Frequently Asked Questions
How many hours do the photoluminescent products glow?
How quickly do the photoluminescent products charge?
How much light do the photoluminescent products need to glow?
Can photoluminescent products be used outdoors?
How long do floor installed glow-in-the-dark products last?
Is photoluminescence radioactive?
What is the life expectancy of photoluminescence?
How many hours do the products glow?
American PERMALIGHT®, Inc. offers you photoluminescent safety markings that range from 8 hours to several days in glow performance, depending on the grade of performance that you select.
We measure the luminance of our products using calibrated photometers in our in-house laboratories. For these comparison tests, the products get activated by 1000 Lux = 93 foot-candles of Xenon Lighting for 5 minutes, in compliance with ASTM E2072-04 Standard, ASTM E2073-02 Test Method and DIN67510 Part 1. Following this activation, the emitted luminance gets measured at 10, 60 and at 120 minutes in full darkness. The luminance decline gets calculated down to 0.3 millicandela per square meter (mcd/m²).
PERMALIGHT® standard photoluminescent safety grade markings are typically photometer-measurable for 8 to 10 hours in the dark.
PERMALIGHT® power 150/22 photoluminescent markings are typically photometer-measurable for 35 hours in the dark.
PERMALIGHT® power 450/60 and higher performing photoluminescent markings are photometer-measurable for several days.
See more information on luminance
How quickly do the products charge?
A few minutes of bright lighting may be enough for an initial quick activation but for a full saturation at the place of installation, the charging of the glow-in-the-dark products ends after about one hour.
Cool light sources, such as fluorescent, daylight/ sunlight, LED, Mercury Vapor, Metal Halide are ideal activating light sources.
How much light do the products need to glow?
Illuminance is the ambient light that shines onto a photoluminescent marking. Per IBC/IFC codes, photoluminescent floor proximity egress path markings need to get activated by a minimum of 1 foot candle which equals 10.8 lux illuminance.
The more activating light you offer, the brighter the photoluminescent marking will glow in darkness. We typically recommend at least 2 foot candles (21.6 lux) for activation.
The best way to test your ambient lighting at the installation location is to use an illuminance meter. Many building engineers already have such a light meter to measure the lighting levels in their corridors and office environments.
See more information on light meter
Can photoluminescent products be used outdoors?
Many PERMALIGHT® markings have successfully passed stringent UV-resistance tests. Yet one important aspect has to be kept in mind regarding outdoor use:
Photoluminescence becomes visible when the ambient lighting is less than the luminance emitted by the photoluminescent product.
Street lighting, car headlights, retail window spotlights may be brighter in the middle of the night than the luminance emitted. If you envision a photoluminescent outdoor application, it has to be in a pitch dark environment and you should only use our high-performance or super high-performance products. Over the years, our products have been successfully incorporated into hunting/ hiking products and used for glowing graphics on custom signage in fully dark areas, to mention a few examples. Yet the most ideal application of photoluminescence is to guide occupants out of a darkened enclosed environment, like a building, railcar or ocean liner.
How long do floor installed products last?
It is important that you
- select a PERMALIGHT® marking that it designed for your particular floor needs. American PERMALIGHT®, Inc. offers a wide range of floor markings from plastic to metal products. Our easy peel-and-stick anti-skid dots and anti-slip tapes are ideal in light-wear environments. Our PERMALIGHT® epoxy paint was used on the steps in the World Trade Center New York City emergency staircases and helped save lives 7 years after installation. This durable photoluminescent 2-component epoxy paint can even resist forklift traffic. Enamel rounds, aluminum discs and epoxy casting resin are designed for tougher floor environments. Contact us for a consultation.
- install the products on clean, dust-free, dry surfaces for years of durable performance. American PERMALIGHT®, Inc. has very detailed installation instructions and offers Installer Training for large projects.
If you follow these recommendations, you will get years of service out of PERMALIGHT® photoluminescent safety markings.
Is photoluminescence radioactive?
No. The photoluminescent effect is accomplished by incorporating non-radioactive, non-toxic pigment powder into the various base materials that we use.
Other terms for photoluminescence are glow-in-the-dark, phosphorescent and self-illuminating.
A similar sounding term is self-luminous but that is a completely different technology to photoluminescence.
Self-luminous EXIT signs are radio-luminescent signs filled with radioactive Tritium-gas. Those self-luminous signs get sold with a Life Expectancy of 10 or 15 or 20 years. Each self-luminous sign has the expiration date visible during installation. Once the expiration date is reached, the self-luminous sign has to get shipped back to the manufacturer for radioactive ingredients recycling (recycling fee incurred).
Permalight products are NOT radioactive, they can be disposed in domestic waste.
Self-illuminating EXIT signs are photoluminescent, non-radioactive, non-toxic signs with no expiration date showing on the face of the sign. No special recycling necessary. This is what American PERMALIGHT®, Inc. supplies!
What is the life expectancy of photoluminescence?
If properly used indoors in compliance with the installation instructions, the typical life expectancy is easily 25 years. Per UL924 standard for Emergency Lighting, photoluminescent exit signs do not have to carry an expiration date.
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