Presentation on theme: "EV Safety GTR Task Force Group #2 – Low Electric Energy #5 EVS GTR Status Briefing May 13, 2014."— Presentation transcript:
EV Safety GTR Task Force Group #2 – Low Electric Energy #5 EVS GTR Status Briefing May 13, 2014
Recent TF Activities TF leader assembled all relevant supporting technical material for TF review and comment. Material was sent out to the TF on March 4 th, 2014 for review and comment. To date, there have not been any formal comments received regarding this information. One member of the TF has indicated that it is still evaluating the information and will likely provide comments in the future. Once these comments are received the TF will schedule a meeting to discuss them and determine next steps. In the meantime, the TF leader is working to generate additional information comparing the relative risk of injury due to shock for this compliance alternative with that for the risk of impact injuries as part of the regulated crash tests (e.g., HIC, Chest Deflection, Neck Injury Criterion, etc).
Summary of Technical Support for Currently Proposed 0.2 Joule Low Energy Limit Criterion Updated SAE J1766 Technical Rational – Forms the basis for the latest version of the GTR Section 1 statement of technical rationale and justification. US Department of Energy (DOE) Electrical Safety Handbook (DOE-HDBK-1092-2013) – Specification of 0.25 Joule electrical energy limits for high voltage (>400V) capacitor delivered electric shocks.
DOE Electrical Safety Handbook DOE Handbook provides a comprehensive set of guidance and standards covering all aspects of electrical safety as well as management practices to ensure that electrical safety safeguards are put into place. It includes a Hazard Analysis appendix that includes both tools for assessing electrical hazards as well as recommended controls for mitigating hazards (including high voltage impulse shock).
DOE Handbook – Section 7 – Appendix D Section 7 of Appendix D provides hazard assessment tables and recommended controls covering eight broad hazard categories: – 60Hz – DC – Capacitors – Batteries – Sub-RF – RF – Inductors, and – Photovoltaic
DOE Handbook - Capacitors Of direct interest to the EV Safety GTR is the hazard assessment and recommended controls for impulse shock hazards represented by capacitor type discharge. Figure D-8 (next slide) – illustrates the potential hazard classes for both high voltage electrostatic and capacitor discharge shocks. For capacitor discharge, hazards are broken into 5 risk categories with the lowest colored green. In this chart exposure up to 0.25 Joules is coded green which indicates “little to no hazards, few or no engineering or administrative controls are needed”. Complementary table D-9 list exposure to energy levels of 400V) as permitting workers to be “alone” with “non- energized level training”, no work controls, no personal protection equipment, and no prior energy removal requirements.
Justification of the DOE Limits The technical justification for the hazard limits in the DOE handbook is contained in an IEEE technical paper No. ESW-23, Entitled “A Complete Electrical Hazard Classification System and its Application”. Originally the 1998 version of the DOE Handbook contained a 10 joule energy limit for high voltage capacitors. In revising the limits downwards they noted that “although this [10 Joule shock limit] is below the energy required to cause ventricular fibrillation, a 10 Joule shock from a high voltage capacitor will definitely cause substantial reflex action.”
Justification of the DOE Limits In setting the 0.25 Joule limit the authors noted that research established the threshold for the beginning of nuisance reflex action to be 0.25 Joules. The paper further notes that by 10 Joules the reflex action can become so severe that a person can be injured from muscle contractions.