The Hydrogen Safety Panel is not aware of any detailed guidelines or requirements. There are general requirements for personal protective equipment (PPE) in relevant codes and standards, but these often defer to the manufacturer’s requirements or a material safety data sheet (MSDS) for specifics. Ultimately, PPE selection is a matter between the employer and the employee and may need to consider state and federal regulations, company policies and the employee’s work assignment. The information below is provided for consideration when working fuel cell systems equipped with hydrogen storage tanks and related hydrogen piping systems.
In general, the pressurized gaseous hydrogen system should be defueled and the high-voltage electrical system de-energized1 (in accordance with standard operating procedures) before any maintenance is performed. If this is done, then the PPE will likely need to be similar to repair garage activities for other (non-hydrogen) vehicles, and may include:
- Safety shoes
- Safety glasses
- Hand protection (to avoid cuts and abrasions)
- Long sleeve shirts and full length pants (Note: Personnel should avoid wearing clothing made of nylon or other synthetics, silk, or wool because these materials produce charges of static electricity that can ignite flammable gas mixtures.)
- Hard hats (when necessary)
- Hearing protection (when necessary)
If the portion of the hydrogen system to be repaired can be isolated (preferably by at least two means) and defueled prior to any maintenance activity, then it may be possible to avoid defueling the entire pressurized hydrogen system on the vehicle. In this case, additional PPE may be required depending on the proximity to other systems that are still pressurized:
- Flash fire resistive garments
- Safety glasses with side shields, goggles or face shields
It is important to consider that the above guidance will not cover every activity or circumstance. Specific activities should be evaluated by safety professionals to determine the necessary engineering controls, work practices and PPE.
Note 1: Since all FCVs have high voltage systems additional PPE may be needed if working on an energized high voltage electrical portion of the vehicle.