For the comfort in the home are responsible for many systems. Water supply, energy supply, heating, lighting make people's lives more comfortable, safer and easier. Light affects the psychological and emotional health of a person, eye fatigue, restfulness, so it is important to choose the right lighting. To create a high-quality lighting system, you need to calculate the number of bulbs, determine the necessary level of illumination and conduct other calculations.
What is taken into account in calculating the illumination of a room
Creating high-quality lighting in each room depends on a number of factors. These include the area of the room, its purpose, the arrangement of furniture, the need for zoning, decoration and other criteria.
Previously, calculations for each specific room were made taking into account the power. Tables were used in which, depending on the type of room, the total lamp power was calculated. This method is incorrect, because power is a unit of calculation of energy, not light flux. There is a connection between these two quantities, but it does not obey a strict ratio suitable for all lighting devices. This method was only suitable for incandescent bulbs. Luminescent, LED and other devices consume a different amount of electricity and give a different level of brightness.
Choosing light sources is based on the luminous flux and illumination. These quantities are related to each other. The luminous flux of 1 Lm to an area equal to 1 sq.m. creates an illumination of 1 lux. Each room has its own norm.
Lighting Standards
The sanitary standards prescribed in the official documents of SNiP and SanPiN require the following level of illumination for residential premises:
- living rooms 150 lx;
- children 200 lx;
- classrooms, libraries 300 lx;
- room for accurate drawing work 500 lx;
- kitchen 150 lx;
- bathroom, bathroom 50 lx;
- sauna, bath 100 lx;
- corridor 50 lx;
- entryway 20 lx;
- dressing room 75 lx%
- porch 6 lx;
- platform next to the emergency entrance 4 lx;
- path at the entrance to the house for 4 meters 4 lux.
Standards of the level of illumination are considered optimal and tested, so they should be adhered to. Greater or lesser illumination can lead to rapid fatigue, the inability to concentrate on the work being done and the negative impact on the human psyche.
Settlement
There are simplified calculations of lighting in the room. They are associated with the area of the room and the necessary luminous flux. Multiplying the area by the stream of light gives illumination, from which you can then calculate the required number of lamps. Similarly, the calculation of lighting power over the area.
Calculation example: there is a living room of 15 sq.m. To illuminate it, you need 15x150 = 2250 lux. Light bulbs are selected for this value. If you take light sources with illumination of 500 lux, 5 lamps are needed to illuminate the living room.
Such calculations of light by area are not entirely correct, since they do not take into account the individual characteristics of the room. A more accurate way to calculate the luminous flux for a room uses the following formula:
Fl = (En × Sp × k × q) / (Nc × n × η)
This calculation of light includes many parameters that take into account the type of lamps used, the color of the walls, the presence or absence of a ceiling on the lamp.
- Fl (lm) - the necessary luminous flux that each lamp in the lamp must have.
- Yong - the norm of illumination, taken in the table for each type of premises.
- Sp - total area of the room.
- K - safety factor. For each type of lamp has its own value.For fluorescent bulbs 1.2, for ordinary incandescent and halogen bulbs 1.1, for LEDs 1.
- q - coefficient of uneven glow. Also different for different light sources. Any incandescent bulbs 1.15, mercury gas-discharge 1.15, fluorescent 1.1, LED 1.1.
- Nc - The estimated number of fixtures.
- N - the number of bulbs in one chandelier.
- η - utilization of the light flux. This parameter takes into account many features of the room, it can be determined from the table. Depends on the area of the room, the height of the light source, reflecting the ability of walls, floor and ceiling, depending on the color of the finish.
The value obtained is suitable only for general lighting. For decorative and accent lighting, the level of illumination cannot be calculated.
All the above calculations can be done using online calculators.
Light source specifications
After calculating the required level of illumination, you can proceed to the choice of bulbs. They are selected taking into account the following criteria:
- Type of cap. Depends on which is used in the lamp. In large devices, E caps are installed, G and other types can be used in spotlights.
- Power consumption. Depends on the specific type of bulb.
- Supply voltage. The mains voltage is 220 V, the frequency is 50 Hz. Not all lamps operate at this frequency; for 12 V and 24 V devices, a step-down transformer is required.
- Colour temperature. The optimal range for the room is from 2600 K to 5000 K. Warm light is given by lamps 2600-3500 K, daylight white 3500-4000 K, cold 4000-5000 K.
- Light flow. Indicates how bright the light will illuminate the area.
In houses for general illumination 4 types of lamps are used - incandescent, halogen, fluorescent, LED. All of them have their own characteristics, pros and cons.
Incandescent lamps
This is the cheapest kind of light bulb. They give a pleasant yellow light. Incandescent lamps are almost completely replaced by other light sources, as they are ineffective. The disadvantages include low efficiency, high energy consumption, short service life, fragility and insecurity.
Halogen sources
They have a similar design with an incandescent lamp, but have their own characteristics. First of all, this applies to the flask - it is made of quartz glass. It allows you to withstand high temperatures, so inside the flask is filled with vapors of iodine, bromine and other halogens. The service life due to the rejection of the brittle filament is increased, but many shortcomings remain. Due to the use of quartz, the flask cannot be touched with bare hands. Grease spots cause the glass to become thin and brittle and may explode.
Advantages - wide variety, higher efficiency, color temperature range from 2800 to 3000 K.
Disadvantages - high temperature during operation, fragility, non-environmental friendliness, complexity of disposal, high energy consumption.
Fluorescent devices
This type was previously represented by long tube lamps. Now there are models with standard socles for a conventional cartridge. In everyday life, fluorescent bulbs are called energy-saving. They consist of a glass flask coated inside with a phosphor and filled with a mixture of gases.
Advantages: high light output, low energy consumption, long service life, a wide range of operating temperatures.
Disadvantages: the presence of mercury inside the flask, the difficulty of disposal, the presence of UV radiation, flicker, a long start, a limited number of on and off cycles.
LEDs
LED light sources are considered the most successful option for the home. They do not contain harmful substances, work only on the glow from a semiconductor crystal. They have a wide range of colors, sizes, shapes.
The advantages include low energy consumption, high efficiency, durability, no flicker, safety, a wide range of operating temperatures, a variety of color temperatures. Due to the low heat, the LEDs can be installed in suspended ceilings without fear that the canvas may be deformed. When buying in a professional store from a well-known manufacturer, a guarantee is given, according to which the lamp can be changed during a manufacturing defect.
LED lamps have one significant drawback - high cost. Cheap models will not be made of quality materials, so the lamps will quickly burn out due to the lack of sufficient heat dissipation. Also, in a device of an unknown production, a driver may be missing - then the lamp will respond to any power surges and will quickly fail.
LED lighting calculation
When calculating the level of lighting created by LED sources, you can use a simple formula:
Luminous flux of one bulb = lighting area * level of illumination of a given room / number of lamps.
Lighting per square meter equals:
Illumination level = number of lamps * luminous flux / room area.
The number of bulbs depends on the method of installation of lamps and chandeliers. If the lamps will be installed in a classic chandelier, the luminous flux should be selected according to the required level of intensity. If point light sources are mounted around the perimeter, the intensity level must be divided into the luminous flux of the lamps. It should also be borne in mind that the luminaires on the stretch ceiling should not be closer than 25 cm from each other.
The effective angle of illumination of LEDs is 120 degrees. Therefore, it is important to ensure that the light spreads evenly and there are no unlit areas of the room. This can be achieved by proportionally reducing the power of each bulb.
The installation height is also taken into account. Point instruments are placed 20-30 cm higher than the bulbs in the chandelier, so the intensity should be higher by about 20%.
Often, the replacement of classic light sources with LED is made during major repairs or other construction works. The result may be that there is not enough light in the room. The main reason is that in the calculation of luminaires by the area of the room, reflection coefficients from surfaces were not taken into account.
For different colors of the premises, the following factors are used:
- white surface - 70%;
- light - 50%;
- gray - 30%;
- dark - 10%;
- black - 0%.
The reflection coefficient will be equal to the sum of the coefficients of the floor, ceiling and walls, divided by 3. The obtained average value can be used in the final calculations.
Calculation of the number of LED lamps in a room with a white ceiling, gray wallpaper and a light laminate
Average reflection coefficient = (0.7 + 0.3 + 0.5) / 3 * 1.2 = 0.6
If LED devices with a luminous flux of 1200 lm are installed in the room, the required luminous flux will be 1200 * 0.6 = 720.
To calculate how many LED lamps you need to illuminate a room of 20 sq.m, you can use the formula: illumination level * room area / luminous flux. Then, for the living room (illumination of 150 lux), the number of 20 W lamps (gives a luminous flux of 250 lumens) will be 150 * 20/250 = 12 pieces.
The calculation of the power of LED lamps for the room is as follows: the area is multiplied by the number of bulbs and the power of each product.
