PRELIMINARY HAZARDS
ANALYSIS
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INTRODUCTION
The Preliminary Hazard Analysis (PHA) is usually the first attempt in the
system safety process to identify and categorize hazards or potential
hazards associated with the operation of a proposed system, process, or
procedure.
The PHA may be preceded with the preparation of a Preliminary Hazard
List (PHL)
It provides rationale for hazard control and indicates the need for more
detailed analyses, such as the Subsystem Hazard Analysis (SSHA) and the
System Hazard Analysis (SHA)
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The PHA is usually developed using the system safety techniques known as
Failure Modes and Effects Analysis (FMEA) and/or the Energy Trace and
Barrier Analysis (ETBA).
PHA development can be somewhat simplified through the use of a
Preliminary Hazard Matrix identifying a Generic Hazard Group.
Generic risk assessments are risk assessments that are filled in but have not
been adapted to a specific site or project. They are completed for a
general activity, for example, roofing, but not for the specific roof you are
about to work on.
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SCOPES OF PHA
• Hazardous components
• Safety related components including software’s
• Operating environments
• Diagnostic test and emergency conditions
• Safety related equipment’s
• Support equipment and training
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PHA PROCEDURE
• PHA pre requisites
• Hazards Identification
• Consequences and frequency estimation
• Risk ranking and follow up action
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PHA TYPICALLY INVOLVES
• Determine the existing hazards
• Determining the guidelines and objectives
• Creating the plan to deal the hazards
• Assigning responsibilities to different teams
• Allocating time and resources to complete the process
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ADVANTAGES
• Identification of the major hazards at early stages
• Serves as basis for designing strategies
• Ensure environment compatibility
• Facilitate the full hazards analysis later
• Prevent wasting of time and resources
• Aids in effective implementation of QMS
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DISADVANTAGES
• Not comprehensive and involve a
complete hazards analysis later
• It itself is quite expensive process
• Require proper follow up by SSHA and
OSHA
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REFERENCES
• https://www.leedeo.es/l/preliminary-hazard-
analysis-how-constructed/
• https://www.slideshare.net/ManiSaro/mani-unit-ii-2
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