PHOTOLUMINESCENT 

Appreciation of  Photoluminescent materials

To begin to really appreciate Photoluminescent materials, one first has to recognize that photoluminescent materials operate on a different principle to the general lighting with which we live every day.

The comparison might be made with the way radiated heat and conducted heat differ in their principles of operation, but produce a similar result.

The electrical emergency system supplies light, usually at low intensity for overall visibility. It is not a guidance system.

The Photoluminescent system makes visible essential objects like;

• Floors

• Walls

• Stairs

• Signs

• Equipment etc, to create an escape route and guidance system

Photoluminescent materials differ from reflective materials which glows only when light is applied (road signs, car number plates) or fluorescent materials which amplify light and increase brightness (road construction safety mesh, certain inks and paints).

A general understanding of the scope of a fully Photoluminescent system can be explained as follows:  

1. When lights fail, a person in an internal room can easily identify the exit door with sign, and door handle area. 

2. The passage wall has a Photoluminescent band or photoluminescent markers.

3. In the main passage, a band and arrows show the direction of an exit. A fire extinguisher is identified with a sign and panel. The exit door is surrounded by a Photoluminescent band (non-exit door unmarked).

4. In the stairwell, bands and stair clips illuminate stairs,  floor and wall marking arrows and signage give direction, Handrails are detailed.

5. At ground level, an exit marked with an arrow, surround and sign.

6. A Photoluminescent exit route plan shows the nearest exit and alternative route.

7. In the basement car park floor direction stripes are used – columns are marked with signage for orientation.  

8. An often-used ladder to machinery area is Photoluminescent; a stripe leads to the main route, the hazardous area is marked off.

9. In the control room, light panels over controls enable a technician to shut down the plant. (Floor hazards are marked.)

A totally safe evacuation system can only be achieved:  

• if the illumination, signs and symbols are not dependent upon any mechanical device.

• if the system does not rely on the assistance of safety wardens who may not be present when the need occurs - nor are dependent upon the correct or trained responses of the building's occupants.

• if the system is functional under any conditions, including heavy smoke.  

Recent research suggests that certain types of modern building such as Hospitals, Nursing Homes and Office complexes pose inherent way-finding difficulties under normal circumstances, particularly if people are not familiar with a building.

Moreover, if there is a fire people unfamiliar with an emergency escape route may well be disinclined to use that route, favouring the more familiar entrance by which they entered the building.

In these circumstances, the provision of effective way-finding signage can be crucial to minimize the likelihood of the wrong exit route being chosen.

The objective of a Photoluminescent system is to provide for every occupant in every part of a building  an easily followed 'light-way' that will guide them safely, in total darkness and smoke, to an approved exit.

We would suggest that this would help to achieve controlled and effective 'flight behaviour'.

A secondary objective is to make it possible to locate and operate essential equipment such as fire extinguishers, alarms, telephones, valves and switches, and to complete essential tasks.  

The major benefits of Photoluminescent systems are:

• They make possible the safe, orderly and speedy evacuation of buildings in blackout conditions.

• In situations when no evacuation is necessary, they provide orientation and confidence and thereby reduce the possibility of panic behaviour.

• Provided they have been exposed to normal lighting levels prior to blackout, they are incapable of failure.

• They function even in heavy smoke that would obscure electrically operated systems (unless these are installed near floor level).

• They are simple and economical to install in any building, and especially suitable for existing buildings.

• They require no wiring, no maintenance, and are unaffected by heat and cold, explosion and to a great degree, vandalism.

Although a Photoluminescent system is dependent upon natural or artificial light to provide it with energy, it is a logical conclusion that if no lighting is available, then the building is most likely unoccupied and the system will not be required at that time.

One overwhelming difference in a Photoluminescent system compared to electric emergency lighting is the psychological 'feeling of safety and security' that a Photoluminescent system creates, which is far more important than the measurable light that it produces.

For some reason, the ability to see important objects clearly, and for instance to walk along a Photoluminescent stripe, inspires more confidence than does dim general lighting.

The eye is drawn to the Photoluminescent parts which contrast strongly with the dark surroundings, and guidance is found without frantic searching.

Occupants can respond instantly to the directions. This is confirmed in recent research by Webber and Hallman (1987), Webber, Hallman, Salvidge (1988) at the Building Research Establishment, UK.

Using an experimental stairway and corridor, Webber and his colleagues found that the Photoluminescent markings alone performed at least as well, in terms of speed of movement, along the 'escape route', as the recommended British Standard Emergency luminance of 0.2 lux (BSI 1975).

Webber recommend future studies to evaluate the placement and excitation of photoluminescent materials on escape routes and the potential incorporation of the results of these studies as recommendations in British Standards.