You should have piping and controls to limit the maximum pressure (MAWP) that can be delivered to the balloon to be less than the balloon’s maximum allowable pressure rating. (Same as with any other component subject to pressure.) How one determines the MAWP of a balloon is a very tough question unless it is a specialty construction with some sort of documented and tested value. For low pressure service (which I assume will be the case) you will need a hydrostatic head relief device which is a bubbler and a safe place to vent the escaping gas in the event of a higher (relief) pressure. Not a hard design.

I also assume you would only use this in a hood or ventilated enclosure and not allow it outside either.

Your hazard analysis and risk assessment will have to address a lot of potential hazards such as:

• Lack of any fire resistance
• Lack of almost any mechanical strength
• Potential for the filled balloon being handled or moved
• The balloon escaping to outside a ventilated area like a hood
• The consequences of any failure leading to a flash fire or similar ignition

Not saying it can’t be done safely but there are usually better ways to do this using more robust containers.

Does anyone have recommendations on how to *safely* fill a balloon with hydrogen? The hydrogen tank in this scenario is in an open lab, and the hydrogen filled balloon is for a hydrogenation reaction. The gas tank is located close enough to a fume hood that piping the hydrogen into the fume hood might be feasible. Wondering what other people’s experiences have been with this.

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