Training Guide: Hazard & Operability Analysis (HAZOP)
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Harm - Physical injury or damage to the health of people or damage to property
or the environment. Harm is the consequence of a hazard occurring and
may take many forms: patient or user safety, employee safety, business
risks, regulatory risks, environmental risks, etc.
Risk - Combination of probability of occurrence of harm and the severity of
that harm. In a strict sense, “risk” is not always explicitly identified in
HAZOP studies since the core methodology does not require
identification (also referred to as rating) of the probability or severity of
harm. However, risk assessment teams may choose to rate these factors
in order to further quantify and prioritize risks if needed.
1.2 Usage
HAZOP is best suited for assessing hazards in facilities, equipment, and processes
and is capable of assessing systems from multiple perspectives:
Design
o Assessing system design capability to meet user specifications and
safety standards
o Identifying weaknesses in systems
Physical and operational environments
o Assessing environment to ensure system is appropriately situated,
supported, serviced, contained, etc.
Operational and procedural controls
o Assessing engineered controls (ex: automation), sequences of
operations, procedural controls (ex: human interactions) etc.
o Assessing different operational modes – start-up, standby, normal
operation, steady & unsteady states, normal shutdown, emergency
shutdown, etc.
+ Helpful when confronting hazards that
are difficult to quantify
Hazards rooted in human
performance and behaviors
Hazards that are difficult to detect,
analyze, isolate, count, predict, etc.
Methodology doesn’t force you to
explicitly rate or measure deviation
probability of occurrence, severity of
impact, or ability to detect
+ Built-in brainstorming methodology
+ Systematic & comprehensive
methodology
+ More simple and intuitive than other
commonly used risk management tools
- No means to assess hazards involving
interactions between different parts of a
system or process
- No risk ranking or prioritization
capability
Teams may optionally build-in such
capability as required
- No means to assess effectiveness of
existing or proposed controls (safeguards)
May need to interface HAZOP with
other risk management tools (ex:
HACCP) for this purpose