Hazards and Safety Management

1. PRELIMINARY HAZARD
ANALYSIS (PHA)
Presented by,
Manikandan V,
2061050002,
M. Pharm (Pharmaceutical Quality Assurance),
Department of Pharmacy,
Annamalai University.
Submitted to
Dr. G. Sivakamasundari, M. Pharm., Ph. D.,
Assistant Professor,
Department of Pharmacy,
Annamalai University.

2. 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).
 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).

3. • PHA development can be somewhat simplified through the use of a
Preliminary Hazard Matrix identifying a Generic Hazard Group. The
PHA Report can be generated based upon the evaluation and analysis of
system hazard risk.
• Preliminary Hazard Analysis (PHA) was introduced in 1966 after the
Department of Defence of the United States of America requested safety
studies to be performed at all stages of product development. The
Department of Defence issued the guidelines that came into force in
1969 (Military Standard (1969, 1999)).
• Preliminary Hazard Analysis is performed to identify areas of the
system, which will have an effect on safety by evaluating the major
hazards associated with the system. It provides an initial assessment of
the identified hazards.

4. PHA SCOPE
The PHA shall consider:
• Hazardous components
• Safety related interfaces between various system elements, including
software
• Environmental constraints including operating environments
• Operating, test, maintenance, built-in-tests, diagnostics, and emergency
procedures
• Facilities, real property installed equipment, support equipment, and
training
• Safety related equipment, safeguards, and possible alternate approaches
• Malfunctions to the system, subsystems, or software

5. PHA PROCEDURE
• PHA prerequisites
• Hazard identification
• Consequence and frequency estimation
• Risk ranking and follow-up actions

6. PHA PREREQUISITES
• Establish PHA team.
• Define and describe the system to be analyzed.
System boundaries (which parts should be included and which should not).
System description; including layout drawings, process flow diagrams,
block diagrams, and so on.
Use and storage of energy and hazardous materials in the system.
Operational and environmental conditions to be considered.
Systems for detection and control of hazards and accidental events,
emergency systems, and mitigation actions.
• Collect risk information from previous and similar systems.

7. HAZARD IDENTIFICATION
• All hazards and possible accidental events must be identified. It is
important to consider all parts of the system, operational modes,
maintenance operations, safety systems, and so on.
• All finding shall be recorded. No hazards are too insignificant to be
recorded. Murthy’s law must be borne in mind: “If something can go
wrong, sooner or later it will”.

8. FREQUENCY AND CONSEQUENCE
ESTIMATION
• The risk related to an accidental event is a function of the frequency of
the event and the severity of its potential consequences.
• To determine the risk, we have to estimate the frequency and the severity
of each accidental event.

9. RISK RANKING AND FOLLOW-UP ACTIONS
• The risk is established as a combination of a given
Event/consequence and a severity of the same actions
Event/consequence. This will enable a ranking of the actions
Events/consequences in a risk matrix as illustrated below,

10. PHA TYPICALLY INVOLVES
 Determining hazards that might exist and possible effects.
 Determining a clear set of guidelines and objectives to be used during a
design.
 Creating plans to deal with critical hazards.
 Assigning responsibility for hazard control (management and technical).
 Allocating time and resources to deal with hazards

11. ADVANTAGES
• It identifies the potential for major hazards at a very early stage of project
development.
• It provides basis for design decisions.
• It helps to ensure plant to plant and plant to environment compatibility.
• It facilitates a full hazard analysis later.

12. DISADVANTAGE
• The disadvantage of PHA is that it is not comprehensive and must be
followed by a full HAZard and OPerability (HAZOP) study.
Subsystem Hazard Analysis/System Hazard Analysis (SSHA)
Operating and Support Hazard Analysis (OSHA)

13. SUBSYSTEM HAZARD ANALYSIS/SYSTEM
HAZARD ANALYSIS (SSHA)
• Subsystem Hazard Analysis (SSHA) or System Hazard Analysis (SHA) is
one requiring detailed studies of hazards, identified in the PHA, at the
subsystem and system levels, including the interface between subsystems
and the environment, or by the system operating as a whole.
• Results of this analysis include design recommendations, changes or
controls when required, and evaluation of design compliance to contracted
requirements.
• These hazards are often handled by updating and expanding the PHA, with
timing of the SSHA/SHA normally determined by the availability of
subsystem and system design data.

14. OPERATING AND SUPPORT HAZARD
ANALYSIS (OSHA)
• Operating and Support Hazard Analysis (OSHA) is an analysis performed to
identify those operating functions that may be inherently dangerous to test,
maintenance, handling, transportation or operating personnel or in which
human error could be hazardous to equipment or people.
• The information for this analysis is normally obtained from the PHA.
• The OSHA should be performed at the point in system development when
sufficient data is available, after procedures have been developed.
• It documents and evaluates hazards resulting from the implementation of
operations performed by personnel.

15. REFERENCES
• Preliminary Hazard Analysis, Marvin Rausand. Department of
Production and Quality Engineering. Norwegian University of Science
and Technology. October 7, 2005 System Reliability Theory (2nd ed),
Wiley, 2004.

16. THANK YOU