Electrostatic Discharge Risk Analysis.
WHA has developed unique testing capabilities useful in determining the electrostatic discharge risk of a system, process, or product. Electrostatic Discharge is a known source of ignition in the fuel gas industry and has been considered to be the source of ignition of several oxygen related fires that occurred in hyperbaric chambers as the result of unsafe practices due to insufficient hazard analysis. Understanding the physics of electrostatic discharge events is crucial to determining the risk. WHA’s approach is consistent with NFPA 77, Recommended Practice on Static Electricity, and API Recommended Practice on Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents.
Hazard Analysis Tools
WHA utilizes qualitative fault tree analysis as a tool to determine the risks associates with systems, products, or processes. The hazards of concern (often fire) are analyzed to determine the elements of causation (faults) that is visually represented in a fault tree diagram. From the fault tree diagram the relationships between faults, identify vulnerability in the design, and areas that are double-fault protected are apparent. These realizations aid engineers in design decisions, and is useful for demonstrating safe design. Qualitative fault trees can further be expanded to quantitative fault trees that are useful for probabilistic risk assessment. WHA performs Fault Tree Analysis consistent with IEC/ISO 31010 Risk Assessment Techniques and NASA Fault Tree Handbook with Aerospace Applications.
ISO/IEC 60601-1 Electrical Source of Ignitions for Oxygen Carrying Equipment Hazard Analysis
The ISO/IEC 60601-1 set of standards is a series of safety standards for medical electrical equipment (ME equipment). Medical device manufacturers must demonstrate compliance with the international standard IEC/ISO 60601 – Part 1: General requirements for basic safety and essential performance, in order to bring their device into markets in the US and EU. WHA analyzes designs against the specific requirements related to oxygen hazards that are contained within IEC/ISO 60601 and are also capable of compiling a probabilistic risk assessment that addresses the source of ignition rate of the electronic componentry if an oxygen rich atmosphere is present. WHA’s methodology utilizes an empirical model approach to develop an “initial assessment” of the source of ignition rate, assesses the failure mode distributions of electrical components in order to determine the failure modes associated with thermal energy release, and a Bayesian process that utilizes specific field and/or testing data for the device in order to update the initial assessment towards a better estimate of the true failure rates. This methodology provides quantifiable estimates that can then be utilized in a Risk Management process as required by IEC/ISO 60601 in subclause 4.2.