The term 'Safety' as used in the process
industries can be divided into three major categories:
(the topic of this ebook);
Of these three the most effective
is Inherent Safety — the topic of this ebook. The basic idea behind the
Inherent Safety concept is simple; process facilities should be built
such that, were there to be any type of failure, the system would reach
a safe state regardless of the existence and effectiveness of
Inherent Safety can be achieved in one of three
1. Remove the hazard;
2. Ensure that the consequences
of an event have no significant impact;
3. Remove people from the
location so that no one can be injured no matter how serious the event.
The next type of safety in the above list is Process Safety. There
are various types of Process Safety — one of which is Passive Safety. A
passive safety system is one that brings an out-of-control condition
back to a safe state without any action required from equipment,
instruments or facility personnel. An example of a passive safeguard is
to do with the containment (bund) walls that are typically located
around storage tanks, as shown in Figure 1.
The volume of the bund is usually 110% of the
volume of the tank. Thus, if the tank fails catastrophically, the
spilled liquid will be contained. The wall is totally passive, requiring
neither equipment nor human intervention in order to be effective. It
will always be there, regardless of what else is going on.
It can be seen that passive safety and inherent
safety have a lot in common. However they are not the same. The bund
wall in Figure 1 is not truly inherently safe. For example the wall has
a drain valve, as shown. The valve is opened to drain off accumulated
rain water. If the valve is inadvertently left open then the passive
safety system has been defeated.
The third item on the above list is Occupational
Safety. This includes issues such as PPE (personal protective equipment)
and basic training in safe operations. Although many occupational safety
programs are developed to respond to failures in inherent and process
safety the principles of Inherent Safety can still be applied, as
discussed later in this ebook.
Examples of Inherent Safety
Features of Inherent
Inherent to Design
Way of Thinking
Safety Independent of Response
Can Help Reduce Costs
Stop an Activity
Timing and Personnel
We provide a
video to do with Inherent Safety in the process and energy industries.
At our Process Risk and Reliability Management
blog site we provide discussion and updates to do with Inherent
This video comes as part of a package; it includes:
- The video
- The ebook
- The storyboard to go with the video
- A test
This package can be downloaded here.