• Johnsonite's Permalight low-location escape route system incorporates zinc sulfide crystals. Zinc sulfide is non-toxic, non-radioactive and is comprised of natural earth elements.
  

• Permalight, AG, Germany, advanced the technology of photoluminescence by increasing luminance to professional life-saving levels.

• Zinc sulfide is processed into crystals in a glass-like shell which are then encased in flexible or rigid sheets, compounds, etc.

• A light source such as ultraviolet (sunlight), fluorescent or incandescent light charges (excites) these crystals, which in turn store this light energy.

• These crystals emit light in darkness ... enough bright light to meet and exceed German DIN standards from about 4 hours to 10 hours.

• Red light and sodium vapor lights will not activate crystals.

• Zinc sulfide crystals may be charged indefinitely.

The chart below is a graphic representation of the effectiveness and longevity of the Johnsonite Permalight photoluminescent Safe-T-First products. The left (vertical) side of the chart indicates the level of luminance given off in total darkness as expressed in mini candles per meter squared. The bottom (horizontal) numbers are expressed in minutes of time that the products luminate. Example shown below (for Rubber Stair Tread) luminates for 465 minutes, or 7 hours and 45 minutes, to a threshold value of 100 times the human eye's ability to see light when totally adapted to darkness.

Luminance Decay Chart

All Johnsonite Permalight Safe-T-First products have individual Luminance Decay Charts specifically developed to describe luminance/time periods.

• Luminance is the measurement of the impression of brightness of an illuminated area or a light source to which the human eye responds.

• The luminance of photoluminescent products can be measured for initial brightness and longevity.

• Lumination measurements are made to specific detailed instructions as defined by DIN standards.

• All Johnsonite Safe-T-First products featuring Permalight technology meet and exceed DIN standards. Johnsonite products emit light up to 10 hours (which exceeds DIN standard of 340 min).

• As a safety factor, all measurements of the longevity of the light are made down to 100 times the perception of light by the human eye once fully adapted to darkness.

*DIN 67510 minimum threshold value, which is at 100 times the human eye's ability to see light when totally adapted to darkness.

NOTE: There are a number of "novelty" photoluminescent products with very short luminescent values. It is important that the products selected for life-safety applications have extended luminance for long periods of time. Johnsonite Permalight Safe-T-First System Photoluminescent products are supported by individual Luminance Decay Charts generated by DIN 67510 test standards and requirements.