Formulas for LED lighting. Number of watts per square meter of lighting

And the quality of the products produced is highly dependent on lighting.

Light represents visible to the eye electromagnetic waves optical range with a length of 380-760 nm, perceived by the retina of the visual analyzer.

From the point of view of occupational health, the main lighting characteristic is illumination (E), which is the distribution luminous flux (F) on the surface area ( S) and can be expressed by the formula E \u003d F / S.

The unit of illumination is taken luxury(lx) - illumination of a surface with an area of ​​1 m 2 with a luminous flux of radiation incident on it equal to 1 lm.

Light flow (F) - the power of radiant energy, estimated by the visual sensation it produces, measured in lumens (lm).

Luminous flux unit -lumen (lm) is the luminous flux emitted by a point source with a solid angle of 1 steradian at a light intensity of 1 candela.

• Steradian - a solid angle with a vertex at the center of the sphere that cuts out an area from the surface of the sphere, equal to the area a square with a side whose length is equal to the radius of the sphere.
• The power of light (I) is defined as the ratio of the luminous flux ( F) emanating from the source and propagating uniformly inside the elementary solid angle ( d), to the value of this angle: I = f/d.
• Candela is the intensity of light emitted from an area of ​​1/600,000 m 2 of the cross section of a full emitter in the perpendicular direction at the temperature of the emitter, equal to the temperature solidification of platinum at a pressure of 101 325 Pa.

In the physiology of visual perception importance is given not to the incident stream, but to the level of brightness of illuminated and other objects. Under brightness understand the characteristic of luminous bodies, equal to the ratio of the luminous intensity in any direction to the projection area of ​​the luminous surface on a plane perpendicular to this direction. Brightness is measured in nitah (nt). The brightness of illuminated surfaces depends on their light properties, the degree of illumination and the angle at which the surface is viewed.

The luminous flux incident on the surface is partially reflected, absorbed or transmitted through the illuminated body. Therefore, the light properties of the illuminated surface are also characterized by the following coefficients:

• reflection coefficient - the ratio of the light flux reflected by the body to the incident;
• transmittance - the ratio of the light flux passing through the medium to the incident one;
• absorption coefficient - the ratio of the light flux absorbed by the body to the incident.

Light parameters and coefficients

There are two sources of light - the Sun and artificial sources created by man. The main artificial light sources currently in use are electrical sources especially incandescent and gas discharge lamps. The light source radiates energy in the form of electromagnetic waves having different wavelengths. A person perceives electromagnetic waves as light only in the range from 0.38 to 0.76 microns.

Lighting and light environment is characterized by the following parameters.

Light flow (F)- part of the electromagnetic energy that is emitted by a source in the visible range. Since the luminous flux is not only a physical, but also a physiological quantity, since it characterizes visual perception, a special unit of measure lumen (lm) has been introduced for it.

The power of light(I). Since a light source can emit light in different directions unevenly, the concept of luminous intensity is introduced as the ratio of the magnitude of the luminous flux propagating from the light source in a certain solid angle W(measured in steradians), to the value of this solid angle

I \u003d F / W.

Light intensity is measured in candelas (cd).

The sun and artificial light sources are the primary sources of luminous flux, i.e., sources that generate electromagnetic energy. However, there are secondary sources - the surfaces of objects from which light is reflected.

Reflection coefficient (r) is called the fraction of the luminous flux ( f pad) incident on a surface that is reflected from it:

r = F negative / F down

The magnitude of the luminous flux ( F neg), reflected by the surface of the object and propagating in a certain solid angle ( W) divided by the value of this angle and the area ( S) of a reflective surface is called brightness (L) object. It is essentially the intensity of light emitted by a surface, divided by the area of ​​that surface:

L = Fotr / (W * S); L = I/S.

The brightness is measured in cd/m 2 .

The greater the brightness of the object, the greater the light flux from it enters the eye and the stronger the signal from the eye to the visual center. Thus, it would seem that the greater the brightness, the better man sees the object. However, this is not quite true. If the surface (background) on which the object is located has a brightness close in magnitude, then the intensity of illumination of the retinal regions by the light flux coming from the background and the object is the same (or slightly different), the magnitude of the signals entering the brain is the same, and the object against the background becomes indistinguishable.

For better visibility of the object, it is necessary that the brightness of the object and the background differ. The difference between the brightness of an object ( L O) and background ( L f) related to the brightness of the background is called contrast:

K = | L o - L f | / L f.

The contrast value is taken modulo.

If the object stands out sharply against the background (for example, a black line on a white sheet), the contrast is considered high, with an average contrast, the object and background differ noticeably in brightness, with a low contrast, the object is faintly visible against the background (for example, a pale yellow line on a white sheet) . At To< 0,2 contrast is considered small K = 0.2...0.5 the contrast is average, and K > 0.5- big.

The value of the brightness of the object is the greater, the greater the reflection coefficient and the light flux incident on the surface.

To characterize the intensity of the luminous flux incident on the surface from a light source, a special quantity is introduced, called illumination.

illumination is the ratio of the light flux incident on the surface ( f pad) to the area of ​​this surface ( S)

E = Ф pad / S.

Illumination is measured in lux (lx), 1 lx \u003d 1 l m / m 2.

Thus, the greater the illumination and contrast, the better the object can be seen, and consequently, the less strain on vision. It should be noted that too much brightness adversely affects vision. As a rule, high brightness is associated not with too much illumination, but with very high reflectances (for example, mirror image). At high brightness, a very intense illumination of the retina takes place, and the decomposing photosensitive material does not have time to recover (regenerate) - the phenomenon of blindness occurs. Such a phenomenon, for example, occurs when looking at a hot tungsten filament of an incandescent lamp with high brightness.

One of the characteristics of visual work is the background - the surface on which the object is distinguished. The background is characterized by the ability of the surface to reflect the light falling on it. Reflectivity is determined by the reflectance G. Depending on the color and texture of the surface, the values ​​of the reflection coefficient vary over a wide range - 0.02 ... 0.95. The background is considered light when r>0.4, average at values r in the range 0,2...0,4 and dark at r<0,2 .

To illustrate the effect of contrast on visual perception, put a black hair on a dark sheet of paper and a white hair on a white sheet of paper, then vice versa. You will notice that in the second case, both hairs can be seen much better, because there is more contrast.

To illustrate the effect of illumination on visual perception, carry out the same experiment with different illuminations in a room. The best result can be achieved in cloudy weather with insufficient natural light in the room. Consider a black hair on a dark sheet with the lights off and on. When the light is on, the hair is better visible. White hair on a dark background is visible even when artificial lighting is turned off.

An important characteristic on which the required illumination in the workplace depends is the size of the object of distinction.

Discrimination object size- this is the minimum size of the observed object (subject), its separate part or defect, which must be distinguished when performing work. For example, when writing or reading, in order to see the text, it is necessary to distinguish the thickness of the line of the letter - the thickness of the line will be the size of the object of distinction when writing or reading text. The size of the object of distinction determines job description and grade. For example, with an object size of less than 0.15 mm, the category of work of the highest accuracy (I category), with a size of 0.15 ... 0.3 mm - a category of very high accuracy (II category); from 0.3 to 0.5 mm - high-precision discharge (III category), etc. With a size of more than 5 mm - rough work.

Obviously, the smaller the size of the object of distinction (the higher the level of work) and the lower the contrast of the object of distinction with the background on which the work is performed, the more illumination of the workplace is required, and vice versa.

Control of lighting parameters

To assess the lighting conditions (natural and artificial), illuminance (E, lx) is measured using luxmeters.

Luxmeter(Fig. 5) is a portable device consisting of a light-sensitive element, a measuring device and a light-absorbing nozzle.

A photocell is a plate on the surface of which a photosensitive layer is applied, which transforms light energy into electrical energy. When a light flux hits a photocell, an electrical signal arises, which is transmitted through wires to an electrical measuring device that has a galvanometer with a mirror scale. The magnitude of the resulting electric current is proportional to the intensity of the light flux. If a cap-absorber made of milky glass is put on the photocell, then the light flux falling on the photosensitive layer is attenuated by 100 times.

The device has three measurement ranges: up to 25; up to 100 and up to 500 lux (set by a special switch on the instrument case), and if an absorber is put on the photocell, then the measurement limits increase 100 times, respectively - up to 2500, 10,000 and 50,000 lux. If the switch is against the number 25, then without a nozzle the price of a scale division (has 50 divisions) is 25/50 = 0.4 lux, and with a nozzle it is 100 times more, i.e. 40 lux. Accordingly, in the position of the switch against the number 100, the division price is 100/50 = 2 lux, and with a nozzle - 200 lux, and, finally, in the position against the number 500, it is 500/50 = 10 lux, and with a nozzle - 1000 lux.

Rice. 5. Luxmeter

The light meter is calibrated for incandescent lamps. When measuring the illumination of fluorescent lamps and natural illumination, it is necessary to enter a correction factor: for fluorescent lamps - 0.9; for white light lamps - 1.1; for natural light - approximately 0.8.

When performing measurements, the light meter is installed horizontally and the position of the arrow is checked - it should be at zero. If the needle is deflected, it must be set against zero using a slot under the galvanometer.

Natural lighting is characterized by the coefficient of natural illumination e,%:

e \u003d E in / E n * 100,

• E in - illumination indoors, lx;
• E n - simultaneous illumination by diffused light from the outside, lx.

The normalized value "e" is determined according to SNiP 23-05-95, taking into account the nature of visual work, the lighting system, the location of the building on the territory of the Russian Federation and its location in relation to the sun.

Artificial lighting, carried out by gas-discharge and electric lamps, according to the design, can be of two systems - general lighting and combined (general and local). The illumination of the working surface, created by general lighting fixtures in the combined lighting system, must be at least 10% of the standard for combined lighting.

Artificial lighting is normalized based on the characteristics of the work, while both quantitative (minimum illumination, permissible brightness) and qualitative characteristics (glare index, pulsation coefficient of illumination, radiation spectrum) are set.

The minimum illumination is set according to the conditions of visual work, which are determined by the smallest size of the object of distinction, the contrast of the object with the background (large, medium, small) and the characteristics of the background (dark, medium, light).

The calculation of artificial general uniform illumination is carried out by the method of light flux (utilization factor).

The luminous flux of an incandescent lamp, an energy-saving lamp or a group of fluorescent lamps combined into one lamp is determined by the formula:

• E n— normalized minimum illumination, lx;
• S- the area of ​​the illuminated room, m 2;
• z- minimum illumination coefficient (1.1-1.5);
• k 3- safety factor (1.3-1.8);
• n- the number of lamps in the room;
• η and- coefficient of use of the luminous flux.

According to the luminous flux obtained as a result of the calculation, according to GOST, the nearest standard lamp is selected and the required electric power is determined. When choosing a lamp, a deviation of the luminous flux from the calculated one within 10-20% is allowed.

The level of illumination of industrial buildings is measured directly at workplaces in the working area (in the zone of cutting and processing parts, on assembly tables, on instrument scales); in administrative and amenity premises, illumination is measured at workplaces, which are desktops, calculating and typewriters, etc. Depending on the nature of production and the design of the equipment, the working area can be in a horizontal, vertical or inclined plane. In rooms where work can take place anywhere in the room, the illumination is measured in a horizontal plane at a level of 0.8 m from the floor.

A very important necessary and time-consuming part of the work related to lighting control is periodic (4-12 times a year, depending on the dustiness of the room) cleaning of lamp bulbs and reflective, scattering and other surfaces and parts of lamps from dust and dirt accumulating on them. Illumination at individual enterprises, as studies have shown, within a few months of operation, if the lamps are not cleaned, can decrease by 2-3 times compared to the design one.

Preservation of the necessary lighting conditions created by the lighting installation largely depends on the timeliness of the replacement of light sources (both burnt out lamps and those that continue to work, but with a significantly lower luminous flux compared to the nominal one).

Replacement of lamps is usually carried out individually or by a group method (after a certain period of work). Large enterprises with an installed total lighting capacity (over 250 kW) must have a specially assigned person in charge of lighting operation (engineer or technician). Illumination is checked at least once a year, after regular cleaning of fixtures and replacement of burnt out lamps.

With the rising price of electricity, the popularization of environmental trends in the world, as well as the reduction in the price of LEDs, LED lighting is becoming increasingly popular. With low energy consumption, durability, safety and a wide range of products, this type of lighting fixture is rapidly gaining a foothold in the market and taking its rightful place in a large number of homes.

Due to the fact that the characteristics of LED-devices differ from classic incandescent lamps and gas-discharge devices, when switching to them, the question often arises,. Difficulties are also added by the dominance in the sale of budget diode lamps, which have low power. As a result, some users may form a false opinion about the technology as a whole, underestimating its real potential. This material is intended to correct the current situation. Its purpose is to help find outhow to calculate the lighting area of ​​led lamps, decide on the most suitable type of lamps and understand what the Chinese often keep back, forming an incorrect opinion about LED.

Fundamental differences between LED and classical technologies

A brief excursion into history

LED devices were invented more than eighty years ago, in parallel by several engineers (among them is the Russian physicist Oleg Losev). Due to the special properties of individual semiconductors, scientists have achieved the effect of their glow when an electric current passes. However, the first samples were distinguished by high manufacturing cost, had very low brightness and the same service life. Later, in the 50-80s of the XX century, the first LEDs that could be used in practice were created in the USA and Japan. Scientists have developed red, green, blue, white, as well as ultraviolet and infrared semiconductor light sources. It wasn't until the 1970s that the technology became relatively affordable, before that each diode could cost hundreds of dollars.

In the 90s, when relatively inexpensive LED elements and equipment for their mass replication (thousands and millions of copies) appeared, it became possible to introduce them as sources of household lighting. Prior to that, they were used mainly as indicators in various electrical engineering. And only in the 2000s, when mass production of cheap LEDs was launched all over the world, and most importantly, in China, the cost of a powerful LED lamp (bright enough to serve as the main light source in the house) decreased from tens of dollars to units. After that, the boom in LED lamps in the world began.

LED lamp device

The design of the LED lamp is fundamentally different from other light sources. The main difference is the multi-element layout. "Ilyich's lamp" emits light in the visible range due to heating to ultra-high temperatures (about 3000 ° C) of a tungsten filament. A gas-discharge (luminescent) lamp does this by glowing a phosphor layer deposited on the inner walls of a gas-filled glass tube when current is passed through it. Both types of such lighting devices are united by the fact that the source of visible radiation in their design, as a rule, is one. Power scaling is achieved by increasing the size of the fixture or using multiple lamps in parallel. Against this background, LED lamps are very different, as they are, in fact, an assembly of dozens of miniature LEDs. By changing their number and modifying the control electronics, it becomes possible to create bright light sources in a compact package. With traditional types of lighting, this is not possible, since an increase in brightness leads to a significant increase in size.

The layout features of LED lamps provide a number of advantages, but also impose a number of limitations that are important to consider before. To interconnect dozens of elements, a special printed circuit board is required, and a control electronics unit must also be placed in the housing. Therefore, LED lamps have significant differences from analogues.

How to calculate LED lighting: types of lamps

Due to the presence of a printed circuit board with a control system, the body of the lamp is partially opaque. Wanting to maintain compatibility with conventional chandeliers, floor lamps, sconces, table lamps, manufacturers are trying to stick to the classic form factor. The most popular are the varieties that have received the names "pear" and "corn" in common parlance. "Candle" is somewhat less common.

Pear lamp

"Pear" refers to the type of LED lamps, the shape of which repeats that of a conventional incandescent lamp. The body of such an LED lamp is half made of opaque plastic with ribs to improve cooling. Its second part is a transparent, shaded or colored hemisphere with a layer of phosphor. On the border of these parts there is a board with diodes directed in one direction. Due to this design, the light scattering angle is not almost 360 ° (as with incandescent lamps, the “dead zone” of which falls only on the area with the base), but only 180 ° or a little more.

Corn lamp

In the "corn" board with placed diodes is perpendicular to the base, along the longitudinal axis of the light bulb. It can be made in the form of a plate, a tube of round, square or polygonal (from 3 to 8) section. LED elements are located on its front part, while the electronics are hidden in the base, the area near it or inside the tube. Due to the similarity of the board on which the semiconductors are placed, with a corn cob, this type of lamps got its colloquial name. Such lamps are distinguished by a large coverage angle, since two "blind zones" are located only in the areas of the base and at the opposite end of the bulb. The latter may be completely absent if the diodes are also present at the end.

Candle lamp

"Candle lamp", due to the elongated body, is a compromise between "pear" and "corn". It provides a wider glow angle than the first, but is limited in size and power. The main scope of "candles" - table lamps and local lighting of small areas.

How to choose LED lamps by shape

Before, how to calculate led lighting for a room, it is necessary to determine the type of light bulbs used. To a large extent, it depends on whether the existing lighting equipment (chandeliers, ceiling lamps, floor lamps) will be used, or new electrical wiring is being designed.

In the first case, it is worth paying special attention to the area and the angle of light scattering. Depending on what type of fixtures is installed in the room, the type of LED-devices is also determined.

• Hanging ceiling or chandelier, in which the lamps are directed downwards, are optimally combined with pear-type lamps, which will scatter light throughout the area and walls. The "blind zone" of such LED lighting will be in the space under the ceiling, which is usually not used. "Corn" with diodes on the end is also great for a hanging ceiling, as it illuminates the floor, walls, and ceiling space.
  
• Spotlights installed in the false ceiling structure,also goes well with pears. The base of the lamp and its opaque part will be hidden by a decorative layer of finishing material, but the light emitted by the working part of the device will evenly fill the entire space. But you shouldn’t put “corn” in such devices - a significant part of the diodes will be directed to the subceiling space.
  
• Chandelier in which the cartridges are directed upwards with "pears" is incompatible! The only exceptions are rooms with a mirrored ceiling. The light of such a diode lamp will be directed upwards, and a shaded area will form under it. Worst of all, the central part of the room will be illuminated, where even a mirrored ceiling cannot fully compensate for the lack of brightness.
  
• Spotlights and sconces installed on the walls,optimally combined with oblong lamps "corn". The light emitted by them is directed both down and up, and on the walls. The orientation of the cartridge (socle up, down or parallel to the ground) in this case has practically no functional significance.
  
• Spotlights recessed into the thickness of the wall, with "corn" are combined worse. Here the situation is similar to ceiling counterparts: only the end of the lamp emits “useful” light (where there are few diodes), and the side LED elements illuminate the niche in which the device is located.
  
• For table lamps, sconces, floor lamps, where the cartridge "looks" down, it is desirable to purchase "pears" or "candles". The task of such lighting structures is to effectively illuminate a site with a small area, and a “pear”, covered with a ceiling lamp on the sides, will cope with it best. "Corn" also suitable, but, again, part of the light will be lost to illuminate the walls of the ceiling (which do not always have good reflective characteristics).
• Ceiling fixtures in which the socket is placed parallel to the floor, combined best with "corn". "Pear" is only suitable if you need to concentrate the maximum light in one part of the room, and the other can be neglected. But even in this situation, a lack of light in the central part of the room cannot be avoided.
  

If the lighting is designed from scratch, and certain goals are set (for example, uniform bright filling of the entire space of the room with light, or its concentration in certain areas), you can choose the type of devices for the type of lamps, and not vice versa. Before,how to calculate the lighting in the room, ledit is enough to analyze the equipment for the presence and location of "dead zones" in order to buy those lamp models that are optimal. Otherwise, everything said in the previous paragraph is applicable in this case.

Before, how to calculate led lighting for a room, it is important to take into account the fact that diodes are afraid of overheating. If the room is large (more than 20 m2), and the lamps will be installed in a compact and closed (partially or completely) case, one central chandelier may not be enough. This is due to the fact that a powerful lamp installed in such a design generates a lot of heat that will not be effectively dissipated, leading to overheating of the LED semiconductors. Although this heat dissipation is many times less than that of the “Ilyich light bulb”, the incandescent lamp is specially designed for ultra-high temperatures, but the degradation process of diodes is accelerated even at temperatures below 100 ° C. The way out of this situation is the use of multi-lamp chandeliers or the installation of additional lamps in the remote corners of the room.

How to calculate the lighting area of ​​LED lamps

Lumens (lm) is the basic unit for measuring the brightness of a light flux, adopted by lighting manufacturers. The related candela (cd) is also popular, but less commonly used because it is more difficult to handle. In SNiP, which regulate the norm of illumination, a unit is used that is derived from the lumen - lux (lx).

1 lux = 1 lm/m2

Thus, beforehow to calculate led lighting for a room, you need to know its area, and also take into account the functional purpose of the room.

Due to the fact that incandescent lamps with a power of 40 to 100 W have been the most popular as a household light source for many years, as well as to reduce the number of “dry” numbers and make the process more clear, it is their characteristics that can be used as a guideline.

In 2011, the authorities of the Russian Federation passed a law prohibiting the sale of incandescent lamps with a power of 100 watts or more. Due to the fact that the exact value of this parameter depends on the mains voltage (which at different times of the day, especially in industrial areas, can vary from 200 to 250 V), as well as the individual characteristics of a particular lamp instance, a detailed power calculation is impossible. Lamp manufacturers, to get around the ban, began to label 100-watt products as 99, 95 or 90 watts (which, at a certain voltage, is true), but the devices themselves have not changed. Therefore, calculations, where a 100 W lamp is taken as a brightness reference, are also applicable to analogues at 90-99 W.

According to the regulations, the luminous flux of a 40-watt incandescent lamp is from 415 lumens, 60 W - 710 lm, 75 W - 935 lm and 100 W - from 1340 lm. As can be seen from the above data, the more powerful the lamp, the more economical it is in terms of brightness, but more voracious in general. LED devices do not have such a drawback, since each diode consumes a fixed current, and the total consumption is almost directly proportional to the number of semiconductor elements. Depending on the price category of the lamp, it is 70-150 lm / W (against 13-16 lm / W for a 100 W incandescent lamp), that is, in general, LED devices are 5-11 times more efficient.

A little about the Chinese

Recently, cheap LED lamps can often be found on sale, costing 100-200 rubles. Often they can be completed with a cardboard package with Russian inscriptions, but sometimes they come in a simple, so-called OEM package, or a box without Russian signatures. These are, as a rule, products of Chinese factories, which are supplied directly from China or through Russian OEMs.

Products from the Middle Kingdom can often be packaged with untrue characteristics. This is the fault of either unscrupulous manufacturers, or their Russian customers who want to reduce the cost of products sold. In the descriptions of the lamps that are on sale, you can often find loud statements like “consumes 10/15/20 times less than a regular light bulb!”. When choosing such products, it should be remembered that this indicator is often rounded up, with an accuracy of 5 or 10. In fact, an LED lamp, priced at 100-200 rubles, simply cannot physically be similar in quality to a product of a world famous brand, like the same Philips. Such companies are aware of competition and value their reputation, so they will not unreasonably wind up hundreds of percent of their profits.

This is what cheap Chinese lamps look like

The statements of sellers who claim that a 5 W LED lamp worth 100 rubles is equivalent to a 75 or 100 W "Ilyich's light bulb" should not be trusted. Practice shows that the actual ratio of their brightness is about 1 to 5, at best, 1 to 7. That is, 1 watt of an LED lamp is equivalent in brightness to 5-7 watts of an incandescent lamp. It is important to consider this beforebudget category.

Users decide whether or not to buy cheap lamps. It is only worth noting that devices sold for nothing (around 100 rubles) may also have control electronics. At best, they will simply burn out in a short time, at worst, they will flicker and gradually lose their original qualities, leading to chronic eye fatigue. Therefore, when buying a cheap lamp, it is better to immediately test it in a store or at a delivery point.

Calculation of the power of LED lamps

According to the SNiP norms in force in Russia, the following lighting standards are approved for the following types of premises:

• An office in which work is carried out at computers - 300 lx (300 lm / m2).
• Office in which drawing work is carried out - 500 lx.
• Conference hall - 200 lx.
• Office stairs - 50-100 lux.
• Stairs of residential buildings - from 20 lux.
• Passage rooms (corridors, halls, lobbies), utility rooms, storerooms and archives, bathrooms, toilets, changing rooms and dressing rooms - from 50 to 75 lux.
• Bedrooms, kitchens, children's and other living quarters - 150-200 lux.
• Office, library - 200 lux.

Considering that the power of a cheap LED lamp is up to 80-90 lm / W, to ensure sufficient illumination of a bedroom with an area of ​​​​10 m2, you need from 1500 lm, and a 100 W incandescent lamp is capable of doing this, a budget LED lamp from 18 W or 3 of these device at 6 watts. When using branded products, the light output will be higher - from 100 lm / W. For the same bedroom of 10 m2, a 14-15 W LED bulb is required.

If incandescent lighting, which has been used indoors for a long time, is satisfactory in terms of brightness, and the transition to LED is caused by the desire to save on utility bills / contribute to environmental protection / keep up with the times / change the color temperature of the light (everyone there may be a reason) - you can simply make a calculation, starting from the available parameters. So, a 100 W incandescent lamp can be replaced by a 13-16 W “LED”, an alternative to the “seventy-five” will be a 10 W LED, and a “magpie” will be replaced by a high-quality 3 W LED lamp.

Selecting a color temperature

LED lamps have one more parameter that is important to consider before. This is the color temperature, which determines the hue of the emitted light. It is measured in kelvins (K). The higher this indicator, the closer to white and blue shades the radiation will be. For incandescent lamps, this figure ranges from 2000 K (25 W) to 2800 K (100 W) and corresponds to a light yellow or light orange color.

The color temperature of LED lighting sources varies from 2500 to 7000 K.

• 2500-3000 K. Warm yellow light, close to incandescent light.
• 3000-4000 K. Warm white, with hints of yellowness, close to daylight.
• 4000-5000 K. Neutral white, close to daylight.
• 5000-7000 K. Cold white, with shades of blue at the upper border.

Which one to choose depends largely on taste preferences. However, it should be borne in mind that experts recommend different color temperatures for different types of premises.

Warm shades (up to 4000 K) are preferred for bedrooms, living rooms, kitchens. Neutral and cold colors are best suited for bathrooms, basements, offices, halls, hallways, bathrooms. Physiologists note that it is under illumination with a temperature of 4000-6000 K that the human body demonstrates maximum labor productivity and best perceives information.

A big fan of high-quality Chinese technology, a lover of clear screens. A supporter of healthy competition between manufacturers. He closely follows the news in the world of smartphones, processors, video cards and other hardware.

The correct choice of the level of illumination of the room is considered one of the conditions for a comfortable stay and is clearly standardized by regulatory documents on labor protection, a number of state standards and, of course, a set of building codes and regulations No. 23-05-95. The calculation of the illumination of the premises in the house is carried out by specialists at the design stage, and during the acceptance of a new building, the indicator can be controlled by the selection committee. In fact, knowing the level of illumination in the house is also important because it affects the health of a person and the state of his vision.

How is the theoretical determination of the level of illumination performed?

The method for calculating lighting is reduced to obtaining the value of the required luminous flux of one lamp used to illuminate a room under specific conditions, with previously known characteristics. Simply put, they make up a simplified model - a light bulb under the ceiling in an empty room. Based on the model, knowing from the recommendations of SNiP the level of illumination for this category of premises, the luminous flux of the lamp and its power are determined.

To calculate lighting and luminous flux, you need to know:

• The norm of illumination for a particular type of premises, usually in reference books, illumination is indicated by the index E n, measured in lux, Lx;
• The total area of ​​​​the room - S, unit of measure in m 2;
• Three correction factors - k - margin rate, z - correction for the unevenness of the light source, n c - efficiency factor for the use of the light flux;
• The number of light fixtures is N, and the number of light bulbs in one fixture is n.

In order to correctly calculate the luminous flux of a lamp, it is necessary to take data from reference tables, use information about the geometry of the room and the characteristics of the light source, and substitute them into a well-known formula that determines the magnitude of the luminous flux.

The luminous flux formula looks like this:

F l \u003d (E n ∙S ∙ k ∙ z) / (N ∙ n ∙ n c).

Advice! When using old reference books, pay attention to the dimensions of the given values.

After calculating by the formula, we obtain the value of the luminous flux for one lamp in lumens. It remains only to choose the right version of the light source. In a similar way, the inverse problem of calculating the illumination is solved, namely, according to the known data of the luminous flux Ф l for a particular light bulb, knowing the other characteristics and coefficients, it is possible to calculate the illumination for specific conditions using the formula:

E n \u003d (F l ∙N ∙ n ∙ n c) / (S ∙ k ∙ z).

Variant of calculating the illumination in the room

There is nothing complicated in how the value of the amount of light and illumination is calculated, it is only necessary to strictly follow the recommendations and choose the right data from the reference tables. For example, let's take an ordinary room with an area of ​​​​20 m 2 with a standard ceiling height of 250 cm. For simplicity, we will assume that the ceiling is white, matte, and the walls have a plain coating without gloss, beige. All these data are needed to calculate the illumination or illumination.

As a lighting device, a ceiling lamp of five light bulbs is used, each of which is covered with a diffusing white shade. The plane of the lamps is at a height of 2.3 m.

To calculate the lighting, the following reference data will be required:

1. Tabular information on the coefficient of use of the lamp;
2. Calculation of the luminous flux utilization factor;
3. Correction for unevenness;
4. stock factor.

The first item in determining the amount of illumination will have to be taken from the table, the rest are obtained by correction or a simple calculation according to the characteristics of the room.

How to choose coefficients for calculating illumination

The simplest is the selection of a correction for unevenness and a safety factor. The latter parameter is used to take into account the decrease in the luminous flux density of the lamp due to the deposition of a layer of dust in the calculation of illumination. For residential premises, with a dust content in the air of less than 1 mg per cubic volume, a value equal to 1.2 for electrified fluorescent bulbs is taken for calculation. For ordinary incandescent 1.1 and for the coldest low-voltage LED devices, the coefficient is taken equal to 1.

The correction for unevenness is used to take into account the nature of the work in the room. For lamps with an incandescent filament, it is 1.15, for LEDs it is 1.1.

The flow efficiency factor is determined by calculating the index according to the formula:

I=S/((a+b)∙h),

where S is the floor area of ​​the room, a, b, h are the length, width and height, respectively. For our case, the calculation of the index gives a value of 0.9 units. Knowing the illumination index of the room, the percentage of reflection - for the white surface of the ceiling - 70%, for beige walls - 50% and gray floor - 30%, the location of the lamp on the ceiling, we determine from the tables the efficiency factor for using the flow n c \u003d 0.51.

Let's select a lamp for lighting

Knowing the required numerical values ​​of the coefficients, we substitute them into the luminous flux formula for our case F l \u003d (E n ∙ S ∙ k ∙ z) / (N ∙ n ∙ n c) \u003d (150 * 20.0 * 1 * 1.1) / (1 * 0.51 * 5) \u003d 3176.25 / 2, 55=1245 lm. This means that for the room we have chosen, with a standard of illumination E n \u003d 150 lux, the luminous flux of one LED lamp should be 1245 Lm. In order to complete the calculation to correctly select the light source, you will need to compare several options for lighting fixtures with different light temperatures, from the warmest at 2750K to cold white at 4500K.

This stage of the calculation is the most time-consuming. In the nomenclature of modern light sources, there are four main types:

• Halogen bulbs;
• Incandescent lamps;
• Luminescent devices;
• LED light sources.

There are conditional tables of correspondence between light output or luminous flux density and power consumption. In our example, table data was used. The most common filament lamp produces a relatively soft warm light but has low light output. According to the calculation of illumination, in order to provide a flux of 1245 Lm, you can take a 100 W light bulb, which produces a luminous flux of 1300 Lm. Among halogen bulbs, the closest in terms of characteristics at 75 W produces 1125 lm, which is clearly not enough. Closer characteristics have a fluorescent lamp of 20 W and 1170 Lm, LED of 12 W and 1170 Lm.

We choose the last option and calculate the illumination in the room according to the above formula E n \u003d (F l ∙N ∙ n ∙ n c) / (S ∙ k ∙ z). As a result, we obtain a value equal to 141 lux, which is allowed by the norms of SNiP. For the living room and bedroom, the illumination value should be from 100 to 200 lux, for the kitchen 200-300 lux, for the bathroom and toilet 50-150 lux. If desired, using the above methodology, you can recalculate a variety of illumination options for various light sources. The most economical was the LED version, with a consumption of 12x5 \u003d 60 W, the lamp gave out 5850 Lm, which corresponds to the power of 500 W of an incandescent lamp.

The most primitive calculation can be performed, guided by the rule - for 1 m 2 a light source with a power of 20 watts is required. But such a determination of the power of a lighting device can only be performed for a square room with white walls and a ceiling, with a ceiling-mounted lamp. For other cases, the error will be more than 20%.

Conclusion

The methodology for calculating lighting, indicated in the SNiP and based on statistical material, was drawn up in an era when, apart from incandescent lamps and fluorescent devices, there were no other options. If only these rules are followed, then LED lamps with a maximum illumination temperature of 4-5 thousand K should be the most profitable and comfortable. In practice, such lamps turn out to be very annoying and blinding during prolonged use, so owners often deliberately use warmer lamps incandescent as more comfortable. The calculation of illumination does not take this into account.

We suggest you figure out how to do it right lighting calculation depending on the type and size of the room.

The degree of illumination of the surface is usually expressed in Lux (Lx), and the amount of luminous flux emanating from a particular light source is measured in Lumens (Lm). We will produce illumination level calculation in two stages:

• the first stage - determining the total amount of light flux necessary for the premises;
• the second stage - based on the data obtained from the first stage - calculation of the required number of LED lamps considering their power.

Stage number 1 of the calculation.

For a simple calculation of the required number of lamps, use the Lamp Quantity Calculator.

The formula = X * Y * Z calculates the indicator of the required amount of luminous flux (Lumens) while:

• X - the established norm of illumination of the object, depending on the type of room. The norms are given in Table No. 1,
• Y - corresponds to the area of ​​\u200b\u200bthe room in square meters,
• Z is the correction factor for values ​​depending on the height of the ceilings in the room. With a ceiling height of 2.5 to 2.7 meters, the coefficient is equal to one; from 2.7 to 3 meters, the coefficient corresponds to 1.2; from 3 to 3.5 meters the coefficient is 1.5; 3.5 to 4.5 meters the coefficient is 2.

Table No. 1 "Illumination standards for office and residential facilities according to SNiP"

Stage number 2 of the calculation.

Having received the necessary data on the magnitude of the luminous flux, we can calculate the required number of LED lamps and their power. Table No. 2 shows the power values ​​\u200b\u200bof LED lamps and their corresponding luminous flux indicators. So, we divide the value of the luminous flux obtained at stage No. 1 by the value of the luminous flux in lumens according to the selected lamp. As a result, we have the right number of LED lamps of a certain power for the room.

Table No. 2 "Values ​​​​of the luminous flux of LED lamps of different powers"

An example of lighting calculation.

150 (X) * 20 (Y) * 1 (Z) = 3000 Lumens.

Now, according to table No. 2, we select a lamp that fits into the installed lighting fixtures, and with which we want to illuminate our room. Suppose we take all 10 watt lamps with a luminous flux of 800 Lumens, then to illuminate our room with such LED lamps we need at least 3000/800 = 3.75 light bulbs. As a result of mathematical rounding, we get 4 light bulbs of 10 watts.

It is important to remember that it is desirable to achieve a uniform distribution of light in the room. To do this, it is better to have several light sources. In case you are planning to create artistic lighting with multiple ceiling-mounted fixtures, we recommend using 8 LED bulbs of 5 watts each and evenly distributing them across the ceiling.

Please note that we took the norms of SNiP adopted in our country as the basis for the calculations. Since these standards were developed and adopted a long time ago, many of our clients say that the level of lighting according to these standards is low for them and there is clearly not enough light. Therefore, we recommend increasing these standards by 1.5-2 times while installing several switches, dividing them by room zones and by the number of lamps. This will turn on some of the fixtures and get soft, not very bright lighting, and, if necessary, turn on full bright lighting.

Lighting in the house is an important component of a comfortable stay in it. In our world, natural lighting cannot satisfy all the needs of people, and artificial light sources are simply indispensable in an apartment.

However, not everyone knows that there are special standards for calculating the level of illumination for each room. According to them, you should calculate the number of light bulbs that should be installed for each particular room. How to do this and why it is needed at all will tell our article.

Light value

Poor lighting is the enemy of vision

The role of light in everyday life is difficult to overestimate, because without lighting the comfort of our home will be greatly reduced. Light has an impact not only on the safety of our movement around the apartment, but also on health indicators. If the room is illuminated by an insufficient number of lamps, the following health problems may occur:

• significant loss of visual acuity. In the worst case, you may need glasses and a consultation with an ophthalmologist;
• decrease in the general health of households;
• the appearance of excessive irritability;
• a drop in immunity and an increase in the incidence of colds;

Note! Incorrect lighting of the room especially negatively affects the health of children.

• decrease in work productivity;
• sleep disturbance;
• decrease in the emotional background of the household.

As you can see, for each room it is necessary to calculate the required number of light bulbs, with the help of which sufficient lighting of the room will be created.

As we found out, lighting in the house plays a huge role. Lamps should give as much light as necessary for a particular room.
In an apartment or a private house, each room has its own purpose and features of operation (kitchen, bedroom, living room, corridor, etc.). Particular attention in this matter must be paid to the children's room, since for children even a slight deviation of the light flux from the norm can lead to a negative effect on the body. Each room should have its own indicator of the number of light bulbs and fixtures.
To calculate the number of lamps that you need for a particular room, you should use special formulas. Ideally, illumination should be taken into account at the design stage of buildings and rooms. With proper planning, the lamps will give enough light for a comfortable stay of a person in a particular room.

Lighting design

The degree of illumination is regulated by some legal acts that are part of the SNiP (building codes and rules), as well as SanPiN (sanitary standards and rules). These documents at the regional level are supplemented by various acts and industry documentation.
The documents for private houses and apartments contain recommended and minimum standards regarding illumination. They are indicated in Lux per m2.
Note! In this documentation, 1 Lux is taken to be the illumination that is available in the tropics during the full moon. At the same time, incandescent lamps of 100 watts give illumination of 1350 Lux.
It is necessary to calculate the required number of light bulbs for each room according to the regulatory documentation with minor adjustments, since only the minimum values ​​\u200b\u200bare given here.

Lighting types

Before proceeding with the calculations of the required number of light bulbs, it is necessary to understand what kind of lighting happens. So, as you might guess, it can be of two types:

• natural;
• artificial, which is created by lamps. It is for this type of lighting that calculations will be made on the number of light bulbs.

artificial lighting

In turn, artificial lighting can create the following types of light bulbs:

• incandescent lamps;
• LED bulbs. These are the so-called LED-lamps. In this context, it is necessary to consider separately Led lamps and Led strips, which work on the same principle;
• fluorescent lamps;
• halogen lamps. Separately, it is worth noting that among the halogen types of light sources there are some more subspecies. This must also be taken into account in the calculations;
• neon lamps.

Luminous flux of lamps

Each of the above types of light bulbs creates lighting in a certain range in Lux. Therefore, when calculating, it is necessary to take into account the type of lamp that will create light in the room.
At the same time, do not forget that artificial light sources can create the following lighting:

• general. In this case, the illumination of the room is carried out using a centrally located lighting device. Often a chandelier plays its role;
• combined. A distinctive feature of such room lighting is that local lighting is formed here - zoning of the room is organized using lighting fixtures. In addition, each zone may differ in the degree of brightness of the light.

Lighting calculation

Lighting calculation is a complex process of determining the required number of light sources for each individual room. It is carried out by several methods and requires taking into account all the parameters of the room, its technical and physical characteristics, as well as an assessment of the type of light bulbs used.
Note! Accuracy in calculating the required number of lamps for rooms in apartments and houses does not require such accuracy. It is enough to fall within the acceptable range to prevent a negative effect on the human body.
But here you need to take into account some caveats:

• the luminous flux that the lamps create. They can be of different types. Particular emphasis should be placed on halogen and LED lamps, as they have another gradation in terms of luminous flux;
• ceiling height (in rare cases, the distance from the floor to the wall lamp). This indicator may be different, since all the buildings of the last century, of which the prevailing majority in our country, were built according to different architectural ideas. This parameter can be varied by choosing, for example, low-hanging chandeliers with high ceilings;

Ceiling height is important

• the purpose of the premises. For the kitchen and children's room, more light is needed than for the corridor or bedroom.

In all other respects, in the course of the calculations, it is necessary to rely only on the individual indicators of the lamps. In this case, the main indicator of the calculations will be the specific power of the lamp. It is determined by the amount of electrical power consumed by the product (not to be confused with light) per 1 m2 of the room. It is this indicator that is indicated on all bulbs in the form of markings.
The electrical power for each room has the following indicators:

• living room and office - 22 W per square meter;
• bedroom - 15 W per 1 m 2;
• kitchen - 26 W per 1 m 2;
• children's room - 60 W per 1 m 2;
• bathroom - 20 W per 1 m 2;
• corridor - 12 W per 1 m 2.

The above parameters are considered relevant for halogen and conventional lamps. In a situation where luminescent light sources are used, the above norms must be reduced by 2.5-3 times. For LED lamps - reduce by 10 times.

Lamp power

In addition, this indicator will also be based on the type of lighting device (chandelier, spotlights, etc.).

How we count

To calculate the number of required lamps for a room, you must be guided by the principle of rounding fractions up. This means that when obtaining, for example, a value of 36 W for a small corridor, it is better to use two 25 W bulbs than one 40 W.
Note! In this matter, it is also necessary to evaluate the color scheme of the room. In the presence of dark tones in the design, preference should be given to brighter light sources.
To get specific numbers, you need to use the formula for calculating spots. Here, the following formula is used to calculate the optimal level of required lighting:
N = (S * W) / P, where these indicators denote the following quantities:

• N is the number of lamps in the room. Measured in pieces;
• S is the area of ​​the existing premises. Measured in sq.m;
• W is the specific power of the luminous flux emitted by the bulbs. The parameter indicates the level that is necessary to create optimal lighting. For each lamp, this indicator is different. Measured in W/sq.m;
• P - power for one lamp. Measured in W.

Remember that the figures obtained during the calculations may fluctuate slightly, but nevertheless they will be as close as possible to the real single parameters.
To make it clear, we give an example of calculations. Let's choose the following options:

• room type - living room;
• type of lighting - basic;
• lamp type - LED;
• spot power (average) - 5 W;
• room area - 20 m2.

The specific power indicator is taken from the table or calculated approximately, as indicated above. For an LED lamp, it is W = 3 W / sq.m. We insert all the indicators into the formula and get N = (20 * 3) / 5 = 12 pcs.
You can also use another formula to determine the illumination:

Lighting in the living room

P=pS/N, where the indicators are deciphered as follows:

• P - illumination;
• p - specific lighting power. For incandescent lamps, the average value is p \u003d 20 W / m2, for halogen lamps - 30 W / m2, for fluorescent -10 W / m2, for LED -3 W / m2. Measured in W/m2.;
• S is the area of ​​a particular room in m2;
• N is the number of fixtures available.

Using the above formulas, you can easily calculate the required number of light bulbs for each room in your house or apartment.

Some nuances

The above formulas for the calculation give average indicators, so they can be slightly reduced. For example, if the room is rarely visited (pantry, corridor), then the number of light bulbs can be slightly reduced, but for frequently used ones (children's room, living room, kitchen), a slight excess of the calculated norm is allowed. In addition, you can use combined lighting, which allows you to additionally highlight a certain area of ​​\u200b\u200bthe room.
As you can see, the calculations are not so complicated, but they are necessary for your health and comfortable pastime at home.

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