This Technical Memorandum was originally prepared as an Annex on the topic of Hydrogen Embrittlement for the AIAA Guide to Safety of Hydrogen and Hydrogen Systems (G-095-2004), then in revision [1]. The Guide establishes a uniform NASA process for hydrogen system design, materials selection operation, storage and transportation, and represents a broad collection of aerospace acumen.

The "draft" report briefly discusses two distinctly different scenarios that create overpressure from an external release of hydrogen into an ambient air environment: Delayed ignition from a pressurized release and Delayed ignition of a flammable gas cloud.

The "draft" technical paper provides a brief gap analysis of the Codes and Standards for Delayed Ignition with a focus on discharge of warm gas and thermal radiation and impingement.

State policy targets on greenhouse gas emission reductions and other decarbonization initiatives are creating a movement toward low or zero-carbon gases and fuels. Given its versatility as an energy carrier and its potential for use in a broad range of applications, hydrogen is gaining in popularity, and natural gas providers are looking at integrating it into their networks.

In collaboration with Parker Hannifin Corporation, the Fire Safety Branch of the FAA conducted testing to evaluate the effects of three potential failure conditions of hydrogen proton exchange (or polymer electrolyte) membrane fuel cell stacks supplied by Nuvera Fuel Cells. The three conditions examined were a loss of coolant to the stack, short circuit, and a crossflow condition.

The Hydrogen Safety Panel was tasked with conducting work under the project “Hydrogen Safety Panel Review of Department of Energy’s Fuel Cell Projects,” through memorandum purchase order DCO-0-40618-01 with the National Renewable Energy Laboratory using American Recovery and Reinvestment Act (ARRA) funding.  Panel members reviewed project safety plans, conducted safety review site visits for selected projects, and prepared safety evaluation reports for the sites visited that included safety recommendations for the project teams.

The Hydrogen Safety Panel brings a broad cross-section of expertise from the industrial, government, and academic sectors to help advise the U.S. Department of Energy’s (DOE) Fuel Cell Technologies Office through its work in hydrogen safety, codes, and standards.  The Panel’s initiatives in reviewing safety plans, conducting safety evaluations, identifying safety-related technical data gaps, and supporting safety knowledge tools and databases cover the gamut from research and development to demonstration and deployment.

The purpose of this guide is to assist users of codes and standards that apply to hydrogen application and use in understanding and applying the approval, certification, listing, and labeling provisions of the codes and standards, in any application where the required certification, listing, and labeling of services, methods, or equipment has not yet been established or achieved.  

Safe practices in the production, storage, distribution, and use of hydrogen are essential for the widespread acceptance of hydrogen and fuel cell technologies. A catastrophic failure in any hydrogen project could damage public perception of hydrogen and fuel cells. Given the nascent nature of the mobile hydrogen applications, incidents involving mobile equipment can have detrimental impacts for the public as well as stakeholders and project proponents who are committed to hydrogen’s use as a safe alternative energy resource. 

The Hydrogen Safety Panel was established by the U.S. Department of Energy (DOE) to provide independent safety reviews and guidance to contractors in the DOE Hydrogen and Fuel Cells Program. In September 2017, the panel set up a task group to compile select hydrogen incidents from the H2Tools.org Lessons Learned database (https://h2tools.org/lessons) in a publication form for written reference, that are most pertinent to various types of DOE contractor projects. This report is the result of the task group’s work.