4. Risk Assessments

Question 1

risk

Answer 1

potential negative impact to something of value that might result from a future event

joint probabilities of an occurence of an event and its consequences

risk involves trying to understand uncertainty

Question 2

different types of risks

Answer 2

-project risks; schedule/resources

-product risks; quality/performance of product

-business risk; orgnisation finances/resources

-operational risks; facility, equipment, people

-enviro. risks; to and from enviro.

-health risk; human, short/long-term/immediate

Question 3

risk equation

Answer 3

risk = probability of an accident x losses per accident

risk = likelihood of occurence x consequence of occurence

Question 4

probability vs likelihood

Answer 4

probability; hypothesis treated as a given (data may vary)
–> figuring out the chance the risk will happen

likelihood; data is given (hypothese may vary)
–> chance that a risk will impact us

Question 5

risks characterized by

Answer 5

probability of an adverse outcome

type + severity of adverse outcome

timing of adverse outcome

distribution of adverse outcome

size of exposed population/enviro.

certainty of risk estimates

Question 6

risk acceptance

Answer 6

always balancing risks with benefits, BUT might disagree on whther risk acceptable or not

accepting consequences of a risk happening, but likelihood and consequences can change over time ad no longer be acceptable

Question 7

hazard

Answer 7

situation posing a level of threat to life, health, property, enviro. potentially harmful situation

source of potential harm
harm = injury/damage to enviro. or people

Question 8

4 types of hazards

Answer 8

a. dormant; situation having potential to be hazardous, currently no one affected

b. potential;hazard in position to affect, likely needs further risk assessment

c.active; hazard is certain to cause harm, no intervention possible before it occurs

d. mitigated; actions taken to ensure potential hazard not incident, may not be absolute guarantee of no risk (reducing danger)

Question 9

Hazard causes

Answer 9

a. natural

b. human-made

Question 10

accident vs incident

Answer 10

incident; sequence of actions/events

accident; incident’s consequences

All accidents are incidents, not all incidents = accidents

Question 11

Risk analysis (2 parts)

Answer 11

quantify the potential harm (risk assessment)
-what can go wrong
-likelihood of going wrong
-consequences

+

evaluate the effectiveness of proposed remediation (risk management)
-what can be done
-options available, tradeoffs, costs, benefits, risks
-impacts of mgmt decisions on future options

Question 12

Risk analysis guiding principles

Answer 12

-scope definition
-hazard location
-failure mode effect analysis
-failure likelihood analysis
-consequences assessment
-risk characterization
-uncertainty/sensitivity analysis
-documentation
-expert review/verification
-analysis update

Question 13

4 risk analysis methods

Answer 13

a. failure mode effect analysis (FMEA)

b. fault tree analysis (FTA)

c. event tree analysis (ETA)

d. bow-tie analysis (BTA)

Question 14

failure mode effect analysis (FMEA)

hazard identification

Answer 14

involves interpreting the analysis and expressing results in terms of some risk metric

S x O x D = RPN (risk priority number)

S x O = criticality (second most weight)

severity; estimate how severe public perceive effect of failure. given the most weight

occurence; estimate of likelihood that the cause will = failure mode

detection; estimate of effectiveness of control to prevent failure mode (assuming it occured)

RPN; from 1-1000, measure help identify critical failure modes associated with process/design

–> any failure mode that has an effect resulting in severity 9-10 would have to top priority

Question 15

fault tree analysis (FTA)

likelihood of system failure

focus on preventive measures
–> multiple causes leading to an event

Answer 15

identifies, models, evaluates unique interrelationship of events leading to failure, undesirable events, unintended events. identifies all possible causes of a specified undesired event (top event)

deductive analysis, reasoning what can lead to occurence of specified undesired event (top down manner, from general to specific

top event = failure
basic events = root causes
intermediate events
logic gates (AND, OR)
=fault tree

steps:
1. define system, top event (potential accident) + boundary conditions
2. fault tree
3. analysis of fault tree
4. report results

–> graphic tool
–> qualitative insight to the system
–> can be used for quantitative assessmet system reliability
–> mainly safety engineering to quantitatively determine probablity of a hazard

Question 16

event tree analysis (ETA)

consequence of system failure

focus on mitigation measures
–> multiple consequences after an event

Answer 16

accidental event may = different consequences (inductive reasing, bottom-up approach)

potential consequences may be illustrated by consequence spectrum

probability that an accidental event will lead to unwanted consequences depends on whether barriers are functioning or not (well dsesigned systems have 1+ barriers implemented to stop/reduce consequences of potential accidental events).

additional events: listed together as barriers (as far as possible in sequence), described as worst case statements

output events; usually 2 alternatives (true vs false)

–> consequence analysis

Question 17

bow-tie analysis (BTA)

risk of system failure

Answer 17

integrated probabilistic technique analyzing the accident by scenarios, assessing the probability/pathways of occurences

couples FTA + ETA by using common top event as critical event

causes; fundamental reasons resulting in failure (basic events)

fault tree (FT); graphic pathways of causation leading to undesired event which is top-event + interactions of causes (basic events, intermediate, logic gates)

critical event (CT); top event of FT = initiating event for ET = critical event

event tree (ET); sequences possible consequences of CE considering barriers

outcome event (OE); final consequences from systematic propagation of CE through barriers

pre-event side = FT
–> preventive controls
post-event side = ET
–> recovery controls

Question 18

risk management ALARP

Answer 18

as low as reasonably practicable

decision actions, control strategies, interventions

estimated value of risk, acceptable value of risk, risk after intervention (risk mgmt)

Question 19

uncertainty

Answer 19

measure of the “goodness” of an estimate

how closely estimated value relates to/represents reality

arises from lack/insufficient knowledge-impossible to exactly describe existing state or future outcome

state where 1+ possible outcome can exist

Question 20

large part of EIA practice is about ….

(3)

Answer 20

1. identifying the potential negative outcomes or risks, of a project.
2. managing/mitigating risks (making decision with knowledge of risks and potential outcomes)
3. perceived risks to people, ecosystem, enviro.
   –> what participation asks proponents to account for and mitigate

Question 21

critiques of FTA/ETA

Answer 21

-assume events (basic events) are independent
–> interdependence among events

-incompleteness/partial ignorance + imprecision
–> likelihood values of input events, requires known probablities

= unrealistic
=uncertainty

–> evidence theory; multisource knowledge = more reliable information about event probability (knowledge is socially constructed, so always incomplete)

Question 22

uncertainty associated with a system is proportional to its…

+

uncertainty arising due to lack of…

Answer 22

DATA UNCERTAINTY
complexity (arising from vaguely known relationships among its entities, and randomness in governing mechanisms)

–> relationships between cause/effect often not well understood
–> often non linear behaviour, combined effects of contributing factors= sub/superadditive

DEPENDENCY UNCERTAINTY
information on dependencies among events (FTA/ETA assume interdependence among risk events to determine joint probability (risk))

Question 23

vulnerability vs capacity

Answer 23

vulnerability; how susceptible something is to harm

capacity; ability to cope with risk if it happens

–> vulnerability>capacity = potential impact of risk higher

–> both are linked, depend on the degree to which people/communities have access to resources to deal with risk

Question 24

2 ways of analyzing risk

Answer 24

a. qualitative risk analysis; prioritize the identified risks on a defined scale based on their likelihood of occurence + their impacts

b. quantitative risk analysis; defines probability of an event occuring
(BTA, ETA, FTA)

–> which one to use depends on data available, type of risk analyzed, amount time

Question 25

Steps risk analysis

Answer 25

1. risk identification/assessment
   –> understand risk sources, impacted areas, possible events, causes
2. risk evaluation; measuring risk = risk profile showing significance of risk
3. managing risk;
   a. avoid
   b. transfer (allow risk to be shared/transferred to 3rd party-insurance)
   c.mitigate (before happens, early actions to reduce/prevent)
   d.contingency (back-up until normal again)
4. risk monitoring/review: continually track risks, see controls effective, decision right
   –> risk registry (description, factors, impacts, actions, assessments, ..)

Question 26

why risk assessments important?

Answer 26

knwoledge-based, informed decisions

identifying and understanding risks and managing them = key part of desinging and operating projects

managing risks is also about ensuring communities understand the ways risks are defined, managed, communicated

Question 27

social, cultural, econ aspect of risk

Answer 27

social risks; impact project might have on communities (affect access to traditional lands, resources, impact on life quality, etc.)

–> managing risks includes understanding how people use land/resources, cultural values attached to specific places, what risk project may pose to these qualities

economic risk presented as a lost opportunity, loss of potential income to provide services to communities
–> often made by government, industry
“without project, funding not available to support people”