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How Do Photoluminescent Exit Signs Work. A Science Explainer

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How Do Photoluminescent Exit Signs Work. A Science Explainer

In public buildings across Canada, glowing green emergency exit signs are becoming a more common sight. But how exactly do these photoluminescent exit signs work their magic to illuminate emergency exit routes even when the lights go out? Read on for a science explainer demystifying the inner workings of photoluminescent exit signs and their benefits.


Understanding Photoluminescence


Photoluminescent exit signs rely on the phenomenon of “photoluminescence” to operate without electricity. Photoluminescence refers to the ability of certain materials to absorb, store, and emit light energy. These photoluminescent materials include phosphors like strontium aluminate and zinc sulfide.


When exposed to ambient light, the phosphors get energized. The absorbed photons excite the phosphors’ electrons to a higher energy state. When the ambient light source disappears, these excited electrons fall back to their normal state, emitting the excess energy as visible light. Hence the photoluminescent material seems to “glow in the dark” after being charged.


The Science Behind Photoluminescent Exit Signs


Photoluminescent exit signs contain non-toxic photoluminescent materials integrated into panels or strips. These get charged when exposed to any ambient light source, whether natural daylight entering through windows or ordinary indoor overhead lighting.


Once fully charged, the energized phosphor-infused panels glow brightly in dim or dark conditions. The glow emitted is a lime green color that meets international standards for exit sign illumination.


The glow duration depends on the strength and duration of the initial charging:


  • After 30-60 minutes of 54 lux ambient room lighting, the signs emit 70+ hours of glow.
  • Even after a short 1-2-minute charge, the signs provide 30-90 minutes of illumination.


This ability to “recharge” themselves using surrounding environmental light makes photoluminescent exit signs completely self-powered and sustainable. They require no external electricity or batteries to operate in dark conditions.


Benefits of Photoluminescent Exit Signs


Photoluminescent exit signs offer numerous advantages that make them an ideal emergency lighting solution:


1. 100% Reliable in Power Outages


Photoluminescent exit signs are completely unaffected by electricity disruptions and will keep glowing in blackouts when traditional electric exit signs may fail. This unmatched reliability during emergencies ensures exit routes remain visible for safe egress.


2. Energy-Efficient and Sustainable


By tapping into ambient light, photoluminescent signs consume zero energy. This saves on electricity costs and carbon footprint. They are an eco-friendly, sustainable solution.


3. Durable for Years


Photoluminescent materials retain their luminosity for over a decade. The signs have a lifespan of 15+ years, unlike electric exit signs requiring regular battery replacements.


4. Highly Visible Photoluminescent Glow


The bright green glow of the signs is designed to meet international standards for exit sign illumination. This high visibility captures attention quickly.


5. Fire and Moisture Resistant


The photoluminescent material is non-flammable and continues glowing even in humid or wet conditions. This makes the signs suitable even for outdoor applications.


6. Easy Maintenance


Photoluminescent exit signs have no electrical components and require only occasional cleaning. This saves on maintenance overhead.


7. Code Compliant


Photoluminescent exit signs meet rigorous visibility standards defined in building codes and EN standards for emergency lighting. This ensures legal compliance.


Becoming the New Code-Compliant Standard


Photoluminescent exit signs are fast replacing traditional electrically-powered exit signs as the new code-compliant standard across Canada and worldwide.


The incentive is the latest building codes and accessibility regulations that promote sustainable designs. For example:


The National Building Code of Canada (NBC) states that newly constructed buildings must incorporate designs and technology that reduce environmental impact and energy consumption. This makes photoluminescent exit signs an ideal eco-friendly solution for new buildings.


The Accessibility for Ontarians with Disabilities Act or AODA mandates enhanced visibility of exit routes through photoluminescent markings. Photoluminescent exit signs help fulfill this legislation.


Provincial codes like the Ontario Building Code (OBC) also reference NBC and AODA in their standards for increased accessibility. By aligning with the latest codes, builders, and facility managers ensure their projects meet regulatory standards while benefiting from the advantages and energy savings that photoluminescent exit signs offer.


Where are Photoluminescent Exit Signs Required?


To comply with emergency lighting codes, photoluminescent exit signs are required in nearly all public buildings. Some key locations include:


  • At exit doors and along exit routes
  • Near stairwells
  • By elevators and escalators
  • In large open lobbies and gathering areas
  • At changes in level or direction along exit pathways
  • Within apartments, condominiums, and housing complexes
  • In commercial buildings like offices, retail stores, etc.
  • At transportation terminals like airports and train platforms
  • Across healthcare facilities like hospitals and nursing homes
  • Inside entertainment venues like theaters, gyms, etc.
  • Within educational institutes like schools and universities
  • Across industrial workspaces and warehouses


Photoluminescent Vs. Traditional Electric Exit Signs


Unlike photoluminescent exit signs, traditional electrical exit signs rely on external power and have high operating and maintenance costs.


Electric exit signs require professional hardwiring into the electrical system. Their illumination depends entirely on the power supply. In a power outage, they cease functioning, causing emergency visibility issues.


Electric exit signs consume energy continuously, even when the building is unoccupied, leading to high energy bills. Battery-powered variants need frequent and costly battery replacements every 1-2 years.


In contrast, photoluminescent signs leverage natural or ambient light at no added energy cost. Their simple plug-and-play installation also saves on labor costs compared to electrical hardwiring. With a lifespan of 15+ years, they have minimal maintenance needs.


By choosing sustainable photoluminescent exit signs, builders and facility managers see a quick return on investment while enhancing building safety and meeting codes.


Frequently Asked Questions


How do photoluminescent exit signs work?


They contain non-toxic phosphors that get energized by surrounding ambient light. The energized phosphors emit a green glow when the lights go out, illuminating the exit signs in darkness.


What types of buildings require photoluminescent exit signs?


Canadian codes mandate photoluminescent exit signs in nearly all public buildings and facilities, including offices, malls, airports, health facilities, educational institutes, and residential complexes.


Do photoluminescent exit signs need electricity or batteries?


No, photoluminescent exit signs are 100% self-powered and require no electrical connection or batteries. They operate by absorbing surrounding ambient light.


How long do the signs glow in dark conditions?


After 30-60 minutes of charging under indoor lighting, photoluminescent exit signs emit 70+ hours of visibility in darkness. Brighter ambient light results in a longer glow duration.


What are the benefits compared to electrical exit signs?


Key benefits are no wiring required, zero energy consumption, a long 15+ year lifespan, high emergency reliability, and low maintenance.


Photoluminescent Exit Signs from Tactile Solution Canada


As a leading Canadian supplier of accessible building solutions, Tactile Solution Canada offers UL-certified photoluminescent running man exit signs from trusted manufacturers like Ecoglo.


Our Ecoglo exit signs offer bright green photoluminescent illumination visible up to 75 feet. Some key features:


  • Meet ULC-S572 Canadian standards for photoluminescent exit signs
  • 100% self-powered illumination, no electrical connection needed
  • Visibility for 70+ hours after a 1-hour ambient light charge
  • Durable anodized aluminum housing
  • 25-year warranty
  • Non-toxic, non-radioactive photoluminescent material


Our team of experts can recommend the ideal exit signage to enhance emergency preparedness, meet Canadian codes, and create a sustainable building equipped for the future.


To make your next project safer, greener, and more code-compliant, explore our range of Exit Signs today!