Although it isn't required, it's a good idea to increase the battery size by a safety factor. A good range is 10 - 20% above the total calculated capacity. Batteries weaken with age and the safety factor provides a good cushion.

Battery drain also must be considered. If the battery must last 24 hours, it cannot expend all its energy in less time. This information can be obtained from the manufacturer.

NOTE: This is an unformatted excerpt from our online fire protection training library.