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Off-Gas Mechanical Ventilation for Lithium-Ion Batteries

Off-Gas Mechanical Ventilation for Lithium-Ion Batteries

Off-Gas Mechanical Ventilation for Lithium-Ion Batteries

Does anybody have experience with the design of exhaust ventilation for off-gas event for lithium-ion batteries?

I have a few questions regarding FM Loss Prevention Data Sheets and NFPA 855.

1. In NFPA 855 4.9.3, the mechanical ventilation rate is defined to be not less than 5.1 l/s/m2. Could somebody clarify the logic behind this? This rate apparently depends on the area of the room, and it would be the same for a small room with x amount of batteries and a big room with a similar x amount of batteries, however, the exhaust rate would be different, so I am not sure how to approach this.
2. NFPA 855 states that if not continuous, the ventilation should be triggered on 25% LFL. Does that LFL refer to CO, since that gas is consistent in the whole process?
3. If the exhaust ventilation is turned on, and off-gas products are taken out of the building, is it necessary to have a supply fan on in order to further lower the percentage of explosive gasses in the enclosure?
4. Is there any requirement for fans to have ATEX? I understand that if we keep below LFL there is no explosive atmosphere, but would also like to clarify this.
5. NFPA 855 states that at least a minimum of 2 hours of standby power is needed. Do you usually connect explosive gas detectors which start the exhaust fans to the same standby power source?

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