Safety Through Design

1. Safety Through Design Bruce W. Main, PE CSP design safety engineering, inc. Ann Arbor, Michigan 10 Sept 2003

2. Presentation Overview • Safety through design • Why you should care • Risk assessment basics • designsafe demonstration and hints • Examples

3. Safety Through Design... • Design - optimizing against criteria • Late changes in criteria - safety • Getting it right the first time

4. Familiar Methods • Government regulations (OSHA, FDA, etc.) • Industry standards • Checklists • Safety factors

5. “Recent” Advances • FMEA • Failure Modes & Effects Analysis • Component failures • Risk assessment • People failures

6. Safety Through Design… • Getting it right the first time • How? • Risk assessment

7. Why you should care… • Your professors think it’s a good idea • Your grade depends on it

8. Other reasons to care • Industry standards are requiring risk assessment • Europe - CE mark requires risk assessment • Customers are beginning to require risk assessment • Condition of sale • Lots of momentum in industry in risk assessment • Risk assessment works • Better, cheaper, faster, more productive

9. The Basics...

10. The Safety Hierarchy… Forms the theoretical basis for design safety The preferred approach to addressing hazards is: 1. Eliminate the hazard by design 2. Substitute less hazardous work methods or materials 3. Incorporate safety devices (guarding systems) 4. Provide warning systems 5. Apply administrative controls (work methods, training) 6. Provide personal protective equipment (PPE) (Manuele: Innovations in Safety Management 2001)

11. 1. Determine the limits of the Machine 2. Hazard Identification 3. Risk Estimation 4. Risk Evaluation 5. Risk Reduction (Countermeasures) 6. Verify Implementation ANSI B11 TR3 7. Document Results

12. Hazard Analysis... • Identify hazards • Task-based is a very useful approach • Focuses on what people do • Users/tasks/hazards • Brainstorming grounded in reality

13. Risk Assessment... • Qualitative / semi-quantitative / quantitative • Working to achieve acceptable risk • risk which remains after protective measures have been taken • risk which is accepted in a given context • Zero risk does not exist

14. Probability of Occurrence of Harm Catastrophic Level of Serious Severity Moderate Minor Very Likely High High High Medium Likely High High Medium Low Unlikely Medium Medium Low Negligible Remote Low Low Negligible Negligible B11 TR3 Matrix

15. (1) CATASTROPHIC (2) CRITICAL (3) MARGINAL (4) NEGLIGIBLE (A) FREQUENT ( X > 10-1 ) (B) PROBABLE ( 10-1 > X > 10-3 ) (C) OCCASIONAL ( 10-2 > X 10-3 ) (D) REMOTE ( 10-3 > X > 10-6 ) (E) IMPROBABLE ( 10-6 > X ) MIL-STD-882D Matrix CATEGORY FREQUENCY UNACCEPTABLE ACCEPTABLE WITH REVIEW UNDESIRABLE ACCEPTABLE WITHOUT REVIEW

16. SEVERITY OF INJURY EXPOSURE AVOIDANCE RISK REDUCTION CATEGORY S2 Serious Injury More than First-aid E2 Frequent exposure A2 Not Likely R1 A1 Likely R2A E1 Infrequent exposure A2 Not Likely R2B A1 Likely R2B S1 Slight Injury First-aid E2 Frequent exposure A2 Not Likely R2C A1 Likely R3A E1 Infrequent exposure A2 Not Likely R3B A1 Likely R4 R15.06 Matrix Table 2 – Risk reduction decision matrix prior to safeguard selection

17. HFMEA Hazard Scoring Matrix

18. Risk Scoring Systems • Bringing structure to a subjective analysis • There is no one right approach • This is subjective • Become comfortable with subjectivity • The goal is acceptable risk

19. Risk Assessment Results • New design requirements/criteria !! • Assessment of risk: severity/probability ratings • Road map for risk reduction activities • Framework for solutions (safety hierarchy) • design changes, guarding systems • warnings, instructions, training, PPE requirements • Risk reduced to acceptable risk

20. A Demonstration designsafe…

21. Key Points about designsafe • Guides you through the risk assessment process • Conforms to current standards • Helps you identify hazards • Prompts your risk reduction effort • Creates the documentation • Free demo at www.designsafe.com

22. Too Much Residual Risk? What do you do? Reduce Transfer Avoid Accept

23. When do we accept risk? • When it’s insignificantly low. • When we are sure it is worth it. • When we do not know it is there.

24. Tips on using designsafe… • It is a guide. Use your head. • Keep your eye on the goal • Identify hazards • Reduce risks to an acceptable level • Risk scoring is not a scientific exercise. • Look for effective shortcuts • All users, all tasks • Cut, copy, paste • Make it work for you.

25. Example – Large Oven System • Oven system to bake finish on parts • Elevated, overhead location • Access required from time to time • Service conveyor, oven • Retrieve fallen parts

26. View Inside of Oven Fallen Parts Tripping Hazards

27. Problems • Lighting insufficient • Access difficult • Introduced hazards to the workplace • Task-based risk assessment finds these

28. Perishable Goods Processing • Packaging system to extend food shelf life • Automated production system in operation • Sales wants small, manual system • customers can “try before they buy” • Prototype hand-held design in development • Risk assessment performed

29. New hazards identified • Electrical equipment in wet environment • - not hard wired • Complex/confusing operation • unmarked/confusing controls • high probability for operator error • equipment damage could occur if not properly done • Hand puncture – needle stick

30. Changes Made • GFI added • Design changes to greatly simplify procedures • Entirely eliminated need for operator to adjust controls • Improved user information – manual, warnings, system ‘package’ • Puncture resistant gloves added

31. Common Themes • Must identify hazards early • Early is better, faster, cheaper and more effective • Task based risk assessment helps identify more hazards • Allows engineers to reduce risks • Risk assessment helps to determine • What, why, how and how much

32. Review Safety through design Why you should care Risk assessment basics Demonstrated the process - designsafe Example risk assessment applications