risk in any industrial endeavour and therefore in practice, safety is about protecting people from unacceptable risk of harm rather than aspiring for a risk-free state. Some energy transition organisations have a zero-harm mission. Whilst the sentiment is admirable and, well implemented, can be expected to drive positive beliefs and actions, the only way to truly avoid harm is not to transition at all. Clearly this will not combat the climate crisis. As a result, “occupational safety” – protecting people when they are at work – is the broadest safety term. All other types of safety are subsets.


Occupational safety is usually expanded to “occupational health and safety” (OHS), where ill health, welfare and mental wellbeing are also considered (see Ref. 1 for example). Providing a safe working environment for all persons at work is a legal responsibility in most countries. OHS requires both the prevention and treatment of any safety, health, welfare, and wellbeing issues that people may experience during or because of their work. 

Rather unhelpfully, occupational safety is often trivialised as the prevention of “slips, trips, and falls.” This implies it is about preventing individuals from injuring themselves – provide some personal protective equipment (PPE) and some training and everyone should be fine. In fact, it encompasses protecting people against anything that can cause harm – whether that is due to unsafe work practices or poor workplace design, or catastrophic failure of engineered systems, and everything in between.

However, the world of safety does not do itself any favours and regularly uses the term occupational safety to mean preventing incidents where a single worker may be harmed. For example, falling from height, electrocution, unguarded machinery, heavy lifting, and so on. This is sometimes and only slightly more accurately called “worksite safety”. Occasionally it is loosely called “personal safety”, but that term implies safety is the responsibility of the individual rather than the employer. Personal safety is better used in the context of individual safety outside of the workplace.

The common practice of assuming occupational safety only refers to protecting the individual worker has probably arisen because many industries do not involve complex, technological assets and have little potential for major incidents that could lead to multiple fatalities. However, some sectors including the energy transition do have this potential. Assets like offshore wind farms, battery storage facilities, and hydrogen plants, for example, have the potential to result in fires, explosions, marine incidents, and dropped objects.


Before moving on to discussing the types of safety that aim to prevent major incidents, it is worth briefly mentioning “behavioural safety”.

Whilst technical safeguards are vital, human behaviour also plays a significant role in ensuring safety. Behavioural safety primarily deals with initiatives focused on promoting a culture of safe practices among workers. This might involve encouraging people to report near-misses, fostering open communication about safety concerns, and implementing incentive programmes to reward safe behaviours. For instance, during the construction phase, the project might conduct regular safety observations to identify any unsafe behaviours and provide corrective feedback to prevent accidents.  

There’s no safety in the term, but “human factors” goes well beyond behavioural safety. It assesses how humans interact with systems, equipment, tasks, and the work environment, and how these interactions can impact safety, performance, and well-being. It recognises that human capabilities, limitations, and behaviours play a crucial role in determining the effectiveness of safety measures and the likelihood of errors or incidents occurring. A common application of human factors is in the design of control rooms where the aim is to prioritise simplicity and clarity, for example, organising information hierarchically, optimising alarm management features, and providing interactive elements such as intuitive control panels. All these features help to reduce the chance of human error and enhance overall system reliability.


Over the last five decades, there have been significant developments in the application of techniques to understand the ways in which complex, industrial assets with interconnected systems, as well as human interactions, can fail and cause major incidents. The terms “technical safety” and “system safety” are generally synonymous and deal with this challenge.

Technical safety is more likely to be used in certain sectors like offshore oil and gas production, where the containment of hydrocarbons is the primary concern but there are other risks arising from the use of mechanical systems such as cranes and helicopters. System safety is more commonly used in sectors like aviation, rail, and defence where the primary concern is the failure of mechanical and electrical systems, whilst also recognising the risks associated with the use of hazardous substances such as aviation fuel, diesel, and chemicals.

Technical/system safety focuses on preventing significant or major incidents arising due to failures within an engineered process or system. The goal is to ensure that such engineered systems and processes are designed, operated, and maintained in a way that the associated risks are reduced as low as reasonably practicable (ALARP). Practitioners of technical/system safety mostly have a background in science, technology, engineering, or maths (STEM), as applying assessment and modelling techniques requires strong technical capabilities.


The specific application of technical safety to the processing of hazardous materials is called “process safety”. The mantra of process safety is “keep it in the pipe” – the goal is to prevent the releases of hazardous materials which have toxic, flammable or explosive effects. Process safety will be the primary concern in the hydrogen sector for example. As such, process safety is essentially a subset of technical safety, where the major hazard potential comes from a hazardous substance rather than from, say, a mechanical or electrical system.


Another specific application of system safety is for a wide range of systems that have safety-related functions, particularly those involving electrical, electronic, or programmable electronic (E/E/PE) systems. This application is termed “functional safety”. These systems can be generally characterised as automation and control systems.

Functional safety aims to ensure that the safety-related function operates effectively and reliably over its full lifecycle, even when faced with potential failures or errors. It considers the safety-related function as a complete loop from the input, for instance, a signal from a wind turbine speed sensor, through to the output such as a command to adjust the turbine pitch angle or activate mechanical brakes to prevent an overspeed condition which could otherwise result in catastrophic turbine failure. Functional safety is particularly relevant in industries where systems play a critical role in ensuring the safety of individuals, such as automotive, aerospace, and industrial automation.


It is hard to be too definitive on “all the safeties” when there are so many grey areas. Purists will continue to debate the definition of many of the terms. Often, practitioners in one domain like to extend their reach into other domains, believing they have valid insights to offer. Furthermore, new terms are introduced, for example, the expression “If you’re not secure, you’re not safe” is becoming associated with the concept of “resilience” – the integration of safety and security. Nevertheless, Figure 1 aims to provide a mental model that illustrates how all the safeties interrelate.

Figure 1- The interrelationship of all the safeties

Whilst this model may be useful to get a feel for how all the safeties relate to each other, does it really matter? For example, technical safety and process safety both address engineered facilities using similar tools, it’s just that technical safety looks at non-processing plants too.

Arguably what really matters is that each of the safeties applies the same risk management process. Fortunately, there is a robust standard that defines that process, ISO 31000 (Ref. 2). Its creation was quite an achievement in that it is applicable to all organisations, regardless of type, size, activities, and location, and covers all types of risk – whether financial, infrastructure (including safety), marketplace or reputational.

At the core of risk management is risk assessment – the identification, analysis, and evaluation of risks. Every type of safety applies risk assessment to its specific context. A worksite construction activity will involve a task risk assessment to protect workers undertaking the tasks. The design of a hydrogen refuelling station will require process hazard analysis to ensure workers and the public are not harmed. Any instrumented safety-related function requires a hazard and risk assessment to allocate the safety requirements. And so on.

For a new project supporting the energy transition, it is best not to get hung up on the nuances of each type of safety. The project should simply come up with a working definition of all the safeties and communicate these across the project and to all sub-contractors to ensure everyone is talking the same language. What does matter is that the project adopts the right risk assessment techniques for the specific context that is being considered. The goal is clear – to reduce all safety risks, whatever their source, to ALARP.


A range of terms are used to describe different types of safety in industry. Projects enabling the energy transition will probably get to hear them all. Sometimes the terms are used accurately, other times they can be misused and create confusion.

There is a relationship between all the terms, with occupational safety being the overarching safety, but what is most important is that they all apply a proportionate and pragmatic risk management process, tailored to the specific context. Arguably the terms don’t matter, as ultimately the goal is quite straightforward – to ensure that all projects are developed, and assets operated in such a way that the associated safety risks are understood and reduced to acceptable levels. Embrace the flavours of safety.


  1. Fundamental Principles of Occupational Health and Safety, Second Edition, Benjamin O. Alli, International Labour Organization, 2008
  2. ISO 31000:2018 Risk management Guidelines


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