risk analysis Flashcards
Safety (Process)
A business objective directed at
preserving and protecting workers, the public,
the environment, and assets against harm
resulting from known conditions, natural
occurrences, malicious acts, accidents, and
risks…
Safety (Condition)
Condition in which there is low probability
that harm will occur
System Safety
The application of engineering and
management principles, criteria, and techniques to
achieve acceptable mishap risk, within the constraints of
operational effectiveness, time, and cost, throughout all
phases of the systems life cycle
or
an optimal degree of safety, established
within the constraints of operational effectiveness, time,
and cost, and other application interfaces to safety, that
is achievable throughout all phases of the system life
cycle
Accident/Mishap
Undesirable event or a series of undesirable
events that result in harm
System
An integrated composite of people, products, and processes that provide a capability to satisfy a stated need or objective
Hazard
Conditions or events in a system that can result in harm
Risk
Likelihood (probability) and severity of a loss (consequence).
or
cost of mishaps stemming from a particular hazard over
life of system
Hazard probability
likelihood of adverse consequence from particular hazard
Hazard severity
Assessment of consequences of specific hazard
Examples of Hazards
Leak of photocopy fluid
Leak of toothpaste
Fire
Radiological release
Death
Total Risk
Unacceptable risk that is eliminated
unacceptable risk that is controlled
residual risk
Residual Risk
Acceptable and unidentified risk
Exposure
The time interval over
which hazard exists
What is the area under the curve of consequence and probability?
Total risk of the hazard
What should you assign each hazard?
Th worst credible consequence (most severe
outcome that can reasonably be expected
to occur) and use this to assign a risk
assessment level (as representative of the
whole hazard)
Safety analysis
Analysis by means of
appropriate analytical tools that
establishes and confirms the design basis
for the items important to safety; and
ensures that the overall plant design is
capable of meeting the acceptance criteria
for each plant state
Design basis
The range of conditions and
events taken explicitly into account in the
design of the facility, according to established
criteria, such that the facility can withstand them
without exceeding authorized limits by the
planned operation of safety systems
Covers plant states during
- Normal Operation
- Emergency
- Maintenance/Testing
What is the philosophy behind system safety?
- Loss Prevention - Complete removal of all hazards
- Secondary Prevention (Loss Control) when hazard cannot be completely removed. System (components, people, environment) protected so that exposure to hazards less likely or consequences less severe.
- Trade-offs
Objective of system safety?
Achieve a minimal level of
risk within the constraints of
operational effectiveness, time, and
cost.
or
can help to reduce human
errors within the sociotechnical system (design,
training, operations, plant management,
organizational env, safety culture …)
System Safety Principles and Methods to
determine how system can fail, how can cause
injury, death, illness, damage, loss of
equipment or property, data, damage to
environment.
Systematic
Hazard Identification
Hazard Elimination
Risk Control
System Safety Process
Define Objectives
System Descriptions
Hazard Identification
Risk Analysis
Risk Assessment
Decision Making
Validation of Control
Modify System/Process
Define Objectives
Define the objectives of the
system under review -
business plans and operating
specifications
System Description
- interactions among people,
procedures, tools, materials,
equipment, facilities,
software, and the
environment - data available
Hazard Identification: Identify
Hazards & Consequences
- internal and external sources
-Create Preliminary Hazard List (PHL)
-Group by functional equivalence for analysis
-Determine Hazard scenarios
-Determine consequence (undesired event) resulting from the hazard scenarios - Hazard scenarios may addressthe following: who, what where, when, why and how.
- Need to determine and document condition and the
consequences that will be used during risk analysis
