The ANSI Process for System Safety Assurance Presented at the Safety Case Workshop Huntsville, AL;...

The “ANSI Process” forSystem Safety AssurancePresented at the Safety Case WorkshopHuntsville, AL; January 14th, 2014

David B. West, CSP, P.E., CHMM, Fellow

NATIONAL SECURITY • ENERGY & ENVIRONMENT • HEALTH • CYBERSECURITY

© SAIC. All rights reserved.

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What do we mean by the “ANSI Process”?

• In this workshop, the “ANSI Process” refers to System Safety processes and methodologies outlined in ANSI/GEIA-STD-0010-2009, “Standard Best Practices for System Safety Program Development and Execution”

• The publishing of best practices in ANSI/GEIA-STD-0010-2009 was done by a working group of the SAE International G-48 System Safety Committee

• Best practices are developed and standardized so that the community of practitioners can advance the state-of-the-art

• The best practices documented in ANSI/GEIA-STD-0010-2009 include:• Designing a System Safety Program around 5 basic elements• Using a modernized risk assessment matrix• Describing hazards in terms of their Source, Mechanism, and

Outcome• Giving consideration to the concept of Total System Risk

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Outline of Presentation

• Brief background on the G-48 System Safety Committee• How standardizing best practices can drive advancements in

the state-of-the-art• The G-48 Committee’s development of ANSI/GEIA-STD-0010-

2009• The 5 basic elements of an effective system safety program,

as presented in ANSI/GEIA-STD-0010-2009• Improvements, covered in ANSI/GEIA-STD-0010-2009, to the

traditional risk assessment matrix • The source-mechanism-outcome model for describing hazards• Risk summation

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Overview of the G-48 System Safety Committee

• Established in 1966 by the Electronics Industries Association (EIA)• System Safety experts from industry, government, military• Advisory body to U.S. Govt. on System Safety issues and standards – e.g., MIL-

STD-882• Develops/seeks consensus on System Safety methodologies• Three meetings per year• Parent organizations after EIA:

– GEIA– ITAA– TechAmerica– SAE International (July 2013)

• Mission Statement:– To promote the development of safe systems, products, and processes: the G-48

Committee compiles, develops, improves and publishes best practices in the discipline of System Safety.

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Overview of the G-48 System Safety Committee (Cont.)

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Overview of the G-48 System Safety Committee (Cont.)

G-48 Meeting No. 133 – Huntsville, AL – January 2013

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How standardizing best practices can drive advancements in the state-of-the-art

• A key motivating factor in developing ANSI/GEIA-STD-0010-2009 was the desire to make improvements in the System Safety state-of-the-art.

• The next five charts graphically present a notional and non-quantitative picture of how improvements in the practice of any human endeavor can be actively brought about through the standardization of best practices.

• This approach for bringing about improvements has been successfully followed in several other fields, including:

– The medical profession– Steam boiler design and manufacturing– Fire protection in building design– The automotive industry

Variation of Practice in a Typical Discipline

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Measure of “Goodness”(Proficiency, Effectiveness, Accuracy, Value, etc.)

Fre

qu

ency

of

Pra

ctic

e

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Standardization Option 1:Define and Document Current Practice

Measure of “Goodness”(Proficiency, Effectiveness, Accuracy, Value, etc.)

Fre

qu

ency

of

Pra

ctic

e

Good news:

Recognition of full spectrumof current practices

Bad news:

No improvement; practice stagnates

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Standardization Option 2 (Good):Option 1 + Identify Central Tendency & Gradations

Measure of “Goodness”(Proficiency, Effectiveness, Accuracy, Value, etc.)

Fre

qu

ency

of

Pra

ctic

e

Consensus

Cutting Edge

Exemplary, or State-of-the-

Art

Minimally Acceptable

Sub-standard

Good news:

Substandard practices req’d to improve

Bad news:

No improvement for most of the spectrum; practice stagnates

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Standardization Option 3 (Better):Option 2 + Decrease Variation

Measure of “Goodness”(Proficiency, Effectiveness, Accuracy, Value, etc.)

Fre

qu

ency

of

Pra

ctic

e

Consensus

Good news:

These are pressured to improve…

Bad news:

…but these might as well “slack off”

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Standardization Option 4 (Best):Option 3 + Improve Mean Practice

Measure of “Goodness”(Proficiency, Effectiveness, Accuracy, Value, etc.)

Fre

qu

ency

of

Pra

ctic

eGood news:

Overall spectrum of practice improves

More good news:

No sacrifice of gains at the top of the spectrum

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The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009

• Background: Acquisition Reform and MIL-STD-882D• Identified Opportunities for Improving System Safety Practice• The G-48 Committee’s Draft of MIL-STD-882E• “De-militarizing” the Draft 882E to Form an Industry Standard• Revision A of ANSI/GEIA-STD-0010-2009

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Background: Acquisition Reform and MIL-STD-882D

• Acquisition Reform efforts by the U.S. DOD in the late 1990’s resulted in eliminating many military standards

• MIL-STD-882 was preserved by making Revision D (Feb 2000) much less prescriptive then it had been in previous revisions (~30 pages, no S.S. tasks, guidance only)

• G-48 Committee received much feedback from 2000-2004 that industry, in general, did not like MIL-STD-882D

• Committee agreed that:– It was time to consider the preparing a revision of MIL-STD-882– A new revision of MIL-STD-882 provided an opportunity for improving standard

practices

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009

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• No universal understanding as to what basic elements are included in a successful System Safety Program

• Risk assessment matrix not laid out in Cartesian coordinates (which would have risk increasing up and to the right)

• Disproportionately scaled risk assessment matrix

These shortcomings were addressed in the System Safety best practices documented in ANSI/GEIA-STD-0010-2009.

• No quantitative bounds for hazard probability categories; mixed probability and frequency terms

• No provision for taking hazard exposure interval into account• Using approach that if hazard risks – taken individually – are acceptable, then

system risk is acceptable (regardless of number or risk level of individual hazards); i.e., no assessment of total system risk

• Inconsistent and/or incomplete methods for describing hazards

Identified Opportunities for Improving System Safety Practice

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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The G-48 Committee’s Draft of MIL-STD-882E

• In late summer 2004, a preliminary Draft 1 of 882E was prepared by Chuck Dorney, a longtime G-48 participant, and distributed to the G-48 Committee for review – numerous comments for improvement in late 2004 and early 2005

• All ideas for improvements presented to G-48 Committee in January 2005• G-48 Action Item 109-01 was to “produce a strawman Draft MIL-STD-882E,

‘adding discipline to our discipline’”• An ad hoc working group was formed from several Huntsville-based

organizations: APT Research, U.S. Army Aviation & Missile Command, SAIC

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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The G-48 Committee’s Draft of MIL-STD-882E (Cont.)

• Throughout 2005 and into early 2006, the G-48’s 882E working group held several meetings to incorporate recommendations for improvement

• Primary Focus:

1) Simplifying Work Elementsand Process Flow

2) Modernizing the RiskAssessment Matrix

3) Introducing Risk Summation

1) Simplifying Work Elementsand Process Flow

2) Modernizing the RiskAssessment Matrix

3) Introducing Risk Summation

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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The G-48 Committee’s Draft of MIL-STD-882E (Cont.)

• February 2006: G-48’s Final Draft MIL-STD-882E submitted for review and approval through U.S. DOD standardization process

• Approved by nearly every DOD standardization member that reviewed it• Key non-concurrence by DOD’s Environment, Safety, and Occupation Health

(ESOH) Integrated Process Team (IPT); ESOH IPT took control• G-48 Committee did not want to lose all the improvements that we worked

so hard to incorporate. So…

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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“De-militarizing” the Draft 882E to Form an Industry Standard

• After the key non-concurrences derailed the G-48's Draft 882E, the Committee embarked on a new effort to rewrite the document as an industry (non-military) best practices standard.

• A 3-person team performed a thorough scrub of the document to remove all military-specific terminology, weapon system references, etc.

• Result was the first real draft of what would become GEIA-STD-0010• Additional Improvements:

– Emphasis on “Worst Case Risk” to replace “Most Reasonable Credible Mishap”– Added “Engineered Safety Features” (ESF) to System Safety order of precedence– Added guidance to describe hazards in terms of Source – Mechanism – Outcome

(SMO)

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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“De-militarizing” the Draft 882E to Form an

Industry Standard (Cont.)

• GEIA-STD-0010 published in October 2008

• Approved by ANSI in February 2009 and re-published as ANSI/GEIA-STD-0010-2009

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

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Revision A of ANSI/GEIA-STD-0010-2009

• Feedback received from industry after the original version of GEIA-STD-0010 was released indicated that the standard needed something analogous to the DOD’s Data Item Descriptions, or DIDs

• In 2011, an effort was begun to develop Task Data Descriptions (TDDs), where appropriate, for tasks from Appendix B of GEIA-STD-0010

• Approach:– Compare tasks from MIL-STD-882C to new tasks in GEIA-STD-0010– Adapt existing DIDs referenced from 882C to become new TDDs for corresponding

tasks in GEIA-STD-0010– Develop new TDDs where necessary

• Purpose of Revision A was stated as:

…provide Task Data Descriptions (TDDs) for System Safety Tasks in Annex (sic) B of the Standard. TDDs are analogous to Data Item Descriptions (DIDs) found in military standards. The TDDs will be placed in a new appendix (Appendix C). This revision will also incorporate numerous editorial corrections to the current version of the standard.

The G-48 Committee’s Development of ANSI/GEIA-STD-0010-2009 (Cont.)

The Five Basic Elements of an Effective System Safety Program

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1) Simplifying Work Elementsand Process Flow

2) Modernizing the RiskAssessment Matrix

3) Introducing Risk Summation

1) Simplifying Work Elementsand Process Flow

2) Modernizing the RiskAssessment Matrix

3) Introducing Risk Summation

The Five Basic Elements of an Effective System Safety Program(Continued)

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Credit: From analysis of various risk management processes and presentation developed by APT Research, Huntsville, AL.

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The Eight Program Elements outlined in MIL-STD-882D and earlier versions were combined and simplified into five, to provide a more concise representation of current consensus practices.

1. Documentation of the system safety approach

2. Identification of hazards3. Assessment of mishap risk4. Identification of mishap risk

mitigation measures5. Reduction of mishap risk to an

acceptable level6. Verification of mishap reduction7. Review and acceptance of

residual mishap risk by the appropriate authority

8. Tracking hazards and residual mishap risk

1. Program Initiation 2. Hazard Identification and

Tracking 3. Risk Assessment4. Risk Reduction5. Risk Acceptance

I – A – R - A

The Five Basic Elements of an Effective System Safety Program(Continued)

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The Five Basic Elements of an Effective System Safety Program(Continued)

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Improvements to the Traditional Risk Assessment Matrix

• Matrix from MIL-STD-882D

• Axes converted to logarithmic scales

• Note:• Highest risk at upper-

left• Huge variation in span

of risk covered by different cells

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A “Pop Quiz”

Identify as many ways as possible that the risk matrix at right could be improved

- Flip vertical axis to have highest risk at upper-right

- Do not mix probability and frequency terms

- Provide quantitative bounds for likelihood and consequence scales

- Consider changing 4C, 3D, and 2E to High, or Yellow, Risk (Bonus question: Why?)

Good attribute: Numbering of consequence categories

Improvements to the Traditional Risk Assessment Matrix

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DesignedOut

IFrequent

ASomewhatFrequent

BOccasional

CIntermittent

D

Hazard Frequency (Mishaps per <exposure interval>)

1 10

Infrequent

E0.01 0.1

VeryInfrequent

F0.001

ExtremelyInfrequent

G0.0001

High

Serious

Near Zero

H

Critical 3

HazardSeverity

Catastrophic 4

Marginal 2Negligible 1

$2M

$200K

$20K

Catastrophic 5$20M

Catastrophic 6$200M

Catastrophic 7$2B

$2K

0.000010

1 Fatal

10 Fatal

100 Fatal

1K Fatal

Low

de minimus

Medium

Typical 4x5 Matrix

Adapted from Fig. 11 of “A Common Mishap Risk Assessment Matrix for U.S. DoD Aircraft Systems,” D. Swallom, 23rd ISSC, 2005.

X

“Minimizability”

The Source-Mechanism-Outcome Model for Hazard Descriptions

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• Previous definitions of “Hazard” did not always, or consistently, require enough information

• This model requires a hazard to be described in terms of its:– SOURCE (the physical presence – situation, configuration, material, items, their

characteristics, proximity and/or potential for interface, energy, etc. – that exists prior to, and enables, the initiation of an mishap sequence)

– MECHANISM (the complete sequence of events – actions, reactions, interactions, etc. – from initiation of the mishap, through to stable end state)

– OUTCOME (the end result of the subject accident sequence, specified in terms of the harm that would come to an asset of value; if a range of outcome severities was possible, it is understood that the outcome stated for the described hazard is that which, when paired with the probability of its occurrence, yields the highest risk, or probability-severity combination)

• Describing a hazard with this model prompts the analyst to identify ways in which:– The SOURCE can be eliminated, isolated, or otherwise protected– The MECHANISM can be interrupted if it should start– The OUTCOME can be mitigated

The Source-Mechanism-Outcome Model for Hazard Descriptions(Continued)

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Source Mechanism Outcome

The Source-Mechanism-Outcome Model for Hazard Descriptions(Continued)

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• A Practical Exercise– Improve upon the following hazard descriptions by re-stating them in terms of a

SOURCE, MECHANISM, and OUTCOME (be creative and invent the context)

• Slippery spot on walkway

• Extremely hot surface in microgravity payload canister

Pipe carrying oil in the space over narrow walkway (SOURCE) develops a leak; leaked oil accumulates on walkway; person using walkway slips on oil and falls (MECHANISM), sustaining a major injury (OUTCOME)

External surface of furnace in payload canister reaches 800○F during normal operation (SOURCE). Emergency abort from orbit necessitates re-entry to atmosphere before surface of furnace can cool; flammable gases in payload bay enter canister and are ignited by hot surface, causing explosion (MECHANISM). Spacecraft disintegrates during descent, causing death of all occupants (OUTCOME).

Summation of Total Risk

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Partial System Risks (r) Assessed Individually:

r1 r2 r3 r4 rn…

Acceptable Level

r1 r2 r3 r4… rn

Total System Risk (R) Assessed as (r1 + r2 + r3 + r4 + … + rn):

Acceptable Level

?

Summation of Total Risk(Continued)

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Individual hazard risk (r)

...

Total System Risk (R)

≈ Σ (ri)i=1

n

RISK TOLERANCE

r1

r2

r3

rn

Presentation Recap

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– The work of the TechAmerica G-48 System Safety Committee in developing and publishing ANSI/GEIA-STD-0010-2009

– How a discipline can be advanced by standardizing its best practices– The 5 basic elements of an effective System Safety Program, as outlined in

ANSI/GEIA-STD-0010-2009– Attributes of a modernized risk assessment matrix– The Source-Mechanism-Outcome model for describing hazards, and how its use

helps in the identification of effective hazard controls– The concept of Summation of Total Risk

QUESTIONS?