The purpose of this action is to make changes to the Risk Management Program (RMP) rule in order to improve safety at facilities that use and distribute hazardous chemicals. Because major and other serious and concerning RMP accidents continue to occur, this final rule aims to better identify and further regulate risky facilities to prevent accidental releases before they can occur.

The three-year HyTunnel CS project culminated in the report titled Deliverable D6.9, “Recommendations for inherently safer use of hydrogen vehicles in underground traffic systems.” The HyTunnel CS project aimed to perform pre-normative research for the safety of hydrogen-fueled vehicles traveling through tunnels or entering confined spaces. The main objective was to compare the relative risk of hydrogen vehicles entering underground traffic systems to existing fossil fuel-powered vehicles [1].

Hydrogen is a key energy carrier for modern society. The breaking of the hydrogen bonds within traditional hydrocarbon molecules has been the primary mode of energy utilization since the industrial revolution. An increased focus on “net-zero” greenhouse gas emissions, specifically carbon dioxide and methane, has resulted in a global push for lower carbon energy vectors, including pure hydrogen.

Several codes require excess flow valves in pipelines so that in the case of line rupture, the flow will be shut off.   In theory, this is a good idea, however, in practicality, it has many limitations.  The sizing and practical uses make the sizing difficult if sometimes impossible, depending on the design parameters.   

Natural gas distribution companies are developing ambitious plans to decarbonize the services that they provide in an affordable manner and are accelerating plans for the strategic integration of renewable natural gas and the blending of green hydrogen produced by electrolysis, powered with renewable electricity being developed from large new commitments by states such as New York and Massachusetts. The demonstration and deployment of hydrogen blending have been proposed broadly at 20% of hydrogen by volume.

An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using available experimental data.

AS THE WORLD SEEKS TO IDENTIFY alternative energy sources, hydrogen-powered fuel cells offer a broad range of benefits for the environment, the economy, and energy security. Hydrogen fuel cells have the potential to replace the internal combustion engine and to provide power in a wide range of stationary and portable applications.

Owner/operators of chemical processing and petroleum refining sites often ask whether unconfined hydrogen vapor cloud explosions (VCEs) can actually occur. This question normally arises during the course of a consequence-based facility siting study (FSS) or a quantitative risk assessment (QRA). While it is generally recognized that a hydrogen release within a process enclosure could lead to an explosion, the potential for an external hydrogen release to cause a VCE is not as widely recognized and is often questioned.

It has been suggested that separation or safety distances for pressurised hydrogen storage can be reduced by the inclusion of walls or barriers between the hydrogen storage and vulnerable plant or other items. Various NFPA codes [1] suggest the use of 60
inclined fire barriers for protection against jet flames in preference to vertical ones. Work by Sandia National Laboratories [2] included experiments and modeling aimed at characterisation of the effectiveness of barrier walls at reducing hazards.

The broad use of hydrogen as an energy carrier to tackle the issue of climate change is unavoidable. The emerging hydrogen economy poses new problems to be solved to ensure a level of safety in hydrogen technologies and infrastructure comparable to that for today’s fossil fuels. The pressure of onboard hydrogen storage in early-market