Indirect Airflow for Safe Extraction of Hydrogen from Lead-Acid Battery Room

[somephy]

Hello,

I need to extract a flammable gas (hydrogen) from a lead-acid battery room.

Is there a way to use a regular fan without putting it in the airflow (hence to produce some degree of negative pressure in the battery room)?

I've made a little sketch to illustrate the actual situation. Thank you in advance for any suggestion.

 

[anorlunda]

You could blow air into the battery room, creating a positive pressure, and let it leak out from walls that at not air tight.

You can also do both, a forced draft fan blowing in and an induced draft fan blowing out. Together, they produce a draft in a zero gauge pressure room.

 

[somephy]

Thank you very much for your quick reply (and for your kind, welcoming words)!

Blowing air in the battery room was my first attempt but the room isn't entirely air tight (as i left some openings at the bottom to allow an airflow through the exhaust pipe). If I will blow air in the battery room, chances are the hydrogen will get mixed with the air and will escape through those bottom openings, too.

Anyway, may I only use an external fan as displayed in the sketch above?

 

[Nik_2213]

Given hydrogen gas is less dense than air, I'd include some passive air vents near the ceiling, too...
Although your choice may come down to local safety ordinances etc, with eg 'mine-grade flame-proof' demanded by your insurance assesor, may I suggest using non-sparking, low-voltage fans ? Plural, lest one fails, of course, of course.
If you're careful, you may be able to run them off the battery bank, ensuring another possible failure mode is nailed down...

 

[russ_watters]

Most belt drive fans have their motors outside the airstream, but this type of system has safety and code implications, so it should really be designed by a registered professional engineer. Thread locked for safety/liability reasons.