MIL-STD-882 (Modified) Hazard Risk Matrix
Calibration Event
Introduce a known event with established probability or
severity to ‘calibrate’ probability estimates, i.e. risk of
death due to car accident during commute to work over 25
year working life.
Probability bins (over service life)
IDLog
A6
B5
C4
D3
Description
Individual
Fleet/Inventory
AIAA
Threshold
Combinatorial
probability
3 X 10 -1
Frequent
Occurs regularly
Continuously
experienced.
> 8 X 10 -2
Probable
Will occur several
times in the life.
Occurs regularly.
> 8 X 10
Occasional
Remote
-3
Unlikely but can
reasonably expect to
occur in life of item
Will occur several
times in the fleets life.
Unlikely but possible
in life of item.
Unlikely but can
reasonably expect to
occur in life of fleet.
> 8 X 10 -5
> 8 X 10 -4
3X
10- 2
3 X 10- 3
3 X 10 -4
Hazard Risk Index Matrix
Severity (log)
Probability log
IV 1
III 2
II 3
I4
A6 (Frequent)
10(7)
6(8)
3(9)
1 (10)
B5 (Probable)
14(6)
9(7)
5(8)
2(9)
C4 (Occasional)
17(5)
13(6)
8(7)
4(8)
D3 (Remote)
19(4)
16(5)
12(6)
7(7)
E2 (Improbable)
20(3)
18(4)
15(5)
11(6)
F1 (Impossible)
21(2)
21(3)
21(4)
21(5)
MIL-STD-882C risk acceptance curves corrected to log scale
E2
Improbable
So unlikely it may not
be experienced in life
of item
Unlikely but possible in
life of fleet.
> 8 X 10 -6
3 X 10 -5
F1
Impossible
Virtually impossible
to occur.
So unlikely it may not
be experienced in life
of fleet
> 8 X 10 -7
3 X 10 -6
Corrected MIL-STD-882C example probability definitions with log scale and AIAA/SETC threshold and combinatorial probability index, fleet numbers
Will affect cumulative risk and should be used to calibrate likelihood.
Severity bins
Description
Mission
Personnel
Equipment
Environment
I4
CATASTROPHIC
Loss of mission
area capability no
reversionary
capability
Multiple deaths to
single death
Total loss of system, >
$1M equipment
damage.
Long-term (5 yrs or greater)
damage or requiring >$2M to
correct and/or in penalties.
Significant
degradation of
mission area
capability
Multiple severe injuries,
to single. Greater than 2
weeks hospitalisation.
>$250K to $1M
equipment damage.
CRITICAL
1-6
High
7-10
Medium
(ALARP)
11-17 Low
Medium-term (1-5 yrs) damage or
requiring $500K-2M to correct
and/or in penalties
III2
MARGINAL
Degradation of
mission area
Multiple Minor injuries
(OH&S reportable) to
single minor injury.
$1K to $250K
equipment damage.
Short-term (<1 yr) damage or
requiring $2K-$500K to correct
and/or in penalties
IV1
NEGLIGIBLE
Minor loss of
mission functionality
No injury
< $1K equipment
damage.
Minor damage, readily repaired
requiring < $2K to correct and/or
in penalties
MIL-STD-882C example severity definitions with log scale.
Risk
Zone
(ALARP)
IDlog
II3
Risk treatment
18-20
V. Low
21
Negligible
Risk treatment
Decision
maker
Intolerable risk must be
reduced.
---
Reduce risk until further risk
reduction is grossly
disproportionate. Residual
risk must be quantitative or
semi-quantitatively assessed
and well understood.
Customer or
Project
Sponsor
Reduce risk until further risk
reduction costs exceed the
benefit gained. Residual risk
may be more subjectively
assessed.
PM
Broadly acceptable with
periodic review.. Application of
existing best practice is
deemed to reduce risk to this
level. Without qualitative risk
assessment
IPT
Record only.
IPT
CC BY-NC