Key elements of a typical system safety program, are
- Identification of safety hazards – All possible ways that any failure, combination of failures, or other combination of circumstances should be discovered by the reliability professional. Analysis of warranty data and customer feedback should also be done along with product testing reports. All available product data should be searched for occurrence of safety hazards and database of similar products should also be analyzed.
- Risk analysis – Various standard analysis techniques like FMEA, FMECA, PRAT, FTA, STA, etc. should be used to estimate the risk associated with various events so as to establish a prioritized list to guide to the root causes which are attacked and resolved.
- Correction and prevention – All steps should be taken for correction and prevention of any hazard. Engineering change requests (ECR) for correcting or preventing flaws in products or processes which result in occurrence of hazardous conditions. Procedures for preventing/mitigating human error are variously called idiot-proofing, mistake-proofing, poka-yoke, and zero quality control (ZQC).
Human errors are categorized into misunderstanding, misidentification, inexperience, inattention, and lack of standards. Hence, design elements to prevent them should be added. Principal types of mistake-proofing techniques, are
- Physical barriers to errors, for example round shaft won’t fit through the square hole.
- Visual reminders, for example a photograph of correct and incorrect results is better than a note on a print or a paragraph of text.)
- Using automated equipment
- Standardizing
