1. 1 Chapter 9: Design for People; Ergonomics, Repairability, Safety, and Product Liability 9.1 Important Definitions Ergonomics (or Human engineering, or Human factors): The discipline to design a product considering humans’ capabilities using the product. See an additional definition of ergonomics on p. 3 of this PPT file. See an illustrative concept of ergonomics on p.4 of this PPT file. Repairability (or Serviceability, or Maintainability): The discipline to design a product to be repaired/maintained throughout its intended useful life span with minimal expenditures of money and effort.

2. 2 9.1 Important Definitions (cont.) Design for safety: The design discipline that reduces the number and the severity of potential hazards by identifying and preventing potential hazards. See an example of design for safety on p.5 of this PPT file. Design for product liability: The design discipline that minimizes the potential liability of a product by identifying all risks, designing to avoid these risks, and maintaining all quality records.

3. 3 Source: http://www.iea.cc/

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5. 5 Example from the Lawrence Livermore National Laboratory (LLNL) web site

6. 6 9.3 Human Interface Type of Human Error –Design induced human error: A type of error caused by the design characteristics that encourage human error –Environmentally induced human error: A type of error caused by the external environment (temperature, snow, rain, etc.) and the internal environment (lack of motivation and/or training, etc.) –Manufacturing induced human error: A type of error occurs in production (Poka yoke is a tool to minimize this type of error). –Maintenance and installation induced human error: A type of error occurs at the time of installation or in routine maintenance actions. –User-induced Human error: A type of error caused by the user of the product.

7. 7 9.9 Repairbility and Maintenability Two types of maintenance tasks –Corrective maintenance: tasks to correct a problems after a failure has occurred. –Preventive maintenance: tasks to be performed to prevent the occurrence of a future anticipated failure.

8. 8 9.10 Design for Safety Design to eliminate or minimize hazard (This sometimes requires design tradeoffs between safety and product convenience. For example, a completely safe knife will not cut.) Safety devices (guard doors of production machines, child safety lock, etc.) See an example of a light curtain (a safe guard) on p.9 of this PPT file. Warning labels (High voltage, Do not touch, etc.) See examples of safety labels on p.10 of this PPT file. Safety procedures (two-hand operations of production machines, wearing safety glasses, etc.) Safety training Safety documentation

9. 9 Example of Industry Safety Device: Light Curtain

10. 10 Examples of Warning/Safety Labels (Based on ISO 3864 - Safety Colors and Safety Signs)

11. 11 9.11 Product Liability Disclaimers: Customers agree to the disclaimer as part of the purchase. The validity of a disclaimer for most products must be determined in court. See examples of disclaimers on p.13 and p.14 of this PPT file. Negligence in manufacturing: How to prove manufacturing negligence is a difficult issue. Negligence in product development: A prominent question in this case is whether the designer could have foreseen the problem. “Degree of foreseeability.”

12. 12 9.11 Product Liability (cont.) Identify all product liability risks Design to eliminate or minimize risks Design to all applicable standards and knowledge of safety research Use stringent inspection and quality control procedures Maintain quality control and safety design record

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