Sandia National Laboratories is developing the technical basis for assessing the risk of hydrogen infrastructure for use in the development of relevant codes and standards. The development of codes and standards is an important step in ensuring the safe design and operation of the hydrogen fuel cell infrastructure. Codes and standards organizations are increasingly using risk-informed processes to establish code requirements.Sandia has used Quantitative Risk Assessment (QRA) approaches to risk-inform safety codes and standards for hydrogen infrastructures. QRA has been applied successfully for decades in 3 many industries, including nuclear power, aviation, and offshore oil. However, the hydrogen industry is a relatively new application area for QRA, and several gaps must be filled before QRA can be widely applied to reduce conservatisms that influence the safety requirements for hydrogen installations.This report documents an early-stage QRA for a generic, code-compliant indoor hydrogen fueling facility. The goals of conducting this activity were threefold: to provide initial insights into the safety of such facilities; to recommend risk-informed changes to indoor fueling requirements in safety codes and standards; and to evaluate the quality of existing models and data available for use in hydrogen installation QRA. The report provides several recommendations for code changes that will improve indoor fueling safety. Furthermore, the report provides insight into gaps in the QRA process that must be addressed to provide greater confidence in the QRA results.4

Steel pressure vessels are commonly used for the transport of pressurized gases, including gaseous hydrogen. In the majority of cases, these transport cylinders experience relatively few pressure cycles over their lifetime, perhaps as many as 25 per year, and generally significantly less. For fueling applications, as in fuel tanks on hydrogen-powered industrial trucks, the hydrogen fuel systems may experience thousands of cycles over their lifetime. Similarly, it can be anticipated that the use of tube trailers for large-scale distribution of gaseous hydrogen will require lifetimes of thousands of pressure cycles. This study investigates the fatigue life of steel pressure vessels that are similar to transport cylinders by subjecting full-scale vessels to pressure cycles with gaseous hydrogen between nominal pressure of 3 and 44 MPa. In addition to pressure cycling of vessels that are similar to those in service, engineered defects were machined on the inside of several pressure vessels to simulate manufacturing defects and to initiate failure after relatively low number of cycles. Failure was not observed in as-manufactured vessels with more than 55,000 pressure cycles, nor in vessels with relatively small, engineered defects subjected to more than 40,000 cycles. Large engineered defects (with depth greater than 5% of the wall thickness) resulted in failure after 8,000 to 15,000 pressure cycles. Defects machined to depths less than 5% wall thickness did not induce failures. Four pressure vessel failures were observed during the course of this project and, in all cases, failure occurred by leak before burst. The performance of the tested vessels is compared to two design approaches: fracture mechanics design approach and traditional fatigue analysis design approach. The results from this work have been used as the basis for the design rules for Type 1 fuel tanks in the standard entitled “Compressed Hydrogen-Powered Industrial Truck, On-board Fuel Storage and Handling Components (HPIT1)” from CSA America.

Automakers and fuel providers have made public commitments to commercialize light duty fuel cell electric vehicles and fueling infrastructure in select US regions beginning in 2014. The development, implementation, and advancement of meaningful codes and standards is critical to enable the effective deployment of clean and efficient fuel cell and hydrogen solutions in the energy technology marketplace. Metrics pertaining to the development and implementation of safety knowledge, codes, and standards are important to communicate progress and inform future R&D investments. This document describes the development and benchmarking of metrics specific to the development of hydrogen specific codes relevant for hydrogen refueling stations. These metrics will be most useful as the hydrogen fuel market transitions from pre-commercial to early-commercial phases. The target regions in California will serve as benchmarking case studies to quantify the success of past investments in research and development supporting safety codes and standards R&D.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Approved for public release; further dissemination unlimited.

This report summarizes the investigation of the release of approximately 300kg of hydrogen at the AC Transit Facility in Emeryville, CA. The hydrogen release was avoidable in both the root cause and contributing factors. The report summarizes the findings of the incident investigation and metallurgical analysis of the failed valve. Hydrogen embrittlement, manufacturing quality as well as miscommunication played significant roles in the event. No injuries or fatalities resulted from the incident.