In order to be comfortable in the room at any time of the day, it is important to achieve not only high-quality natural, but also artificial lighting. Compare with quality natural light difficult, but you can still try. This requires knowing how to calculate the luminous flux.

Why calculate illumination?

Regardless of which lamp and lamp it uses, it is recommended to calculate the lighting separately for each room, taking into account the lamps, fixtures, color and type of finish used. Only by correctly placing the lighting fixtures in the right amount, it will be possible to achieve a harmonious effect. This is necessary for:

1. Comfortable stay in the room and life.
2. The work of the human visual apparatus, depending on the tasks performed by it.
3. Exceptions for decreased visual acuity.

The assessment process takes into account:

• Illumination is measured in lumens. This parameter is considered the most important, because it affects the value of the luminous flux that is distributed throughout the room.
• Brightness, the main meter is lux.
• Light intensity in candela.

Expert opinion

Alexey Bartosh

Specialist in the repair, maintenance of electrical equipment and industrial electronics.

Ask an expert

Important! The optimal illumination parameter is important for the state of human health. Lack or excess of light affects not only visual acuity, but also psychological condition. As a result, imbalance, disorder and general deterioration.

The difference between natural artificial lighting

Best Lighting for human eyes, natural, that is, daytime, morning, evening, including what comes from the sun behind the clouds. The light from the lamps is artificial, it is formed as a result of the transformation of electrical energy into electromagnetic radiation. The key task of calculating the lighting of a room is the approximation of artificial light (regardless of the type of lamp used) to natural light.

Calculation methods

The required and sufficient luminous flux can be calculated using one of three methods:

1. Specific power. Used to evaluate general illumination. To calculate the total power, it is required to multiply the normative data (power density) by the area of ​​the room. In order to correctly determine the standard indicator, it is necessary to take into account: the type of lamps, the purpose of the room, the distribution of lamps on the wall and ceiling. At the same time, after the calculations, the configuration and lighting conditions that are convenient and comfortable for a person are determined.
2. Application coefficient. To begin with, the location of light sources is determined with an eye to the configuration of the room and the possibility of reflecting or absorbing light. The formula provides for the multiplication of the illumination standard by the area of ​​the room by the safety factor and by the min illumination factor. Divide all this by the number of fixtures multiplied by each other and.
3. Spot. This method considered suitable for any room, can be used to calculate light sources on the street. To obtain the results, the illumination is evaluated at individual points that are exposed to light. In this case, lighting fixtures can be placed anywhere. The assessment is carried out at key points for the user. This technique is especially relevant in rooms where on the walls dark finish and complex ceiling configuration.

These methods are not very complex in implementation, but there is still a much simpler way, it is presented below.

The choice of calculation method depends, among other things, on the type of lamps used

Simple Calculation Method

The proposed calculation option is more suitable for the premises correct form- square or rectangular. Illumination is measured in Lux (Lx), the calculation of the luminous flux parameter will consist of two stages:

1. Calculation of the continuous luminous flux required to illuminate a room with a certain quadrature.
2. Determination of the number of light sources.

At the first step, we calculate the required luminous flux parameter for the room. The calculation is made according to the formula:

Svp=X*Y*Z, where

X - normative indicator of illumination for the room. You can find these standards in the list below.

Y is the area of ​​the room in m².

Z - correction factor taking into account the height of the ceilings. So, for ceilings up to 2.7 m high, this parameter = 1, for 2.7–3 - an indicator of 1.2, for rooms with a ceiling of 3–3.5 m - 1.5, for rooms over 3.5 - a coefficient of 2 .

Standards for rooms in the house:

1. Corridor, entrance hall - 50-75 Lx.
2. Pantry - 50 Lux.
3. Kitchen – 150 Lx.
4. Any living room - 150 Lux.
5. Children's - 200 Lux.
6. Bathroom - 50 Lk.
7. Study or library - 300 lx.
8. Staircase - 20 Lux.
9. Sauna, swimming pool - 100 Lx.

How much light you need depends on the purpose of the room

The second step will help determine the number of light sources, in this case Get LED bulbs. Approximate indicators by which you can navigate:

Examples

Initial data:

1. Children's room with an area of ​​25 sq. m.
2. Ceiling height - 3 m.
3. It is planned to use 8 watt lamps.

First stage:

200(X)*25(Y)*1.2(Z)= 6000lm

The lamps that will be used are 10 W, their luminous flux, declared by the manufacturer, is 900 Lm. That is, the required amount is 6000/900=6.66. Rounding gives the number 7 lamps.

If you use lighting lamps with a lower power, for example, 4 W, place them around the perimeter of the room on the walls, then 13 light bulbs will be required. In this case, the distribution of light will be more uniform. It should also take into account the type of lamp used, its design and interior solution.

The quality of lighting for the nursery is especially important

Similar calculations can be carried out for incandescent and fluorescent lamps, the table will help in the calculations:

We calculate for the same room. Incandescent lamps need:

1. At 60 W - 6000/700 \u003d 8.57, rounded up - 9 pcs.
2. At 75 W - 6000/900 = 6.66, rounded up - 7 pcs.
3. For 100 W - 6000/1200 = 5 pcs.

Fluorescent lamps:

• 10–12 W – 6000/400=15 pcs.
• 15–16 W - 6000/700 \u003d 8.57, round 9 pcs.
• 18–20 W - 6000/900 \u003d 6.66, rounded up 7 pcs.

These calculations are based on the norms of Soviet SNiPs, so experts recommend multiplying the result by a factor of 1.5–2, depending on the finish of the room and interior solutions.

Advice! In order not to count with your own hands, you can use special devices, for example, Cromatest. This device helps to measure the intensity of light. Another device is a light meter, the main component of which is a selenium photocell. You can also turn to specialized companies that will assist in the calculation for a certain fee.

The difference between the color temperatures of the lamps

What should be taken into account when calculating?

Before making any calculations, you should decide which lamp will be used. On the this moment available options lamps:

1. Incandescent.
2. Halogen.
3. Fluorescent: compact or linear.
4. LED: lamps, ribbons or spotlights. In the case of led strip the density of the LEDs is important. You can find out this parameter by examining the tape carefully.

The type of lighting device also has an impact, primarily on the dispersion of light, the place of use. Any of these light sources is characterized by parameters that can measure the luminous flux. Specifically:

• Power. This is the amount of energy that the lamp consumes, the unit of measurement is W.
• Light flow. As already mentioned this is the amount of light that is emitted.
• Housing heating - used for incandescent and halogen lamps.
• Color rendition. This setting includes: color temperature and hue. The first point is from red to blue (1800-16000 Kelvin). The shade for modern lamps is warm or cold. It is he who sets the overall perception of illumination.

Color rendering different types lamps:

1. Incandescent lamp - from 2200 to 3000 Kelvin (K).
2. Halogen - 3000 K.
3. Fluorescent lamp (warm light) - 3000K.
4. Fluorescent lamp (white light) - 3500 K.
5. Daylight fluorescent lamp - 5600-7000K.

Important! The lower the color temperature, the closer to red, the higher, the closer to blue.

Two more important parameters: luminous flux and luminous efficiency. The first is the amount of light that the lamp emits, the second is the ratio of luminous flux to power - lm / W, that is, how efficient and economical it is.

Formula for calculating luminous flux

When choosing a particular lamp and calculations, it is important to consider such factors:

• Lamp location. Options - ceiling or wall.
• Mounting height in case of wall mounting.
• The transparency of the shades and the presence decorative elements on them.
• Direction of light: up, down, sideways.
• The color of the walls, furniture: light reflect light, dark absorb.

Inaccuracies and errors: what are they connected with

Difficulties arise when, during a scheduled repair, one lamp is replaced with another, lamps are changed, a new finish is mounted on the ceiling and walls. All this affects the calculations. The main problem is that the reflection coefficient of surfaces is not taken into account. The decrease in luminous flux is affected by:

1. Darker wallpapers.
2. Laminate, linoleum shade darker than it was before.
3. Hanging or stretch ceiling, its type and reflectivity.

All these points relate to general lighting, since locally, for example, there is enough light in the working area at the desk. This is understandable, because in such areas separate lighting devices are most often mounted.

In order not to be mistaken, you should keep in mind what reflectance each color has. Thus, white surfaces reflect 70%, other light surfaces reflect 50%, gray surfaces reflect 30%, and black surfaces reflect 0%.

Often, when calculating, SNiPs are taken as a guideline, but do not forget that they were developed back in Soviet times. To begin with, at that moment there were no modern light sources, the second moment - there was no special concern for the comfort of staying in the room and the condition of the eyes.

Remember, if there are a lot of lamps, then you can reduce their number, especially if you mount your own switch for each lighting group.

Conclusion

Calculating the luminous flux is not difficult, but it is important to take into account many points: the type of lamp, the color of the ceiling, walls, floor, even the shade of the furniture. It is important to remember that it is better to have more lights to control than to save money.

Have you ever wondered why in some rooms you immediately feel sleepy, while in others you just want to develop vigorous activity? Turns out it's all about the lighting in the room! Bright light promotes vivacity and activity, and subdued adjusts to peace and relaxation. In addition, the level of lighting can be dictated by necessity: much more light is needed in work areas than in recreation areas. Let's figure out how to calculate required power lighting!

Let's break it down into pieces

Before proceeding with the calculations, think about what functions the rooms in your house perform. The brightest lighting is required in the children's room, as well as in the office and in the kitchen - games and work processes take place here. Enough bright light should be provided in the living room and bathroom. Slightly softer lighting is suitable for the bedroom, and the most subdued lighting will be enough in the hallway, toilet or pantry.

In the nursery and office, in addition to general light, it is important to provide lighting for work areas.

Also note that the same room can perform different functions depending on the time of day and the situation. For example, in the living room, when all the household is assembled or guests have arrived, a bright light is needed; in the evening, when you watch TV or get ready for bed, it will be more comfortable with dimmed lights. In the nursery and office, in addition to general light, it is important to provide lighting for work areas. Think over and calculate each of the lighting scenarios separately so that you can change them as needed.

Advance paynemt

Now that you understand what kind of light each room needs, you can get straight to the numbers. The degree of illumination discussed above is expressed in terms of power per unit area. P (W / m 2). Its value ranges from 9 to 40 W / m 2 and even higher, while 20 W / m 2 is taken as the average. To calculate the total lighting power Pr (W) for each room, you need to multiply the power value P (W / m 2) per room area S (m 2).

As a result of these simple calculations, we obtain a table of values ​​for the required total illumination Pr (W) for rooms of various sizes:

Room area	Total lighting powerPr, W
	Very bright light	Bright light	Soft light
Lighting power per unit area P, W / m 2
Illumination, lx

For a rough calculation, it is enough to divide the obtained value for each lighting scenario and each room by the number of light sources N- and you will get the power value for each light bulb in the house.

Correction by type of light source

When selecting light sources, do not forget to take into account that different types of lamps are characterized not only by power, but also by luminous flux, measured in lumens (lm). This parameter, like power, is indicated on the packaging of the lamp. For example, an ordinary 100 W incandescent lamp emits a luminous flux of 1350 lm.

With equal powers, different types of lamps give a different amount of light, which must be borne in mind when calculating.

It is the luminous flux that makes it possible to compare the efficiency of different types of light bulbs (incandescent, energy-saving, fluorescent, halogen) and to select them correctly. With equal powers, different types of lamps give a different amount of light, which must be borne in mind when calculating.

It is also important to take into account illumination surface, measured in lux (OK), depends on the distance of the light source and decreases inversely with the square of the distance to it. That is, the farther the place in the room is from the light source, the less illumination will be in it. According to ergonomic standards, the optimal general illumination in the room should be about 200 lux, while the workplace requires illumination of about 500 lux.

We take into account the error

With a more accurate calculation of lighting, it is necessary to make adjustments for the shape and size of the room, the amount of furniture, colors, and the amount of natural light. For example, our preliminary calculations are valid for rooms with a ceiling height of no more than three meters. If the ceilings are higher, then the obtained values ​​\u200b\u200bare recommended to be increased by one and a half times.

In rooms larger than 15 square meters, instead of one lamp in the center of the room, it is more efficient to place several equal light sources evenly distributed along the ceiling - this technique will help to achieve more uniform illumination of the room.

If the interior is dominated by dark colors or there is a lot of furniture in the room, it is worth slightly increasing the number of lamps and the overall lighting power.

When choosing energy-saving lamps, remember that perception is affected by the color of light - warm yellow or cool blue.

Maximum lighting efficiency

To achieve the most balanced and uniform illumination of your home, use light sources of various kinds: general ceiling lights and local or decorative ones - floor lamps, sconces, table lamps, lamps under wall cabinets in the kitchen or on the mirror in the bathroom. Use dimmers to smoothly adjust the lighting power.

Choose chandeliers with frosted glass shades - they evenly scatter softened light throughout the room.

Choose chandeliers with frosted glass shades - they evenly scatter softened light throughout the room, including the darkest and most inaccessible corners. In local fixtures, reflective surfaces are welcome for more intense spot lighting.

When making calculations, it is better to slightly overestimate the number and power of lamps, creating an additional reserve of lighting.

Effective lighting of residential and utility rooms in a house or apartment, along with heating, ventilation, water supply, energy supply, can rightfully be attributed to systems that provide comfortable conditions residence of all family members. And if we consider it on a larger scale, then there will certainly be a direct connection with the level of security created conditions life support. Agree, it is impossible not to note the influence of light on the psycho-emotional state of a person, on the degree of his fatigue in the process of performing certain works, on the usefulness of rest. All this affects the current state of health, general condition of the body, and with a long-term negative impact of improperly organized lighting, generally sad prospects loom ahead with visual impairment, other health disorders that will no longer be corrected. And in particular it is dangerous for the developing organism of children.

But, Unfortunately, to the issue of proper organization of lighting, very many homeowners are extremely frivolous. It must be difficult for them to overcome the stereotype that they once had - they say, about 100 watts is enough for this room, for example. Well, first of all, personal feelings are often wrong. And secondly, to evaluate the level of illumination in units of consumed energy is already “the day before yesterday”. Moreover, in our time a very wide selection of lighting lamps is offered, the light output of which per unit of energy consumed is radically different.

Therefore, we propose to carry out a more competent calculation of lighting for the area of ​​\u200b\u200bthe room, using completely different units of measurement.

Once upon a time, in the late 80s, the author of these lines worked as part of a rather representative commission of the USSR Ministry of Defense, which checked registration and draft work and the state of preparation of young people for military service in one of the regions of the South Ural region. In one of the districts, attention was drawn to the fact that the percentage of people with limited health due to ophthalmic diseases clearly exceeds the average.

In the commission, we had a very meticulous lieutenant colonel - a military doctor who "ate his teeth" in this field. And he immediately declared - it just doesn’t happen, so there is some reason. They began to understand more deeply - almost all conscripts with a persistent decrease in visual acuity, with anomie refraction, with astigmatism - from one fairly large village and fairly remote from the regional center. I was struck by the explanation of the representatives of the local military registration and enlistment office - “And in Karinovka they all have some kind of blind…”

We decided to go to the place and take a closer look. And what did you see? There was an eight-year school in the village. It has three classrooms. And in each of them there are a couple of very small windows overlooking the street (which, in principle, is understandable given the severity of the winter climate in this treeless steppe zone). But all the lighting is two cartridges under the ceiling, in which there are ordinary incandescent bulbs of 75 watts. In a word, in the classroom, if not twilight, then a clear lack of illumination.

And imagine that all the inhabitants of this village once studied in such conditions for 8 years! Naturally, this gave the very result that alerted the inspectors. It is clear that an act was drawn up on the revealed violations of elementary sanitary standards, reported to the appropriate authorities at the regional and even the union level. There must have been serious repercussions. But the health of those people who lost it due to the carelessness of local officials cannot be returned by these administrative measures.

All this was said with one goal - do not joke with normal lighting in your house or apartment. Invisible initially negative influences on vision (and on the psyche too) tend to accumulate, and result in such consequences that it will no longer be possible to correct. Especially when it comes to children!

On the what is the basis for the calculation of illumination of rooms?

To be more correct with the definitions, the proposed calculation method takes into account not only the area of ​​​​the room. A number of other important criteria are taken into account, reflecting the specifics of a particular room.

Simplified calculation method in units of power consumption and its imperfection

Not so long ago, in the field of lighting, complete dominance belonged to incandescent lamps. Here, apparently, one should look for the origins of the ingrained habit of evaluating the illumination of a room in units of the electrical energy consumed for this.

A fairly stable range of these 15 lamps was presented on sale; 25; 40; 60; 75; one hundred; 150 watts or more. Any of the owners knew approximately how much lamp power and in what quantity he needed to provide lighting for each of the rooms. Naturally, most often such an assessment was carried out subjectively, on the basis of personal experience and perception, which did not always correspond to the norm.

Surely this stereotype is still firmly in the mind of many - that illumination is measured in watts. And the more these same watts, the greater the effect can be achieved by installing the appropriate lamp.

It was customary to proceed approximately from the norm of 15 ÷ 20 W per square meter. Accordingly, in the course there were, and even remain to this day, approximately the following tables:

It would seem - everything is simple, and what more could you want? However, we are sorry - such calculations are very far from perfect. And above all, for the reason that a watt is still a unit of measurement for the energy consumed by a lamp, and not at all for the luminous flux created by a lamp. Of course, there is a relationship, but it will not work to call it a direct dependence, subject to some strict ratio. This is about the same as estimating the speed of arrival at the final destination on a particular intercity transport, based on the cost of a ticket - the values ​​seem to be interconnected, but the incorrectness of the assessment is obvious.

And even more so, this technique has lost in its already not outstanding accuracy with the advent of successful "competitors" of incandescent lamps - fluorescent and LED. Here, the indicators of energy consumption and light output are completely different.

But old habits take their toll, and still the most widespread Many people still have an estimate based on watts. They simply began to resort to tables that show the approximate ratio of the parameters of different types of lamps with approximately the same luminous efficiency. An example of such a table is shown below.

Room area, m²	Conventional incandescent lamps, W	Fluorescent lamps, W	LED lamps, W	Approximate luminous flux, Lm
1	20	5÷7	2÷3	250
2	40	10÷13	4÷5	400
3	60	15÷16	6÷10	700
4	75	18:20	10÷12	900
5	100	25÷30	12÷15	1200
7÷8	150	40÷50	18:20	1800
10÷12	200	60÷80	25÷30	2500

In favor of such a "patriarchal" principle of evaluating the effectiveness of lighting, many manufacturers place on the packaging of fluorescent energy-saving and LED lamps, in addition to its power consumption, an approximate comparative "equivalent" in watts for incandescent lamps. A typical example is shown in the figure below.

Pay attention to the word "exemplary" in the previous sentence. It is not mentioned by chance, since there is still no unambiguous available system for “transferring one watt to another watt”. And why? We repeat - yes, the illumination of the room or the luminous flux emitted by the source in watts is not measured!

By the way, in the example shown above, a serious mistake has already been made on the packaging itself. In particular, “Light output 60 W” is written, which can confuse an unknowing person, and he will be even more convinced that this is exactly what it really is. It would probably be more correct to write like this: "Light output approximately corresponds to a 60-watt incandescent lamp."

And in what units then will it be correct to evaluate the light source? Please note: in the table above, the rightmost column gives the value in lumens (lm) - this is the SI units of luminous flux. If we continue the example shown above, then, looking into the passport of the demonstrated lamp, we can find this characteristic - 550 lm.

Lumens (lm) are closely related to other units - lux (lx), which in the SI system just measures illumination. The relationship between them is as follows: a luminous flux of 1 lumen creates an illumination equal to 1 lux on an area of ​​1 square meter.

In the future, we will build on these units - lux and lumens.

Lighting standards for residential premises

To carry out the calculation, you need to know from which “stove to dance”.

It is clear that the area of ​​​​the room in which it is planned to organize lighting will appear as one of the initial values. And the second most important parameter is sanitary standards that set the level of illumination for rooms for various purposes.

These norms are clearly spelled out in SNiP and SanPiN for almost all categories of premises, residential and industrial, and even in detail by the nature of the work performed. But in this case, we are more interested in those that we encounter when calculating the lighting system in our house or apartment.

We will not refer the reader to the "primary sources" - the table below contains extracts, which, probably, will be quite enough.

Type (purpose) of premises	Illumination standards in accordance with the current SNiP, lux
living rooms	150
Children's rooms	200
Study, workshop or library	300
Cabinet for precise drawing work	500
Kitchen	150
Shower room, separate or combined bathroom, bathroom	50
Sauna, locker room, swimming pool	100
Entrance hall, corridor, hall	50
entrance hall	30
Stairs and landings	20
Wardrobe	75
Sports (gym) hall	150
billiard room	300
Pantry for strollers or bicycles	30
Technical premises - boiler room, pump room, electrical panel room, etc.	20
Auxiliary passages, including in attics and basements	20
The area at the main entrance to the house (porch)	6
A platform at an emergency or technical entrance	4
Footpath at the entrance to the house for 4 meters	4

It is from these values ​​that we will proceed when carrying out calculations. Expressed precisely in lux, and not in watts, "candles", etc. The norms shown are considered optimal, so you should not go to the other extreme - excessively "flood" the premises with light. It's not even that it's worthless. in terms of energy saving. Too bright lighting can also become a very annoying factor, negatively affect the emotional state, and lead to eye fatigue, which is fraught with serious consequences. So the given normalized values ​​are just that “ golden mean", which should be aimed at.

Carrying out an independent calculation of illumination

Well, it would seem that clarity has been obtained. Lighting standards are available, the area of ​​\u200b\u200bthe room is easy to determine. That is, there is no problem to determine the total luminous flux, which should provide the necessary degree of illumination.

For example, a living room with an area of ​​14.5 square meters. It is easy to calculate that a light source with a total luminous flux of 15.5 m² × 150 lux = 2325 lm is needed to illuminate it. And then you can already pick up those lamps and lamps for them, in the right amount, which will "cope with the task." Let's say, if we proceed again from the example of the lamp that was given above (with a luminous flux according to the passport of 550 lm), five such lamps will be required.

Indeed, the simplified calculation looks exactly like this. But here it still does not differ in due accuracy - except for the area, other features of the room, in particular, its decoration, are not taken into account. The type of luminaire, its location in the space of the room, the predominant direction of the light flux, due to the position of the light source and the type of ceiling lamp (diffuser) used, are not taken into account.

Therefore, we propose a different algorithm for performing calculations. He, too, cannot fully claim to be "complete professionalism", but still the results are much more accurate, closer to reality.

General calculation formula

You should immediately understand correctly - the proposed algorithm involves the calculation of the main lighting. This should not include decorative lighting, which in our time are in great demand in the interior design of rooms. Individual lighting fixtures that provide local illumination of a specific limited area (for example, bedside sconces) are not included in the calculation.

So, the main formula on which the calculation is based will be the following:

Fl = (En ×Sp ×k ×q) / (Nc ×n×η)

We deal with the parameters included in the formula:

Fl- the desired value, that is, the indicator of the luminous flux, which each of the lamps installed in the fixtures should have. The value will be received in lumens.

Yong- norms of illumination of residential and utility rooms. Exactly those that are shown in the table above (in suites), in accordance with the current SNiP.

Sp- the area of ​​the room for which the calculation is made (m²). this parameter is easy to calculate on your own - in the vast majority of cases, the premises are rectangular. But even if the room has a more complex configuration, you just need to break the total area into more simple plots and remember the basic rules of geometry.

If there are difficulties with the calculation of the area - you are here ...

Sometimes an unusual configuration of a room can puzzle the owner, who has somewhat forgotten the laws of geometry. Don't worry - we can help! Follow the link to the article on - there and detailed descriptions various cases, and handy calculators that simplify calculations.

k- this is a correction factor, which is also called a safety factor. It takes into account several factors at once. So, some lamps tend to dim during operation, lose in the emitted light flux. And this decrease in luminous intensity is not the same for different types of lamps. In addition, the correction takes into account the degree of interference for normal spread Sveta. True, this applies to a greater extent to industrial premises, where there may be high levels of dust or steam concentration. Based on the fact that good hosts this is not observed in the house, then the safety factor can be taken equal to:

q- coefficient of non-uniformity of a luminescence. This value is especially important when calculating the illumination of rooms where it is planned to carry out precise work related to drawing, operations with small details, with a large amount of reading or typing or handwriting.

The values ​​are shown in the table below:

Nc- the number of fixtures planned for installation.

n- the number of lamps (horns) in one lamp.

The product of the last two parameters, quite understandably, shows total lamps that will be involved in lighting the room. If only one light source is planned, then, naturally, units are substituted into the formula both here and there.

With this approach, by the way (when Nc =n=1), it is possible to determine in general the entire total luminous flux required for high-quality lighting. Sometimes the purpose of the calculation is precisely this - and then the owners begin to “conjure” over the optimal placement of lamps or lamps of various denominations, in accordance with the design idea of ​​the interior design.

η - coefficient of use of a light stream.

This value is somewhat more difficult to determine - several criteria will have to be taken into account here. Therefore, we will take it out in a separate subsection of the article.

Determination of the utilization factor of the luminous flux η

This value can be determined from the tables. But first you have to figure out the parameters for entering these tables.

• First, let's define an intermediate parameter. It is commonly referred to as the room index. It will take into account to the necessary extent both the size of the room and the planned height of the light source. This index is calculated using the following formula:

i =Sp / ( ( a +b) ×h)

i- the desired value, that is, the index of the room.

Sp- the area of ​​\u200b\u200bthe room already previously included in the calculations (m²)

a and b- respectively, the length and width of the room (m).

h- the estimated height of the light source. An important nuance - not to be confused with the height of the ceiling in the room! This refers to the height of the lamp above the floor surface.

For example, it is planned to install a pendant lamp with a suspension (or rod) length equal to 0,6 m. And the ceiling height in the room - 3 meters. So the value h for substitution in the formula equals 3,0 – 0,6 = 2,4 m.

It is easy to do arithmetic calculations. But even easier is to use the proposed online calculator.

Room Index Calculator

"CALCULATE ROOM INDEX i"

Room length, meters

Room width, meters

Luminaire height above floor level, meters

After the room index is calculated, it should be rounded up to the nearest value from among those indicated in the following list:

0,5;0,6;0,7;0,8;0,9;1,0;1,1,1,25;1,5;1,75;2,0;2,25;2,5;3,0;3,5;4,0;5,0

So, we already have one parameter for entering the table.

• Going further - now it is necessary to evaluate the reflectivity of the surfaces, in accordance with the existing (or planned) interior finish.

The reflection coefficients are taken equal to:

Now it is necessary to write down the values ​​​​of this coefficient in the sequence "ceiling - walls - floor". This is not so difficult. In fact, with white, everything is clear. The other extreme, that is, deep black, in the interior design on large areas usually not applicable. This means that the whole choice is limited to only three options - 50, 30 or 10%. Certainly, there is a certain amount of subjectivity in the assessment, but it is difficult to make any serious mistake.

For example, the ceiling is white, the walls are light beige, the floor is brown. Get 70% - 50% - 10% .

• Next, you should take into account the type of luminaire, and already select a table according to which the desired value of the luminous flux utilization factor will be determined η .

Possible options for fixtures and the corresponding tables for them are summarized in the following table (sorry for the tautology).

Features of the lighting device and its placement	Illustration	Tables for determining the coefficient of use of the luminous flux. (The selected table will enlarge when clicked).
The luminaire is placed directly on the surface of the ceiling. The main direction of light is down.
The luminaire is suspended from the ceiling or on the wall, equipped with a diffuser that gives a preferential distribution of light downwards.
Suspended luminaires with plafonds providing uniform distribution of light in all directions. The same effect is given by simply hanging lamps without a ceiling.
Luminaires with plafonds, mainly directing light towards the ceiling, for reflection from the ceiling surface.
Luminaires with opaque or opaque shades that give a narrow directional stream of light in a selected area.

• We have all the data to enter the table. And to determine the coefficient of use of the luminous flux from it is not difficult at all.

Just for example:

It is planned to install a pendant lamp of a spherical shape, studying the light in all directions. Open the corresponding table (all tables are enlarged with a mouse click).

A preliminary calculation showed that the room index, rounded up, is 1.25.

The reflectivity coefficients were determined in advance: those same 70% - 50% - 10% .

We enter the table. To do this, first, by the reflection coefficients, we find the desired column:

In the far right column we find the value of the room index - 1.25. This will set the string.

The intersection of the row and column leads us to the desired value of the luminous flux utilization factor η. In this example, it is equal to 0.55.

Now we have already collected all the data for the main formula, which allows us to make the final calculation of the required luminous flux for the full illumination of the room.

In order not to bother the reader with calculations, we suggest that he use the built-in online calculator.

Calculator for calculating the required luminous flux

Specify the requested values ​​and click "CALCULATE THE NECESSARY LIGHT FLUX OF THE LAMP"

ROOM AREA, m²

TYPE OF ROOM

PLANNED TO INSTALL LAMPS

PREVIOUSLY DEFINED LIGHT FLUX UTILIZATION FACTOR η

PLANNED NUMBER OF LIGHTS IN THE ROOM, pcs

NUMBER OF HORNS (LAMPS) IN THE LAMP, pcs

So, the obtained value directly shows us what kind of luminous flux the lamps should have, which, under the given conditions, will provide full-fledged illumination of the room. Or, as we have already said, if you specify the number of fixtures and lamps equal to one, the value of the total luminous flux will be obtained - and you can use it to navigate when arranging lighting devices.

For some areas, for example, a desktop or a workbench in a workshop, you can also approach with this calculation, but already based on the area of ​​\u200b\u200ba specific working area, if a separate lamp is used for these purposes. At the same time, you can even ignore the general lighting - if it is assumed that the local one should be quite enough to create comfortable working conditions even when the main room lighting is turned off.

And now let's at least briefly look at the main characteristics of the most common lamps.

What is important to know about lamps for lighting fixtures

General characteristics of lighting lamps

If the value of the required luminous flux is calculated, then you can proceed to the selection of lamps. Some luminaires do not require much choice - they are directly designed for the installation of a particular type. But most devices still allow you to consider several options.

• All lamps, regardless of their type, can be distinguished by a base. And if certain lighting fixtures are already outlined in the plans of the owners, then the choice will narrow down to a specific type of base.

In large luminaires, threaded socles of the E series are most often used. But spotlight devices may have different versions of cartridges - you should pay attention to this in advance.

• Power consumption - that is, the amount of energy that the lamp will consume when operating at full load per unit of time. Here, as we have already seen from the tables above, various types lamps with an equal luminous flux - a very large spread. We will dwell on this a little later, when analyzing specific types of lamps.
• Supply voltage. Not all lamps are able to work directly from a 220 V 50 Hz network. Some are designed to be connected through a step-down transformer, for example, 12 V. In addition, certain varieties require direct current, that is, the polarity of the connection is also important here. As a rule, luminaires with such lamps are equipped with special power supplies or drivers, with connectors that exclude connection errors. This should be taken into account, because for additional equipment you will have to provide a place for its hidden placement.
• Light temperature. This, let's say right away, is a conditional value, which has nothing to do with the heating temperature of the lamp. The indicator of light temperature characterizes the visual effect of the perception of the source. From a purely physical point of view, this is the glow of an absolutely dark body heated to a certain temperature (expressed on the Kelvin scale).

It’s better not to go into reasoning, but to offer a visual table - everything should become clear with it:

Once upon a time, in the era of the complete dominance of incandescent lamps, such a value was practically not remembered, and most often it was not even indicated on the labeling of lamps. Today, almost all products, of any type, have this indicator in the list of characteristics.

Here, for example, is what is indicated on the packaging of an arbitrarily taken lamp:

1 - type of base.

2 - power consumption (and the approximate equivalent of the power consumption of an incandescent lamp with the same light output).

3 - glow temperature: in given case 4100 K.

4 - luminous flux of the lamp, expressed in lumens (540 lm).

The choice of a lamp according to the glow temperature, of course, is made by the buyer himself, guided by personal considerations and preferences. But still, some recommendations will be superfluous.

Temperatures from 2600 to 5000 K. Sometimes lamps are installed with a higher glow temperature - when this is necessary due to the peculiarities of the purpose of the room.

Color temperature range	Approximate perception	Where is it recommended to use
2600 ÷ 3000 K	Warm light with a reddish-orange tint.	Create a cozy atmosphere in the bedroom or living room. Great for bedside lamps, floor lamps, installed in the resting places of the owners.
3000 ÷ 3500 K	Warm light with a yellowish tint.	The main lighting of living rooms, nursery. Good for a child's desktop.
3500 ÷ 4000 K	daylight white light	The main lighting of the premises of the apartment, including in the utility and special rooms. "Cold" for constant perception.
4000 ÷ 5000 K	cold white light	Sometimes it is used for some styles of interior design (such as hi-tech), but it does not create a cozy atmosphere - a clear feeling of a “hospital environment”. Suitable for lighting utility rooms, local area.
5000 ÷ 6000 K	Cold light with a white-blue tint	It is used for office lighting on large areas, in industrial premises. Can be applied in the workshop to perform fine work, in the drawing room. It often finds application in the illumination of greenhouses, greenhouses, etc. Can cause eye fatigue. Not used in residential areas.
Over 6000 K	Cool white with a deep blue or lilac hue.	Only for street lighting. It does not find application in residential and special premises.

• Finally, the luminous flux caused by the lamp is exactly the value that we calculated using the calculator. This indicator must be specified on the packaging, on the lamp or in its passport.

Below we will briefly go through the main types of lighting lamps. There will be several tables with parameters. It should be correctly understood that these data are taken as an example only, and can only correspond to certain lamp models. That is, it is simply impossible to reveal the whole variety of these products on the scale of one article. In any case, when choosing lamps, you should carefully study their passport characteristics.

Incandescent lamps

Once reigning supreme, they gradually "leave the scene." Advantage - low cost. And there are more than enough shortcomings. Extremely low efficiency (usually not exceeding 5%), that is, most of the energy consumed goes into completely unnecessary heating. Service life is low, rarely exceeds 1000 hours.

The illustrations and the table below show the main characteristics of such lamps. Pay attention to the parameter of light output - how many lumens the product produces from each watt of energy consumed. This directly affects the efficiency of using a particular type of lamp.

The model shown has a glow temperature of about 2800 K (warm light). Energy class - E.

Characteristics depending on power:

	Luminous flux (lm)	Luminous efficacy (lm/W)
10	50	5,0
25	220	8,8
40	415	10,4
60	710	11,8
75	935	12,5
95	1300	13,6
100	1340	13,4

Incandescent lamps can also have frosted glass for optimal light diffusion. True, this slightly reduces the luminous flux.

Approximate characteristics are shown in the table:

Although incandescent lamps are still widely available on the market and attract low cost, they are not the best option. It is better to choose something more modern and efficient.

Halogen lamps

Halogen lamps, in fact, also work on the principle of filament heating. However, they have features in execution. In particular, this applies to special quartz glass that can withstand very high heating temperatures, and filling the flask - iodine and bromine vapors are used here, which significantly increase the durability of the spiral.

These lamps are produced in a very wide variety, but in the conditions of a house or apartment, compact models designed for spotlights are usually used. Lighting fixtures of the type of searchlights are less commonly used - usually to illuminate the territory or buildings for agricultural purposes.

The advantages of such lamps include their higher (compared to conventional incandescent) efficiency. The service life reaches several thousand hours. They are attracted by compactness with high luminous efficacy, a well-perceived range of light temperatures - usually within 2800 ÷ 3000 K.

The disadvantages are also considerable. These are very high heating temperatures during operation. Lamps require very careful handling during installation - touching the quartz bulb with your hand will cause the device to quickly burn out. The cost of " halogens"- significantly higher than incandescent lamps. The gases used to fill the flask cannot be classified as harmless. So there is also a problem with safety and with the disposal of used lamps.

For example, one of the lines of halogen lamps. Supply voltage - 12 V. Base - GU4. Glow temperature - 3000 TO. Energy class - V. Approximate service life - up to 1500 hours.

The characteristics of this model range are shown in the table. Please note: here and below, another column appears - an approximate correspondence to an ordinary incandescent lamp.

Lamp Power Consumption (W)	Luminous flux (lm)	Luminous efficacy (lm/W)
10	150	15	13
20	300	15	26
35	525	15	46
50	750	15	65
75	1125	15	75
100	1500	15	130
150	2250	15	150

Halogen lamps can be used to illuminate residential areas, but they are still far from the optimal option. The number of shortcomings is large, energy saving indicators are not outstanding.

Fluorescent lamps

This type has been well represented in the past. well-known long tubular lamps. They are still widely used today. But still, in the field of home lighting, compact lamps with bases for standard cartridges are more popular. In everyday life, they received the name "energy-saving". Indeed, even before the advent and widespread use of LED sources, such lamps literally made a "revolution" in terms of cost-effectiveness for lighting houses and apartments.

The glass bulb of such lamps is filled with a special mixture of gases, which, when certain conditions are created, cause the phosphor to glow.

The advantages of such lamps include high light output at moderate consumption of electrical energy. They are presented in a very wide range of color temperatures. The service life can be up to several thousand hours.

One, and they have enough shortcomings. So, in the filling of the flask, mercury is almost always present - an extremely dangerous chemical element for human health. That is, the lamps require special care and proper disposal. The efficiency of the lamp, although high, is still far from ideal - up to 25% of the energy consumed is spent on creating conditions for the appearance of a glow. Light flickering is often noticeable, which can increase with gradual technological wear. Sometimes there is an unevenness of the created light flux, which can even visually distort perception natural colors items. Lamps may have inertia - they need a certain time to enter normal operation.

For example, characteristics one of model ranges compact fluorescent lamps. Power - 220 V. Color temperature - 2700 K. Estimated service life - from 8 to 10 thousand hours. Energy class - A.

Lamp Power Consumption (W)	Luminous flux (lm)	Luminous efficacy (lm/W)	Approximate equivalent power of an incandescent lamp (W)
9	450	50	45
11	535	48	55
13	665	51	56
15	800	53	75
20	1170	58	100
26	1525	58	125
30	1900	63	150
35	2285	65	175
45	3080	68	225
55	3800	69	275
85	6700	78	425
105	6900	65	525

The use of such lamps for lighting a house or apartment can be considered quite justified. And in se in terms of convenience, safety, durability, economy, they lose to LED ones.

LED lamp

It is time to write a separate article about the variety of LED lamps - it is so wide. But in any case, they can be considered the most successful option among all those mentioned above.

The advantages of LED lamps primarily include high light output at minimum consumption of electrical energy. The efficiency of such products is usually above 90% - a very small amount of energy is spent on unnecessary heating. That is, the savings effect is the highest. Lamps can be given any shape, up to the most compact. The absence of quartz glass parts makes such products durable, not afraid of moderate impact. Lamp life is estimated at tens of thousands of hours. The variety of LEDs used makes it possible to produce a lamp with almost any glow temperature. The product itself does not contain any substances harmful to humans or environment substances.

The disadvantages of LED lamps, noted by consumers, are mostly associated with poor-quality manufacturing. We have to admit that this market segment is saturated with low-grade products or even fakes for well-known brands. So it is better to buy LED lamps in trusted retail outlets, with filling out a passport and setting the warranty period.

The disadvantages are often the high cost of LED lamps. However, firstly, it is justified by a large resource of work and a pronouncedly low energy consumption. In fact, it is these lamps that more deserve the name “energy-saving”, but how it happened ... And secondly, manufacturing technologies do not stand still, and the cost of such light sources is last years decreased significantly, no longer looks frightening. And this trend of cheaper LED lamps has not stopped yet.

The table below will show the characteristics of one of the model ranges - just for comparison.

Glow temperature - 3000 TO. Energy class - A. The estimated lamp life is up to 40,000 hours.

Lamp Power Consumption (W)	Luminous flux (lm)	Luminous efficacy (lm/W)	Approximate equivalent power of an incandescent lamp (W)
3	250	83	40
4	280	70	40
5	340	68	40
6	440	73	50
7	520	74	60
8	550	68	65
10	850	85	75
12	1170	97	95
16	1600	100	150
20	2100	105	200

In a word, LED lamps can rightly be considered the best option. And it is most reasonable at the stage of creating your own lighting system not to spare money for them. There is no doubt that these costs will be fully recovered.

When planning a room lighting system, it is recommended to adhere to some more quick tips shared by experienced craftsmen.

• It is clear that the calculations above are aimed at creating illumination corresponding to the established sanitary standards. But quite often, such an amount of light becomes redundant - just based on the current mood, from the desire to relax, you want a more subdued backlight. This, of course, can be organized by a "parallel system" - located in right places local lighting devices. A typical example is bedside sconces. But still, it is recommended not to do the main lighting system with a single light source - nowadays there is a sufficient variety of lamps for sale designed for several lamps. As necessary, it will be possible to use only the required minimum number of them.

In addition, dimmers provide a greater degree of convenience in adjustments - special devices that can smoothly change the intensity of the glow of the lamps. If there is a desire, due creativity and available funds, “dimming”, even on the scale of one spacious room, can be further divided into zones.

True, it should be borne in mind that not all lamps are amenable to such adjustment. For example, with fluorescent lamps, such a “number” does not work.

• The use of lamps of various types in the same room is not welcome - the effect can be completely unpredictable, but definitely negative.
• Much has been said above about the power consumption of lamps. In particular, about the fact that it should not become the determining criterion in the calculation of illumination. However, you need to know this parameter. The point here is not in the light parameters of the lamps, but in the operational capabilities of the luminaires planned for installation.

The fact is that these devices have a certain limit on the possible electrical load. Firstly, wires are laid inside them, usually of a very small cross section, and if the total power of the lamps is too high, overheating of the wiring is not excluded, with all the ensuing consequences. And secondly, most of the lamps are assembled from polymer parts. As we have seen, some types of lamps convert a significant amount of consumed energy into heat. And overheating can cause softening, melting of plastic, deformation of parts.

So when choosing lamps, it is necessary to sum up the value of their powers immediately. And if it exceeds the allowable limit for a particular lamp, you will have to look for some other solution.

• If, as a result of the calculations carried out, a lamp luminous flux value is obtained that is simply not in the range produced, or the use of lamps becomes impossible for other reasons (for example, the same unacceptably high power consumption), then nothing can be done - you will have to revise your system. Usually this is solved by increasing the number of fixtures, using other types of lamps, and using other methods. There must be a way out!

* * * * * * *
At the end of the publication - a short video clip, which, perhaps, will expand the understanding of readers in the field of calculating the optimal lighting for residential premises.

Video: How much light is needed for a comfortable and healthy environment in a room?

Calculation of LED lighting in the apartment

R The calculation of LED lighting allows you to organize an effective lighting system. One of the main features of such lamps is the high brightness of the light, and, in addition, they are characterized by directional radiation, which under certain conditions is a plus, in others - a disadvantage. In order for the room to be lit by diode lamps as evenly as possible, you should use some tricks.

Room lighting standards

The efficiency of light radiation in the apartment should be different. If in any of the rooms the glow is equally bright, directional or, conversely, diffused, then the level of comfort will noticeably decrease.

Room lighting standards

Therefore, in rooms for various purposes, SNiP provides for several levels of illumination:

• entrance hall of the apartment - 100-200 lux;
• home office - 300 lx;
• living room - 150 lux;
• bedroom - 200 lux;
• kitchen - 150-300 lux;
• children's - 200 lux;
• bathroom - 50-200 lux.

The area of ​​the room and its height are key factors in determining the sufficient brightness of the light. Much depends on the type of lighting: main light; local; functional; decorative lighting. The norms indicate different indicators of illumination for some rooms.

When creating a functional lighting system, the luminaire should emit a brighter light. Decorative lighting involves the need to install lamps of low efficiency. The named indicators of illumination are suitable for residential premises with a height of 2.5-3 m.

How to achieve uniform lighting?

If LED emitters are involved, then their location should be considered, taking into account the main parameter - the luminous flux. The brighter the radiation of the lamps, the further they are installed from each other.

To cover the entire area of ​​​​the room or a separate area, it is recommended to pre-calculate a sufficient number of lamps.

Uniform ceiling light is organized by mounting different types of lighting elements. You can choose from various combinations: a central luminaire (chandelier) and spotlights installed along different schemes; several ceiling fixtures of the main light and decorative light; point emitters in the right quantity and with suitable characteristics, used in the organization of the main light without the use of a chandelier.

Determining the level of illumination

The total intensity of the glow of lamps for rooms of different purposes is determined as follows:

• F \u003d E * S * kz,
• where E is the illumination of 1 sq. m;
• S is the area;
• Kz - safety factor.

The last of these parameters directly depends on the installation height of the fixtures and reflectivity different surfaces(walls, ceilings, floors). For housing, but only if diode-based lamps are installed, this figure is 1.1.

As an example, consider the calculation of LED lighting for a nursery:

Accordingly, in such conditions, it is necessary to use emitters that are characterized by a luminous flux of the desired value, so that in total it is possible to obtain a value of 1,320 lm.

How many lamps do you need

There are different formulas for calculating the number of lamps and appliances. Much depends on their type. For example, in point models, only one light source is usually installed, respectively, in order to calculate the number of such devices, you need to divide the total illumination (F) by the luminous flux of one emitter.

If there is another task: to determine how many lamps with several bulbs are required, then it is recommended to apply the following formula:

• N \u003d (E * S * kz * z * 100) / (n * F * ɳ),
• where E is the normalized illumination, lx (table value);
• S is the area of ​​the room, sq. m;
• kz - safety factor (1.1);
• z is the value of illumination unevenness (for diode lamps it is equal to 1);
• Ф – emitter luminous flux, lm;
• ɳ - coefficient of the lighting element (equal to 1);
• n is the number of lighting elements in one fixture.

As a result, you can calculate the desired level of illumination as accurately as possible and find out how much you need to set. lighting fixtures. In any case, it is always better to be guided by approximate data than to organize lighting “by eye”.

The type of light bulbs used should also be taken into account. They may differ in base (threaded, pin), color temperature (from warm to cold shades), power.

In particular, diode emitters for the home are characterized by a small load on the network: from 3 to 15 watts. This is enough to provide bright light for residential areas.

Thus, the total illumination of the room will depend on the number of devices. But, besides this, the parameters of the lamps must be taken into account: color temperature, luminous flux, power. To get a uniform glow using LED devices, you need to be guided by calculations, otherwise some parts of the room may not be well lit, while others, on the contrary, are too brightly lit.

You can choose any of the existing lighting schemes. The most commonly used options: with a chandelier and spot lighting; without the main lighting device, spotlights provide functional light.

Calculation of room illumination LED lamps

The reduction in prices for LED lamps and the increase in electricity tariffs make their installation in an apartment more attractive every day. In addition to tangible savings in energy costs, they allow you to create lighting that is closest in spectrum to daylight.

The most pressing question when replacing ordinary incandescent bulbs with LED ones is how to calculate the required number of LED lamps. It is customary for us that a 60 W light bulb shines in the toilet, and three or four 100 W lights in the hall. But for LEDs, such parameters are not applicable. When installing, it is necessary to determine the total luminous flux.

Calculation of illumination of premises for various purposes

For each room, the level of illumination is selected individually and depends on what work will be carried out in the room. In those rooms where you will read or write, the brightness should be maximum, and for the corridor, the illumination level is almost an order of magnitude lower.

The easiest way to choose a replacement for filaments is according to the table of their light fluxes.

Luminous flux of an incandescent lamp

Let's take as an example a living room with an area of ​​20 square meters, in which there are four ordinary 100 W incandescent lamps. The total luminous flux of such a chandelier will be 1200*4=4800 lumens. We divide the luminous flux by the area of ​​\u200b\u200bthe room: 4800/20=220 lumens/m2 (lux) .

Calculation of lighting with LED lamps, online calculator

Very simple formulas are used here:

The calculation of the number of LED lamps by area is based on the size of the room and the required level of illumination.

Luminous flux of one lamp = light level * room area / number of lamps

Calculation of LED lighting per square meter:

Illumination level = number of lamps * lamp luminous flux / lighting area

How many LED luminaires are needed per square meter depends on the type of luminaire installation. If the LEDs are installed in a conventional chandelier, their luminous flux is selected based on the required level of light intensity. During installation spotlights along the perimeter - we divide the required level by the indicator of the luminous flux of the lamps that we plan to install.

It should not be forgotten that the effective light angle of LEDs is about 120 degrees, so the number of fixtures per square meter should be such that the light is uniform, without drops. This is achieved by increasing the number of light sources with a proportional decrease in the power of each source.

It should be noted that the light bulbs located in the ceiling are 20-30 cm higher than in the chandelier, so the light intensity should be 15-20% higher.

To determine the number of light sources, you can use the calculator for calculating the illumination of a room with LED lamps:

Which lamps to choose for lighting

When choosing LED bulbs, you should pay attention to the most critical parameters that are important for the quality of lighting.

• Colorful temperature;
• diffuser type;
• Light flow.

The color temperature of LEDs traditionally has three categories

• WW- warm white (color temperature 2500-3000 K);
• W- white (color temperature 3000-4200 K);
• CW- cold white (color temperature above 4500 K).

Visually, a higher color temperature shines brighter. So at the same power, the visual brightness of CW is a quarter higher than WW.

The diffuser can be matte or transparent. The matte diffuser provides a more uniform distribution of the light flux, but the intensity loss in it can reach 25-30%. To illuminate a relatively large area of ​​​​the room, it is more rational to use lamps with a transparent diffuser, but in a table lamp, a matte type of diffuser is better.

When choosing a light bulb, be sure to pay attention to its nominal luminous flux. It depends on the type and quality of LED matrices.

The required power of the LED lamp depends on the parameters discussed above. When using warm light, the rated power should be 25-30% higher than cold light lamps.

Inaccuracies and errors in the calculation of LED lighting

Often the replacement of ordinary light bulbs with LEDs is carried out during a scheduled repair. After, during operation, it turns out that there is not enough light.

The main reason for such incidents is the lack of consideration of the reflection coefficient of surfaces.

Plywood more dark wallpaper, the use of linoleum or laminate in dark shades, a matte false ceiling can significantly reduce the illumination in the room. In this case, we are talking about general illumination. Light intensity on desk, over which the LED lamp is mounted, may be sufficient. But an attempt to read your favorite book while lying on the couch will cause discomfort if the walls reflect little light from the ceiling lights.

To determine the reflection coefficient, it is customary to take into account the following coefficients:

• 70% — White color surfaces;
• 50% - light;
• 30% - gray;
• 10% - dark;
• 0% - black;

There are many correction tables for determining the illumination of a surface at various reflection coefficients. For the sake of ease of calculation, you can use a simplified formula.

Total reflection coefficient = (Ceiling EC + Wall EC + Floor EC) / 3

So we get the average, which will allow us to put a correction factor in our calculations.

The room has a white ceiling (KO 70%), peach wallpaper (KO 50%) and light laminate (KO 50%).

Average reflectance = (0.7+0.5+0.5)/3*1.2 = 0.7

If LED lamps with a nominal luminous flux of 1400 lumens are installed in the room, we take 1400 * 0.7 = 1000 lumens.

Lighting calculation.

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 is to determine the total amount of light flux required 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.

To easily calculate the number of lamps you need, 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 the 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 fixtures. This will turn on some of the fixtures and get soft, not very bright lighting. and if necessary, turn on full bright lighting.

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. normative documents on labor protection, a number of GOSTs 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 the 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 in specific conditions, with a predetermined known characteristics. Simply put, they make up a simplified model - a light bulb under the ceiling in 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 a regular room with an area of ​​​​20 m 2 with standard height ceiling of 250 cm. For simplicity, we will assume that the ceiling is white, matte, and the walls have a plain coating without gloss, beige colour. All these data are needed to calculate the illumination or illumination.

Used as a lighting fixture ceiling lamp of five light bulbs, each of which is covered with a diffuse 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 room illumination index, the percentage of reflection - for a white ceiling surface - 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 the use of flow n c = 0.51 required for calculation.

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 ∙ nc) \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 an illumination standard of 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 the most different variants illumination at various sources Sveta. The LED version turned out to be the most economical, with a consumption of 12x5 = 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 you are guided only by these rules, 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.