A quick, plain-English walkthrough of what tritium exit signs are, how they glow without power, and when they’re the right choice.
Last updated: June 2026
What is a tritium exit sign?
A tritium (self-luminous) exit sign is a code-listed egress sign that glows continuously without wiring or batteries. It’s ideal when you need a reliable, always-on legend but running power is expensive or impractical. If you’re shopping now, start with our self-luminous exit signs.
How self-luminous signs glow (diagram)
Inside the sign are sealed glass tubes filled with tritium gas. As tritium decays, it releases low-energy particles that excite a phosphor coating on the tube interior. The phosphor emits visible light behind the EXIT legend—no external power or charger is required.
For a full buyer’s overview—including placement, testing expectations, and disposal—see the Tritium Exit Signs – Complete Guide.
Brightness & lifespan
- Service life: commonly rated for 10 or 20 years of continuous glow.
- Gradual dimming: brightness declines over time; replace when your AHJ/UL 924 visibility requirements aren’t met.
- Even illumination: dark segments can indicate damage or end-of-life.
Where they fit best
- Hard-to-wire areas: block walls, historic finishes, remote structures.
- Fast retrofits: swap non-compliant signs without opening walls.
- Long outages: signage remains visible even with total power loss.
Is it safe?
When intact and used as directed, tritium exit signs are considered low-risk. Owner duties focus on keeping labels intact, maintaining an inventory, and reporting any lost, stolen, or broken devices. Get the printable checklist in the Tritium Compliance Handbook.
Compliance snapshot
- UL 924 listing: choose listed models and install per instructions.
- Owner responsibilities: labels, inventory, and incident reporting.
- AHJ basics: verify letter color, mounting height, visibility along the egress path.
End-of-life basics
Expired or damaged tritium signs must be recycled via a licensed facility—never landfilled or scrapped. Follow the 4-step process in our Disposal (step-by-step) guide.
How they compare to LED & photoluminescent
- Tritium: no power, always on; plan for compliant recycling at end-of-life.
- LED: bright and versatile, but needs wiring and battery testing.
- Photoluminescent: no power, but requires reliable ambient charging light.
See cost and maintenance differences in our Exit Sign ROI comparison.
FAQ
Do tritium exit signs need electricity or batteries?
No. They’re self-powered; the glow comes from radioluminescence inside sealed tubes.
How long do they last?
Most models are rated for 10 or 20 years. Replace when visibility falls below code or the labeled service date.
Can I use them everywhere?
They’re great where wiring is impractical. For well-lit interiors with reliable ambient light, photoluminescent can also work; standard interiors often favor LED.
Choose tritium only when the no-power fit is real
Tritium exit signs solve a specific problem: continuous visibility without electrical wiring, batteries, or charging light. They are not the default for every door, so compare the application, inspection path, and end-of-life plan before buying.
| Project signal | Best next path | What to confirm |
|---|---|---|
| Remote corridor, stair, shelter, or utility area without reliable power | Tritium self-luminous exit signs | Confirm face count, arrow direction, service life, listing, and AHJ acceptance. |
| Well-lit area where the sign can charge during normal operation | Photoluminescent exit signs | Verify charging light, viewing distance, placement, and inspection expectations. |
| Standard building wiring is available | LED and battery-backup exit signs | A wired LED sign is often simpler when power, testing, and replacement access are normal. |
| Existing tritium sign is expired, damaged, or being replaced | Tritium disposal and recycling | Plan return paperwork and replacement timing. See the disposal guide before removal. |
For the broader no-electric decision, compare the photoluminescent vs tritium guide.
Related exit sign planning links
- For project selection, compare photoluminescent vs tritium exit signs by charging light, service life, and disposal.