Ventilating a Gel cell Battery Room 1

[Q9fromNJ]

Need recommendations for ventilating an open area Gel cell type battery area. Surrounding conditions: air temp is @78 degrees F. NFPA 70E states to provide ventilation to maintain (battery) design temperature to prevent thermal runaway.

 

[cabalen]

09fromNJ,

Use 10 ACH for exhaust air.

Cheers!

 

[stookeyfpe]

You can do 10 ACH if you want to pay those energy costs. However, the 2006 IFC only requires that the mechanical ventilation system be designed to limit the volume of hydrogen in the room to a maximum 1% by volume -or - the exhaust system must be designed to exhaust air at a rate of 1 CFM/Sq.Ft. over the area of the room.

See 2006 International Fire Code, section 608.6.1.

Temperature control is also required for thermal runaway when dealing with valve regulated lead acid batteries (e.g., gel cells). However, some of the manufacturers have developed safety devices that de-energize the battery or battery string if it appraches a temperature to initiate thermal runaway. These devices are permitted to be used by IFC section 608.3.

 

[TChad86]

1 CFM per square foot is definitely the answer, not the 10 ACH. One other item to note though. If you do the calculations to confirm the 1% by volume, you will get even much smaller numbers than the 1 cfm/sf. In general (depends on battery H2 release rates) you will get a number so low, the ventilation codes for occupied spaces will covern. In CA, title 24 requires a minimum 0.15 cfm/sf for any space (occupied or not) and this will be the governing rate. Many companies though (and their insurance carriers) will request the 1 cfm/sf sizing criteria.

Definitely don't use 10 ACH!