Safety signs have a wide range of applications: they serve to warn people about immediate or possible danger, prohibit, order or permit certain actions, as well as to inform about the location of objects and means, the use of which eliminates or reduces the impact of dangerous and/or harmful factors.
Safety signs can be made of various materials; the main condition for their use is that they must be clearly visible. Therefore, signs made from non-luminous materials should be used in conditions of sufficient lighting.
Need for Photoluminescent signs
In the event of an accident or other emergency, the clarity of the information displayed on signs becomes especially important. At the same time, in situations where the evacuation of visitors from buildings takes place during a possible shutdown of lighting and the onset of darkness, the need to create conditions under which stable legibility of signs would be provided becomes urgent.
In order to ensure the safe and quick exit of people from emergency areas, glow-in-the-dark signs are used that are part of photoluminescent evacuation systems, the requirements for which are regulated by the the ASTM E2072 Standard “Photoluminescent evacuation systems”as required by NFPA 170,.
Before deciding whether there is a need to install fire, evacuation and other signs and plates made of photoluminescent materials, it would be wise to take a closer look at how they work.
What is special about photoluminescent signs?
Once installed, the sign, made of photoluminescent material, absorbs natural or artificial light. Then, if the main lights are turned off and the emergency lights are not activated in the event of a fire or other emergency, the sign will be illuminated and the message on it will be clearly visible. Whereas when the influence of the light source on them ceases, ordinary, non-luminous signs will not be visible.
The main properties of photoluminescent exit signs that allow them to be used in the security field are light accumulation and afterglow.
Assuming that the sign is made of photoluminescent materials, such as photoluminescent film or photoluminescent plastic that meets the requirements of NFPA 170, it will glow for the time required to evacuate visitors from the burning building (provided that it has accumulated sufficient amount of light before an emergency), providing reliable visibility during partial or complete shutdown of lighting.
Thus, the main criterion for choosing a photoluminescent material for a sign is the feasibility of using its glow-in-the-dark property. It is unlikely that anyone, when the lights are turned off in an emergency, will think about looking for a place to smoke; accordingly, the sign indicating such a place does not have to be made luminous.
Whereas fire and evacuation signs made of photoluminescent materials help panicking people navigate at a dangerous moment and quickly find a safe exit from the building.
The durability of safety signs as part of the designed evacuation system depends, among other things, on the quality of the photoluminescent materials used .
Advantages of photoluminescent signs:
- Safety: photoluminescent materials do not contain phosphorus or radioactive additives and do not support combustion;
- Easy installation: placing signs does not require special skills;
- Easy maintenance during operation: mounted signs do not require regular maintenance, except for cleaning if necessary;
- Durability: photoluminescent signs can function for quite a long time without loss of quality; their service life indoors is up to 25 years.
Due to their properties and availability, glow-in-the-dark safety signs are used everywhere: schools, hospitals, libraries, theaters, shopping and entertainment centers, restaurants, office centers, museums and other public places with high traffic.
In the late 1990s, fire safety companies recognized that creating signs using glow-in-the-dark material could provide a real benefit to building visitors. This is a practice that continues to this day, with photoluminescent signs accounting for the majority of total safety sign sales in Russia.
Now that the reason for using photoluminescent signs is clear, we can consider which signs to choose.
How to choose the right photoluminescent signs?
First of all, you should choose the type of sign, the colorographic image of which correlates with a certain semantic meaning. In this case, you need to start from the need to convey warning information about danger, the prohibition of certain actions in conditions of lighting outage and designation of the locations of important objects along the entire length of evacuation routes: exits, directions of movement along the stairs, fire department call points, fire protection equipment.
Depending on the specific semantic meaning and scope of application, safety signs are divided into several groups.
The following groups of basic signs are used as part of photoluminescent evacuation systems:
The use of photoluminescent signs is not limited to the use of graphic symbols of basic safety signs.
Combined and group photoluminescent signs can be a combination of different signs and explanatory inscriptions.
Signs with important information during evacuation and in an emergency situation can also be photoluminescent, for example, designating doors that do not lead to an exit with a “no exit” sign, or with other information, for example, supplemented with text in a foreign language, as in the illustration below.
Since the elements of a photoluminescent evacuation system must be located in such a way that they are clearly visible, floor elements are often used in its composition. During a fire, smoke rises upward; therefore, signs located on the upper level will be difficult to distinguish in such a situation. Floor signs are easier to visualize, which is critical during an evacuation.
Floor photoluminescent signs are most often made of luminescent film with an anti-slip coating.
A special type of signs made from photoluminescent materials are ship signs, which are better known as IMO symbols. The requirements for IMO symbols are more stringent than for safety signs: they must be made only of photoluminescent materials (IMO Resolutions A.954(23) and A.999(25)).
IMO symbols serve to place information: instructions for the actions of crew members and passengers of the ship, indication of the direction of movement during evacuation to the location of life-saving equipment and the prohibition of dangerous actions.
Image and Size of Signs
Photoluminescent materials – film and plastic – are suitable for using signs made from them outdoors. Our practice included the production of photoluminescent signs on plastic for placement on gas pipelines. In this case, when choosing a material, the decisive factor was the need to distinguish the image of the sign when darkness fell.
In addition to choosing a suitable image of the sign, you need to decide on its size.
The sizes of photoluminescent signs according to the requirements of the standard “Signal colors, safety signs and signal markings” are determined depending on the expected distance to the observer, taking into account the coefficient: the sizes of luminous signs must be at least 125% of the average size of normally illuminated safety signs. To make it easier to determine the size of a photoluminescent sign, based on the table of average sizes of non-luminous signs, you can choose the next standard size after that recommended for signs up to 300 mm, and after 300 mm – one standard size after the other.
Photoluminescent signs, with their illuminating properties, transcend mere safety tools. They stand as reliable guardians in emergencies, offering visibility, durability, and ease of use. From IMO symbols on ships to floor signs aiding evacuation, the versatility of photoluminescent signs continues to shine, making them an indispensable aspect of safety systems.