Sharing our Guidance

Integral Batteries vs. Inverter Systems

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Outline

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1. Code requirements for emergency lighting systems2. Integral battery systems

What are they? Advantages/disadvantages

3. Inverter systems What are they? Advantages/disadvantages

4. Cost analysis5. Conclusion

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What do the codes say about emergency lighting?

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• NEC: Emergency lighting system includes:o Egress lightingo Illuminated exit signso Any other lights specified as necessary to provide required

illumination• NFPA 101: Must maintain power for emergency lighting system for

a minimum of 90 minutes uninterrupted• IBC: Must maintain an average of 1fc on the entire path of egress

and not less than 0.1 fc at any point on the path of egress• NEC: Power sources can include generators, integral batteries,

inverters, UPS systems, fuel cells, etc.

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Integral Battery Systems

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• Exit signs/egress fixtures are supplied with a 90 minute integral battery and wired to normal power

• Remote heads are wired to an exit sign or provided with a 90 minute remote battery pack

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Integral Battery Systems

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• Light fixtures noted as emergency are supplied with emergency ballasts

• Emergency ballasts consist of:o Rechargeable 90 minute batteryo Battery charging meanso Provisions for one or more lamps mounted on the

equipment or terminals for remote lampso Relaying device arranged to energize the lamps

automatically upon failure of normal power to the fixture

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Integral Battery Systems

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• Advantages:o Come as a complete packageo Easy to install/wire – very similar to normal light fixtureo Fixtures can be wired to area lighting circuito Integral batteries charge themselveso Cheaper individual cost

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Integral Battery Systems

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• Disadvantageso Most times need to replace the entire unit/emergency

ballast when batteries failo Only certain fixtures come with emergency ballasts – no

pendants or customized fixtureso Egress fixtures (bug eyes) are not aesthetically pleasing to

look at – owners hate themo Integral batteries can take 24 hours to rechargeo Limited to 90 minutes of backup powero Light output limited by battery pack size

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Integral Battery Systems

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Integral Battery Systems

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Fixture w/ (2) 18W lamps• Rated at 1250 lumens each (2500 total lumens)• At 12’-0” AFF, (2) lamps provide 4.6 fc at beam center and

0.7 fc at beam edge (26’) • (1) lamp provides 2.3 fc at beam center• Lose 0.15 fc per foot from center of beam

Provide 650 lumen battery pack (1 lamp)• 650/1250 = 0.52 * 2.3 = 1.2 fc at beam center• Will not cover entire egress path (0.9 fc 2 feet from center)

Provide 900 lumen battery pack (1 lamp)• 900/1250 = 0.72 * 2.3 = 1.66 fc at beam center• Will cover entire egress path (1.36 fc 2 feet from center)

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Inverter Systems

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• Emergency circuit is wired to the inverter output• Integral sensor switches the load to battery power when normal

power fails (typically within 500ms)• The inverter converts battery DC power to AC power• Batteries are charged when normal power is on

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Inverter Systems

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• Input/output voltage can be 120 or 277V• Can control normally on, normally off, and switched loads• Compatible with any lighting source• Can be provided with output circuit breakers (usually up to 10)

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Inverter Systems

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• Advantageso Can connect any type of fixtureo Can connect both normally on and

normally off fixtureso Good for large spaces with a large

number of emergency fixtureso The full output of any light fixture wired

to inverter is available – less fixtures required to get 1fc on path of egress

o Batteries take 6-12 hours to rechargeo Can be designed to provide power for

longer than 90 minutes if desired

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Inverter Systems

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• Disadvantageso Higher upfront costo Inverter is large – need to find

spaceo More wiring required – must

wire emergency circuits to the inverter

o Batteries need replaced every 5-7 years and are more expensive

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Cost Analysis

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Conclusion

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• Best uses for integral battery packs and emergency ballasts:• Small spaces: less fixtures w/ integral batteries = less cost• Spaces using fixtures with emergency ballasts readily

available• Spaces with hard ceilings• Spaces with tenants who are okay with the use of bug eye

fixtures in the sales area• Best uses for inverter systems:

• Large spaces: more fixtures w/ integral batteries = higher cost• Spaces using many different types of fixtures• Spaces with open ceilings• Spaces with tenants who want to eliminate use of bug eye

fixtures in the sales area

CONCLUSION

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