Lighting basics
Lighting Terminology. Information. Tips
Luminous Flux
- the quantity of light emitted by a light source
- measured in lumens (lm)
The luminous flux (Φ) describes the quantity of light emitted by a light source per second. The luminous efficacy is the ratio of the luminous flux to the electrical power consumed (lm/W). It is a measure of economic efficacy of a light source.
Luminous Intensity
- the quantity of light radiated in a particular direction
- measured in candelas (cd)
The luminous intensity (I) describes the quantity of light emitted in a particular direction per unit solid angle. This is a useful measurement for directive lighting elements such as reflectors. It is represented by the luminous intensity distribution curve.
Illuminance
- the quantity of luminous flux falling on a surface
- measured in lux (lx)
Illuminance (L) describes the amount of luminous flux falling on a surface. Relevant standards specify the required illuminance according to location and activity (e.g.: EN 12464-1 “Lighting of indoor workplaces”, EN 12464-2 “Lighting of outdoor workplaces”, EN 12193 “Sports facility lighting”).
Luminance
- specifies the brightness of a surface
- measured in candelas per square meter (cd/m2)
The intensity and brilliance of light emitted from an item in a given direction. Luminance is often used to characterize emission or reflection from flat, diffuse surfaces. The luminance indicates how much luminous power will be detected by an eye looking at the surface from a particular angle of view. Luminance is thus an indicator of how bright the surface will appear.
Power Consumption
Power (electrical power), indicates the energy quantity that the electrical devices consume unit of time. The unit of power is Watt (W).
Lighting equipment consumes some energy as all electrical devices. The Watt indicates the amount of energy a light source uses to produce light.
A lighting equipment can provide both low power consumption and high light. In other words, two light sources with same lumen value can have a different power consumption than another one. The important issue here is Lumen/Watt efficiency. The important thing is how many lumens light is produced for spent 1 W energy.
In past, Watt was used to indicate the light power of a lamp. However, today the light efficiency increasing constantly. Therefore, Lumen value becomes important in selection of lighting devices. When choosing lighting devices customers should focus on Lumen value instead of Watt.
Luminous Efficacy
Luminous efficacy indicates, how efficiently a lighting equipment converts electrical power into the light. The ratio of light flux to power is expressed in lumen and symbolized as lm/W.
Luminous efficacy establishes the direct relationship between the luminous flux generated by a light source and the electrical power consumed. The figure gained by dividing the total luminous flux by the power consumed. Used to express the luminous flux (amount of light) gained per Watt, the higher the figure the more efficient is the luminaire. Luminous efficacy relates the luminous flux produced by a light source and the actual luminous flux emitted, i.e. how much light a light source is capable of producing and how much light it actually emits.
As an example, a light source emitting 500 lumens with 10W of power. In that case the luminous efficacy would be 50 lumens per Watt. Another light source of 10W and it has the capacity to emit 1000 lumens, in this case its efficacy will be 100 lumens per Watt and therefore much more effective than the first one, since we’ll have more luminosity with the same power consumption.
If we compare the current technologies; the performance of incandescent lamps are (approximately) 15 lm/W, halogen lamps are 20 lm/W, fluorescent lamps are 80 lm/W, high-pressure sodium vapor lamps are 100 lm/W, LEDs are 130-180 lm/W.
LED technology has established itself as one of the most efficient systems, far ahead of incandescent, fluorescent and energy-saving lamps.
Since its commercialization at the end of 20th century, the evolution of its performance has grown exponentially from 5 lm/W to well over 180 lm/W (or even more) today. LEDs luminous efficiency are 30% – 50%.
Accessories which form lighting fixture such as lens, reflector, housing, glass may cause a little amount of light loss. Therefore, when we specify the technical specifications of lighting fixture, total light output of lighting fixture and the power drawn by electrical network should be measured. Luminous efficacy should be calculated according to these values.
Luminous efficacy is an easier value to find in a technical data sheet or documentation of a luminaire and therefore, it will be more useful as a reference to compare two or more light sources.
Luminous Efficiency
Luminous efficiency is the relationship between luminous flux and power consumption. Its value is expressed as a percentage and the following factors are taken into account to establish an evaluation:
Internal temperature of the system
The lower the operating temperature of the light source, the better the efficiency of the luminaire. This aspect is very important and is determined by the quality and shape of the heat sink as well as the location and ventilation capacity of the heat sink.
Optical components
The reflectors and optics of a luminaire absorb and redirect the direction of the emitted lumens. They can therefore reduce the amount of light output from the luminaire.
Diffusers
Depending on the material and type of finish, diffusers can significantly vary the percentage of luminous flux affecting the overall efficiency of the system.
CRI
The higher the colour rendering index of a luminaire, the lower its luminous efficiency.
Colour temperature
Warm colour temperatures reduce luminous efficacy to a greater extent than cooler ones. This is because the former need more compounds to achieve the desired degrees Kelvin.
Why two luminaires of the same power have different light output? Choosing a light source we usually focus our attention on lighting parameters such as power, luminous flux or colour temperature. As explained above, there are other factors, although less well known, are important for lighting approach, such as luminous efficacy.
Recommended Levels of Illuminance
The recommended level of lighting depends on the purpose of the room or area. It is measured in lux (lx).
These standards can be found in the official Lithuanian standard (e.g. LST EN 12464-1) or Lithuanian hygiene regulations. If the luminaires will be installed in another country, check the applicable requirements in that country.
| OPTIONS | Typical recommended level of maintained illuminance, lx | UGR | Uo | Ra |
| OFFICES | ||||
| Writing, typing, reading, data processing | 500 | 19 | 0,6 | 80 |
| Computer work stations | 500 | 19 | 0,6 | 80 |
| Technical drawing | 750 | 16 | 0,7 | 80 |
| Conference and meeting rooms | 500 | 19 | 0,6 | 80 |
| Reception desks | 300 | 22 | 0,6 | 80 |
| Filing, copying, etc. | 300 | 19 | 0,4 | 80 |
| Archives | 200 | 25 | 0,4 | 80 |
| CIRCULATION AREAS WITHIN BUILDINGS | ||||
| Circulation areas and corridors | 100 | 28 | 0,4 | 40 |
| Stairs, escalators, moving walkways | 100 | 25 | 0,4 | 40 |
| Elevators, lifts | 100 | 25 | 0,4 | 40 |
| Loading ramps/bays | 150 | 25 | 0,4 | 40 |
| REST, SANITATION AND FIRST AID ROOMS | ||||
| Canteens, pantries | 200 | 22 | 0,4 | 80 |
| Rest rooms | 100 | 22 | 0,4 | 80 |
| Rooms for physical exercise | 300 | 22 | 0,4 | 80 |
| Cloakrooms, washrooms, bathrooms, toilets | 200 | 25 | 0,4 | 80 |
| Sick bays | 500 | 19 | 0,6 | 80 |
| Rooms for medical attention | 500 | 16 | 0,6 | 90 |
| EDUCATIONAL BUILDINGS | ||||
| Classrooms, tutorial rooms | 300 | 19 | 0,6 | 80 |
| Classrooms for evening classes and adults education | 500 | 19 | 0,6 | 80 |
| Black, green wallboards and whiteboards | 500 | 19 | 0,6 | 80 |
| Entrance halls | 200 | 22 | 0,4 | 80 |
| Stairs | 150 | 25 | 0,4 | 80 |
| Circulation areas, corridors | 100 | 25 | 0,4 | 80 |
| Sports halls, gymnasiums, swimming pools (general use) | 300 | 22 | 0,6 | 80 |
| STORE ROOMS, FROZEN FOOD STORES | ||||
| Store and stockrooms | 100 | 25 | 0,4 | 60 |
| Dispatch packing handling areas | 300 | 25 | 0,6 | 60 |
| STORAGE RACK AREAS | ||||
| Gangways: unmanned | 20 | – | 0,4 | 40 |
| Gangways: manned | 150 | 22 | 0,4 | 60 |
| Control stations | 150 | 22 | 0,6 | 80 |
| Front of (high-bay) racks | 200 | – | 0,4 | 60 |
| FACTORY ASSEMBLY AREAS | ||||
| Rough work | 300 | 25 | 0,6 | 80 |
| Medium work | 500 | 22 | 0,6 | 80 |
| Fine work | 750 | 19 | 0,7 | 80 |
| VERY FINE WORK | ||||
| Instrument assembly | 1000 | 19 | 0,7 | 80 |
| Jewelry assembly/repairs | 1500 | 16 | 0,7 | 90 |
| Hospital autopsy tables and dissecting tables | 5000 | – | – | 90 |
| SPORTS FACILITIES | ||||
| Aerobics, athletics, dancing, gymnastics, swimming | 500 | – | – | 60 |
| Basketball, football, handball, table tennis, volleyball, weight lifting | 750 | – | – | 60 |
| School sports | 750 | – | – | 60 |
UGR – Unified glare rating serves to define the psychological glare (visual discomfort) of lighting installations in indoor spaces
Uo – Uniformity is the ratio of minimum illuminance to average illuminance on a surface
Ra – Colour rendering index (CRI)
Beam Angle
The Beam Angle is the angle between the two directions opposed to each other over the beam axis for which the luminous intensity is half that of the maximum luminous intensity.
The beam angle indicates how a light source distributes light. Beam angle is expressed in degrees (°).
Light sources can be classified as narrow (<45°) beam angle, medium (45° – 60°), wide (>60°).
Lighting beam angle is calculated with Full-Width Half Maximum (FWHM). The angle which referred as beam angle is the point between the initial density of light beam till where it is dropped to 50%. The angle is multiplied by 2. This is the beam angle.
Light beam is calculated according to ceiling height indoors, pole or mounting place height at outdoors. If a lighting equipment placed on high point, narrow angle should be preferred. If a lighting equipment placed on a low point, wide angle should be preferred.
Lighting equipment with wide angle does not emit more light than narrow angle. It only distributes light wider. Lumen value will stay constant when beam angle becomes narrow. But light intensity which is candela value will increase.
The light of the wide beam angle lighting equipment does not transmit the light to distant points. That is why narrow angle is preferred when lighting equipment placed on high points. For example, outdoor luminaire which is placed on high point of a pole generally distributes the light with narrow angle.
Indoor, for low ceiling height, wide beam angle luminaire should be preferred as possible. This prevents the formation of dark and very bright spots. More homogeneous lighting is obtained.
As the ceiling height increases, illuminated area will be wider, light will be distributed to the wider area. However, light level will be decreased in such situations. In each case, the most optimal option can be found.
At what height and how much area will be illuminated of a specific beam angle can be calculated using lighting simulation software like DIALux, RELUX and similar programs.
Light distribution diagram represents a two-dimensional cross-section through the three-dimensional light distribution curve.
Which Beam Angle for Which Purpose?
- Narrow: Focuses light into tight, intense spots. Best for highlighting artwork, accent walls, or task lighting.
- Medium: Provides a balanced spread. Ideal for general ambient lighting in residential rooms and kitchens.
- Wide: Floods large areas with softer light. Best for open-concept living spaces, warehouses, and general floodlighting.
In most living spaces, a wide angle of up to 120 degrees is recommended for basic lighting. For targeted illumination of specific path areas, 90 degrees have proven successful. Accent lighting and directed light, for example from a reading lamp, usually have a much smaller beam angle.
Two examples (distance between lamp and object is 2 meters):
- 15 degree beam angle: 60 x 60 cm area
- 60 degree beam angle: > 2 x 2 m area
Correlated Colour Temperature (CCT)
What does Kelvin (K) mean for light sources?
CCT
CCT stands for Correlated Colour Temperature. It is the expression that determines and categorize the colour of light source. Colour temperature indicates the colour of visible light that emitted from a light source (not its temperature).
The unit of colour temperature in Kelvin (K). “Kelvin” is named after The British physicist William Thomson (Lord Kelvin), who introduced and established the thermodynamic temperature scale.
Different places have different lighting requirements. Colour temperature requirement can be changed according to the usage area and its purpose. Warm white colours are used in living rooms, bedrooms, restaurants. Cold white colours are preferred in offices, working areas, learning areas, garages.
There are several different advantages of warm white and cold white lightings. The most important advantage of warm white is to have relaxing effects. The most important advantage of cold white is helping to increase concentration.
Colour temperature (K)
Used to numerically express the colour of light sources, the redder the colour the lower the number and the bluer the colour the higher the number
2700K – extra warm white
3000K – warm white
4000K – natural white
5000K – cool white
6500K – day light
The Kelvin number is an important factor when choosing a light source.
What does Kelvin mean for light source?
The unit Kelvin indicates the colour temperature of a light source. The Kelvin value of a light source indicates whether the lamp or LED emits warm light or cool light. A light with a low Kelvin number emits warm white light. The higher the Kelvin value, the cooler the lighting effect.
Where can I find the information on the light colour?
Information on light colour can usually be found in the specifications of the respective light. The light temperature of a luminaire should also be taken into account as part of the lighting design of buildings, properties and commercial spaces.
What colour temperature is pleasant?
White light consists of many different frequency ranges in the visible range of the electromagnetic spectrum. Light with a high red component appears warmer and darker, whereas light with a high blue component appears cooler and brighter.
We perceive warm white light as cozy and comfortable; its colour temperature ranges up to 3300 Kelvin. If the colour temperature of LEDs, xenon lamps, etc. is below 3300 Kelvin, the light is reminiscent of a sunset and is suitable for living rooms and bedrooms with this unobtrusive light.
Neutral white light activates and is therefore suitable for working in the hobby room or office. Light between 3300 and 5300 Kelvin has a sober but inviting effect. The upper limit for neutral white light is 5300 Kelvin. Up to this value, the light temperature of a luminaire is called neutral white.
Above this is the range of daylight white light that promotes concentration and is suitable, for example, for bright factory hall and shop lighting. Office lights should also emit daylight white light.
Colour Rendering Index (CRI)
Colour Rendering
Colour rendering describes how a light source makes the colour of an object appear to human eyes and how well subtle variations in colour shades are revealed.
CRI (Colour Rendering Index)
CRI stands for Colour Rendering Index. CRI is an important criterion of the visual performance of a light source. Colour Rendering Index measures the ability to reflect colours of electrical light sources according to natural light sources which mean sunlight. In short, in lighting devices, CRI expresses how the objects are closed to their true colours.
In detail: CRI is a measure of the ability to show colours that close to its true or natural colour according to a reference source known as incandescent or sunlight.
CRI value expressed with a numerical value between 0 – 100. If CRI value close to 100, it shows the colours well. 100 represent the maximum CRI value.
Sunlight represents perfect light and CRI value accepted as 100.
If CRI value is greater than 80, it is acceptable for most of the applications. However, CRI value 90 and above lights are needed in areas where colours are more important.
Lightings with high CRI value used in art galleries, retail stores, food sections in markets, textile sector, hairdressers and, health facilities. As in the examples, lighting with high CRI value is needed indoors.
Using high CRI value lights makes the colours more clear, vivid colour and, distinguishable in illuminated areas.
The same Kelvin values of a light source can correspond to completely different spectral compositions: Different light sources of the same light colour can therefore reproduce the colours of their surroundings differently in terms of realism (colour rendering index). This is particularly significant with LEDs: cheap products in particular often have only a very limited spectrum of wavelengths of visible light; their light can be perceived as unpleasant.
N.B. The higher the colour rendering index of a luminaire, the lower its luminous efficiency.
This image displays 14 standardized colour swatches labeled R1 through R14, which are used to measure the Colour Rendering Index (CRI) of light sources.
Glare, Unified Glare Rating (UGR)
Glare is a visual perception caused by light that is scattered excessively and uncontrolled. Exposed to bright sunlight or artificial light (electrical lights) may lead to visual impairment which is called glare.
Glare may occur day or night. Glare problem can occur directly or as a result of reflection.
Bright lights may disturb people or it may be painful. Glare is divided into three groups according to its effects: disruptive glare, temporary glare, and blinding glare.
Even when the bright light is removed from the eye, if it is difficult to see or select objects, it is called blinding glare. If the intense light in the field of vision causes temporary visual loss, this is called temporary glare. If bright light leads to loss of comfort, tiredness, and pain, it is called a disruptive glare.
Glare can occur in both indoor and outdoor lightings. Both of them has negative effects when the eyes are exposed to a light that is more intense than normal.
Glare problems can be seen, if there is a difference between dark spots and bright spots in an illuminated area.
Sunlight that comes from the windows directly or reflected from bright surface in our offices can reach our eyes. This situation causes the loss of visual performance and feels uncomfortable.
Well-designed light fixtures and good planning can minimize glare and its negative effects.
Unified Glare Rating (UGR) is a method of calculating glare from luminaires. The UGR value is calculated using a complex equation that includes the luminance value of the luminaire, the value of background luminance, the solid angle of the luminaire as seen by the viewer and several other values. Within an office setting, for the luminaire to be classified as “low glare” it must have a UGR below 19 at desk level. Anything above this may cause discomfort – this further enforces the need for high quality interior lighting that is rated UGR≤19.
UGR limits (UGRL) that must not be exceeded:
≤ 16 Technical drawing
≤ 19 Reading, writing, training, meetings, computer-based work
≤ 22 Craft and light industries
≤ 25 Heavy industry
≤ 28 Railway platforms, foyers
Lumen
Luminous Flux (Lumen)
A lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In other words, the lumen measures the total amount of visible light emitted by a light source in all directions. The lumen (lm) is a standard unit in the International System of Units (SI) for luminous flux.
The lumen is based on the sensitivity of the human eye to different wavelengths of light. It provides a measure of the total light output, regardless of the direction in which the light is emitted. One lumen is equivalent to the luminous flux emitted uniformly in all directions by a point source of one candela (a unit of luminous intensity).
Different light sources such as incandescent bulbs, energy-saving bulbs and LEDs produce very different luminous flux per Watt. When incandescent bulbs were almost exclusively used for lighting in the home, their brightness was simply identified by their power consumption in Watts. But now manufacturers have to state how many lumens a light source emits.
In summary, the lumen is a unit of measurement for luminous flux, representing the total visible light output of a source. It is a valuable metric for comparing and specifying the brightness of light sources in various applications, including lighting design and product labeling.
A light fixture with high lumen value means the higher light output. If we use a general and simple expression, it can be said that lumen is equal to brightness.
The necessary amount of lumen in a lighting application depends on some variables such as; size of the room, ceiling height, painting, type of light source, and placement.
Light sources are now much more efficient and need far fewer Watts to shine even brighter than the incandescent bulbs of the past. A high-quality LEDs, for example, can produce an incomparably higher luminous flux than an incandescent lamp with the same energy consumption. Today, the wattage serves primarily information about energy consumption.
Luminous flux to power ratio
When considering the luminous flux of a lamp in combination with its wattage, one quickly arrives at another physical quantity: luminous efficacy. Luminous efficacy is measured in lumens per Watt (lm/W) and indicates how efficiently a lamp shines. The luminous efficacy therefore indicates how much energy is converted into light. The higher the value, the more efficient a light source is.
As a guide, you can roughly use the following values for luminous efficacy:
- Incandescent bulb: approx. 10 – 17 lm/W
- Halogen lamp: 15 – 25 lm/W
- Fluorescent lamp (CFL): 50 – 70 lm/W
- LED: 80 – 150+ lm/W
How Many Lumen do you Need?
How many lumens should be planned per square meter to illuminate the home optimally and comfortably?
The amount of brightness required depends primarily on the needs of the occupants and the activities that take place in the room. In rooms such as the kitchen or the study, a larger amount of light is needed to cook or work without problems. The living room, on the other hand, is primarily used for relaxation: It should be cozy here, bright light is hardly needed.
- Kitchen: about 280 lumens per square meter (lm/m2)
- Bathroom: about 280 lm/m2
- Bedroom: about 140 lm/m2
- Living room: about 140 lm/m2
- Children’s room: about 140 lm/m2
- Study: about 280 lm/m2
- Hallway: about 140 lm/m2
If, for example, you want to illuminate a 30 square meter living room pleasantly, your light sources should produce a luminous flux of about 4200 lumens total (30 square meters x 140 lm = 4200 lm).
Candela
The physical unit candela (cd) quantifies the luminous intensity, i.e. that part of the luminous flux that points in a certain direction. An analysis of the luminous intensity in relation to all directions can be modelled into a so-called luminous intensity distribution curve (LVK). Depending on the design of a luminaire or light source, the luminous intensity is distributed evenly or irregularly over a certain solid angle.
Only in a few cases do manufacturers specify candela values, because these always refer to specific directions. They would therefore only be relevant for light sources that emit approximately the same luminous flux in all directions. Another physical quantity that informs the consumer about the properties of luminaires is the beam angle. The values for beam angle and lumens can be put into relation to compare different luminaires in terms of their luminous intensity in candela:
The larger the beam angle of a light source, the fewer candela are allotted to a steradian (solid angle) with the same lumen value.
Luminous intensity I (cd) = luminous flux Φ (lm) / space angle Ω (sr).
Lux
Illuminance (Lux)
Illumination or illuminance is the total quantity of light per unit area on a surface. The unit of illuminance is lux (lx).
1 lux is equal to 1 lumen per square meter. 1 candela light intensity provides 1 lux light level in 1-meter distance.
Illumination of an environment is expressed with lux value. Higher lux value means higher illuminance. However, it should not be forgotten that excess lighting does not mean good lighting. Excessive lighting has also negative effect like insufficient lighting.
If we mention about the proper common illuminance; in a sunny day 10000 lux, in a cloudy day 1000 lux, sunset 10 lux, in a moonlight 0,1 lux illuminance can be seen.
Lux value is related to lumen which expressed the total light output of a light source. As you move away from the light source, lux value decreased.
If the light concentrated on a small area, this area perceived as brighter and reached to high lux value. However, the same amount of light concentrated on a wider area, more soft light occurred and has less lux value measured. Although both light sources emitted same amount of light, in the concentrated light source, it is perceived as brighter because the light is more intense.
In general, lux is the measure of the intensity of light that reaches an area.
If lighting equipment with high light output in other words high lumen value is used in an area, high level of illumination is obtained. This means high lux level is obtained.
For example, in the office, 500 lux lighting is required and 100-150 lux lighting is sufficient in the living room. In areas like drawing offices, textile mills and laboratories require high light levels such as 1000 lux. At this point, updated lighting requirements should be reviewed according to the type of application.
LED, Light-emitting Diode: Structure and Function
How does a Light-emitting Diode Work?
LED Lifetime (h)
LED light-emitting diode
An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs are widely used in various applications due to their energy efficiency, compact size, and long operational life. The technology behind LEDs is based on the phenomenon of electroluminescence.
Key characteristics and features of LEDs include:
Electroluminescence: The process by which LEDs emit light is called electroluminescence. It involves the recombination of electrons and electron holes in a semiconductor material, resulting in the release of energy in the form of photons (light).
Semiconductor structure: The basic structure of an LED consists of a semiconductor material, which is typically a compound semiconductor like gallium arsenide (GaAs), gallium phosphide (GaP) or gallium nitride (GaN). The semiconductor is doped with impurities to create regions with excess electrons (n-type) and regions with electron deficiencies or “holes” (p-type).
Energy band gap: Electroluminescence occurs when electrons in the conduction band of the semiconductor recombine with holes in the valence band, releasing energy in the form of photons. The energy band gap of the semiconductor determines the colour of the emitted light.
Colours: LEDs are available in a variety of colours, including red, green, blue, and white. The choice of materials and the doping process influence the wavelength of the emitted light, determining the colour.
Energy efficiency: LEDs are highly energy-efficient compared to traditional incandescent bulbs. They convert a higher percentage of electrical energy into light and generate less heat.
Long lifespan: LEDs have a long operational life, typically lasting tens of thousands of hours. This longevity is attributed to the absence of a filament or glass bulb, which can wear out or break in traditional light sources.
Instantaneous on/off: LEDs light up quickly when an electric current is applied, and they can be switched on and off rapidly without impacting their lifespan or performance. This characteristic is beneficial in applications like lighting and displays.
Compact size: LEDs are small and can be manufactured in various shapes and sizes, making them suitable for diverse applications, including indicator lights, displays, automotive lighting, and general illumination.
Directional emission: LEDs emit light in a specific direction, contributing to their efficiency in applications where focused or directional illumination is desired.
LEDs have become ubiquitous in everyday life, finding applications in various industries, including lighting, electronics, communications, signage, and more.
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There are several LED types such as; power LED, mid-power LED, COB LED. Each of them has advantages and disadvantages against each other according to the purpose and shape of use.
LEDs can be seen in high brightness. Also, LEDs can emit light ultraviolet or infrared wavelength.
LEDs have many advantages over previous technologies like low power consumption, long-lasting lifespan, smaller sizes, and faster switching. Those advantages are used in automotive, aviation, advertisement, signaling, general lighting, photography.
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The lifetime of a LED
The lifetime of a LED luminaire illustrates the target life expectancy (for example 50 000 hour life expectancy) which is a combination of light output degradation (L80 when the light output has reduced to 80% of its initial level) and source performance expectation (B10 when 10% of the LEDs lumen outputs falls below 80% of the nominal initial value) under specific conditions.
L – Lumen maintenance. L value tells that how many percent of luminous output is still left from the original.
B – Failure fraction. The value B10 means that minimum 90% of the LED modules will meet the declared L-value and only 10% will have a lower flux level.
LED Driver
LED is a long-lasting lighting technology with low energy consumption and high light output. This technology requires special power sources to operate. LED driver is an electronic device that provides necessary current and voltage in order to operate a LED or LED series.
LEDs require a certain amount of voltage to operate. This voltage can be changed according to temperature of the LED. As the LEDs warm up, the voltage is reduced. This will cause an increase in current consumption. Constant current LED driver has constant current output within a certain voltage range. In this way, damage to the LED can be prevented in case of increase in current depending on temperature changes.
Exposure of LEDs to high current may cause lumen loss, therefore, shorten the lifespan. LED drivers provide protection against current and voltage fluctuations to LEDs. In any negative situation, it provides that LEDs are not affected by the fluctuations in the mains and remain within the operating range, thus ensuring long-lasting use.
There can be internal and external LED driver in lighting equipment. It can be said that systems which have the LED and the LED driver in the same housing is called internal such as used in houses. In outdoor lighting such as street light fixture, floodlight usually preferred external driver. In most of the LED lighting faults caused by the driver. The maintenance, repair, and switching of external driver have become easier.
Input voltage, output voltage, output current, control options, and IP protection class should be taking into consideration when selecting LED drive.
First of all, input voltage decided as AC/DC. AC voltage should be preferred for the systems that feed with mains voltage. DC voltage should be preferred for the systems that are powered with battery. After choosing the voltage type, the input voltage range should be determined according to the requirement.
Constant current or constant voltage choice should be made according to the requirement. This choice should be determined according to the design of LED card. Constant current LED drivers are usually preferred in LED lighting applications.
Determining the output voltage and driving current is extremely important. These values should be selected according to the LED specifications. The power of LED driver is determined by these values.
If you want to control the brightness of light source, it must be ensured that the driver has proper dimming properties such as 1-10V, DALI.
IP protection class should be determined according to the usage area of lighting fixture, the purpose of lighting fixture and the specifications of placing sections of driver. High level of IP protection means, superfine protection against water, dust, and moisture.
Degrees of IP Protection
IP is an acronym “Ingress Protection”. It is a measurement of the protection an item will have against solid objects (dust, sand, dirt, etc.) and liquids. An IP rating is comprised of 2 numbers. The first number refers to the protection against solid objects (dust, etc.) and the second number refers to protection against liquids. More…
Degrees of IK Protection
The IK rating is an international code which measures the degree of protection against mechanical wear and tear as well as the amount of impact a specific fixture can take. Essentially it is a measure of a fixtures robustness and durability. More…
Reflector
The reflectors and optics of a luminaire absorb and redirect the direction of the emitted lumens. They can therefore reduce the amount of light output from the luminaire.
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Optical elements that direct the light through reflection and refraction at a certain angle is called reflector. Reflectors gather light, increase the density and direct the light to the surface which desired to illuminate.
The reflector ensures that light emitted from the light source is controlled as desired. There is reflective material inside the reflector to shape the light. It is important that reflecting feature of internal surface is very important for system efficiency.
Reflector is an optical solution which is easy to use and cheap. However, they don’t have wide control potential or flexible application ability according to lenses.
The angle of radiated light and its distribution shape depends on the shape of reflector. The pattern of light can be changed by applying different processes to the reflecting surface of reflector.
Reflectors are usually made of glass, metal or plastic material. Plastic reflectors are covered with metals like aluminum in order to obtain reflecting feature. Aluminum covering will direct the light with high efficiency.
Reflectors are used in general lighting products such as; light fixtures, automobile headlights, signaling lamps, hand lamps, and similar equipment with light.
Light fixtures require optical materials to distribute the light accurately. In solid-state lightings, secondary optical materials like lenses and reflectors are commonly used.
There are single and serial reflector types with different sizes and different light angles that are used for several applications. Reflectors can be installed to the system by screw, clips or glue.
Using reflectors on a light source is helping to reduce the glare. Placing reflector on a light source does not help to hide the light source. Lenses should be preferred as optical material for applications which desired to hide the light source.
Lens
Lens is an optical material that controls the light emitted from a light source and allows it to distribute in a certain angle and density. Lenses provide precision control over light angle.
Lenses can be made of plastic, silicon or glass material in various shapes and sizes. It can be designed to use with one LED or with a LED arrays.
The dome placed on a LED is called primary optical material. Primary optic is attached to LED. The light emitted from this dome, which is attached to the LED, is usually emitted at wide angle. The light emitted with wide angle disappears before it reaches the surface to illuminate at far distances. This will cause the necessity of secondary optic usage in LED lighting.
LEDs are multidirectional light sources and can emit the light maximum angle of 180 degrees. Typical LED packages that combined with primary optical material generally have about 120 degrees light angle. However, 120 degrees light angle is not suitable for many applications.
Lenses are secondary optical materials that collect light and transport it to the surface to be illuminated. Lenses collect the light and transport it to the surface to be illuminated with controlled angle.
Lenses distribute light on the vertical and horizontal axis. If each two-axis has the same light angle, this type of lenses is called symmetrical lenses. If vertical light angle is different from horizontal light angle, this type of lenses is called asymmetrical lenses. Asymmetrical lenses used in indoor and outdoor lighting where light is needed in a particular direction.
Asymmetrical lenses should be used for illuminate the road surface in street lighting with LED light sources. For example, an asymmetric lens with 60×110 degrees means that the light distributed with 60 degrees of angle through the road width and 110 degrees of angle through the road length. By this way, bright spots and dark spots are prevented under the poles and between the poles. Therefore, homogeneous lighting can be obtained.
Lenses can be mounted to LED by screw, glue or connecting tab. Also, it can be mounted to printed wiring board or can be attached to a housing.
The efficiency value should be considered when choosing lens. This value must be as high as it can. Because this value which expressed as percental indicate how much light can go out of the lens.
In lighting applications, lens selection should be made according to project requirements. As secondary optical, reflector can be used instead of the lens. The main difference and advantage of lenses from reflectors are that lenses can hide the light source and by this way, it reduces the glare.
Diffuser
Optical material takes control of bright light comes from a light source and emit it softly is called diffuser. Diffusers control the angle of light and allow a homogeneous lighting.
Diffuser allows the light source to be dispersed in a wider area by emitting the intense light softly. Using diffuser prevent the formation of bright and dark spots and allows homogeneous lighting in areas illuminated with artificial lights.
It is hard to look at a bright light with the naked eye. Long-term exposure to bright light and high-intensity light can lead to vision loss and some health problems.
Especially new and efficient lighting technologies, high-intensity light is emitted from a very small area. At this point, it is necessary to hide the light source and control the light coming out of the source. Diffuser can minimize the effects of glare by hiding the light source.
Diffusers are generally as thin panel shape and made of acrylic or polycarbonate material. Diffusers are frequently used in both photography and lighting industry. Diffuser used to soften the flashlight in the photography sector.
The most important parameter in the diffuser is transmission efficiency in other words light conductivity. Diffusers with low conductivity some parts of the light cannot pass through the diffuser. This will cause a loss of light.
Transmission efficiency indicated as a percentage by the diffuser manufacturer. This value is used for light output calculations of the fixture. For instance, when you use a diffuser with 92 percent efficiency in front of a light source with 3000-lumen light flux, the light output will decrease to 2760-lumen levels.
Special optical materials in film form can also be used instead of diffuser panels.
PC (Polycarbonate)
Amorphous and transparent polycarbonate, which is frequently used in today’s industrial and commercial fields, is a thermoplastic polymer that stands out with its high mechanical impact resistance, transparency, recyclability, and lightness. Polycarbonate is preferred in many sectors, especially because it is strong and durable enough to replace glass.
Properties of Polycarbonate
Polycarbonate is suitable for use in many fields due to its various properties:
- High Impact Resistance: Polycarbonate has high durability in every sense. It is stronger than glass and resistant to breakage.
- Lightweight and Flexible: Compared to alternatives such as glass or metal, it is very light, making it easy to transport and install. It also has a flexible structure.
- Resistance to Heat and Weather Conditions: It is resistant to high temperatures and UV rays, making it long-lasting.
- Transparency and Light Transmission: It can be as transparent as glass and has high light transmittance.
- Recyclability: One of the most important features of polycarbonate is that it can be heated up to its melting point, cooled, and reheated without deterioration. Thanks to this property, it enables recycling. It is an environmentally friendly material and can be reprocessed.
Applications of Polycarbonate
Thanks to its unique properties, polycarbonate has become an indispensable material in many industries:
- Aviation and Automotive: Used in aircraft windows, headlight covers, and interior components.
- Electronics and Medical Devices: Found in electronic screen protectors, medical equipment, and security devices.
- Construction and Building Materials: Used in roof coverings, greenhouse panels, and security barriers.
- Industrial and Safety Products: Applied in protective coatings and durable enclosures for various machines.
- Signaling and Road Safety Products: Utilized in signaling, road safety, and lighting products.
PMMA (Polymethyl methacrylate)
PMMA (Polymethyl methacrylate) is a transparent and rigid thermoplastic material. It is also known as acrylic, acrylic glass and plexiglass. PMMA is widely used in the production of lenses, diffusers and light guides in lighting industry because of its high light transmittance providing property.
PMMA has many advantages over other transparent polymers. PMMA is a strong, durable and lightweight material. It has high resistance to UV lights, weather conditions and other environmental factors, also offers unlimited colouring options and provides excellent light transmission. It offers unlimited colouring options and provides excellent light transmission. PMMA allows 92% of the light to pass through it. PMMA is the thermoplastic with the highest surface hardness. It has high resistance to chemicals and scratching.
The most well-known usage of PMMA is roof panels that can withstand weather conditions such as sun, rain and snow. It can be used in interior and exterior lighting, indicators, spoiler and similar parts in the automotive sector. Besides, PMMA is used in the screens of devices such as TVs, computers and etc.
RAL
RAL is a standard colour description system used in many countries. RAL stands for Reichs-Ausschuss für Lieferbedingungen in German. It can be translated in English as State Commission for Delivery Terms.
RAL was founded in 1925. Since then, it used to describe colours in Germany and other European and non-European countries.
Classical RAL codes were originally composed of only 40 different colours. Then this number increased 213.
Classical RAL codes are defined with four-digit numbers. Four-digit number that describes the colour is written after RAL word. For example, RAL 1012, RAL 2008, RAL 3001.
The first digit of numerical value describes the class of colour. In the first digit; 1 is yellow, 2 is orange, 3 is red, 4 is purple, 5 is blue, 6 is green, 7 is grey, 8 is brown and 9 is used for white and black tones. The remaining three digits are described other tones of the specified colour.
RAL codes are commonly used to describe the colours in construction, architecture, production, automotive and road safety industries. In the lighting industry, RAL codes are used to describe the body colour of light fixture and the colour of lighting pole.
Uniformity
Uniformity can be expressed by division of minimum bright level to average bright level in the bright field. It is represented by U0. The uniformity of lighting has significant effects on visual performance in both indoor and outdoor areas.
Uniformity (U0) value can be found by dividing the minimum brightness (Emin) resulting from calculations according to the current lighting order, to the average brightness value (Eavg).
U0=Emin/Eavg
Uniformity value determined according to the type of fixture, number, light angle and mounting position.
Human eye needs some time to adapt to different light levels. For this reason, homogeneous lighting is required in illuminated areas.
Uniformity value greater than 0,60 is recommended in working areas. Because, above this level, the change in light levels cannot be sensed by people and that makes them comfortable. Proper lighting of the environment also helps employees work more comfortably when looking at the computer screen.
Flicker
Flicker is the light flicker that occurs as a result of the brightness of light changes rapidly and repeatedly. The flickers that occur periodically are divided into two as visible flicker and invisible flicker.
If the light flickers are below 100 Hz frequency it is called visible flicker. If it is above 500 Hz, it is called invisible flicker. Both visible and invisible flicker has negative effects.
Most of the researches proved that light flickers cause security, performance and health problems. Especially in offices, exposing to flicker effect may cause decrease in performance, tiredness and headache problems who are light-sensitive people.
People can see light flickers under 50 Hz, which means light flashes 50 times per second. Some people can sense fast flickers up to 100 Hz. If light flashes greater than 100 Hz frequency, these flickers cannot be noticed for most of the people. However, even it cannot be noticed by naked eye, it can cause the negative effects mentioned above.
Flicker can cause stroboscopic effect, which can lead to optical illusion. Objects moving under the flicker light may seem to move or stop slower than usual. This may lead to security problems, especially in industrial facilities.
Flicker is less visible in LEDs according to fluorescent lights. The flicker problem in LED lighting can be overcome with high-frequency output drivers called flicker-free. This drivers outputs are 10kHz and above, therefore, this eliminates the flicker problem.
DALI
DALI stands for Digital Addressable Lighting Interface. DALI is digital technology that provides two-way data communication for lighting systems. DALI is a common automation system, especially in commercial buildings.
Through the DALI standard, systems that produced by different manufacturers such as ballasts, drivers, control units, luminaires, emergency lighting fixtures can be managed by a single control system.
In DALI system, a message is sent from the center just like in a computer network. These messages are received by each unit via addresses.
In DALI system, the data line is made with a standard 1,5 mm2 diameter binary cable. Polarity doesn’t matter. DALI power and data are carried over the same pair of cables. Cabling up to 300 meters can be done in a subnet. Maximum of 64 devices can be controlled on a subnet. With the help of hub/router/gateway, DALI subnets can be created to use more than 64 devices.
DALI can perform commands such as open, close, and dimming received by data.
DALI lighting systems are cost-effective, simple, energy efficient and compatible with future technologies. It is easy to install and flexible. Saves time and resources. Easy to maintain control and monitoring systems. Gives priority to user comfort.
Casambi
Casambi is a smart, wireless lighting control platform based on Bluetooth Low Energy (BLE). It allows users to control, dim, and automate lights wirelessly via a smartphone, tablet, or smartwatch. Developed in Finland, it is widely used in both commercial and residential projects.
Every Casambi-enabled light source, driver, or switch communicates with the others. If you turn on a light at one end of a room, that light relays the signal to the next, creating a robust “mesh” network. Because the network is decentralized and the intelligence is stored in every node, the rest of the system will continue to work normally even if one light is removed or fails. Using the Casambi App, users can group lights, set colour temperatures, program schedules, and create specific “scenes”.
The system can also connect with motion and daylight sensors to automate adjustments for energy efficiency. Casambi isn’t locked to one brand. The technology is embedded in thousands of products by hundreds of lighting manufacturers worldwide, giving users the freedom to mix and match fixtures. It eliminates the need for extensive communication wiring, making it highly flexible for both new builds and retrofitting historic or existing spaces.
Zhaga
Zhaga is a global association of lighting companies.
Zhaga aims to standardize interfaces of components of LED luminaires, including LED light engines, LED modules, LED arrays, holders, electronic control gear (LED drivers), connectors and sensing/communication modules. Zhaga does not standardize components but the interface between components. This allows for interoperability of components but does not limit their performance and the further development of innovations.
The Zhaga Consortium and the DALI Alliance collaborate on joint certification programs for interoperable luminaires and components, which enable intelligent, future-proof products and IoT connectivity.
Zhaga creates interface specifications for components of LED luminaires to enable multi-vendor eco-systems of interoperable products.
This helps to streamline the LED lighting supply chain, and to simplify LED luminaire design and manufacturing. Zhaga continues to develop specifications based on the inter-related themes of interoperable components, smart and connected lighting, and serviceable luminaires.
Benefits for specifiers and end-users are that Zhaga-based luminaires are future-proof, that certified components can be purchased from multiple vendors and latest generation LED technology can be adopted. Luminaires can be specified for future projects, knowing that a current, up-to-date LED light source can be fitted when the project is actually installed.
Emergency Lighting
Emergency lighting is a type of lighting that is engaged when normal lighting fixtures are disabled for any reason and helps people to leave the building safely.
Emergency lighting has two purposes; one of them is escape lighting and the other one is backup lighting.
The escape lighting allows the building to be evacuated in situations such as fire, earthquake, etc. It also makes it easier to rescue teams while searching the buildings.
Backup lighting provides the lighting is maintained at safe levels when black outs or other failures occur.
Emergency lighting makes easier to reach the firefighting and safety equipment. It guides through the escape route by creating sufficient vision conditions.
Emergency lighting has different applications and requirements according to the countries. So the design of the emergency lighting can be changed according to application area.
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Signs placed at all emergency exits along escape routes should be so illuminated as to indicate the direction to a place of safety in an unambiguous manner (EN1838 Lighting applications. Emergency lighting). Exit and direction signs should be clearly visible from anywhere along the escape route. All signs indicating emergency exits and escape routes should be in the same colour and format, whereas their minimum illuminance should be 2 cd/m2.
As people in the building may not be familiar with its layout, internally illuminated, permanently powered safety signs are recommended.
Note that internally illuminated safety signs are visible from a greater distance than the same size signs illuminated from the outside.
Warehouse Lighting
Good lighting in warehouses makes the shipment faster. It makes it easy to distinguish the products in the warehouse and helps prevent workplace accidents.
Warehouses are usually areas that are deprived of natural light and inside the warehouses, there are high shelves and narrow corridors. Therefore, light fixtures that designed especially for narrow light beam angle should be used.
Generally, in warehouses, 100 lux light level is sufficient. However, it can be changed according to the usage and the area. For instance, 200 lux light level may be needed to ensure that small products are recognized in the areas where they are stored. In cold storages, 300 lux light levels are recommended.
In addition to the general lighting of the storage area, it is also very important to lighting the shelves. In this way, the products can be easily placed on the shelves with the help of a forklift and it can then be found quickly when needed.
Vertical lighting is required to light the shelves in the warehouse at a minimum 50 lux light level.
Glare created by the lighting in the warehouse can be disturbing to the forklift driver and warehouse workers. As a result of work accidents and serious injuries may occur. Therefore, it is important to minimize glare caused by lighting.
High-bay or low-bay luminaires are used in the lighting of warehouses depending on the ceiling height. These light fixtures are designed to use in industrial facilities and they are resistant to water, dust, and moisture just like an outdoor lighting fixture.
The use of LED lighting in warehouses eliminates periodic tasks such as lamp control and replacement. LED lighting makes the products in the warehouse look closer to their true colours, emits less heat and saves up to 80 percent energy compared to conventional lighting systems.
Lighting costs are not limited to energy costs, the cost of operation and maintenance should be considered as an important element. When selecting lighting, the total costs of the system should be taken into consideration.
Warehouses are usually very large areas, and not all of this area is actively used at any time. Therefore, the use of motion detection sensors and intelligent lighting systems enables lighting to be activated in a regional time of need. In this way, unnecessary lighting is avoided and the energy saving rate is increased.
Office Lighting
Lighting is an important element in the office. Lighting in offices has a direct impact on employee performance. Moreover, they affect their sleep pattern, eye health, and overall health. Good lighting helps you increase employee productivity. On the other hand, bad lighting can lower their performance and deteriorate their health.
People spend approximately 9-10 hours of their day in closed environments and offices. Therefore, the environment in the office takes a big place in their lives. If good lighting is done in the office, employees feel better and this helps them to increase efficiency in their work.
In general, 500 lux light levels are recommended in offices. However, in some cases, it was understood that 300 lux light levels were also accepted.
In office lighting, panel lights, linear lights, downlights, and pendant lights are used. The common feature of these lighting units is that they contain a layer that diffuses the light. In this way, it can provide a homogeneous lighting without creating glare.
It is important to achieve a homogeneous lighting throughout the office. If there are very bright and very dark areas in an office, this may cause eye strain and eye pain. Therefore, it is recommended to use lighting fixtures that distribute light more smoothly.
It is important to ensure that lighting elements that used in offices have no flicker or it should be at the minimum level. When exposed for long periods of time to spontaneous light intensity change in light source, this will cause headaches, dizziness, and nauseation.
Salon Lighting
Minimum 500 lux light level is recommended for salons. However, in some applications, 300 lux light levels are sufficient according to users’ experiences.
There are two more important topics in salons as important as light levels. These are CCT and CRI.
CCT represents the colour temperature of the light sources. If you want to create a relaxing atmosphere in the hairdressing salon, you can choose 3000K colour temperature and 4000K for more natural light.
CRI means colour rendering index. It shows how close the objects look to their true colour. The higher the CRI value, the objects under this light appear closer to their true colour. Indoor lighting which commonly used in the market has a value of 70, 80 or 85 CRI. In salons, the colour rendering index should be as close as 90. CRI value 86 and above light sources should be preferred.
About 25% – 50% of the energy consumption in salons is due to lighting. For this reason, in such areas, the use of energy-efficient lights and lights with high light output per Watt would be a good choice.
Hospital Lighting
Each department has a separate purpose of use in hospitals, for this reason, hospitals need different lighting requirements. Therefore, lighting in hospitals becomes complicated for lighting designers and engineers.
In hospitals, lighting is sometimes provided with artificial lighting only, and sometimes it is provided by the combination of artificial lighting and natural lighting (sunlight).
The quality of light has important effects on human health. Good lighting in hospitals can contribute to the patient’s recovery process. Lighting has direct effects on patients, patient’s relatives and employees.
Energy consumption is also important in hospitals. However, it should be the first priority to provide necessary lighting conditions and also patients comfort should be considered when it is done.
At this point, glare is an important element. Because patients are rest for a long time without moving. During this time, they exposed to the light. Light glare can disturb patients eye and this may lead new health problems.
It is very important to minimize the flicker effect in the light. Many studies stated that the effects of flicker cause health problems such as headaches, eye strain. Therefore, the use of flicker-free lights in hospitals would be a good choice.
There are lighting requirements in various areas of the hospital, ranging from 100 lux to 100000 lux.
Recommended light levels in hospitals are; 200 lux in general purpose rooms, 150 lux in receptions and waiting rooms, 100 lux in stairs and corridors, 300 lux in staff room, 100 lux in observation room, 500 lux in general examination room, 300 lux in eye and ear examination rooms, 300 lux in delivery rooms, 500 lux in general treatments room, 1000 lux in surgery, 100 lux in intensive care units, 500 lux in laboratories and pharmacies, 300 lux in sterilization and disinfection rooms, 500 lux in dissecting room and morgues.
The related standard for these areas, the glare rating limit is given as UGR 19 and 22. The colour rendering index is also known as CRI is requested to be greater than 80, however in some areas it is requested to be greater than 90.
The international standard EN 12464-1 contains all necessary information for lighting in hospitals and health facilities. Even in a single room may require different lighting needs in different sections. For this reason, this standard should have analyzed in details, and it is important to make sure that each areas requirement should have provided.
Restaurant and Cafe Lighting
Restaurant lighting is an important part of interior design. The lighting should also be included in the architectural planning of cafes and restaurants. The ambiance of the cafe and restaurant is as important as food and service. You can impress your customers with good lighting and make them visit you again.
Generally, 150 lux light level is recommended in cafes, bars, and restaurants. In other sections of the restaurant; 100 lux entrances, 150 lux in food storage section, 300 lux in washing section, 500 lux light level is required in the cooking section.
Four lighting techniques are applied in restaurants; general lighting, accent lighting, decorative lighting and natural lighting.
General lighting is the most important element in a cafe or restaurant. Lighting equipment that placed in a specific order at equal intervals will provide homogeneous lighting. Having good general lighting will create a more hospitable impression on your customers.
Accent lighting can be used to point out the sections you want to attract attention in the restaurant. That kind of lightings you can draw attention to the decor, plants, tables or products in the restaurant.
Decorative lighting is the accessories with lighting that used to complete your design. Decorative lighting can be done with classical lighting, as well as modern lighting. Also, it can be created by special lighting techniques.
General lighting, accent lighting, and decorative lighting provide all necessary artificial lights in restaurants. However, there is one thing that cannot be forgotten; natural light in other words daylight. Sunlight should be brought in by the help of windows. In this way, more comfortable lighting will be provided during the day, also this provides energy saving.
Lighting in cafes and restaurants are made by pendant lighting, chandelier, wall lamp, spotlight, LED bulb and LED filament lamps.
About 10% – 15% of the electrical energy used in restaurants is due to lighting. For this reason, the need to save energy in cafes and restaurants becomes very important. The maximum amount of daylight should be utilized for energy savings. Energy efficient light sources should be preferred.
Gas Station Lighting
A good lighting at gas stations makes the stations more secure and create an attractive environment for drivers. Some studies show that lighting plays an important role in the selection of gas station by drivers during the journey.
Lighting at the gas station should be considered as a whole, including canopy lighting, convenience store lighting, and environmental lighting.
Under the canopy, 400 lux light level is sufficient at ground level. In addition to that, 150 lux vertical illuminance is recommended for gas pumps.
The entrance and the exits of the gas stations should have minimum 10 lux light level. 150 lux light level is sufficient in the crossing area between canopy and store.
It would be a great choice to keep the light level 30 lux and above at gas station and store environment.
Providing good lighting conditions at gas stations will create more secure and inviting environment. Also, it will help customers spend more time and more shopping at the gas stations.
Provide a good lighting in a store section can make the products look more attractive. This will significantly affect the preferences of the customers who visit the store.
Lighting of gas stations; canopy lights, street lighting fixture can be used as outdoor lighting, LED panel, downlight and linear lights can be used as indoor lighting. In the car wash, it is appropriate to use waterproof lighting fixtures.
Using lighting control systems at the gas stations will help to save energy.
Food Production Lighting
Food production is a business that needs to be taken very seriously. The lighting in the plants where the food production is made must also be made very carefully. A lighting failure in the production plant can be very costly by interrupting the production. Moreover, it can lead to a problem that threatens the health of people.
Light fixtures to be used in food production plants should be safe, energy efficient and long life. In addition, it must meet the safety standards for food production, be resistant to water, dust, and moisture.
It is also very important that the luminaires have a solid structure, and the durability of the shocks is very important. If the parts belong to the luminaire or the broken glass fall into the foods and if this is not noticed, it may lead serious health problems.
Generally, 600-700 lux of light level is required throughout the food production plant. Different lighting fixtures are needed in different parts of the production plants. 1200 lux light level is sufficient where the foods are controlled visually, 800 lux in packing department, 800 lux in maintenance and repair department, 500 lux in administrative offices, 400 lux in dressing rooms, 300 lux in material store light level is sufficient.
High-bay and low-bay lights, waterproof light fixtures, linear industrial lights and LED panels are used in food production plants to reach these light levels.
Classroom and School Lighting
In order to improve education environment, schools and classrooms need a good lighting. A good lighting makes the students feel safe, improves learning. In addition to this strengthen the schools brand value.
In many studies stated that there is a close relation between lighting and the performance of the students.
Generally, about 30% of electricity consumption in schools is caused by lighting. It is important to establish good learning conditions rather than energy saving. Because a good lighting in classrooms helps the students learn more.
250 lux light level is sufficient in classroom where students spend most of their times and focus on learning. In order to draw attention to the area where the teacher is located, to contribute to the students’ concentration of 750 lux light level can be done here.
Control systems were needed after projection systems and smart boards. With the control systems, some lights can be turned off or turned on at any time.
Other important issue in school and classroom lighting is flicker and glare. Flicker and glare effect may cause eye strain and headache beyond disturbing students. It is obvious that this situation will affect learning negatively.
LED lighting systems are a good option for schools and classrooms. These systems provide energy efficient lighting and reduce maintenance costs to minimum. Thus, significant savings have been achieved in costs.
Homogeneous lighting that achieved with LED lighting systems reduces shadows and improves visibility. In most of the situations, light levels can be easily changed. There will be less interruption with remote monitoring and management systems. Therefore security is improved in schools.
LED panels, linear lights and spotlights are generally preferred for classroom lighting.
Lighting for Retail Store
Four different types of lighting products used in retail stores. General lighting, task lighting, accent lighting and decorative lighting.
General lighting is main lighting source that provides the ambient lighting of the retail stores.
Task lighting is used to lighten the special areas better where more lights are required. Those special areas can be sorted as payment points, entrance of retail stores, dressing rooms etc.
Accent lighting is used to highlight the specific products, certain areas, displays and decors in retail stores. For instance, new season products and special offers for products can be lighten by accent lighting and spot lights.
Decorative lighting is the special lights which used to make the retail store more attractive. Chandeliers, special design lights can be example of decorative lighting.
Different needs may emerge in retail store lighting depending on retail store types. The ideal light level in a basic retail store is specified as 500 lux. In addition to 300 lux ambient lighting, 750 lux accent lighting suggested in medium-sized retail stores. In addition to 150 lux ambient lighting, 1000 lux accent lighting suggested in high level retail stores.
Ambient lighting needs to be reduced partially in order to make the product more significant in medium-sized retail stores. Accent lighting will attract the attention to products. High level retail stores prefer the combination of low general lighting with high level accent lighting. Therefore that will create more contrast.
Although the above explanations consist of general descriptions, retail store lighting is the identity of that store. For this reason, different solutions are needed for different needs. Retail store design and lighting design are considered as a whole.
Lighting in retail stores can influence the purchasing behavior most of the times. You may draw attention on your products, guide your customers, even you may influence customers preferences with light.
Lighting of retail stores demands high colour rendering index. Therefore, it provides the best recognition of colours and materials. Although in retail stores lighting generally colour rendering index is CRI 80, especially in high level retail stores, CRI 90 and above is suggested.
It is also important to use right light distribution according to needs of retail stores.
Two important problems of retail store lighting are heat and energy consumption. Traditional lighting has higher heating load because it consist of IR radiation and UV components. This situation may cause overheating of the retail stores and may cause cooling systems to be forced in summer. Lighting in retail stores have a large share in total electricity consumption. This will increased the electricity bills.
Both problems can be overcome by LED technology. When an energy efficient light is combined with the right thermal management, both the heat problem is eliminated and energy saving is ensured.
Lighting in a Supermarket
Every area in the supermarkets has its own significance. It is necessary to design those areas as have sufficient lighting and define them with light. Products that are important or requiring attention can be illuminated with accent lighting. Doing supporting lighting with spots for this areas may increase the interest to store and products.
At the same time lighting may guide the customers in stores. By using different colour combinations, lighting may affect the customers decisions. Therefore when the lighting used correctly, you can lead your customers to the departments that can take their interests.
You can perform lighting control by using presence detectors, you can do creative work by changing the colour temperature.
Surface mounted, recessed or track lighting fixtures can be used in supermarket lighting. The fixture preference depends on the ceiling type of the supermarket.
Vertical lighting is as important as horizontal lighting in the markets because the products are exhibited on the shelfs. The lighting level which obtained by vertical lighting express how much the product on sale is illuminated.
Generally 750 lux lighting level is recommended for the supermarkets. Supermarket shelves must be designed as full size in project phase, calculations must be done by using lighting simulation software like DIALux, RELUX and similar programs.
Luminaires are selected according to the ceiling height of the supermarket and calculated light center height. Therefore you may have enough light on the shelves and on the ground.
Effective spot lights should be used in high ceiling supermarkets. Areas illuminated under spotlight will undoubtedly attract customers attention.
Colour temperature which used in supermarket lighting is the key factor to altering the mood. The store which illuminated with warm light colour namely which is near to yellow, makes the customers feels at home. But cold light colours which are white and near to blue colours lights will give a fresher, more luxury feel.
Colour temperature selection is depend on the ambiance that you want to create. But the combination of colour temperatures may create more dynamic and more interesting supermarkets.
Fixture types frequently used in supermarket lighting; track mounted linear lights, LED panels, pendant lights, spotlights.
Energy consumption caused by lighting in supermarkets, corresponds to about 25% of all electricity consumption. For this reason, the use of suitable and energy-efficient LED luminaires will be the right decision.