Battery Installation Requirements

Note: The source of the technical material in this volume is the ProfessionalEngineering Development Program (PEDP) of Engineering Services.

Warning: The material contained in this document was developed for SaudiAramco and is intended for the exclusive use of Saudi Aramco’semployees. Any material contained in this document which is notalready in the public domain may not be copied, reproduced, sold, given,or disclosed to third parties, or otherwise used in whole, or in part,without the written permission of the Vice President, EngineeringServices, Saudi Aramco.

Chapter : Electrical For additional information on this subject, contactFile Reference: EEX21105 W.A. Roussel on 874-1320

Engineering EncyclopediaSaudi Aramco DeskTop Standards

Battery Installation Requirements

Engineering Encyclopedia Electrical


Saudi Aramco DeskTop Standards

CONTENTS PAGES

DETERMINING BATTERY ROOM REQUIREMENTS FOR SAUDI ARAMCOINSTALLATIONS............................................................................................................. 1

DETERMINING BATTERY AUXILIARY EQUIPMENT REQUIREMENTSFOR SAUDI ARAMCO INSTALLATIONS..................................................................... 8

WORK AID 1: PROCEDURE AND REQUIREMENTS FROM SADP-P-103AND THE NEC FOR DETERMINING BATTERY ROOMREQUIREMENTS FOR SAUDI ARAMCOINSTALLATIONS................................................................................. 18

WORK AID 2: PROCEDURES AND REQUIREMENTS FROM SADP-P-103, THE NEC, AND ESTABLISHED ENGINEERINGPRACTICES FOR DETERMINING BATTERY AUXILIARYEQUIPMENT REQUIREMENTS FOR SAUDI ARAMCOINSTALLATIONS................................................................................. 22

GLOSSARY.....................................................................................................................25



Saudi Aramco DeskTop Standards 1

DETERMINING BATTERY ROOM REQUIREMENTS FOR SAUDI ARAMCOINSTALLATIONS

The first step in the installation of a new battery is to determine the battery roomrequirements. The battery room must be designed and constructed to prevent the build up ofexplosive gases in the room, to prevent the exhaust of explosive concentrations of gas, toprevent the ingress of dirt and contaminants, and to minimize the potential of dangerousexplosions and injuries to personnel. The battery room requirements refer to the batteryroom's design and support equipment. This section will discuss the following topics that arepertinent to battery room requirements:

_Physical Requirements_Ventilation Requirements_A/C Requirements

Physical Requirements

The physical requirements for a battery room include the following:

_Battery room size_Interior walls and floors_Battery room doors_Lighting fixture requirements

Battery Room Size

The size (ceiling height and floor space area) of a battery room is a key physical requirement.All battery rooms should be designed with the maximum ceiling height that is possible. Theceiling height should never be less than 3m. A high ceiling allows the hydrogen (H2) toaccumulate at the greatest distance from the battery and from potential sources of ignition. Ahigh ceiling also increases the total volume of air in the battery room. A larger volume of airreduces the concentrations of H2 that are produced during a battery charge cycle; therefore,false ceilings that would decrease this volume of air are not permitted in battery rooms.

Batteries must not be housed in cabinets or in other similar enclosures that would limit thedispersion of H2. The only exceptions to this requirement are that small batteries can beplaced in a single cabinet with a volume of 2m3 (70 ft3). Work Aid 1 contains a complete listof the requirements for placement of batteries in a cabinet.




Working Space

Sufficient access and adequate working space are required in battery rooms to permit safeoperation and maintenance of the battery and the battery support equipment. Adequateworking space is defined as a minimum of 1m (3 ft.) of work space on all four sides of thebattery. The measurement of one meter is defined as the distance from the exposed liveelectrical parts of the battery and the associated equipment to ground.

The working space in battery room also must be sufficient to allow the access of two workersto perform routine inspections, maintenance, and testing of the battery. Additional space mustbe allowed for the movement of equipment in and out of the battery room. The workingspace and the access space must be kept clear and must not be used for storage of equipmentor materials. Wall-mounted storage facilities should be provided for safety equipment andother battery-related service equipment.

Interior Walls and Floors

Because battery rooms normally are constructed from porous materials, the interior walls of abattery room must be sealed to prevent the leakage of potentially flammable gases from thebattery room to the spaces that surround this room. The floor and the lower 150mm (6 in.) ofthe walls of the battery room also must be protected with paint that is resistant to acids and tocaustics. The use of the protective paint on the lower portion of the battery room wallsensures that an electrolyte release will not damage the floor and will not leak into the areasthat surround the battery room.

Except for air conditioning (A/C) and ventilation ducts, penetrations through the interior wallsof battery rooms cannot be more than 2.1m (7 ft) from the floor. Where penetrations for A/Cand ventilation ducts exist in the battery room, the area around the penetrations must havevapor-tight seals to prevent the leakage of H2 gas to other parts of the building. Thesepenetration requirements prevent the leakage of H2 gas to other parts of the building becauseH2 gas is lighter than air and will accumulate near the ceiling. Through maintenance of allpenetrations near the floor, the only means through which the H2 gas can escape is throughthe exhaust duct.




Battery Room Doors

The doors to a battery room must be designed to open out and away from the battery. Thisrequirement allows for a rapid exit from the battery room in the case of an emergency. Adoor that opens inward would seal shut in the event of a positive pressure in the battery room.Because a door that opens inward also would require additional space to open, use of such adoor would increase the effective size of the battery room. Devices that could prevent thedoor from opening cannot be installed. Such devices could prevent personnel from exitingthe battery room in the event of an emergency.

Lighting Fixture Requirements

The lighting fixtures in battery rooms must be suspended from the ceiling so that the fixturesare below the level at which H2 gas accumulates. The fixtures must be positioned directlyover the battery racks. Such placement of the lighting fixtures will ensure that adequate airspace exists above the fixtures for the dispersion of H2 gas, and that the battery area receivesmaximum illumination for maintenance. The lighting fixtures that are installed must beenclosed and must be gasketed to prevent H2 leakage into the lighting fixture. The lightingfixtures also must be resistant to corrosion that is caused by sulfuric acid fumes.

Because the atmosphere in a battery room has the potential to become explosive, devices thatproduce arcs, such as a light switches, must be installed at least 1.5m (5 ft) from the batterycells. This distance is considered sufficient to ensure that an explosive concentration of H2gas will not exist in the vicinity of the switch.

Ventilation Requirements

The goal of a battery room ventilation system is to ensure that H2 gas does not reach anexplosive concentration. H2 gas is generated by the electrolysis of the battery electrolyteduring the charge cycle. The rate at which H2 gas is produced depends on the rate at whichthe battery is charged; high battery charging rates produce more H2 than do low batterycharging rates. If sufficient ventilation does not exist, the H2 that is produced will accumulateand eventually will reach an explosive concentration.

H2 can be explosive when its concentrations in air are between 4% and 79%. H2concentrations that are below 4% are too low to cause an explosion. H2 concentrations thatare above 79% do not contain enough oxygen to cause an explosion.




A battery room ventilation system must be designed so that the H2 concentration does notexceed 2% of the air volume in the battery room. The 2% requirement provides an adequatesafety margin between the actual concentration and the concentration that would be necessaryto cause an explosion. Battery room exhaust must be vented to the outside atmosphere so thatno H2 is transferred into the adjacent rooms and buildings.

In most battery installations, exhaust fans are not required because the positive pressure that iscreated by the battery room ventilation supply will produce sufficient exhaust air flow.Battery room exhaust ducts, without exhaust fans, must be large enough to pass the necessaryvolume of air. In cases where exhaust fans are necessary to produce the required air flow, theexhaust fan motors are not required to be explosion-proof.

A battery room that meets requirements for ventilation is regarded as a non-hazardous area;therefore, special electrical equipment enclosures to prevent fire and explosion are notrequired. However, physical location of electrical equipment enclosures is to comply withSaudi Aramco design specifications.

The following four steps must be used in the determination of the proper amount ofventilation air flow:

Step 1: Determine the total air volume of the battery room and the 2% airvolume of the battery room.

Step 2: Determine the H2 production rate of the battery.

Step 3: Determine the number of air changes that are required per hour tomaintain the H2 concentration at less than 2% of total volume of thebattery room.

Step 4: Determine the volumetric air flow to produce the necessary air turnoverrate.

Step 1 in the calculation of air flow is to determine the battery room air volume. The airvolume of the battery room is determined through use of the following formula (see WorkAid 1):

Battery Room Air Volume = Total Room Volume - Battery and Battery Rack Volume

where: the total room volume is equal to the product of the length, width, and height ofthe room.




The battery room air volume is multiplied by .02 to determine the 2% air volume of thebattery room.

Step 2 in the calculation of air is to determine the amount of H2 that is generated by thebattery. The volume of hydrogen that is generated by a storage battery is determined throughuse of the following formula (see Work Aid 1):

Step 3 in the calculation of air flow is to determine the number of air changes that are requiredto keep the H2 concentration below the 2% limit. The number of air changes that are requiredper hour can be determined through use of the following formula (see Work Aid 1):Step 4 in the calculation of air flow is to determine the volumetric air flow that is required toproduce the necessary air turnover rate. The volumetric air flow that is required can bedetermined through use of the following formula (see Work Aid 1):

Example Calculation of Battery Room Ventilation

In order to perform the four steps in the determination of the proper amount of ventilation airflow, the following information that pertains to the battery installation must be known:

_Type of battery.

_Ah rating of the battery.

_Number of cells in the battery installation.

_The dimensions of the battery room.

_The dimensions of the battery racks and batteries.

_The battery charging current rate that will result in the maximum H2production.

For this example calculation, the following information is given:

_The type of battery is lead-acid._The battery is rated for 100 Ah._The installation contains 120 cells._The volume of the battery room is 43.74 m3._The volume of the battery racks and batteries is 2.68 m3._The charge rate that results in maximum H2 production is 7.19 amperes.




The following steps must be performed to determine the proper amount of ventilation air flowfor this example:

_The first step is to determine the battery room air volume and the 2% airvolume of the battery room.

Battery Room Air Volume = Total Room Volume - Battery andBattery Rack Volume

= 43.74 m3 - 2.68 m3

= 41.06 m3

2% Air Volume of Battery Room = (Battery Room Air Volume) (2%)

= (41.06 m3) (.02)

= .8212 m3

_The next step is to determine the H2 production rate for the example battery inm3/h.

_ The next step is to determine the number of air changes that are requiredper hour.

_The last step is to determine the volumetric air flow (liters/second) that isrequired to provide the required number of air changes per hour.

Air Flow Required = (Battery Room Air Volume)(Required Air Changes/Hour)(Conversion Factors)

To maintain the Battery Room H2 concentration at less than the 2% by volume, theventilation system for the example installation must provide a volumetric flowrate of 5.5 l/s.The Electrical Engineer can use this information to check existing systems or can provide thisinformation to the Mechanical Engineers for design purposes.




A/C Requirements

Batteries are designed to operate at an optimum level when the operating temperature (of theelectrolyte) is maintained at 25oC (77oF). The service life of a battery depends on theoperating temperature of the battery. The service life of a lead-acid battery is approximatelyhalved for every 10oC (18oF) rise in the operating temperature above the 25oC (77oF)optimum value.

All lead-acid storage battery installations at Saudi Aramco, whether manned or unmanned,should be air-conditioned to maintain the battery room temperature below 25oC (77oF). Inunmanned areas where provision of air conditioning is not feasible, the use of nickel-cadmium batteries should be considered. Nickel-cadmium batteries are less susceptible toservice life degradation that results from heat. In unmanned areas where A/C is feasible, theA/C system should be designed with a 100% backup capacity. This requirement is to ensurethat a loss of the normal A/C supply does not result in damage to the battery. A backupsource of A/C is not required in manned installations because the personnel that work in theseinstallations should be able to detect and to correct the A/C problems before battery damageoccurs.

The air conditioning ducts that supply battery rooms must be sized to ensure that thefollowing criteria are met:

_That an adequate positive pressure is provided to ensure that the requirednumber of air changes occur per hour.

_That adequate cooling is provided to maintain the battery room temperature at25oC (77oF).

A/C return ducts are not permitted in battery room installations to prevent fumes and H2 frommixing with the building air.

The actual design and construction of air conditioning systems is beyond the scope of thisModule and should be addressed by the Mechanical Engineer. The Electrical Engineer mustunderstand the function of the air conditioning system and its importance in the efficientoperation of the battery.




DETERMINING BATTERY AUXILIARY EQUIPMENT REQUIREMENTS FORSAUDI ARAMCO INSTALLATIONS

Battery auxiliary equipment includes all of the equipment that is necessary to ensure the safeand proper operation of the battery. Battery auxiliary equipment that is improper or that isimproperly installed can lead to personnel injuries, equipment damage, and unplannedoutages. The requirements for the following battery auxiliary equipment will be discussed inthis section:

_Battery racks_Wiring_Grounding_Maintenance instruction plates_Drains_Safety

Battery Racks

Battery racks are insulated metal racks that are designed to provide a stable surface on whichthe individual battery cells of an installation can be arranged. The arrangement of the batterycells on the battery rack supports the cells above the floor and also provides for ease of accessto the battery cells for maintenance.

Battery racks can be categorized in accordance with their physical configurations. Figure 1shows a front view, a side view, and an isometric view of three different types of batteryracks. Figure 1A shows a single row, one tier rack that is used for batteries that contain asmall number of battery cells.

Figure 1B shows a single row, two-tier rack in which the battery cells are stacked on top ofeach other. This single row, two-tier rack provides, without the use of additional floor space,more space for a larger number of cells than the one-tier rack. The disadvantages of the singlerow, two-tier rack are the inaccessibility of the bottom row of cells and an increased difficultyof cell installation. This single row, two-tier rack should not be used with larger battery cellsthat weigh more than 75 lbs.

Figure 1C shows a single row, two-step rack that is designed to hold the same number of cellsas the single row, two-tier rack. The design of the single row, two-step rack eliminates thedisadvantages that are associated with the single-row, two-tier rack. The access to the top ofeach cell is not impeded, and the installation of the battery cells can be accomplished from thetop. Although the two-step configuration takes up more room than the single row, two-tierrack, the advantages of the two-step configuration make it more practical.




Battery Rack ConfigurationsFigure 1




The configuration of a battery rack will be determined through use of the followinginformation:

_The cell dimensions._The number of cells._The dimension of the battery room._The maximum weight allowance per square meter of battery room floor._The cell access requirements for inspections and maintenance._Seismic requirements.

No compromise should be made that affects the accessibility of the battery cells. Thetechnician should be able to service the individual battery cells without being crowded byadjacent cabinets or other facilities.

Battery racks are available from most manufacturers in four basic designs configurations.Each configuration fulfills the need of different seismic criteria. Seismic criteria is normallyexpressed in g-levels and seismic zones. The g or g-level is the symbol or value that is usedfor the unit of acceleration that is defined as the acceleration that is produced by the force ofgravity at the surface of the earth. The exact value of one g will vary with lattitude andelevation of the point of observation. The g-level requirements for a particular equipmentapplication will be provided by the specifying geological engineer.

The chart that is shown in Figure 2 lists two g-level coefficients: Static and Dynamic ZeroPeriod Acceleration. The static coefficient relates to bodies at rest or forces in equilibrium,while the Dynamic Zero Period Acceleration coefficient values are obtained from floorresponse spectra based on g-levels at the "zero period" (approximately 35 Hz). If more thanone method of designating the g-level is provided by the geological engineer, use the worsecase value that is provided to select the proper battery rack. If a worse case value is notobvious, use the following order of selection:

_g-level, Dynamic Zero Period Acceleration_g-level, Static

Seismic zones that are normally associated with a seismic risk map represent risk damagemagnitudes that result from earthquake intensity. The four basic battery rack configurationsare:

_Standard battery racks_Shock-protected battery racks_Seismic Zone 2, Zone 3, and Zone 4 battery racks_High seismic battery racks




The standard battery rack should be used where there is no seismic activity. However, siderails and end rails are recommended for all types of battery installations to provide addedsupport to the battery cells.

The shock protected battery rack should be used where there is a low seismic g-levelrequirement. The shock protected design consists of side rails, end rails, and related hardwarethat adapt to the standard battery rack configuration. The Zone 2, Zone 3, and Zone 4 batteryracks should be used where there is a moderate to a high seismic g-level requirement. Thehigh seismic battery rack is used where there is a very high g-level requirement. The Zone 2,Zone 3, and Zone 4, and the high seismic battery racks are designed and constructed to meetthe applicable g-level requirements. As a result, these racks are much heavier and muchlarger than the standard and the shock protected designs.

The following guidelines can be followed to select the proper battery rack for a given batteryinstallation:

_Determine the g-level requirement of the area in which the battery will beinstalled.

_Determine if the battery and the battery rack are considered essential or non-essential equipment. (Essential facilities are those structures or buildings thatmust be safe and usable for emergency purposes after an earthquake in order topreserve the health and the safety of the general public. Such facilities shouldinclude but should not be limited to hospitals, police stations, fire stations,disaster operation, and communication centers.)

_Use Figure 2 to determine the correct battery rack type. Find the properheading for the g-level requirement and follow down the table until the g-levelthat is equal to or that is greater than the required g-level is found. Thecorresponding battery rack would be the proper selection.

_Determine the proper physical configuration of the battery rack on the basis ofthe cell dimensions, number of cells, dimensions of the battery room, themaximum weight allowance per square meter of battery room floor, and thecell access requirements for inspections and maintenance.




Battery Rack Selection ChartFigure 2

Wiring

The guard requirements for wiring in a battery installation are similar to the requirements forwiring in other electrical installations; the wiring must be rated to carry the connected load onthe dc system without overload, and the voltage drop across the wiring must not exceed apredetermined value. The maximum voltage drop that is allowed across battery cables andbattery connectors is 3%.

The caustic atmosphere that is inside of a battery room can create potential problems with theinstalled wiring that do not exist in non-caustic atmospheres. These potential problemsinclude short-circuits and ground faults. The fumes and the electrolyte deposits that resultfrom the normal operation of a battery can break down the insulation on wires. Suchinsulation breakdown can then directly result in short-circuits and in ground faults.




Because they conduct electricity, the electrolyte deposits also can indirectly result in short-circuits and in ground faults. A large buildup of electrolyte on the battery cell jars can cause ahigh resistance short-circuit between the terminals of the cell; this short-circuit will increasethe rate of self-discharge. Such deposits also can provide a high resistance path to ground;this path will result in a ground fault.

To compensate for these potential problems, all of the wires, the inter-cell connectors, and thebattery cables should be corrosion resistant and should be compatible with the fumes from theelectrolyte. The types of insulation that are recommended for use in sulfuric acidenvironments and in potassium hydroxide environments are polyvinylchloride, neoprene, andpolyethylene. One of these insulation materials should be used for conductor insulation. Inaddition, all exposed conductors and exposed connections should be coated with a suitablecorrosion inhibitor to mitigate the buildup of corrosion.

Grounding

Grounding of battery systems is divided into two categories: system grounding and equipmentgrounding.

System grounds and circuit grounds are installed to limit the impressed voltages that arecaused by lightning, line surges, or unintentional contact with higher voltage lines and tostabilize the voltage to ground during normal circuit operation. Batteries that are associatedwith communication systems use a ground on the positive bus of the battery. The positive andthe negative buses of a non-communication dc system battery are isolated from ground.

Equipment grounding refers to the connection of all non-current-carrying components of asystem to ground. Equipment grounding conductors are bonded to the system groundedconductor to provide a low impedance path for fault current; this path will facilitate theoperation of overcurrent devices under ground-fault conditions. All battery racks must begrounded through a suitable grounding conductor.

Maintenance Instruction Plates

Maintenance instruction plates are installed in battery rooms to ensure that the propermaintenance procedures are followed. Performance of maintenance in strict accord withinstructions on these plates will promote equipment and personnel safety. The maintenanceinstruction plates are mounted on the wall to ensure easy access to the instructions and toensure that all personnel use the same, most up-to-date revisions of the instructions.




Maintenance instruction plates should provide enough information to perform themaintenance action without the occurrence of undue complications. All danger and cautionstatements must be highlighted to ensure that personnel are aware of the safety concerns. Thebattery maintenance instruction plates also should provide the minimum requirements forbattery operation, equalizing charges, and recharging.

Battery maintenance instruction plates are developed from the information in themanufacturers' technical manuals and should be written in English and Arabic to ensure thatall personnel can read the instructions. Instructions must be engraved on permanent-typeplastic, on stainless steel, or in some other permanent marking method.

Drains

Floor drains should be installed and should be located near the battery rack to permitelectrolyte that is accidentally spilled to be flushed away. The floor drain also serves as aneyewash drain. The battery room floor drain should be a trapped, vented drain that isconnected to a neutralization tank before any drainage enters the sanitation or the sewersystem. All piping that is upstream of the neutralization tank and the drain vent should beacid resistant.

For remote battery room locations that do not have sewer or drainage lines available, the drainmay be pumped to a dry sump. Drains are not required for sealed battery installations.

Safety

As part of the installation process, safety cannot be overlooked. Each battery room must havethe following signs posted to inform workers of the special requirements and possiblehazards:

"DANGER CAUSTIC/ACID""DANGER NO SMOKING"

Eye wash facilities are required at all battery installations with the exception of sealed batteryinstallations. Stationary and portable eyewash facilities are acceptable for use in allinstallations; however, all remote location facilities require a self-contained water supply.




The following safety items should be installed or should be made available for immediate use:

_Chemical worker's gloves

_Face shield

_Rubber apron

_Acid and alkali resistant gloves

_Wall-mounted storage for safety equipment

_Supply of bicarbonate of soda for the neutralization of battery acid

_Supply of citric acid to neutralize potassium hydroxide in nickel-cadmiumbatteries

_Cell lifting straps

_Electrolyte thermometer

_Hydrometer




WORK AID 1: PROCEDURE AND REQUIREMENTS FROM SADP-P-103 ANDTHE NEC FOR DETERMINING BATTERY ROOMREQUIREMENTS FOR SAUDI ARAMCO INSTALLATIONS

Work Aid 1A: Procedure for Determining Battery Room Equipment.

1. Determine whether the battery can fit in a single cabinet that has a volume that is lessthan 2m3. If the battery will fit in such a cabinet, design the cabinet to meet thecriteria. If the battery will not fit in such a cabinet, continue to follow the next step ofthe procedure.

2. Determine the physical requirements of the battery room in terms of size, illumination,doors, sealing, and switching devices.

3. Determine the amount of ventilation that is required.

4. Determine whether the battery requires air conditioning. If the battery does require airconditioning, determine the temperature and the safeguards that are required by thesystem.

Work Aid 1B: Battery Room Requirements

Small Batteries

Small batteries that will fit into a single cabinet that has a volume that is less than 2m3 arepermitted as long as the following criteria are met:

a. The enclosure and the cell supports must be constructed of steel that has beencoated with an appropriate acid resistant or alkali resistant paint. The supportsfor nickel-cadmium batteries can be constructed of wood.

b. A drip tray that is constructed of an acid/alkali-resistant plastic or of stainlesssteel must be installed under each tier of cells.

c. The enclosure must be ventilated at the top and the bottom.

d. An adequate clearance must be maintained above each cell to permit filling andtesting operations.




e. No more than two rows of cells can be installed on each tier.

f. The enclosure must be provided with a bottom drain outlet.

Exception: items b, d, and f are not required for enclosures that house sealed batteries.

Battery Room Physical Requirements

Size - The battery room must be of sufficient size toallow for 1m of workspace on each side of the battery.The height of the battery room ceiling must be at least3m, and the preferred height for battery room ceilings isthe maximum possible height.

Note: In order to avoid ventilation difficulties, falseceilings are not permitted in battery rooms.

Illumination - Lights must be suspended at least 600mm (2 ft)from the ceiling. The lights must be enclosed, gasketed,and corrosion resistant to sulfuric acid fumes or topotassium hydroxide fumes as applicable. Light fixturesmust be placed directly above the battery.

Doors - Battery room doors must open outward, awayfrom the room, and must be fitted with closing devicesand panic hardware. Hasps, padlocks, or other sidedevices can not be installed because such devices willhinder the operation of emergency door opening devices.

Sealing - The battery room must be coated with a finish toseal the building material.

The floors and the lower 150mm (6 in.) must be sealedwith an acid resistant and caustic resistant epoxy.

With the exception of ventilation and A/C ducts,penetrations through the walls of the battery room that aremore than 2.1m (7 ft) from the floor are not permitted.




Switching Devices - Because the atmosphere in the battery room ispotentially explosive, light switches, circuit breakers, orother devices that produce arcs must be installed aminimum of 1.5m (5 ft) from the battery cells.

Ventilation Requirements

- Sufficient volumetric flow must be provided to maintain the H2 concentrationat or below 2% by volume.

- Determine the necessary ventilation flow rate through use of the followingprocedure:

1. Determine the air volume of the battery room and the 2% air volume ofthe battery room.

a. Battery Room Air Volume = Total Room Volume - Battery andBattery Rack Volume

Volume = (length) (width) (height)

b. 2% Air Volume of Battery Room = (Battery Room Air Volume)(2%).

2. Determine the H2 production rate during charging.

a. Determine hourly charging currentwhere: BIF = Battery inefficiency factor: 1.15 for lead-acid

batteries, and 1.4 for nickel-cadmium batteries.

Ah = Ampere hours removed during discharge

RT = Recharge time

b. Determine the H2 production rate.

3. Determine the required number of air changes per hour.




4. Determine the necessary volumetric air flow in liters/second.

Air flow required = (Air Battery Room Volume) (Required Air Changes/Hour)(Conversion to liters/second)

- The necessary volumetric air flow normally can be provided through provisionof adequately sized exhaust ducts. In cases where such ducts will not providethe necessary volumetric air flow, an exhaust fan should be installed.

Air Conditioning Requirements.

- A/C is required in all lead-acid battery installations.

- If A/C cannot be provided, nickel-cadmium batteries should be installed.

- Battery room A/C systems in unmanned locations must be designed with a100% backup capacity.

- The A/C must maintain the battery room temperature at 25oC (77oF).

- In manned buildings, battery rooms must be air conditioned to 25oC (77oF).

- A/C return ducts cannot be installed in battery rooms.




WORK AID 2: PROCEDURES AND REQUIREMENT S FROM SADP-P-103, THENEC, AND ESTABLISHED ENGINEERING PRACTICES FORDETERMINING BATTERY AUXILIARY EQUIPMENTREQUIREMENTS FOR SAUDI ARAMCO INSTALLATIONS

Work Aid 2A: Procedures

1. Determine the required battery rack configuration.

2. Determine the necessary dimensions (length, depth, height) of the battery rack.

3. Determine the required battery rack construction.

4. Determine the allowable wiring voltage drop.

5. Determine the battery grounding requirements.

6. Determine the formation that is required to be on the maintenance instruction plates.

Work Aid 2B: Requirements

Battery Racks

- Not more than two rows of cells should be installed on a tier level.

- No more than two battery levels are allowed.

- Battery rack construction

_Welded steel with floor-mounting connections

- All material must be coated with an acid resistant plastic or an equivalentmaterial.

- The maximum height of the batteries that are installed will not exceed 110 cm(44 in.).

- The length of the battery rack should be sufficient to provide at least two tothree centimeters of separation between the individual cells.




Wiring

- All of the conductors must be insulated to prevent corrosion.

- The battery cables must be sized for a voltage drop of less than 3%.

- The positive and the negative cables must be run in the same conduit.

- Connectors

_For lead-acid batteries, the connectors must be lead-plated brass orstainless steel.

_For Nickel-Cadmium batteries, the connectors must be nickel plated.

Grounding

- The battery racks must have a safety ground.

- The positive and the negative buses on non-communication dc systems must beisolated from earth ground.

- In dc systems that are shared between industrial and communication circuits,Consulting Services must be consulted to determine the groundingrequirements.

- The positive bus of communication system batteries must be grounded.




Maintenance Instruction Plates

- The following types of information must appear on the maintenance installationplates:

_Dangers_Cautions

_Procedure for float operation_Procedure for equalizing operation_Procedure for recharging operation

- The maintenance instruction plates must be marked through use of one of thefollowing methods:

_The words must be engraved on permanent-type plastic._The words must be etched on stainless steel.

- The maintenance instruction plates must be mounted on the wall.




GLOSSARY

earth ground - A path that is provided by a connection to a piece of electricalequipment through which fault current can travel to ground.

electrolysis - The passage of an electric current through an electrolyte that resultsin a chemical change.

electrolyte - A conducting medium in which the flow of electric current takesplace by migration of ions.

g-level - The unit of acceleration that is defined as the unit of accelerationthat is produced by the force of gravity at the surface of the earth.

gassing - The evolution of gases from one or more of the electrodes of abattery during a charge.

seismic - Describes objects that are subject to earth vibrations or that arecaused by earth vibrations.

service life - The expected length of time that a battery can perform its designfunction.

2% air - 2% value of the Total Room Volume less the Battery and BatteryRack

volume Volume.

Battery Installation Requirements

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