Religious-pilgrimage system
Liza Julie 89
lecture_slide_notes_4.4_week_12_.pdf
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NUG ANALYSIS OF ACCIDENTAL HAZARDS 15 NOVEMBER 2020 HRVA, FALL 2020
Introduction
Purpose of today’s class is to apply all that we have learned with NUG analysis for
natural hazards and apply it to accidental hazards.
Homework 4.2: Far too many cadets keep copying the incomplete and terribly
inaccurate answer to Problem 4. Do you even read what the question asks? And you
wonder why so many people gets Ds and Cs, while so few get Bs and As.
Homework 4.4: Due Saturday 11:59PM November 28
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Accidental Hazards: Key Characteristics
Accidental hazards emerge from within the asset, such as a production facility.
Not caused by external hazard, as in natural hazards.
Cause of Accidental Hazards?
1. Lack of safety training of workers. 2. Lack of safety concerns of production managers.
3. Insufficient safety monitoring by safety inspectors 4. Unwilling to follow government safety mandates, laws or regulations. 5. Willful ignoring of safety rules by managers to boost profits (Intentional Hazard?)
6. Why? Safe operations require more expensive or time-consuming production processes.
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Mitigating Accidental Hazard Risk
Natural Hazard Risk = Hazard Probability x Vulnerability Probability x Loss
This assumes the hazard is completely independent of the asset.
But this does not apply for accidental hazards: The hazard emerges from the asset!
So, there is only one Risk equation:
Accidental Hazard Risk = Accident Probability x Accident Loss
So we have two strategic options for mitigating accidental hazard risk:
1. Lower the accident probability through human safety systems to stop accidents from occurring (non-structural)
2. Lower the accident loss magnitude through protective safety solutions (structural)
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Mitigation Tactics for Reducing Probability of Accidents (Non-structural, behavioral)
1. Establish safety rules for workers to follow (Variable cost) 2. Make sure safety inspectors/managers update safety rules and rules are being followed
(Variable Cost)
3. Make sure dangerous machines that generate high temperatures, high pressures, fast
moving parts, and toxic chemicals are carefully monitored to ensure safe operating
conditions (Variable Cost)
4. Computer hardware and software that automatically controls machines to prevent
dangerous performance levels from occurring (Investment).
5. Sirens and warning lights when dangerous conditions are emerging (Investment)
6. Testing of sensors and human operators with safety drills (Variable Cost)
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Mitigation Tactics for Reducing the Magnitude of Loss (Structural)
1. Pressure release valves to release high pressure steam or gases to prevent catastrophic explosion (Investment)
2. Automatic sprinklers to put out fires before they spread (Investment)
3. Fireproof building materials (Investment) 4. First aid equipment to reduce human losses (Investment)
5. Emergency-evacuation routes established to reduce human losses (Investment) 6. Gas masks to limit human losses when toxic gases get released (Investment) 7. Water sprayers to dissolve toxic gases that when vented into the atmosphere
(Investment).
8. Structural containment vessels to prevent toxic gases or liquids from escaping into environment (Investment)
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Accidental Risk Management Independent Variables
Structural Mitigation Investments to Reduce Accident Loss Magnitude = M
Performance of Non-Structural/Behavioral Safety System to Reduce Accident
Probability = q
How accurately can safety managers monitor operations to detect unsafe
conditions?
How well are workers restrain or stop production operations when unsafe conditions
emerge?
What percentage of safety rules followed? How well do safety practices conform to
law and government regulations?
Investment in Behavioral Safety System = P
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Safety System Investments
1. Computer monitoring systems 2. Sensors on machines 3. Hazard detection systems: smoke alarms, poison-gas alarms
4. Safety training classes for workers 5. Shrouds and barriers to keep workers from contacting dangerous moving parts
6. Fencing and railings to keep workers from falling 7. Active control systems that automatically shut down machinery when dangerous
conditions are reached.
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Accidental Risk Management: Dependent Variables Risk = R(q, M)
In other words, risk of accident depends only on behavioral safety system
performance, q, and structural mitigation investment, M. It doesn’t depend on
investment in behavior safety system, P.
Total safety system variable cost = TVC(q, P)
This is the direct cost of operating the safety system. Increased investment, P
reduces this cost for a given performance level.
Example I: greater investment in computer and sensor system means fewer
safety managers are required to monitor dangerous machine operations.
Example II: great investment in worker safety training means safer production
with fewer costly shutdowns or disruptions of production system due to injuries.
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Net Utility Gain Equation
Net Benefit, NB(q, M) = R(0,0) – R(q, M) – M
Total Cost, TC(q, P) = TVC(q, P) + P
Net Utility Gain, NUG(q, P, M) = NB(q, M) – TC(q, P) = [R(0,0) – R(q, M) – M] – [TVC(q, P) + P]
Basic strategic question in accidental risk management:
What levels of q, M and P will generate highest level of Net-Utility Gain, NUG?
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$
TVC(q, P1)
P1
M1
q, Safety Performance)
Fig. 1
R(0, 0))
R(q, M1)
What level of q will provide the highest level of Net-Utility Gain?
$
TVC(q, P1)
P1
M1
q, Safety Performance)
Fig. 2
R(0, 0))
R(q, M1)
TC(q, P1) = TVC(q, P1) + P1
x
x TB(q, M1) = R(0,0) – R(q, M1)
NB(q, M1) = R(0, 0) – R(q, M1) – M1
q*
NUG(q*, M1, P1) = NB(q*, M1) – TC(q*, P1)
When q = q*, NUG will be at the highest possible or maximum level.
TVC(q, P3)
$
TVC(q, P2)
TVC(q, P1)
P1
P2 P3
M1 M2 M3
q, Safety Performance)
Fig. 3
R(0, 0))
R(q, M1)
R(q, M2)
R(q, M3)
When you have three different mitigation investment options, M and three different safety system investment options, P, what level of q and which investment choices will give you the high possible or maximum level of NUG?
TVC(q, P3)
$
TVC(q, P2)
TVC(q, P1)
P1
P2 P3
M1
M2 M3
q, Safety Performance)
Fig. 4
R(0, 0)) TB(q, M3) = R(0,0) – R(q, M3) TB(q, M2) = R(0,0) – R(q, M2)
TB(q, M1) = R(0, 0) – R(q, M1) R(q, M1)
R(q, M2)
R(q, M3)
You first want to determine the total benefit function, TB, For each level of mitigation investment: M1, M2, and M3
TVC(q, P3)
$
TVC(q, P2)
TVC(q, P1)
P1 P2
P3
M1 M2 M3
q, Safety Performance)
Fig. 5
R(0, 0)) B(q, M3) = R(0,0) – R(q, M3) B(q, M2) = R(0,0) – R(q, M2)
B(q, M1) = R(0, 0) – R(q, M1)
TC(q, P3) = TVC(q, P3) + P3
$
TC(q, P2) = TVC(q, P2) + P2 TC(q, P1) = TVC(q, P1) + P1
P1
P2 P3
M1 M2 M3
q, Safety Performance)
Fig. 6
NB(q, M3) = TB(q, M3) – M3 NB(q, M2) = TB(q, M2) – M2
NB(q, M1) = TB(q, M1) – M1
Now let’s shift up the TVC curves by P to get the total cost functions, TC. Then let’s push down the TB curves by M to get the net benefit function, NB
TC(q, P3) = TVC(q, P3) + P3
$
TC(q, P2) = TVC(q, P2) + P2 TC(q, P1) = TVC(q, P1) + P1
P1
P2 P3
M1 M2 M3
q, Safety Performance)
Fig. 7
NB(q, M3) = TB(q, M3) – M3 NB(q, M2) = TB(q, M2) – M2
NB(q, M1) = TB(q, M1) – M1
q*
NUG(q*, P1, M3) = NB(q, M3) – TC(q, P1)
Maximum Net Benefit
Minimum Total Cost
Now let’s draw the minimum total cost dotted line, and the maximum net benefit dotted line. So, to find the maximum level of NUG, determine where the difference is the greatest between these two curve combinations.
Exercise 1: Draw total benefit and total cost functions
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P1
M1
TVC(q, P1)
q
P2
M2
TVC(q, P2)
R(q, M1)
R(q, M2)
Exercise 2: Draw the net benefit and total cost functions
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P1
M1
TVC (q, P1)
q
P2
M2
TVC (q, P2)
TB(q, M1)
TB(q, M2)
Exercise 3: Draw with Dotted Line the Maximum Net Benefit and Minimum Total Cost, and Determine Maximum NUG and q*
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P1
M1
TC (q, P1)
q
P2
M2
TC (q, P2)
NB(q, M1)
NB(q, M1)
