Battery Room Design for Ventilation 1

[wendee]

hello,

I am just new on my job and I usually deal with batteries.
I hope you can help me on this situation.

There's a battery room that will be designed to have a forced ventilation ( using exhaust fan ) and air-conditioned to maintain the temperature within the room and to exhaust H2 gas.

The battery is an AGM type. I already computed the hydrogen concentration in the room based on EN standard and it shows 0.04% hydrogen concentration. And the time for the critical hydrogen concentration to accumulate (without ventilation) is within 6 hours. The room is to have 3 ACH (air-change per hour). (Actually, 1 ACH is enough but owner wants it to have 3 ACH.)

The problem is that the design for the battery room is having its exhaust air, 80% of it, will be recirculated through ducts as an input for A/C, while the remaining 20% of exhaust air will be drawn out from the room. Is there any standard that allow this kind of design?
Is it possible?

There's a tendency that some H2 gas (80%)will go through ducts and accumulate inside the ducts. If I will provide hydrogen gas sensor inside the ducts to monitor the percent concentration, I still doubt if recirculation is permitted for battery rooms.

Please advise me. Thanks!

 

[pauljohn]

Hi wendee

it was my understanding (from battery salesman mind you!) that AGM batteries along with Gel cells don't gas when charged properly. Is this information wrong?

 

[stevenal]

Not wrong. Room design should not be based on the no contingency situation, though.

 

[peebee]

Not sure if this helps you or not:

Per IBC 608.5, "Ventilation shall be provided in accordance with the IMC and ... shall be designed to limit the maximum concentration of hydrogen to 1 percent of the total volume of the room....". See also IBC 609.6.

 

[avijo]

hi, i think that this information can helps, this is only informative.

http://www.bhs1.com/batteryroom/ventilation.htm

so long

 

[bertramh]

Wendee,

Could you shed some loght on how you computed the hydrogen concentration in the room based on EN standard? I have some battery rooms and there is this question that keeps poping up as to weather we need to put hydrogen sensors that activates the exhaust fans.