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H2Incidents: Hydrogen Incident Reporting and Lessons Learned

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Definitions

Incident
An incident is an event that results in:
  • a lost-time accident and/or injury to personnel
  • damage to project equipment, facilities or property
  • impact to the public or environment
  • an emergency response or should have resulted in an emergency response.
Near-Miss
A near-miss is an event that, under slightly different circumstances, could have become an incident. Examples include:
  • any unintentional hydrogen release that ignites, or is sufficient to sustain a flame if ignited, and does not fit the definition for an incident
  • any hydrogen release which accumulates above 25% of the lower flammability limits within an enclosed space and does not fit the definition of an incident
Non-Event
A non-event is a situation, occurrence, or other outcome relevant to safety that does not involve a particular incident or near miss. For example, a non-event might consist of a failed safety inspection.
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Navigation

The left navigation on the H2Incidents website is two-fold.

  1. Links
    By clicking on the links in the left navigation, you can view all incident reports matching that lone selection. For example, clicking on "Minor Injury" within the "Damages and Injuries" category will return a list of all incident reports that included "Minor Injury."
  2. Checkboxes
    Selecting checkboxes next to navigation items—then clicking the "Update Criteria" button—will provide a restrictive search on the criteria selected. Each selected checkbox will restrict the results to only incident reports that include that criteria. For example, selecting the checkbox next to "Minor Injury" in the "Damages and Injuries" category and selecting the checkbox next to "Decision Making" in the "Factors" category will return a list of all incident reports that included both "Minor Injury" and "Decision Making."
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New! Lessons Learned Corner

Welcome to the new Lessons Learned Corner! Key themes from the H2Incidents database will be presented here and several safety event records will be highlighted to illustrate the relevant lessons learned. Please let us know what you think and what themes you would like to see highlighted in this safety knowledge corner. You can find all the previous topics in the archives.

Lessons Learned Corner - Hydrogen Leak Detection

Hydrogen leak detection systems may be required by the Authority Having Jurisdiction (AHJ) or may be installed as a means for enhancing safety. Leak detection can be achieved by providing hydrogen (or flammable gas) detectors in a room or enclosure, or by monitoring the internal piping pressures and/or flow rates for changes that would suggest a leak is present in the system. Other methods include providing detectors in close proximity to the exterior piping or locating hydrogen piping within another pipe and monitoring the annulus for leaks.

Regardless of the method used, leak detection systems should, at a minimum, incorporate automatic shutoff of the hydrogen source when hydrogen is detected. For systems designed to monitor hydrogen concentrations in rooms or areas, the leak detection system should also warn personnel with visible and audible alarms when the environment is becoming unsafe.

The number and distribution of detection points and time required to shut off the hydrogen source should be based on factors such as leak rates, ventilation rates, and the volume of the space being monitored. Locations to consider include:

Performance criteria for an area hydrogen leak detection system should be established for the specific application intended. Parameter values for consideration include the following:

The design of a leak detection system must ensure that any leaking hydrogen would pass by the detector. The sensitivity of the detector to other gases and vapors should be considered in the selection of the detector and should be explained to personnel.

A good practice is to set the detectors to alarm at 1 vol% hydrogen in air, which is 25% of the lower flammability limit (LFL). If automatic shutdown is incorporated into the system, manual reset should be required to restart the system.

Portable gas detectors are valuable for local leak detection. Portable detectors should be used for entry or re-entry into rooms in which an alarm has occurred to ensure that the hydrogen has dissipated.

Maintenance and recalibration of leak detectors should be performed every 3-6 months and recorded in facility records or manufacturer's instructions. Best practices for system checkout include:

The following safety events occurred in a variety of settings, but each of them illustrates some key lessons learned about the critical need for hydrogen detection equipment: