Risk Analysis for Engineering Design J. M. McCarthy Fall 2003 Definitions Hazard Analysis Hazard Analysis Report Example for Mini Baja Nationally Recognized Testing Laboratories (NRTL)

Definitions Safety: The condition of being safe; free from danger, risk, or injury. Hazard: An activity or condition that is dangerous, that poses the threat of loss (property damage) or harm (personal injury or death). Risk: The potential for loss or harm over time for a given hazard; the combination of hazard severity and the exposure. Severity: The degree of the loss or harm associated with a hazard. Exposure: The amount of exposure to a hazard. Risk Tolerance: The acceptable of level of risk selected for all hazards. Mitigation: An action taken or a feature adopted to reduce the risk for a hazard. For example, safety devices, guarding, warning devices, procedures, and training. Hazard Assessment: A process of identifying and analyzing sources of danger. Risk Analysis: A process of evaluating the severity of consequences and frequency of exposure to hazards, and evaluating of risk tolerance and mitigation. Risk Management: Activities related to monitoring and evaluating hazards to maintain a given level of risk.

Hazard Analysis Steps in Hazard Analysis 1.Identify Risk Tolerance: Determine levels of acceptable risk. Create risk assessment matrix (risk level v. severity and exposure). 2.Hazard Assessment: Identify hazards by reviewing designs, codes, standards, and interviewing workers and users. 3.Evaluate Severity and Frequency of Exposure: Assign severity and frequency of exposure for each hazard. 4.Assign Risk Level: Categorize each hazard to a risk level using the risk assessment matrix. 5.Design Mitigation: Apply mitigation to hazards with unacceptable risk levels. 6.Repeat Hazard Analysis: Repeat until all hazards have an acceptable risk level. The hazards in a machine system are primarily fire, electrical shock, chemical exposure, and personal injury (impact, cut, pinch, and crush).

HA Flow Chart Identify All Hazards Risk Assessment Matrix Determine Severity and Frequency of Exposure Apply Mitigation Assign Risk Level Acceptable Unacceptable Next Hazard For Each Hazard

Risk Analysis Risk Level (1) High – Imperative to reduce risk level. (2) Medium – Requires a mitigation plan. (3) Low – No special risk mitigation activities are required. Severity of Consequences (1) Catastrophic – Death or system loss. (2) Critical - Severe injury or major system damage. (3) Marginal - Injury requiring medical attention or system damage. (4) Negligible - Possible minor injury or minor system damage. Frequency of Exposure (A) Frequent - Expected to occur frequently. (B) Probable - Will occur several times in the life of an item. (C) Occasional - Likely to occur sometime in the life of an item. (D) Remote - Unlikely, but possible to occur in the life of an item. (E) Improbable - So unlikely, it can be assumed occurrence may not be experienced.

Example: Risk Assessment Matrix

Hazard Analysis Report Section 1. Definition of Severity and Frequency of Exposure Section 2. Risk Assessment Matrix Section 3. Itemized list of Hazards, Initial Risk Level, Mitigation and Final Risk Level

Example: Mini-Baja HAR

Example: BattleBot HAR

Nationally Recognized Testing Laboratories Nationally Recognized Testing Laboratories (NRTL’s) are third-party organizations recognized by the Occupational Safety and Health Administration (OSHA) that can provide product safety testing and certification services to manufacturers for a wide range of products. Some NRTL Organizations Underwriters Laboratories, Inc. (UL) TUV America Inc. (TUVAM) Canadian Standards Association (CSA) Applied Research Laboratories, Inc. (ARL) Communication Certification Laboratory, Inc. (CCL)

Summary A hazard analysis report describes each hazard in a product and how it is mitigated to reduce the risk to the desired level. An NRTL can be helpful in defining and executing test to verify safe performance.