Risk analysis

Question 1

Why is system mapping performed?

Answer 1

It is important to develop a clear understanding of the structure and behaviour of the system to be assessed by the proposed risk study. Mapping the system to be studied assists such focus.

Question 2

What are task diagrams?

Answer 2

Task diagrams describe a hierarchy of operations (tasks) and plans (necessary conditions to undertake these operations). They are a diagrammatic representation of the structure of activities (nodes) and their relationships (links).

Question 3

What are organisational diagrams?

Answer 3

Organisational diagrams describe a hierarchy of people and/or roles within single or multiple organisations. They are a diagrammatic representation of departments, teams and individuals (nodes) and their relationships (links).

Question 4

What are information diagrams?

Answer 4

Information diagrams describe a hierarchy of information and/or material (things) used or needed in physical or electronic form. They are a diagrammatic representations of the structure of information or documents (nodes) and their relationships (links).

Question 5

What are system diagrams?

Answer 5

System diagrams represent how data (or objects) are transformed through activities, where such data are stored and how such activities are sequenced. They are a diagrammatic representation of the data-flows/ functions and
events/state-transitions within a dynamic system.

Question 6

What are flow diagrams?

Answer 6

Flow diagrams, which include traditional flow charts, and swim-lane diagrams, represent activities occurring in sequence or in parallel. They are a diagrammatic representation of the ordering of activities, showing key steps (nodes) and the conditions for moving between them (links).

Question 7

What are communication diagrams?

Answer 7

Communication diagrams represent information and material flows between people (stakeholders) linked by some common process. They are a diagrammatic representation of the information and material flows (links) between stakeholders (nodes).

Question 8

Name 6 methods of system mapping

Answer 8

Task diagrams
Information diagrams 
Organisational diagrams 
System diagrams 
Flow diagrams 
Communication diagrams

Question 9

Name 10 methods of risk assessment?

Answer 9

• SWIFT (Structured what if technique)
• HAZOP (Hazard and operability analysis)
• Influence Diagram
• Barrier analysis
• FMEA
• HEART
• APJ
• Event tree
• Fault tree
• Risk matrix

Question 10

What is SWIFT?

Answer 10

Ask what if questions to help identify hazards

SWIFT is a structured team-based study that uses “what-if” questions to help a team think about and identify relevant hazards and risks. It focuses on deviations from normal operations and the impact they may have on a system, procedure or organisation.

Question 11

What is HAZOP

Answer 11

Assess the effect, cause and actions taken for a deviation for the expected performance of a system

A hazard and operability study (HAZOP) takes a product or process design which is assumed to be sound and systematically assesses the consequences and likely causes of abnormal behaviour.

Question 12

What is an influence diagram?

Answer 12

Show the factors that influence an event

An influence diagram is a graphical technique for representing all relevant factors that can influence the occurrence of an event, including organisational, individual, team, system and external influencers.

Question 13

What is barrier analysis?

Answer 13

How barriers can be used to prevent harmful energy passing to vulnerable objects

Barrier analysis is a safety analysis technique that focuses on how harmful energy is passed to vulnerable people (objects) and provides qualitative and functional analysis of the barriers that are/need to be in place to prevent the transfer of energy and enhance safety.

Question 14

What is FMEA?

Answer 14

Analyse the different possible failure modes of each component

FMEA (Failure Mode and Effect Analysis) assesses the consequence of failure
(total or partial) of a single component. Each component is analysed in turn against standard failure modes (e.g fails open, fails closed).

Question 15

What is HEART?

Answer 15

Evaluate the probability of human error during a task

HUMAN ERROR ASSESSMENT AND REDUCTION TECHNIQUE
HEART is a human reliability method that is used to evaluate the probability of a human error occurring during the execution of a specific task.

Question 16

What is APJ?

Answer 16

Evaluate the probability of human error during a task

ABSOLUTE PROBABILITY JUDGEMENT
APJ is a human reliability method that is used to evaluate the probability of a human error occurring during the execution of a specific task. It involves a group of experts (front line staff, engineers, managers etc.) using their knowledge and experience to estimate and determine human error probabilities.

Question 17

What is an event tree?

Answer 17

depict event sequence to identify actions leading to an event and possible consequences

An event tree is a graphical device used to logically depict an event sequence in order to help investigate the sequence of operator actions leading to an event and identify the possible consequences of these sequences.

Question 18

What is a fault tree analysis?

Answer 18

Depicts factors that lead to a fault

A fault tree is a graphical device for identifying and analysing factors that contribute to the occurrence of an adverse or undesired event. They are treelike diagrams that pictorially represents such factors and their logical relationship to the adverse/undesired event. Provides insight into the relevant causes of failure, and can be quantitative or qualitative.

Question 19

What is a risk matrix?

Answer 19

Plot events on impact and likelihood axes

Risk matrices allow individuals to rank the consequence and likelihood of an undesired event, act or activity to provide a risk rating. They can be used in conjunction with a range of methods, such as HAZOP and FMEA, to rank and prioritise risk.

Question 20

How do you design a fault tree?

Answer 20

You start with the main top level event/fault at the top (ie the product fails to do its function) and then you move down through AND or OR gates, outlining the factors/events that could happen to cause the failure. AND gates are used if all the related events would have to occur for failure to occur.

Question 21

What is HAZOP, and what could 4 column headings be in a HAZOP table?

Answer 21

HAZOP (Hazard and Operability Analysis) takes a process design which is assumed to be sound and systematically assesses the consequences and likely
causes of a deviation from the intended performance of the system. Each process flow is analysed in turn against standard key words (e.g. turn none, more
of, less of).

Column headings:
First choose a parameter to study eg. Beer volume
-Keyword (eg More of, Part of, less of)
-Effect
-Cause
-Action (what should happen in the process if this fault happens)

Question 22

How to calculate total standard deviation when adding subtracting variables?

Answer 22

You find the total variance by summing the individual variances, and then sqrt to get the total standard deviation

Question 23

What is a good way to present solution principles?

Answer 23

They can be presented in a combination chart which is a table with sub functions down the row headings and then conceptual ideas for solutions in the columns (the column titles would just be the solution idea number)