Nuclear Exit Signs: A Practical Guide to Tritium-Powered Self-Luminous Signs

Table of Contents

• What Are Nuclear Exit Signs?
• Why They're Called “Nuclear”
• How Much Tritium is Needed for 10 vs 20 Years?
• Are They Dangerous?
• Disposal and Recycling
• How to Purchase One
• Federal, State & Local Regulations
• Alternatives to Nuclear Exit Signs
• Final Decision: What Should You Choose?

What Are Nuclear Exit Signs?

Nuclear exit signs are also known as tritium exit signs or self-luminous exit signs. These signs require no electricity or batteries, using tritium gas to emit a constant glow visible even in complete darkness.

The glow is generated by a chemical reaction inside sealed glass tubes, making them ideal for remote areas, hazardous zones, or buildings with frequent power interruptions.

Why They're Called “Nuclear”

The nickname comes from the radioactive gas inside the signs—tritium (H-3), a byproduct of nuclear reactors. While the signs are completely safe when intact, they do use nuclear decay to power their glow. That's where the name “nuclear exit sign” comes from—even though there’s no danger from nuclear power plants or radiation exposure during use.

How Much Tritium is Needed for 10 vs 20 Years?

Because tritium decays over time, the amount used affects the lifespan:

• 10-year signs: ~7.5 curies of tritium
• 20-year signs: ~12 curies of tritium

More tritium means a longer-lasting, brighter sign—but also a higher cost and stricter end-of-life handling.

Are They Dangerous?

No—nuclear exit signs are safe in normal use. The tritium is sealed within the tubes, and the signs are UL 924 listed. The only risk occurs if the sign is broken, which may release gas and require professional cleanup.

Safety Practices

• Don’t tamper with or disassemble the sign.
• Install away from high-impact areas to avoid damage.
• Ensure proper disposal once the sign expires.

Disposal and Recycling

Tritium exit signs must be recycled through a licensed handler. Never discard them in the trash.

We offer a compliant, easy-to-use program here: Tritium Exit Sign Recycling Service

Learn more in our full buyer's guide: Tritium Exit Sign Disposal Buyer's Guide

How to Purchase One

You can purchase nuclear exit signs through any authorized distributor. We carry a wide range of compliant options on our Nuclear Exit Signs collection page.

No special license is required, but customers must acknowledge the federal handling guidelines at checkout.

Federal, State & Local Regulations

Here’s what to know before you buy:

• Federal (NRC): No license needed, but you are responsible for proper use and disposal.
• State rules: May require registration of the sign or impose disposal reporting requirements.
• Local codes: Some areas (like NYC) prohibit tritium exit signs in new installations.

Alternatives to Nuclear Exit Signs

Photoluminescent Exit Signs

These glow-in-the-dark signs absorb ambient light and are ideal for buildings with 24/7 lighting. Explore options here: Photoluminescent Exit Signs

Learn more in our detailed comparison: No Power? No Problem — Choosing Between Photoluminescent and Tritium Exit Signs

LED Exit Signs

Standard electric signs with battery backup, ideal for high-visibility locations and everyday use. See collection: LED Exit Signs

Final Decision: What Should You Choose?

Here’s a quick breakdown:

Still unsure?

Read our in-depth guides:

• Tritium Exit Signs Explained
• Why Choose Tritium Exit Signs
• Photoluminescent Exit Signs Guide

With proper planning, you can find a solution that’s safe, compliant, and tailored to your building’s emergency needs.