Sandia conducts controlled liquid-hydrogen pooling tests to inform safety codes

Presenter (Sandia National Laboratories) said the laboratory is conducting controlled dumps of liquid hydrogen to observe how the fuel pools, vaporizes and disperses and to validate models that will inform updates to safety codes and standards. "We're gonna use this data to validate models and then use those models to update safety codes and standards around liquid hydrogen," the Presenter said.

The experiment, held at the blast tube in the center of the Thunder Range test site, uses instruments intended to capture pool formation and vapor behavior so researchers can refine predictive models. A staff member described the blast tube as uniquely able to handle fire and explosion risk while providing a constant cross flow to simulate wind conditions for dispersion testing. "So we're doing this test at the blast tube located in the middle of Thunder Range," the staff member said.

Why it matters: the Presenter said liquid hydrogen has largely been kept behind facility fences for commercial use, but planned consumer-facing deployments—fuel-cell vehicles, truck stops, shipping and potentially aviation—will place liquid hydrogen closer to the public. "The understanding around liquid hydrogen is still pretty nascent as it's been used widely in urban settings and commercial uses," the Presenter said, adding that closer proximity to consumers could create new safety challenges.

How the tests are measured: the team is using contact and air thermocouples to detect cold temperatures where liquid hydrogen contacts probes and where evaporative cooling affects ambient air; extractive concentration sensors provided by the National Renewable Energy Laboratory will measure hydrogen concentration as vapor disperses; and infrared and visible photometric cameras will record pool behavior and condensed vapor clouds. The Presenter said these diagnostics aim to deliver "well conditioned data" for model validation.

Operational precautions: before beginning the operation, a staff member confirmed that range gates were closed and non-test personnel were clear of the tubes and issued a brief countdown as personnel prepared the test. "Please confirm you guys are clear of thunder tubes," the staff member asked; later the staff member announced "4321. Mark. Veil is open." The staff member also confirmed that the area had been cleared of non-test personnel.

The Presenter framed the work as part of Sandia's ongoing hydrogen safety program and said previous experiments and modeling had already supported changes to codes and standards. "So we've had a long standing safety codes and standards program around hydrogen use at Sandia, and we've managed to use the data that we've collected and the models that we've developed to update safety codes and standards previously," the Presenter said. The lab intends to apply findings from the current tests to update guidance and standards that regulators, code bodies and industry use to site and operate hydrogen infrastructure.

Next steps: researchers said they will analyze the conditioned data to refine dispersion and pooling models and to propose updates to safety codes and standards. No regulatory decision, timeline for code adoption, or specific code document was specified during the remarks.