1 Scope
NOTE This standard covers the design, performance, equipment, and installation of emergency lighting, egress-path illumination, and exit signage for the means of egress. (1.1)
NOTE Emergency and egress lighting exists to keep the path to a public way visible and usable when normal power is lost, so occupants can evacuate without the building's primary lighting. (1.2)
NOTE The means of egress comprises three connected parts: the exit access (the path from any occupied point to an exit), the exit (the protected route such as an enclosed stair), and the exit discharge (the path from the exit to a public way, including the exterior). (1.3)
1.4The Work includes emergency luminaires, exit signs, integral and remote battery equipment, emergency transfer devices, central inverter systems where specified, photometric demonstration of egress illumination, and connection to the emergency power source.
NOTE The illumination performance levels, the 90-minute duration, the 40:1 uniformity limit, and the equipment listing requirements in this standard are common to NFPA 101 and the International Building Code; where an Authority Having Jurisdiction adopts a different edition, the more stringent provision governs. (1.5)
NOTE The normal architectural lighting layout, fixture types, and finishes are specified in
Lighting Fixtures; this standard governs only the emergency function added to or independent of those fixtures.
(1.6.1) NOTE Normal and automatic lighting controls, including occupancy sensing and daylight dimming, are specified in
Lighting Controls; emergency lighting shall override controls to full output on loss of normal power.
(1.6.2) NOTE The on-site generator, its fuel system, and its transfer scheme as an emergency power source are specified in
Generators and
Emergency And Standby Power; this standard governs only the lighting load and the bridging equipment at the luminaire.
(1.6.3) NOTE Fire alarm notification appliances and the fire alarm control panel are specified in
Fire Alarm Systems; this standard governs only the supervised interface between emergency lighting and that panel.
(1.6.4) 2 Referenced Standards
NOTE The publications listed below are referenced in this standard; the edition adopted by the Authority Having Jurisdiction governs, and where editions conflict the more stringent provision applies. (2.1)
| Standard |
Title |
| NFPA 101 (2021) |
Life Safety Code (Sections 7.8 Illumination of Means of Egress and 7.9 Emergency Lighting) |
| NFPA 70 (2023) |
National Electrical Code (Article 700, Emergency Systems) |
| NFPA 110 (2022) |
Standard for Emergency and Standby Power Systems |
| IBC (2021) |
International Building Code, Chapter 10 Means of Egress (Sections 1008 Means of Egress Illumination and 1013 Exit Signs) |
| UL 924 |
Standard for Emergency Lighting and Power Equipment |
| UL 1994 |
Standard for Luminous Egress Path Marking Systems |
| UL 508A |
Standard for Industrial Control Panels (central inverter and battery control cabinets) |
| IES LM-79 |
IES Approved Method for the Electrical and Photometric Measurements of Solid-State Lighting Products (manufacturer's IES photometric files for egress-path compliance) |
3 Definitions
NOTE The following terms are used in this standard: (3.1)
- Emergency luminaire: a luminaire energized by the emergency power source that provides egress-path illumination when normal power is lost.
- Unit equipment: a self-contained device with an integral rechargeable battery, charger, and one or more lamp heads that operates independently of any central battery or generator.
- Integral emergency battery pack (IEBP): a battery and control module installed within or adjacent to a standard architectural luminaire that drives that luminaire's light source on loss of normal power.
- Emergency transfer device (ETD), also called an automatic load control relay (ALCR): a listed line-voltage device that keeps a normally-ON luminaire on its normal circuit and transfers it to a battery or inverter source on power loss, so the luminaire stays continuously illuminated.
- Central inverter system: a centralized static inverter and battery plant that feeds dedicated emergency branch circuits serving multiple luminaires from a single maintained source.
- Exit sign: a listed sign marking the location of, and direction to, an exit, illuminated internally or by passive photoluminescence.
- Duration: the time the emergency source sustains the required illumination after loss of normal power; the code baseline is 90 minutes.
4.1 Illumination Levels
NOTE Emergency illumination is specified at the floor along the egress path, not at a work plane, because occupants navigate the floor and obstructions during evacuation. (4.1.1)
NOTE NFPA 101 permits the illumination to decline over the duration as the battery discharges; the standard therefore specifies both an initial and an end-of-duration level. (4.1.2)
4.1.3The emergency lighting system shall provide an average of not less than 1 fc and a minimum at any point of not less than 0.1 fc, measured at the floor along the entire egress path, at the start of the 90-minute duration.
4.1.4The emergency lighting system shall provide an average of not less than 0.6 fc and a minimum at any point of not less than 0.06 fc, measured at the floor along the entire egress path, at the end of the 90-minute duration.
4.1.5Illumination of the means of egress shall be continuous during the time the building is occupied under normal power, at not less than 1 fc at the floor.
4.1.6Stairways that are part of the means of egress shall be illuminated to not less than 10 fc at the walking surface while in use.
NOTE A uniform path prevents both dark pockets that hide hazards and bright spots that constrict the pupil and leave adjacent areas effectively dark. (4.2.1)
NOTE Checking only the average illumination is a common error; widely spaced or high-output fixtures near exits with low output at corridor midpoints can satisfy the average yet exceed the uniformity limit and fail inspection. (4.2.2)
4.2.3The ratio of maximum to minimum illumination along any portion of the egress path shall not exceed 40 to 1.
1040
40
Default: 40 ratio (max:min)
4.3 Duration
NOTE The 90-minute duration covers the time required to evacuate and for responders to operate; equipment rated for shorter durations does not meet the code. (4.3.1)
NOTE Sixty-minute equipment is sold and is sometimes substituted, but it does not satisfy NFPA 101 or IBC for egress and shall not be accepted; the duration is therefore stated explicitly. (4.3.2)
4.3.3Emergency luminaires and exit signs shall provide the required illumination for a minimum of 90 minutes after loss of normal power.
4.4 Photometric Demonstration
NOTE Because the consequence of an under-illuminated egress path is concealed during normal operation and only revealed in an emergency, compliance shall be demonstrated by calculation rather than assumed from fixture count. (4.4.1)
4.4.2The Contractor shall submit point-by-point photometric calculations, using the manufacturer's published IES files, demonstrating the required initial and end-of-duration illumination and the uniformity limit along the entire egress path.
4.4.3The photometric calculation shall include the exit discharge, including the exterior path from the exit door to the public way.
4.4.4The calculation shall account for the lumen depreciation of the battery-supplied source at the end of the 90-minute duration, not only the initial output.
5 Emergency Power Source
5.1 Selecting the Source
NOTE The emergency power source determines the wiring, transfer, and maintenance approach for the entire system and is therefore the first decision in the design. (5.1.1)
NOTE Three sources are recognized: self-contained unit equipment and integral battery packs at each luminaire, a central battery or inverter plant feeding dedicated emergency branch circuits, and an on-site generator feeding emergency branch circuits through an automatic transfer switch. (5.1.2)
NOTE Unit equipment distributes the battery to each device for simple installation and graceful partial failure but multiplies the number of batteries to maintain; a central system concentrates maintenance at one plant but introduces a single point of failure and dedicated emergency feeders. (5.1.3)
Self-contained unit equipment (integral battery per device)
Integral emergency battery packs in architectural luminaires
Central inverter system on dedicated emergency branch circuits
On-site generator with automatic transfer switch
5.2 Self-Contained Unit Equipment
NOTE Self-contained unit equipment is the most common solution for corridors, stairs, and discrete egress points because each unit is independent and needs no dedicated emergency feeder. (5.2.1)
5.2.2Unit equipment shall be UL 924 listed.
5.2.3Unit equipment shall accept a dual-voltage input of 120 V and 277 V, or a universal MVOLT input spanning 120 V through 277 V, to suit the available branch circuit.
5.2.4Unit equipment shall include an integral charger that automatically recharges the battery to full capacity within 24 hours after a full 90-minute discharge.
5.2.5Unit equipment shall include a visible charge-status indicator and a manual test means accessible from the floor or by standard means.
5.2.6Unit equipment located in damp or wet locations shall be listed for the location and shall be housed in a die-cast or corrosion-resistant enclosure.
120/277 dual-voltage
MVOLT (120 through 277)
347 (where served by 347 V system)
Thermoplastic, dry/indoor location
Die-cast aluminum, damp location
Die-cast aluminum, wet location listed
5.3 Battery
NOTE Battery chemistry sets the temperature tolerance, the maintenance life, and the disposal handling of every unit, so it is specified rather than left to the supplier. (5.3.1)
NOTE Nickel-cadmium cells tolerate wide temperature ranges but contain cadmium that some jurisdictions restrict at disposal; nickel-metal-hydride cells are cadmium-free; sealed lead-acid is typical only for larger central plants. (5.3.2)
5.3.3The battery shall be rated to deliver the full 90-minute duration at the lowest ambient temperature of its installed location.
5.3.4The battery and its housing shall be rated for the ambient temperature of the installed location, and battery rooms or cabinets shall be maintained within the manufacturer's rated range.
Nickel-cadmium (NiCd)
Nickel-metal-hydride (NiMH)
Sealed lead-acid (SLA, central systems)
5.4 Integral Emergency Battery Packs
NOTE An integral battery pack turns a standard architectural luminaire into an emergency luminaire, avoiding a separate emergency fixture and keeping the ceiling appearance uniform. (5.4.1)
NOTE Not every LED driver is compatible with every battery pack; specifying a pack without confirming the driver pairing produces a field substitution or a request for information, so a factory-matched or tested combination is required. (5.4.2)
5.4.3Integral emergency battery packs shall be UL 924 listed.
5.4.4The battery pack and the host luminaire's LED driver shall be a factory-matched or manufacturer-tested combination, confirmed in the submittal.
5.4.5The battery pack shall drive the host luminaire to a constant emergency lumen output sufficient to satisfy the egress illumination requirement, and that output shall be stated in the submittal.
5001500
1100
Default: 1100 lm
5.5 Emergency Transfer Device (ETD / ALCR)
NOTE Where a luminaire is normally on and switched by lighting controls, an emergency transfer device keeps it lit through a power loss without the visible flicker of a dark-to-bright transfer. (5.5.1)
NOTE Because lighting controls may switch a circuit off during normal occupancy, the transfer device monitors the upstream normal supply, not the local switch leg, so loss of normal power forces full output regardless of control state. (5.5.2)
5.5.3Emergency transfer devices shall be UL 924 listed.
5.5.4The emergency transfer device shall sense the normal line voltage ahead of any local control or dimming and shall force the connected luminaire to full output on loss of that normal supply.
5.5.5The emergency transfer device shall restore the luminaire to normal control automatically when normal power is restored.
6 Exit Signs
NOTE Exit sign type, color, and legend are coordinated with the Authority Having Jurisdiction because requirements vary by jurisdiction and occupancy. Most United States jurisdictions require red letters; some adopt green, and some municipalities require a bilingual legend, so the color and legend are confirmed before procurement. (6.1)
6.2 Type and Listing
NOTE Internally illuminated LED exit signs are the common solution; edge-lit and photoluminescent types serve specific aesthetic or maintenance goals. (6.2.1)
NOTE A passive photoluminescent sign above a door is code-recognized only when it is UL 924 listed; UL 1994 listed products are egress path markings and are not recognized as exit signs, and Authorities routinely reject UL 1994-only signs at door positions. (6.2.2)
NOTE A photoluminescent exit sign requires continuous ambient illumination to charge; in zones where controls dim the ambient lighting below the charging threshold, the sign will not sustain its glow and shall not be used. (6.2.3)
6.2.4Exit signs shall be UL 924 listed.
6.2.5Internally illuminated exit signs shall use LED light sources.
6.2.6Battery-backed exit signs shall sustain the legend illumination for a minimum of 90 minutes after loss of normal power.
6.2.7Photoluminescent exit signs, where used, shall receive not less than 5 fc of continuous ambient illumination at the sign face during occupied hours to maintain the listed 90-minute glow performance.
6.2.8Photoluminescent exit signs shall not be used in zones where lighting controls reduce the ambient illumination below 5 fc at the sign face.
LED internally illuminated, AC with integral 90-minute battery
LED internally illuminated, AC only on emergency/inverter circuit
LED edge-lit, AC with integral 90-minute battery
Photoluminescent, UL 924 listed (passive)
6.3 Color and Legend
6.3.1Exit sign letter color shall be as required by the Authority Having Jurisdiction.
6.3.2The legend and any additional language shall be as required by the Authority Having Jurisdiction.
EXIT
EXIT / SORTIE (bilingual)
6.4 Mounting and Direction
NOTE Single-face, double-face, and combination configurations and the directional chevrons are determined by the sign's position in the egress path. (6.4.1)
Ceiling-mounted
Wall-mounted
End-mounted (perpendicular to wall)
6.5 Combination Exit / Emergency Units
NOTE A combination unit houses an exit sign and emergency lamp heads in one enclosure, reducing the fixture count at exit doors where both functions are needed. (6.5.1)
6.5.2Combination exit and emergency units, where used, shall be UL 924 listed and shall meet both the exit sign and the emergency luminaire requirements of this standard.
☐ Provide combination exit/emergency unit at designated doors
7 Photoluminescent Egress Path Marking
NOTE Floor-proximity path markings supplement exit signs in stairs and along egress paths; smoke accumulates at head height, so markings near the floor remain visible when overhead signs do not. (7.1)
NOTE These markings are a supplement and never a substitute for UL 924 listed exit signs; their separate listing standard reflects a different, supplemental role. (7.2)
7.3Photoluminescent egress path marking, where provided, shall be UL 1994 listed.
7.4Photoluminescent path markings shall not be substituted for UL 924 listed exit signs at door positions.
7.5Photoluminescent path markings shall receive the continuous ambient charging illumination required by their listing to maintain the rated glow duration.
☐ Floor-proximity strips
☐ Stairway nosing markers
☐ Handrail markers
8 Central Inverter Systems
NOTE A central inverter feeds many emergency luminaires from one maintained battery plant, concentrating maintenance and testing at a single location at the cost of dedicated emergency feeders and a single point of failure. (8.1)
NOTE Sizing the inverter only to the steady connected wattage ignores LED driver inrush on transfer, the power factor of the load, and future expansion, and produces nuisance tripping or an undersized plant; a design margin is therefore required. (8.2)
8.3Where specified, the central inverter system shall be UL 924 listed; custom or field-assembled control cabinets shall additionally be UL 508A listed.
8.4The inverter shall be sized to not less than 125% of the connected emergency lighting load, accounting for LED driver inrush and power factor.
8.5The inverter output voltage shall match the served luminaire driver input voltage.
8.6The inverter shall transfer to battery and maintain output within the interval required to keep the connected luminaires continuously illuminated, with no perceptible interruption.
Sealed lead-acid (SLA)
Nickel-cadmium (NiCd)
9 Generator-Fed Emergency Lighting
NOTE Where the emergency power source is an on-site generator, normal architectural luminaires on dedicated emergency panels become the egress lighting, transferred by an automatic transfer switch. (9.1)
NOTE A generator is not instantaneous; the transfer switch and the generator start introduce a delay that battery equipment at critical points must bridge so the egress path is never dark during the transfer. (9.2)
NOTE The transfer switch for an emergency system has stricter listing requirements than a standby switch; a switch listed only for optional standby use does not qualify. (9.3)
9.4The automatic transfer switch serving emergency lighting shall be listed for emergency system use per NEC 700.5(C), and shall be electrically operated and mechanically held.
9.5Transfer of the emergency lighting load to the generator shall occur automatically within 10 seconds of loss of normal power, per NEC 700.12.
9.6Battery-equipped luminaires or exit signs shall be provided at exit signs, stairs, and other critical egress points to bridge the transfer interval, and shall be specified wherever the generator start time may exceed 10 seconds, such as in cold climates without an engine pre-heat system.
NOTE The generator set, fuel storage, and testing intervals are governed by NFPA 110-2022 and are specified in
Generators; the transfer time, bridging-battery requirement, and testing provisions shall be coordinated with that specification.
(9.7) Listed for emergency system use per NEC 700.5(C)
☑ Provide battery-backed exit signs and stair lighting to bridge transfer
10 Electrical Installation
10.1 Wiring Independence
NOTE Emergency wiring is kept entirely separate from normal wiring so a fault on a normal circuit cannot disable the emergency system; inspectors check this separation specifically. (10.1.1)
NOTE Emergency circuit conductors run in the same raceway or box as normal branch-circuit conductors are a code violation, so the separation is documented on the drawings. (10.1.2)
10.1.3Emergency system wiring shall be kept entirely independent of normal-system wiring per NEC 700.10, in separate raceways, boxes, cabinets, and panelboards.
10.1.5Emergency wiring shall not be installed in the same raceway, cable, box, or cabinet as normal branch-circuit wiring, except where permitted for transfer equipment by NEC 700.10.
10.2 Connection of Unit Equipment
10.2.1Unit equipment and integral battery packs shall be connected ahead of any local switch, to the same branch circuit and unswitched supply that feeds the normal lighting in the area served, per NEC 700.12(I).
10.2.2The branch circuit feeding unit equipment shall not be controlled by any switch other than the system's overcurrent device.
10.3 Surge Protection
NOTE The 2023 NEC added a surge protection requirement for emergency panelboards and switchboards that was not present in the 2020 edition; where the 2023 NEC is adopted this provision applies. (10.3.1)
10.3.2A surge protective device shall be provided on emergency system panelboards and switchboards where required by the adopted edition of NEC Article 700.
10.4 Exterior Exit Discharge
NOTE The exit discharge path from the exit door to the public way is part of the means of egress and must be illuminated, yet emergency circuits are frequently placed only inside the building, leaving the exterior path dark. (10.4.1)
10.4.2The path of egress from the exit door to the public way shall be illuminated by emergency luminaires on the emergency circuit or by battery-backed luminaires, per NFPA 101 §7.9.1.1.
11 Monitoring and Self-Testing
11.1 Test Regime
NOTE Emergency equipment is tested on a fixed schedule because a battery that has silently failed provides no warning until the moment it is needed. (11.1.1)
NOTE A manual regime requires a 30-second functional test monthly and a full 90-minute discharge test annually; listed self-testing equipment may perform these automatically and is frequently specified to reduce inspection labor. (11.1.2)
11.1.3Manually tested equipment shall be subjected to a 30-second functional test monthly and a 90-minute full-duration test annually, with results recorded.
11.1.4Self-testing equipment, where specified, shall be UL 924 listed for self-testing, shall automatically perform the monthly and annual tests, shall record the results, and shall annunciate a failure locally.
Manual (monthly 30-second, annual 90-minute)
Listed self-testing / self-diagnostic
11.2 Monitoring Output
NOTE A self-testing unit that fails its test annunciates only at the device unless it is connected to a monitoring system; without a reported output the failure can go unseen, defeating the purpose of self-testing. (11.2.1)
11.2.2Self-testing equipment and central inverter systems shall provide a supervised output reporting trouble and test-failure status to the building automation system or fire alarm control panel.
11.2.4Testing provisions and the supervised interface shall satisfy NEC 700.3.
Dry contact (supervised)
RS-485 (Modbus)
BACnet
Proprietary network
Building automation system (BAS)
Fire alarm control panel (FACP)
Both BAS and FACP
12 Submittals
12.1 Action Submittals
12.1.1The Contractor shall submit the following action submittals for review before procurement:
- Product data for each emergency luminaire, exit sign, battery pack, transfer device, and inverter, with UL 924 listing identified
- Point-by-point photometric calculations covering the entire egress path including the exterior exit discharge, at initial and end-of-duration levels
- Battery data sheets showing chemistry, duration rating, and ambient temperature rating
- For integral battery packs, documentation of the factory-matched or tested driver-and-pack combination
- For central inverter systems, sizing calculations showing the 125% minimum design margin and the UL 924 (and UL 508A where applicable) listing
- Exit sign schedule showing type, color, legend, faces, mounting, and chevron direction by location
- Monitoring output protocol and the interface to the BAS or fire alarm control panel
☑ Product data with UL 924 listing
☑ Photometric calculations (egress path + exterior discharge)
☐ Battery data (chemistry, duration, temperature)
☐ Driver-and-pack matched combination documentation
☐ Central inverter sizing and listing
☑ Exit sign schedule
☐ Monitoring output / interface documentation
12.2 Closeout Submittals
12.2.1The Contractor shall submit the following closeout submittals before final acceptance:
- Operation and maintenance manuals for all emergency equipment
- Record of the initial 90-minute acceptance discharge test for each unit and system
- Warranty documentation for equipment and batteries
- Battery replacement schedule and recommended spare quantities
- Final as-installed exit sign and emergency luminaire locations
☑ Operation and maintenance manuals
☑ Initial 90-minute acceptance test record
☑ Warranty documentation
☐ Battery replacement schedule
☐ As-installed locations
12.3.1The Contractor shall submit the following informational submittals:
- Manufacturer's installation instructions for each product type
- Certification that all emergency luminaires and exit signs are UL 924 listed
- Authority Having Jurisdiction confirmation of exit sign color and legend
- Field test reports for the monthly and annual or self-test verification
☑ Installation instructions
☑ UL 924 listing certification
☐ AHJ confirmation of exit sign color/legend
☐ Field test reports
13 Quality Assurance
NOTE All emergency luminaires and exit signs shall be UL 924 listed, regardless of technology type; UL 924 is the single required listing that makes the equipment code-recognized by NFPA 101 and the IBC. (13.1)
NOTE The installer shall be experienced in emergency lighting and Article 700 wiring separation and shall be able to demonstrate prior projects of comparable scope. (13.2)
13.3All emergency luminaires, exit signs, and power equipment shall bear a UL 924 listing mark.
13.4Photoluminescent egress path marking shall bear a UL 1994 listing mark.
13.5The installation shall comply with the emergency system wiring separation requirements of NEC Article 700.
14 Testing
NOTE Acceptance testing confirms that the system delivers its rated duration and illumination as installed, not merely as specified, since installation errors and weak batteries are not visible under normal power. (14.1)
14.2The Contractor shall perform a full 90-minute discharge test of every emergency luminaire, exit sign, and emergency system after installation and shall record the results.
14.3During the acceptance discharge test, the illumination along the egress path shall be field-verified to meet the required end-of-duration levels and the uniformity limit.
14.4The transfer of generator-fed and inverter-fed systems shall be tested to confirm transfer within the specified interval and continuous illumination of bridged points.
14.5Any luminaire, sign, or system that fails to sustain the full 90-minute duration or to meet the required illumination shall be repaired or replaced and retested.
15 Installation
15.2Exit signs shall be installed so that no point in the exit access is more than the code-permitted travel distance from a visible sign, and so that a sign is visible from every required direction of approach.
15.3Emergency wiring shall be installed in raceways, boxes, and panels kept entirely separate from normal wiring per NEC 700.10.
15.4Unit equipment shall be mounted at a height and location that keeps the charge indicator and test means accessible.
15.5Photoluminescent exit signs and path markings shall be installed only where the ambient charging illumination meets the listed requirement during occupied hours.
15.6 Coordination
NOTE Emergency luminaire and exit sign locations shall be coordinated with the architectural reflected ceiling plan, structure, and mechanical and fire-suppression equipment to maintain required illumination and visibility. (15.6.1)
NOTE The emergency lighting monitoring interface shall be coordinated with the building automation and fire alarm installers so the supervised output is terminated and verified. (15.6.2)
16 Delivery, Storage, and Handling
NOTE Batteries lose capacity and can be damaged by prolonged storage at temperature extremes or in a discharged state, so storage conditions are controlled. (16.1)
16.2Equipment shall be delivered in the manufacturer's original packaging with listing marks intact.
16.3Battery-containing equipment shall be stored in a dry, conditioned space within the manufacturer's storage temperature range.
16.4Batteries shall be charged on installation per the manufacturer's commissioning instructions, and equipment stored beyond the manufacturer's permitted shelf interval shall have batteries verified or replaced before acceptance.
17 Warranty
17.1Emergency lighting equipment shall carry the manufacturer's full warranty for the luminaire, sign, or inverter for a minimum of 5 years from Substantial Completion.
17.2Batteries shall carry a warranty for a minimum of 5 years, prorated as permitted by the manufacturer, from Substantial Completion.
18 Spare Parts
NOTE Spare batteries are stocked because they are the wear component most likely to require replacement within the equipment's service life, and a stocked spare avoids egress equipment being out of service awaiting delivery. (18.1)
18.2The Contractor shall furnish spare batteries for the emergency luminaires and exit signs in the quantity scheduled.
18.3The Contractor shall furnish spare LED lamp heads for unit equipment where the heads are field-replaceable.
010
2
Default: 2 % of installed
010
2
Default: 2 % of installed