Mitigating uncertainty: A risk informed approach for deploying hydrogen refueling stations
Bibliographic record
Abstract
Regulatory gaps and safety concerns induce uncertainty amongst stakeholders, increases investment risk and impedes the deployment of hydrogen refueling stations (HRS). In this study, a risk-informed approach was employed on a potential HRS in Canada, to optimize separation distances, and identify regulatory gaps. This risk assessment improves upon previous ones that assumed uniform hydrogen leak sizes throughout the entire HRS. This analysis considers variable leak sizes based on the varying pipe flow area in different parts of the HRS like the tube-trailer area, hydrogen system area and the dispenser area. For each area, the potential leak sizes of 0.1%, 1%, 10%, and 100% of the pipe flow area were evaluated to cover a range of possible leaks. Leak frequency for 1% and 10% leak sizes were found to be 2.38E-02/year and 2.68E-03/year indicating relatively smaller difference as compared to other leak sizes. Leak frequency and consequence distances were assessed using HyRAM+ (V5.0) and Safeti (V8.9) respectively. Separation distances, which refer to the required spacing measured from the hydrogen process areas beyond which the risks are considered tolerable, were assessed for the tube-trailer area, storage area, and dispenser area at 350 bar and 700 bar dispensing pressures. Results indicated that 700 bar scenario requires substantially larger separation distances up to 39.1 m due to extended harm distances at lower temperatures. This study proposes safety barriers which reduced jet and flash fire frequencies by 100 and 20 events/year, respectively, that enables decreasing separation distances for each area. The comprehensive evaluation of separation distances generates important insights into separation distance criteria and guidelines, addressing the identified gap in existing codes and standards. While the study focuses on a potential HRS in Canada, the methodology, approach, and results presented are broadly applicable and transferable to similar contexts globally. • 10% leak size optimized separation distance for areas in hydrogen refueling station. • 700 bar dispenser required the largest separation distance of 39.1 m • Proposed safety barriers reduced jet fires by 100, flash fires by 20 per year. • Canadian Hydrogen Installation Code lacks guidelines for risk-informed separation. • Regulatory alignment needed with hydrogen requirements in provincial fire code.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".