7.5 Risk Identification (Step 3)
169
According to the risk management standards set by the ISO, risk identification is defined as the process of finding, recognizing, and recording risks. This
identification involves recognizing potential accident scenarios, with all of their
corresponding elements. As shown in Fig. 7.2, scenario elements include process
hazards, the sequence leading up to a loss event, and the resulting consequences.
If safeguards are present, they should also be considered. The output of this risk
identification step can be thought of as a list of m potential consequences.
7.5.1 Methods for Risk Identification
Using on-site knowledge and experience is indispensable for the effective identification of risks. To systematically identify them, a wide range of methods are available
and used within the chemical process industry. They each differ slightly in their
assumptions, focus, complexity, and the results they deliver. While some of the
methods are comprehensive and suitable for the identification of accident scenarios,
others can be only used for the identification of process hazards or the detection of
single equipment failures.
Two simple methods include preliminary hazard analysis and checklist analysis.
Preliminary hazard analysis generates a list of process hazards based on hazardous
properties (e.g., flammable or toxic material) and hazardous conditions (e.g., highpressure reaction). Checklist analysis uses previously developed lists to verify the
compliance of a system with standard practices, and identification of noncompliance
can indicate the presence of process hazards.
Two other comprehensive and well-known methods used to predict accident
scenarios are what-if analysis and hazard and operability (HAZOP) studies. Whatif analysis is a brainstorming method in which experienced personnel focus on
deviations from safe process conditions, designs, constructions, etc. that can lead
to loss events. This method is suitable for nearly all stages of process development,
with the required time and effort being proportional to the complexity and size of
the system to be analyzed.
HAZOP studies also focus on deviations, but they use a more structured
brainstorming approach. Here, a set of guide words are combined with specific
process parameters and applied to specific operating steps to identify possible
process deviations. Examples of guide words could be “no,” “high,” etc. Combined
with the process parameters “flow” and “pressure,” this can result in “no flow” and
“high pressure.” Tables 7.1 and 7.2 depict standard HAZOP guide words and some
common HAZOP study process parameters. Table 7.3 shows some examples of
deviations resulting from the combination of guide words and process parameters.
The HAZOP method requires considerable process knowledge as well as design
and operation information, which makes it suitable for later stages of process
development. The advantage of this method is its capacity to stimulate creativity
and new ideas within the team, as well as its systematic approach. The use of both
of these methods results in a list of scenarios, each with a unique combination of
causes and consequences, considering the presence of safeguards.
169
According to the risk management standards set by the ISO, risk identification is defined as the process of finding, recognizing, and recording risks. This
identification involves recognizing potential accident scenarios, with all of their
corresponding elements. As shown in Fig. 7.2, scenario elements include process
hazards, the sequence leading up to a loss event, and the resulting consequences.
If safeguards are present, they should also be considered. The output of this risk
identification step can be thought of as a list of m potential consequences.
7.5.1 Methods for Risk Identification
Using on-site knowledge and experience is indispensable for the effective identification of risks. To systematically identify them, a wide range of methods are available
and used within the chemical process industry. They each differ slightly in their
assumptions, focus, complexity, and the results they deliver. While some of the
methods are comprehensive and suitable for the identification of accident scenarios,
others can be only used for the identification of process hazards or the detection of
single equipment failures.
Two simple methods include preliminary hazard analysis and checklist analysis.
Preliminary hazard analysis generates a list of process hazards based on hazardous
properties (e.g., flammable or toxic material) and hazardous conditions (e.g., highpressure reaction). Checklist analysis uses previously developed lists to verify the
compliance of a system with standard practices, and identification of noncompliance
can indicate the presence of process hazards.
Two other comprehensive and well-known methods used to predict accident
scenarios are what-if analysis and hazard and operability (HAZOP) studies. Whatif analysis is a brainstorming method in which experienced personnel focus on
deviations from safe process conditions, designs, constructions, etc. that can lead
to loss events. This method is suitable for nearly all stages of process development,
with the required time and effort being proportional to the complexity and size of
the system to be analyzed.
HAZOP studies also focus on deviations, but they use a more structured
brainstorming approach. Here, a set of guide words are combined with specific
process parameters and applied to specific operating steps to identify possible
process deviations. Examples of guide words could be “no,” “high,” etc. Combined
with the process parameters “flow” and “pressure,” this can result in “no flow” and
“high pressure.” Tables 7.1 and 7.2 depict standard HAZOP guide words and some
common HAZOP study process parameters. Table 7.3 shows some examples of
deviations resulting from the combination of guide words and process parameters.
The HAZOP method requires considerable process knowledge as well as design
and operation information, which makes it suitable for later stages of process
development. The advantage of this method is its capacity to stimulate creativity
and new ideas within the team, as well as its systematic approach. The use of both
of these methods results in a list of scenarios, each with a unique combination of
causes and consequences, considering the presence of safeguards.