The importance of signs and colors

In industry and in areas with risk of explosion Cortem Group, always careful about the evolution of new technologies, has designed the...

In industry and in areas with risk of explosion

Cortem Group, always careful about the evolution of new technologies, has designed the EVL-60B and EVL-70B series floodlights with focused optics (typical angle 40°) and different colors suitable for different lighting needs as shown in Table 1.

Table 1- Available colors with EVL-60B and EVL-70B series lighting equipment











Typical 120/240/277 VAC


Typical 120/240/277 VAC


These colors may be used in plants with explosion hazard in order to give to operators a further element to recognize hazardous situations and to alert the security personnel in charge for the evacuation or for making safe a plant’s part affected by the unusual event.

For example, these floodlights can be used to advise, through their lighting, a specific event and a no-go area.   

Nature, through colors, allows us to establish a communication relationship with the surrounding environment and, through our senses, the colors put us into contact with reality allowing us at the same time to convey messages that can express, depending on the circumstances, feelings, concepts and signals, sometimes up to create a real language.

The mental association code = color, promotes learning and memory and, for this reason, identifying colors are used in all commercial and industrial sectors, in order to recognize the components, both of process flux and electrical and electronic conditions, and for all matters concerning the safety of the operators responsible for the production and maintenance activities.

The coded use of color expresses defined characteristics (partly complying with the standards) and it’s assigned to it a specific meaning related to safety or to the identification of certain components and/or actions to be taken for keeping in operation the plant or for the occurrence of critical situations during an incorrect plant operation.

The aim of this dissertation is to highlight the several types of colors used in the engineering practice of a plant, with particular reference to the safety of electrical installations and machines.

Typical subdivision:

Table 2 - Color of control devices (buttons)

Table 3 – Color of the signal lights

Table 4 - Color of light towers

The legislative references are the Legislative Decree 493/96 and the Directive 2014/27/ EU of the European Parliament and of the Council dated February, 26th 2014 amending the Directive 92/58/EEC, concerning the minimum requirements for security signals and safety in the workplace. 

That decree lays down the obligations for the employer, such as:

  • Make use of safety signs for: prevent dangerous behavior, dangers warning, prescribe safe behavior, provide information about emergency exits and rescue systems and other information relating to safety.
  • Information and training for workers and safety representatives.
  • Apply the rules of good practice, for the cases not mentioned in that decree.

As reported in UNI 7543-1 standard and in the Legislative Decree 493/96, which calls for colors and safety signs to be used in order to prevent emergency situations in the workplace, the main definitions to be taken into account are the following:

The general meaning of color assigned to safety must be as specified in Table 5. 

Table 5 – Meaning of colors

  • Safety color - Color of defined characteristics, it’s assigned to a specific safety meaning.
  • Contrast color - Color of defined characteristics, having the purpose of stand out another one.
  • Staining (safety) - Safety color applied to a surface without any reference to geometric figures or graphic signs, in order to attract attention for safety purposes.
  • Safety signal - Signal that expresses a safety message, obtained with the combination of a geometric shape, colors and a graphic sign, symbol or pictogram, provides specific information. It can be equipped with an additional signal.
  • Prohibition sign - Signal in which is used a graphic sign, symbol or pictogram which forbid behavior likely to incur or cause danger.
  • Warning or danger - Signal in which is used a graphic sign, symbol or pictogram warning of a hazard or danger.
  • Signal of obligation or prescription - Signal in which is used a graphic sign, symbol or pictogram prescribing specific behavior.
  • Rescue or distress signal - Signal in which a graphic sign, symbol or pictogram is used to give information about emergency exits or the means of emergency or rescue.
  • Location signal of fire equipment - Signal in which a graphic sign, symbol or pictogram is used to give information about the location of fire equipment.
  • Information signal - Signal providing different information such as prohibition, warning, obligation and rescue.
  • Additional signal - Signal that is used only in combination with one of safety signs types listed above which provides supplementary information.
  • Outline (or contrast edge) – The area surronding the signal having the function of highlighting it against the background. The outline, if present, must not have size smaller than 1 mm and it must be of white color for all signals and white or yellow for warning or danger signals.
  • Graphic sign, symbol or pictogram - Image that is used in one of the safety signals to transmit information about safety, not using text.

At the same time should be considered the standard ISO 3864 "Colors and safety signals" and IEC 80416-1 standard “Basic principles for graphical symbols for use on equipment - Part 1: Creation of graphical symbols for registration”.

The workers, to not compromise the achievement of the stated purposes, must observe to certain rules such as to not modify or remove, without authorization, the safety warning or control devices (Art. 5 of Legislative Decree 626/96).In plant engineering system, there are no regulations that, in this moment, may apply the use of new LED lighting technologies which, by their nature, are able to provide different colors respect to the color of the traditional filament, fluorescent and discharge lamps. Therefore, LED lighting fixtures would give an important further technical/informative support for critical situations that usually can occur during the processes in industrial plants both in safe zones and in those at risk of explosion.We conclude this brief discussion, hoping that our contribution could be an incentive for designers, in order to adopt all measures that can further enhance the concept of "SECURITY" in the management and maintenance of plants in general and, particularly, in those at risk of explosion and/or fire.