Safety Requirements Back to Basics

Mission - People - Innovation

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Safety Requirements

Back to Basics

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What’s Important

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Regulatory vs System Safety

• Requirement verification can not replace

the System Safety process– Emphasis on all safety requirements is clouding the

true intent of System Safety

– Too much time and effort spent on low level hazards

– Risk of missing the big stuff

– Costly

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Regulatory

• Regulate (reg’yə lāt) reg·u·la·to·ry1. To control or direct by a rule, principle, method, etc. 2. to adjust

to some standard or requirement, as for amount, degree, etc.

• Regulatory Agencies

– OSHA

– EPA

– Army Corps of Engineers

– Consumer Product Safety Commission

– FAA

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AFSPCMAN 91-710 is not a regulation


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AFSPCMAN 91-710

• AFSPCMAN 91-710 is a manual

– Manual is defined as: extensions of instructions, providing

additional guidance for performing standard tasks, or supporting

education and training programs

– An AF Instruction is considered a general order

that absolutely must be followed – regulation

• The 91-710 predecessors (EWR 127-1,

ERR/WRR 127-1, ESMC/WSMC 127-1,

1STRD 127-9) were a compilation of lessons

learned

– Also included unique reqs for missile systems

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AFSPCMAN 91-710 cont

• AFSPCMAN 91-710

– Describes the Range Safety Program

– Defines responsibilities and authorities

– Delineates policies, processes, and approvals

– Covers life cycle of launch vehicles and

payloads

– Defines Range User responsibilities

– Defines Range User and Range Safety

interfaces

– Establishes Range User safety requirements

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91-710 Vol 3

• Vol 3 covers launch vehicle and payload design solutions

– Provides specific requirements: • e.g. All flexible hoses that are not lined shall be subjected to a flow-induced

vibration analysis.

• The minimum burst factors for battery cells and sealed battery cases shall be 1.5.

– Provides general safety requirements: • e.g. If a system failure may lead to a critical hazard, they system shall have

two inhibits (single fault tolerant).

• The design of hypergolic systems shall take into consideration limitations imposed on individuals dressed in SCAPE during fill and drain operations.

– General and specific requirements are meant to be detail oriented attempting to cover all concerns

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91-710 Vol 5

• Vol 5 covers facility design safety

– As with Vol 3 it contains specific and general

safety requirements

– As with Vol 3 the intent is to be detail oriented

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91-710 Vol 6

• Vol 6 covers operations

– Provides requirements for procedure content

– Provides requirements for crane testing

– Test and inspection plans

– PPE

– Hot work

– Fall protection

– Motor vehicle

– Launch operations

• As with Vols 3 & 5 the intent is to be detail oriented

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Some Problem Areas

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Labor intensive upkeep

Technology advances

Changing consensus reference standards

New technologies require new requirements

New ways to use old equipment

Original authors retired/moved-on

Original intent of req’s have not been maintained

‘If you meet these requirements you are safe’ mentality

Every requirement must be dispensed

YOU

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HING


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EVERY Requirement

• AFSPCMAN 91-710 (NASA STD 8719.24)

is meant to be tailored

– Because the document is detail oriented it is

intended to account for all payloads despite

size, shape, color, sexual orientation, religion

– Current process is to address EVERY requirement

– “WE LEAVE NO REQUIREMENT BEHIND”

– Thorough but time consuming and expensive

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Where We Stand Today

• Commercial practices and government

budgets are driving everyone to become

leaner, cheaper, faster, cheaper, quicker,

cheaper, more efficient, and cheaper

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The Problem

How do you save money

without compromising

safety?

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Answer

Accept more risk

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It’s OK to fail


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Failure

• Failure encourages the strong and

discourages the weak

• There is acceptable failure

– Propellant spill is not acceptable

– Small vapor leak below IDLH is acceptable

• Not every day

• Determine your level of acceptable risk

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The System Safety Process

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System Safety Program

Functional Hazard Analysis

Define Safety-Critical functions

& Assign LOR

Tailored Safety Requirements

& Constraints

ID preliminary, system, subsystem

Hazards & Failure modes

Determine effects at the

System level

Determine Haz Severity & Probability

Determine causes

(HW/SW/Human)

Document Hazard Mitigation

Requirements

Verify requirement implementation

Final Hazard Severity & Probability

Document and Accept Residual Risk


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What We Have To Do

• Rewrite the current requirements to be performance based

• Include design solutions as text boxes (how to meet the intent of the requirement but not absolute)

• Emphasize the system safety process

• Work closely with the project safety team to develop safety requirements

– Write specific/unique requirements for the system

• Utilize a database approach to document generation and submission

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Summary

Look to the future. The future will require us to be

smarter, cheaper, and effective

The system safety engineering process to identify

hazards, quantify risk, mitigate or reduce wherever

possible, and ensure residual risk is accepted at the

right level is effective, saves money, and is proven

Challenge yourselves to find better ways to get the

job done

Don’t be afraid to fail

Accept and document low level risk

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BRIDGE IS

OUT

Documents

Safety Requirements Back to Basics