Installation, commissioning and operating instructions

5.1.1 Calculation of safety distance

In close proximity of the batteries the dilution of explosive gases is not always given. Therefore a safety distance has to be realized by a clearance, in which there must not be any sparking or glowing equipments (max. surface temperature 300 °C). The diffusion of the oxyhydrogen depends on the gas release and the ventilation close to the battery. For the following calculation of the safety distance ‘d’ it can be assumed that the oxyhydrogen expands spherical. Figure 5–1 depicts a graphic approximation of the safety distance ‘d’ depending on the battery capacity. Subsequently a detailed calculation is shown.

Safety clearance:

Required safety clearance needs to be calculated according to formula stated in EN 50272–2.

Volumes of a hemisphere:

Air volume flow required to reduce the concentration of generated hydrogen H

2

in the air to 4% max.:

.

Required radius of the hemisphere:

.

Fig. 5–1: Safety distance based on battery capacity

Battery capacity C [Ah]

Installation, commissioning and operating instructions for vented stationary lead-acid batteries

7140203152 V1.2 (09.2015)

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