How to calculate the luminous flux knowing the area of \u200b\u200bthe room. Calculation of room illumination with LED lamps
Despite all the achievements of modern times, best lighting the sun provides us. It remains for us to achieve the indicator of natural light as close to the ideal as possible. Comfortable lighting in the house creates a favorable environment for creativity, for rest, for work. In addition, the wrong light can be detrimental to health. And in order to avoid adverse consequences, you need to approach this topic wisely.
When calculating the illumination of a room, the number of fixtures and lamps is taken into account, more precisely, the power of lighting objects is calculated. But do not forget that there are a number of some factors that affect the value of power.
In this article:
What factors should be taken into account when calculating
The most common circumstances that are taken into account when calculating. We have prepared them in the form of questions. So:
- What is the room used for (children's room, kitchen, bathroom, office or other)?
- What is the ceiling height?
- What is the floor made of and what is its color scheme? It is also important to know what color furniture is in the room?
- Are there mirrors in the room?
Now let's deal with each item separately. In order for the light in the room to be pleasant and not cut the eyesight, it is necessary to calculate the lighting power based on the purpose of the room. So, the scheme of lamps used in the living room or kitchen is definitely not suitable for the bedroom. This is due to the fact that the bedroom will simply be too bright. Conversely, the light used in the bedroom will be too dim for the kitchen.
Ceiling height plays an important role. The standard ceiling height reaches 3 meters. If the ceiling is above this mark and reaches 4 meters, in the calculations all results are multiplied by 1.5. For ceilings whose height exceeds 4 meters, the results are multiplied by 2.
The color scheme of the room is also taken into account. A room dominated by a dark palette of colors will need more light sources. When counting, special indices are used. Only with their help can you correctly subtract the required number of watts.
Mirrors have the ability to reflect light. And so that the light reflected from the mirrors does not interfere with a comfortable stay in the room, they must be taken into account when calculating.
What should you know when calculating?
First, let's decide what method the calculation will be made. There are two methods:
Methods differ in formulas and certain norms. And their main difference from each other is the unit of measurement. In the first case, the unit of measurement is watts, in the second - lumens.
Calculation method for electric power
Although this method is used more often than the light method, it is nevertheless not the most accurate. Its popularity is due to the fact that it is quite simple to calculate. All you need to know is:
- Room area;
- Required power.
So, how many watts per square meter of lighting do you need? Let's start the calculation. The area is calculated according to the school formula. The area is equal to the product of two sides. Next, multiply the area by the number of watts required (20 watts is taken as a standard). The resulting number is considered the total power.
To calculate how many light bulbs you need, you need to divide the total power by the power indicator of the lamp itself. 
For example: let's say the total power indicator is 300, and the bulbs used are 60 watts. 300/60=5 bulbs are needed for proper lighting.
Here are the wattages for incandescent lamps that we are all familiar with. This does not mean that users of more modern and economical lamps need more of them. It should be remembered that on the packaging of economical light bulbs, it is indicated what is the corresponding power in terms of incandescent lamps.
Luminous power calculation method
The calculation in lumens is certainly closer and more accurate, but for some reason it is not considered practical. Many refuse it because of its complexity. But if you delve into the essence, you will notice that its complexity lies in the units of measurement. The measurement is in lumens. That is, this method shows how much luminous flux will be per square meter. 
The calculation follows the same principle as before. The area is taken, multiplied by the illumination we need, so we find out the power of the luminous flux given per square meter (however, now it is considered in lux). Further, to find out the total power, we multiply the area by the already known power of the luminous flux. The total output is now referred to as lumens. Now you can see for yourself that the method is complicated, only because the measurements are made in lumens and lux.
If the answer during the calculation is not equal to an integer, then it must be rounded up. So, if the answer is 4.6, then it is rounded off by 5. This is due to the fact that it is better to exceed the norm a little than to resort to additional lighting devices in the future.
The uniform arrangement of lighting fixtures around the perimeter has a positive effect on the quality of illumination. In such cases, take large quantity light bulbs, but less power.
As you have already noticed, even a fifth grader will cope with the calculations. But the main thing in this matter is to know all the factors that affect lighting. Thus, with the right approach and correct calculations, you can comfortably and pleasantly illuminate the house.
It would probably be great if people could see in the dark like cats. Probably you also asked yourself this question, once again stumbling over something in the dark. Therefore, you are not related to Count Dracula, then you need light. Light is good.
And how much light do we need? Would a simple candle suffice? Or put an industrial spotlight? But in our case, a lot does not mean good. It is necessary to correctly calculate the lighting not only for the comfort and health of the eyes, but also for reasons of economic utility.
Usually, during repairs, they think about the calculation of lighting, choosing and buying chandeliers as a last resort, like "we'll think about it and buy it later when we finish everything." And by the way, proper lighting it is necessary, not only that it would be convenient to read.
Properly calculated light affects both vision and eye comfort, and overall well-being in general. Plus, your child also does homework with the light you calculated, so think in advance and correctly calculate the lighting in your apartment even at the stage of repair.
How to calculate room lighting
P=r*S/N
- P - the level of illumination that we expect
- p - lamp power per 1 sq. m (approximate values see below)
- S - room area
- N - the number of light sources (light bulbs, lamps)
Average "p" values depending on the purpose of the room
- Living room - 10 -35 w / sq.m;
- Children's room - 30 - 90 W / sq.m;
- Corridor - 5 - 15 w / sq.m;
- Bedroom - 10 -20 w / sq.m;
- Kitchen - 12 - 40 w / sq.m;
- Bathroom - 10 - 30 W / sq.m;
- Storage room or garage - 5 - 15 W / sq.m.
Please note, if you have poor eyesight, then take the minimum value of "p" 25-30.
This is a table for calculating the specific power of lighting, depending on the type of lamps and the purpose of the room (for different rooms different requirements).
Also, many experts believe that with the correct calculation of lighting, it is necessary to take into account not only the area of \u200b\u200bthe room, but also its shape, the decoration of the room (dark or light), the type of chandelier or lamps, etc. For example, from a chandelier with a lampshade, the light will fall down and slightly to the side, and the corners will be darkened and additional lighting will be required. Also, the behavior of light in a room can be affected by glossy stretch ceiling and mirrors, especially the mirror cabinet, which are so often in the bedrooms.
It is also worth considering such a factor as the intensity of lighting. Maybe you prefer soft light and a cozy warm atmosphere, or vice versa, you like bright daylight so that every corner is illuminated.
And for this, there is also a useful table that will show the recommended lighting intensity for rooms of various sizes when using incandescent lamps. If you want to use energy-saving lamps, then the indicated data must be divided by 5.
| Room area, sq.m | Very intense light | Soft light |
| less than 6 | 150 watts | 60 watts |
| 6-10 | 200-250 watts | 80-100 watts |
| 10-20 | 300-500 watts | 120-200 watts |
| 20-30 | 600-700 watts | 240-280 watts |
How to Calculate LED Lighting
What about LEDs. LED lighting is gaining more popularity as it significantly reduces energy costs. What would correctly calculate LED lightening we need such an indicator as a luminous flux, or by a simple number of lumens.
For comparison, I will say that a 75-watt incandescent lamp produces a flux of about 900 lumens. By analogy, we calculate - in order to replace a 100-watt light bulb, we need 1200 lumens, and for a 60-watt lamp - 600 lumens, respectively.
Let's give an example so as not to overload the brain with unnecessary technical information. Let's calculate the number of LED lamps per room of 15 squares. The LEDs are very bright, but consume very little electricity. At 1 watt, an LED lamp gives us 50-100 lumens, versus 12 lumens per 1 watt for a conventional incandescent lamp. Not bad right? Let's take as a basis a minimum, that is, 50 lumens.
To illuminate a 15 meter room, usually 2 incandescent lamps of 100 watts are more than enough (we consider as above: 100 watts - 2400 lumens). We divide the resulting 2400 lumens by the number of lumens per 1 watt of the LED lamp, that is, we took 50 lumens. We get 48 watts - the required power, but already LED lamps. We calculate - we get that 6-7 LED lamps of 7 watts or 5 of 9 watts will be enough for a room.
How to determine the level of illumination
To accurately determine the actual level of illumination for each specific case, a special device will help - a luxmeter, consisting of a photocell and a pointing device. The photo sensor converts the energy of the light flux into electrical energy, the value of which will depend on the intensity of the incident light.
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 required in work areas than in recreation areas. Let's figure out how to correctly calculate the required lighting power!
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.
Estimation
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.
At equal capacities different types of lamps give different amounts 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, color scheme, 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 dark tones 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 even illumination of your home, use different types of light sources: general ceiling lamps and local or decorative - 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, the general condition of the body, and with prolonged negative impact not right organized lighting- generally sad prospects looming 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 a question proper organization Many homeowners take lighting very lightly. 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 it is offered very wide selection lighting lamps, 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, operating with 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 if we are talking about kids!
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. Consideration is given to a number of other important criteria 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 energy consumed for this purpose. electrical energy.
A fairly stable range of these 15 lamps was presented on sale; 25; 40; 60; 75; 100; 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 effect can be achieved by installing an 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 parameters different types lamps with approximately the same luminous efficacy. 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 simpler sections 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 the normal propagation of light. True, this applies to a greater extent to industrial premises, where there may be high levels dust or steam concentration. If we proceed from the fact that this is not observed in good owners 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 the total number of lamps that will participate 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. 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
LED lighting systems are the youngest of all, but the rapid surge in their development, which takes place in the twenty-first century, has allowed them to leave all competitors far behind. Of course, led (light emitting diode) technology is the most promising today and can replace any other light sources in a private house or apartment.
No matter how perfect lighting fixtures a home is equipped with, the desired effect can only be achieved if they are correct application. Properly organized arrangement of fixtures will help ensure favorable conditions for the health of the human visual apparatus and will create a comfortable atmosphere for the life of the owners. Therefore, it is very important to responsibly approach the design and calculation of the main lighting parameters of the room.
When evaluating the required lighting, parameters such as illuminance (measured in lumens), brightness (measured in lux) and luminous intensity (measured in candela) are taken into account. The first value is considered the most important and depends on the value of the light flux, which is distributed over the working plane.
Benefits of led technology
You will not surprise anyone with LED lamps now. Products with good luminous efficiency, high efficiency and low power consumption confidently continue to move around the planet by leaps and bounds. Gradually, they are replacing the recently popular compact fluorescent lamps, and also come to replace incandescent lamps, the effectiveness of which has long since become yesterday.
Perhaps the only drawback of LEDs is their rather high cost. However, their advantages over traditional sources of photon radiation will allow them to repeatedly recoup their high cost.
To the main positive qualities LED lighting fixtures include:
- long service life (from 50 thousand to 100 thousand hours);
- the absence of mercury vapor and other toxic substances in the composition;
- reliability and safety of use;
- compact dimensions;
- resistance to mechanical vibrations;
- lack of external control gear;
- safety for the environment;
- the ability to operate in conditions of high humidity;
- reliable start at low temperatures;
- good color rendering index;
- high efficiency of the luminous flux (in modern designs - from 60 to 140 Lm / W).
The main types of LED lighting
Under the lighting calculation in broad sense words, the totality is assumed mathematical operations, which connect the parameters of the lighting installation (number, power and location of lamps) and a quantitative measure of lighting indicators.
Before considering the calculation, it is worth mentioning the existing types of lighting, on which the requirements for it directly depend. In lighting engineering, there are traditionally three types of lighting:
- accentuated
- local (functional),
- general.
The first is often used for interior decoration, creating a certain atmosphere in the room, an interesting play of shades, complementing the room with unique visual effects. There are no special requirements for this type, and it consumes little electricity. As a rule, the accented type is performed by compact LED lamps directional light and led-stripes of various lengths and shapes.
A spot light group is used to create enough light on the work plane. For example, it could be written or kitchen table in the apartment, milling machine at the factory, assembly line household appliances in a factory, etc. It can also be used for zoning a room.
The general type is used to maintain a certain level of light in the entire apartment or room of a large area.
Rationing of lighting and basic principles of calculation
In our country, there are average normalized illumination values for various classes of premises. They are regulated by building codes and regulations (SNiP). It will be convenient to present these data in the form of a table.
| Room type | Required level of illumination per 1m² |
| Hallway | 100 lux |
| Landing | 100 lux |
| Study | 300 lux |
| classroom | 300 lux |
| Gym | 400 lux |
| Public catering point | 200 lux |
| Office rooms | 380-490 lux |
| Living room | 450 lux |
| Bedroom | 200 lux |
The illumination values presented above correspond to the value of the luminous flux, which falls on 1 square meter of the illuminated area and is sufficient for the visual comfort of a person. It should be noted that the given data are taken for rooms with a ceiling height of 2.5-3.0 meters. If the floor overlap is higher, then the level of illumination in suites can be taken 1.5-1.7 times more. This is due to the fact that the illumination changes in direct proportion to the square of the distance to the illuminated object. Therefore, the closer to the working plane the chandelier with lamps is located, the more efficiently the useful flux emitted by the LED will be used.
Calculation example
Guided by the data in the table, it is not difficult to calculate the lighting of a house with LED lamps. AT technical passport Each led device contains information about the amount of light produced by it. Then, in order to determine the required amount of lighting, it will be enough to multiply the number of square meters of the room by the value of illumination normalized by SNiP, and then divide the resulting product by the luminous flux of one led bulb in lumens.
For example, if there is a lighting device with a luminous flux of 400 lumens, then for a bedroom of 12 square meters you need 6 of these products:
(12m 2 x 200 lux)/400 lumens=6 pcs.
Or 3 with a luminous flux of 800 lumens:
(12m 2 x 200 lux)/800 lumens=3 pcs.
Note! Standard light with a power of 11 W, it has a luminous flux of 700-800 lumens and is equivalent to a 75 W incandescent lamp.
Thus, it will be possible to find out how many light bulbs are needed to create a comfortable level of light in the room. As a rule, this number is not a whole number and needs to be rounded up or down.
Inaccuracies and errors: what are they connected with
The method proposed above for assessing the illumination of an apartment by LED sources is simplified and cannot take into account all the factors that affect the quality of light. These indicators include:
- light reflection coefficients of various surfaces,
- parameters of luminaires, diffusers and reflectors,
- room index,
- room efficiency, etc.
However, even qualified engineers cannot estimate the required level of led lighting with 100% accuracy, because even calculations using exact methods involve the introduction of a number of assumptions and generally accepted average factors.
In addition, the illumination standards themselves are not strictly justified, so a compromise between the desired and possible results is always maintained in a certain section of the illumination scale.
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