IV404E Rev.000 SIEL S.p.A.
Issue date: 2017-06-05 Pag. 15 di 90 + FR
2.4
Air change for battery premises
The premises housing the battery cabinet must have sufficient air circulation to ensure that the
concentration of hydrogen issued during battery charging is kept below the danger limit.
The air change in the premises should preferably be provided by natural ventilation, otherwise by forced
ventilation.
The standard EN 50272-2 for air change envisages that the minimum opening must satisfy the following
equation:
A = 28 x Q = 28 x 0.05 x n x Igas x C10 (1/10³) [cm²]
where:
A = free opening for air intake and outlet
Q = flow of air to be removed [m³/h]
n = number of battery elements;
C10 = battery capacity over 10 hours [Ah]
Igas = current that produces gas [mA//Ah]
in accordance with the standard: Igas = 1 VRLA type battery (*)
(*) for open vase or nickel batteries, contact the battery manufacturer.
When the equation is applied for 240 element (40 battery) hermetically-sealed lead batteries:
A = 336 x C10 / 10³ [cm²]
When using 120Ah batteries, the minimum aperture should be approximately:
A = 41 [cm²]
The air intake and outlet must be positioned to ensure the best possible circulation; for
example:
- apertures on opposite walls,
- a minimum distance of 2 m when they are on the same wall
.
