WHAT IS SYSTEM
SAFETY?
The field of safety analysis in which systems are evaluated
using a number of different techniques to improve safety.
There are a variety of techniques each designed to examine a
particular aspect of a system with regards to safety.
HOW DOES SYSTEM
SAFETY IMPROVE
SAFETY?
System safety improves safety by:
• Identifying unsafe parts of a system
• Identifying unsafe steps in a procedure
• Identifying changes or improvements that could be made to a
system
WHERE IS SYSTEM
SAFETY USED?
System safety techniques are used in virtually any field and
type of company.
At the more complex end of system safety, systems in the
space shuttle are evaluated to determine if the space shuttle
will work in a reliable and safe manner.
System safety could be a simple as analyzing the steps
necessary to perform a task.
THE GOAL OF SYSTEM
SAFETY
Hazards are known and controlled to an acceptable level.
Your priority.
• Eliminate or control hazards.
• Reduce the potential for accidents and losses.
THE SYSTEM SAFETY
PROCESS
Identify each component and operational procedure.
Identify and analyze potential hazards for each component.
Eliminate the hazards by design, minimize effects, revise
operating procedures.
• Acceptable risks are judgments made by people responsible
for making them (management).
SYSTEM LIFECYCLE
Based off of the MIL Standards
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Concept Definition phase
Development and test phase
Production phase
Operation phase
Disposal
CONCEPT DEFINITION
PHASE
• Basic System is roughly designed
• Overall system goals and objectives are defined
• Develop System Safety Program Plan
DEFINITION PHASE
• Preliminary design
• PHA
• SSHA
• FTA
• FMEA
• HAZOP
DEVELOPMENT AND
TEST PHASE
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Preliminary design
Detailed designs
Critical design review
System testing
Go/no go decision
PRODUCTION PHASE
• Product approved for production
• Training
• Equipment operators
• O & SHA (operating & support hazard analysis)
OPERATION PHASE
• Product becomes operational
• Safe system operation and maintenance
DISPOSAL PHASE
• Disposal procedures
PREVENTION
THROUGH DESIGN
Addresses occupational safety and health needs in the design
and redesign processes to prevent or minimize work related
hazards and risks associated with the manufacture, use,
maintenance and disposal of facilities, materials, and equipment.
SAFETY THROUGH
DESIGN
Integration of hazard analyses and risk assessment methods into
the early design and redesign processes.
Taking actions necessary to so risks are at an acceptable level.
ANSI/ASSE Z590.32011
Prevention Through Design: Guidelines for Addressing
Occupational Hazards and Risks in Design and Redesign
Processes was approved and went into effect in January 2012.
ANSI/ASSE Z590.3-2011 provides guidance on including
prevention through design concepts within an occupational safety
and health management system.
SYSTEMS
TECHNIQUES
There are numerous systems techniques available.
Each has a purpose and an expected analysis outcome.
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Fault Tree Analysis
Failure Mode and Effects Analysis
HAZOP
What If Analysis
THERP
MORT
RISK
PROBABLE LOSSES OVER A SPECIFIED TIME PERIOD
COMPRISED OF THE FOLLOWING:
• EXPECTED LOSS PER MISHAP
• ANTICIPATED MISHAP RATE
• EXPOSURE TO THE MISHAP
RISK INDEXES
MISHAP RATE
• NUMBER OF MISHAPS PER UNIT OF
EXPOSURE
LOSS FROM EXPOSURE
• MEASURED IN DOLLARS
RISK INDEX = RATE x LOSS
RANK BY INDEXES
• LARGEST RISK INDEX GETS RANKED FIRST
PRIORITIZING RISKS
PROBABILITY
SEVERITY
CAN BE:
• QUALITATIVE
• QUANTITATIVE