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Do Exit Signs Need Battery Backup?

Exit signs play a critical role in helping people evacuate safely during emergencies. But a common question from building owners, electricians, and facility managers is: Do exit signs need battery backup? The short answer: Yes, in almost every case they do. Codes like UL 924, NFPA 101, the International Fire Code (IFC), and OSHA all require emergency exit signage to remain illuminated for at least 90 minutes after a power failure.

Table of Contents

Let’s break down the primary standards that govern exit sign battery backup requirements:

  • UL 924: Specifies performance requirements for emergency lighting and power equipment. UL 924-listed exit signs must illuminate within 10 seconds of power loss and stay lit for 90 minutes using internal batteries or an emergency power source. If an exit sign is not UL 924 listed, it likely isn’t code-compliant.
  • NFPA 101: The Life Safety Code requires illuminated signs along egress paths and mandates a 90-minute emergency illumination period. The battery backup must automatically kick in when power is lost.
  • IFC: The International Fire Code aligns with UL and NFPA standards, stating exit signage must be visible, illuminated at all times, and remain lit for 1.5 hours without normal power.
  • OSHA: OSHA 29 CFR 1910.37 requires that all exit signs remain visible and illuminated during outages. Though it doesn't mandate battery backup specifically, it requires a system that meets the above performance metrics—battery is the most common solution.

Pro Tip: When in doubt, look for the UL 924 label. It's the most widely accepted standard for compliance.

Nearly all Battery Backup Exit Signs on the market today are UL 924 listed and designed to meet these national requirements.

Where Battery Backup Is Not Required

While battery backup is the norm, there are a few rare exceptions where it’s not strictly required:

  • Self-Luminous Exit Signs: Tritium-based signs emit light without electricity or batteries and meet UL 924 standards. Browse Tritium Signs.
  • Photoluminescent Exit Signs: Glow-in-the-dark signs absorb ambient light and glow during outages. No batteries needed. Explore Photoluminescent Options.
  • Central Emergency Power: If an exit sign is hardwired to a generator or inverter that provides 90-minute backup, it doesn't need an internal battery.

Note: These options still must meet 90-minute illumination requirements and be UL 924 listed. Confirm with your Authority Having Jurisdiction (AHJ) before installation.

What Building Inspectors Look For

During fire safety inspections, here’s what inspectors will typically evaluate related to your battery backup exit signage:

  • Function Test: Will the sign illuminate without building power?
  • Labeling: Is the fixture UL 924 listed and marked appropriately?
  • Physical Condition: Are signs clearly visible, unblocked, and intact?
  • Battery Status: Does the unit show green charging light or self-test status?
  • Duration: In some cases, inspectors may require proof of a 90-minute illumination test.

Alert: Exit signage failure is one of the most common reasons buildings fail inspection. Avoid these common mistakes.

Best Practices for Compliance and Maintenance

  • Test Monthly: Press the test button and verify 30-second illumination on battery power.
  • Test Annually: Conduct a 90-minute test under simulated outage conditions.
  • Log Results: Maintain a record of all tests and maintenance actions.
  • Replace Batteries: Every 3–5 years, or sooner if signs fail illumination tests.
  • Upgrade to Self-Testing Models: These units automatically run diagnostics. View Self-Testing Exit Signs.

Tip: Keeping a few spare batteries and test logs in your maintenance room will save time—and maybe your next inspection.

Final Thoughts

Battery backup exit signs aren’t just a code requirement—they’re a life safety essential. Whether you’re a contractor installing new units or a property manager prepping for inspection, make sure your exit signage meets or exceeds code. If you’re not using a UL 924–listed sign with verified backup, you’re likely out of compliance.

Need to upgrade? Start with our complete Battery Backup Exit Signage Collection.

Want to go deeper? Read our full UL 924 Compliance Guide.