1. Introduction It’s appropriate to clarify some beliefs about LED lighting fixtures and, more specifically, about their use in the...
It’s appropriate to clarify some beliefs about LED lighting fixtures and, more specifically, about their use in the segment of environments with a risk of explosion and fire: as men progressed in a continuous research of new technologies through by the technique of breaking stones for tools and the creation of energy by exploiting the natural flow of the rivers, in the same way Cortem is pursuing this philosophy approaching new technologies and adapting them to specific projects of research and development without being fossilized in the past.
First, we analyzed carefully what the LED market was offering us by comparing the production quality of each manufacturer. The analysis has led to choose products that could give us the appropriate functional guarantees about the very low "infant mortality" of LED and, therefore, we continued with the engineering of new lighting fixtures designed depending on application parameters guaranteed by the producers themselves. These parameters must be appropriate to the right temperature dissipation for an adequate and sustainable use in terms of the warranty for the customer.In fact, as you can see from the following photos, the new series of LED lighting fixtures and floodlights designed by Cortem have nothing in common with lighting fixtures and floodlights for discharge lamps. The old "enclosures" are not suitable to be used as a support for LED and do not lend themselves to dissipate the temperature generated, compromising the proper functioning and durability. Unfortunately, the "adaptation" and the transformation of old Ex lighting fixtures to new LED lighting fixtures are very widespread practices in the market. This leads to poor performance and limited benefits in terms of energy and cost savings for the end user.
The use of appropriate LED lighting fixtures allows to obtain numerous advantages. Consider that a discharge lamp of 400W can be replaced with LEDs with a power of 160 W, with an energy saving of about 60%. Furthermore, current Cortem LED lighting fixtures, in addition to being not much more expensive to lighting fixtures for discharge lamps, are plenty amortized over time due to the lower costs of maintenance. The frequency of maintenance, in fact, decreased by 1.7 compared to the activity required for the re-establishment of a discharge lamps lighting fixtures. It’s well known that a discharge lamp has an average life ranging from 3.000 to 10.000 hours and then stops working, while LEDs have an average life of 50.000-70.000 hours and continues to work, only losing luminous efficiency. The use of LEDs in the new range of Cortem products allowed us also to get floodlights with T5 class temperature, much lower than the class temperature of the floodlights with discharge lamps (T2 / T3). They can therefore be installed in hazardous areas where, until now, it was unthinkable to install a floodlight.
One of the main problems encountered, in order to ensure the safety in the workplace, is to ensure an adequate level of illumination of the plants. In particular, the characteristics of electrical equipment installed in areas with danger of explosion are designed with even greater attention to get good illumination and reduction of risk conditions. About 80% of all our sensory impressions are of optical nature and they need of light as a vehicle of information. Good lighting, therefore, not only facilitates the vision and the recognition, but it greatly reduces the danger of accidents.The devices that are installed in hazardous areas must therefore ensure, in addition to explosion protection, the proper lighting required for the execution of all work operations in conditions of maximum security and must have other characteristics, such as the reduced need for maintenance in order to minimize risks associated with the equipment operation.
The LED is a light-emitting diode, otherwise, an optoelectronic device that uses the optical properties of some semiconductor materials to produce photons through the phenomenon of spontaneous emission. The first LED was developed in 1962 and, from that moment on, the technology has made great strides. Today we have components that can be effectively used for industrial lighting.The main advantages of using LEDs in lighting fixtures can be summarized as follows:
In the specific case of the use of such components in the construction of lighting equipment used in classified areas, the main advantage lies surely in the long duration that, in addition to being convenient in economic terms, means a smaller number of maintenance interventions (lamping) on lighting equipment. This is very positive in terms of safety, because, as you know, every intervention on equipment installed in areas with risk of explosion increases the risk level of the system.
Another advantage of LED is that, unlike other sources of artificial lighting, once reached its limit of life, not shut down abruptly, but continues to operate with a luminous flux reduction. This is synonymous of safety, especially in those places of the plant where the lighting is fundamental to prevent accidents or injuries.
2.1 The light spectrum
The light spectrum of white LEDs of the latest generation, such as those used for the realization of our LED range, is about as close to sun light spectrum. In the diagrams below, you can appreciate the differences between the spectrum of sunlight and of other light sources, such as fluorescent lamps, discharge lamps and white LEDs.
For our LED products, we use only Cree LEDs with maximum efficiency, in order to obtain the best light quality and the maximum lumen output. All lighting fixtures have a CRI (Color rendering index) > 70 and a standard light color cool white 5700° K. For special needs, can be requested a different color temperature.
After analyzing the characteristics associated with the use of LED technology, let’s see the features of LED lighting fixtures that allow their use in classified areas for the presence of an explosive atmosphere. For use in areas with danger of explosion is obviously necessary that the lighting equipment are designed, built and certified according to technical regulations implemented by the ATEX Directive 94/9/ EC and by the new ATEX Directive 2014/34/EU entered in force on March, 30th 2014. It will repeal, with effect from April 20th 2016, the ATEX Directive 94/9/EC. The protection methods that can be used are the following:
Cortem has designed and manufactured a full range of lighting equipment and floodlights that use the latest LED technology generation. The LED technology in the coming years, will certainly replace other sources of artificial lighting designed to obsolescence because of operating costs, environmental problems and ease of use.
4.1 EWL series lighting fixtures and floodlights - High Bay
EWL series consists of three models of High-bay lighting fixtures, EWL 70, EWL-80, EWL-100, and three models of floodlights, EWL-70/ .., EWL-80/..., EWL-100/... with different optics: Narrow (10°), Medium (20°) and Wide (40°).
Through the use of optics with different angles, you can get the optimal light beam in well-defined areas. This allows maximum versatility of use, ensuring the proper illumination of the workplace.
A new feature for these lighting fixtures is the possibility to be powered at 24 VDC. For the first time in the lighting history of areas with danger of explosion, it’s available a lighting system with a lighting efficiency comparable to that obtainable with discharge lamps, powered directly with alternative systems such as wind turbines, solar panels, battery systems.
As we said in the introduction, the LED lighting fixtures must be designed and constructed specifically. The construction of bodies in aluminum alloy, designed with elements of heat dissipation, is the key to obtain an efficient and long lasting system. The housing of the feeder must be correctly calculated in terms of volume to allow easier heat dissipation.In the picture below you can appreciate the thermo-graphic survey.
The finned body, made of aluminum alloy, acts as a heat sink for the LED plate mounted directly inside, on the body of the lighting fixture allowing it to dissipate more quickly and effectively the heating generated by the operation of the LEDs themselves.The design of the lamp body, in addition to being functional to the duration of the system, has allowed obtaining equipment with high luminous efficiency in relation to the maximum surface temperature. This is a very important factor for the installation of lighting fixtures in places of danger, containing gas or powders at low ignition temperature.
A further saving is obtained thanks to the fact that, while discharge lamps requires a preheating time for their complete ignition and, for this reason, the lights of a plant are lighted up 24 hours, LEDs have an Instant Restrike. A LED system can be effectively connected to automatic ignition system in case of low light, allowing the use only for periods actually needed and, consequently, with a further saving of energy costs. LED technology allows also adjusting the light output according to the real needs of the room to be lighted (dimming).
EWL series features with 'Ex de' method of protection for Gas and 'Ex t' for Dusts. This choice allows powering the equipment through a 'Ex e' cable gland and without the need to perform sealings on field.
A tapped hole opposite to the entrance of the cable, allows the connection through wiring.
It’s now available a new version of the EWL-80 series, the EWL-801, both in lighting fixture and floodlight version.The EWL-801 makes it possible to obtain, with the same size but with a power consumption of 110W, a lumen output almost twice respect to EWL-80, 10100 lm compared to 6050 lm, and a maximum light intensity much higher: 4330 cd for the lighting fixture version and 118670 cd (EWL-801/10), 51680 (EWL-801/20) and 20900 (EWL-801/40) for the version with optical concentrating of the light beam.
The series EWL has been certified and complies with the requirements of the following standards:• EN/IEC 60079-0 Electrical apparatus for explosive atmospheres due to the presence of gas - Part 0: General requirements;• EN/IEC 60079-1 Explosive atmospheres - Part 1: Equipment protected by flameproof enclosures "d";• EN/IEC 60079-7 Explosive atmospheres - Part 7: Equipment protection by increased safety "e";• EN/IEC 60079-31 Explosive atmospheres - Part 31: Equipment with protection by enclosure "t" for use in presence of combustible dust.
It was also subjected to the tests required for the photo-biological risk assessment regulated by IEC/EN 62471 standards.These tests measure the amount of emissions of UV, blue light and infrared radiation (IR), which may cause damage to the skin and eyes (retina and cornea) operators.The lighting fixtures and floodlights EWL series are EXEMPT from the photo-biological risk.4.2 EVL series lighting fixtures
The new LED compact lighting fixtures EVL series features Multichip LED formed from a matrix of LEDs connected together and covered with a layer of diffused phosphorus. This technology allows obtaining high values of lumen output and the installation at low heights, without the risk of disturbing the operator. The EVL series consists of three lighting fixtures sizes: EVL-60, EVL-70 and EVL-80.
It represents the LED alternative for all those areas in which it was usual to use lighting fixtures with discharge lamps of low and medium power up to 400W. It’s equipped with fins that act as a heat sink and the electrical connection is easier thanks to a ‘Ex e' terminal box, which allows the entry with a ‘Ex e’ cable gland (no barrier). In addition, a tapped opposed hole allows the loop in/loop out facility.
In the following table, we can compare the power of EVL series lighting fixtures and of traditional lamps. You will immediately appreciate the savings you can get.
4.3 EVE-L series lighting fixtures with LED remote phosphor technology - Low Bay
EVE-L series Cortem lighting fixtures are designed to provide an optimal replacement to the conventional incandescent lamps from 50W up to 200W. It’s available in two sizes: EVE-5050 end EVE-5060. The peculiarity of these new lighting fixtures consists in the use of the LED Remote Phosphor Technology on explosion-proof lighting fixtures. This represent an absolute evolution in the world of LEDs and an important step forward in terms of energy efficiency, lighting efficiency and chromatic yield quality. The LED Remote Phosphor Technology is based on a yellow semi-spherical light diffuser that, when the lighting fixture is on, absorbs the light produced by the internal LEDs and releases white light. The EVE series allows to replace the lighting fixtures which use incandescent and energy-saving lamps with a long lasting light source that ensures a better efficiency and an equal brightness comfort.
4.4 FLF-...L and FLFE-…L series lighting fixtures
Lighting fixtures for LED tubes FLF-...L (Ex d) and FLFE-...L (Ex de) series have two low copper content aluminium heads with G13 lamp holder, a tempered borosilicate glass tube, that is resistant to changes in heat, and a white painted aluminium reflector. Both the series are available with one tube or with two tubes. FLFE-...L series, in ‘Ex de’ way of protection, features an “Ex e” terminal board housing that allows entry to the fixtures with a cable gland with an “Ex” seal (normal), while FLF-...L series, in ‘Ex d’ way of protection, as specified in the appropriate installation standard (EN/IEC 60079-14), the entry to the fixture must be through an Ex “barrier” cable gland (sealed) or, in the case of a conduit system, with an EYS, EZS series sealing fittings. The use of LED tubes, which have the same dimensions of fluorescent ones, allows to obtain economy in operating costs, due to their long life, high-efficiency lighting, thanks to directional light, and LED light quality with a color rendering index of 85 (CRI).Furthermore, LEDs do not ionize the particles of air around the lamp and do not attract, then, the dust particles suspended in the air. The round cross section of the lighting fixtures provides a better “Cx” coefficient with less resistance to the wind and less accumulation of dust. FLFE series has been designed to facilitate and speed up maintenance operations. As the electrical components are housed on a frame with guides, re-lamping is quick and efficient. Furthermore, the different types of mounting attacks and the absence of sealing fittings make the lighting fixtures particularly well performing.
4.5 EXEL-L series lighting fixtures (Work in progress)
EXEL-L series increased safety lighting fixtures for LEDs tubes are suitable to be installed in hazardous areas 1, 2, 21 and 22 where a high degree of protection and resistance against corrosion is required such as in chemical and petrochemical plants, off-shore and on-shore plants, processing areas in food industries etc… EXEL-L series is polyester made, with ‘Ex e-mb’ method of protection for LED tubes with remote phosphor diffusers to reduce glare. The through wiring double ended makes installation on field easier and faster than normal lighting fixtures. The transparent cover is clipped into place on both sides of the fixture body with 8 clips on the 785 mm model and 14 clips on the 1370 mm unit. This ensures excellent protection against dust and water over time despite of degradation caused by ageing.
4.6 EVML-50 series lighting fixtures - Low Bay (Work in progress, end 2014)EVML-50 lighting fixtures, in the design development phase, have been conceived to offer a Low Bay lighting fixture that could replace incandescent equivalents at lower costs. They are suitable for the illumination of small areas in which it’s necessary to limit the obstruction such as tunnels, passages, corridors, stairways, perimeter walls and command and control cabins. The EVML-50 series features the 'Ex e mb' method of protection: the electronic board and the LEDs are protected with silicone of high transparency.
4.7 EVOLED series lighting fixtures (Work in progress)
The new EVOLED series lighting fixtures are designed for the internal lighting of boilers, tanks, evaporators, silos, storage tanks, pipelines or other containers present in all those areas where hazardous vapors, gases, dust or other fuels are present during the normal operation of a plant. In addition to ensuring low power consumption and light efficiency, the lighting fixture is provided with an external switch for an easy switching on and off after installation.
4.8 SLED series floodlights (Work in progress)SLED series rectangular floodlights, in the design development phase, are equipped with "Wide area" optics for the symmetric and asymmetric illumination of industrial areas, in general, and of hazardous areas. Designed with ‘Ex m’ method of protection (encapsulation), SLED series floodlights are characterized by size, weight and power consumption much lower than the floodlights fitted with conventional discharge lamps.
Safety is essential for workplaces and, especially in areas with potentially explosive atmospheres, the risks are very high. Any system, therefore, that allows to reduce the level of risk is always well accepted. Furthermore, if there are savings in money and energy, then the advantage is total.The LED lighting in industrial sector is a path just started, but it's definitely the way to be followed to ensure a future of light and safety.We summarize here, in conclusion, the main advantages that presents the range of Cortem’s LED products with which we set ourselves several steps ahead in terms of technology against competitors: