INTRODUCTION The correct lighting of work places is a growing concern in order to guarantee the safety of people who works on plants. In...
The correct lighting of work places is a growing concern in order to guarantee the safety of people who works on plants. In particular, in electrical plants installed in hazardous area, lighting features are considered as a means to reduce risks of explosion. About 80% of our sensorial perception is visual and needs light as a vehicle of information, to interpret information from visible light reaching the eyes. A good illumination helps to see and recognize things, but also improves working performances and physical wellness, since it increases concentration and reduces tiredness. Equipment installed in classified zones, hence, have to guarantee the ex-proof protection and a good light stream in order to guarantee work operations in safety conditions.
A lighting fixture is a unit consisting of: a light source or lamp, a power supply, devices for igniting and supplying power, optical elements directing the luminous flux and all the mechanical parts necessary for containment, wiring and installation. Three are the main functions of a lighting fixture:
The basic functions to consider in lighting design are:
When projecting a lighting system, it is not only important to consider the visual comfort; it is also very important to consider that lighting devices loose efficiency with passing of time (lamp flux decreases and dust deposits on reflectors and diffusers). The data of aged lighting fixtures shall therefore be considered, during the project stage, in order to foresee the flux deterioration in percentage after installation.
Equipment for hazardous areas must be designed, assembled and certified according with ATEX 94/9/CE standard.
Following are described the main protection methods applicable to lighting fixtures:
We can therefore conclude that there is no universal or perfect protection method. The important thing to remember is that all the methods are effective provided that they are applied correctly following their construction criteria, and that the equipment is kept in its original condition of safety by careful maintenance.