25 October 2004
BATTERY MAINTENANCE FACILITIES
FUNCTION. Battery maintenance facilities contain space and equipment
for receiving, cleaning, testing, charging, and issuing batteries. Sizes range from a small
booth to a room with storage area. In these facilities, batteries are not in operation while
being charged. Two types of electrochemical battery in general use are lead-acid and
nickel-cadmium (NICAD). This chapter does not address battery-post repair operation.
Design of facilities for installation of battery banks, such as UPS, will be covered in a
OPERATONAL CONSIDERATIONS. Batteries generate a small amount of
hydrogen and other gases while they are being charged or discharged. Hydrogen build-
up could lead to an explosion. Provide ventilation to keep the hydrogen concentration
below 25 percent of the LEL (LEL = 4 percent) to prevent an accumulation of an explosive
DESIGN CRITERIA. Design the facilities using NAVFAC DM-28.4, General
Maintenance Facilities. Design the ventilation system using general technical
requirements in chapter 4 of this UFC and the specific requirements in this Chapter.
Exhaust System. Design exhaust ventilation to have both high-level
exhaust for hydrogen and low-level exhaust for electrolyte spills (acid fumes and odors).
Distribute one-third of the total exhaust flow rate to the high-level exhaust to ventilate all
roof pockets. Locate low-level exhaust at a maximum of 304.8-mm (1-ft) above the
floor. See Figure 8-1 for a floor plan of a battery maintenance room.
Minimum Flow Rate Calculation. To determine the amount of required
volumetric airflow rate, the amount of hydrogen produced must be calculated for the
total number of battery cells in the room. The volume of hydrogen generated is
governed by the amount of charging current (ampere) supplied to the fully charged
battery by the charger. Significant amounts of hydrogen are evolved only as the battery
approaches full charge. To determine a minimum required volumetric airflow rate, use
the following formulas:
(FC/100) x AH x K x N