Calculation of interior LED lighting

In order to convert lumen into lux, you should know that in order to get 1 lux of light, 1 lumen should light 1 square meter. This means, that if you use an 6w LED light bulb, which has an output of 600 lm, and if you manage to light exactly 1 square meter with all the lumen, and without any other lost light, than you have achieved 600 lx lighting.
In actuality, things are not so simple because light disperses and it is very difficult to measure exactly how many lumen are being emitted without a light meter. Also, when measuring your lighting, you should keep in mind that the size of the room as well as the purpose of the room is the norm of the lighting is measured in different places.
In most work spaces, the light’s norm is measured on the work table/desk, which is usually up to 80cm, while in the rooms where no work is expected to be done, the light norm is usually measured on the floor. Here are several examples:
- Lighting for halls and conference rooms - 500 lx
- Lighting for shops for food - 400 lx
- Lighting for shops on self serving – 300 lx
- Lighting for classrooms – 300lx
- Lighting for doctor’s cabinet – 200 lx
- Lighting for kindergartens – 200 lx
- Lighting for service rooms of theaters, movie theaters and schools: 150 lx
- Lighting in laundry rooms - 100 lx
- Lighting of stairs in public buildings - 75 lx
- Lighting in rooms for sleep in kindergartens – 75 lx
- Lighting for stairs in residential buildings and hotels - 50 lx

In order to find out if your lighting is in accordance to these requirements , add up the lumen output of all lights (the lumen is marked on the LED lamp's packing). The sum of all lumen must be divided in the number of square meters of the room (including the walls and ceiling) and if the result is close or larger to the norms, then you have definitely covered the lighting standards.
Here is an example for how to measure the light without a light meter, as well as how many LED lamps you need for a room of 5x5 sq.m and 3m ceiling with a minimum norm of 100lx and to be sure that the lighting is enough.
- first calculate the square meters of the floor, all walls and the ceiling
 the result (110 sq.m) is multiplied by the minimum norm for lighting of laundry rooms (100lx)
 The final result is 11,000 which is amount of lumen from all lamps used
 as we know, a 20W LED lighting has an output of about 2200lm, so you can easily calculate that you will need 5 LED lighting products of this type.
Calculated this way, the lighting will definitely cover all standards and norms for your needs, but won't be the most economic one, because if you use LED lamps with reflectors instead, you will need only half of the power.

How long is the warranty of the new energy saving LED and CFL light bulbs?

One of the most popular false beliefs for consumers is about the warranty period and life of energy saving light bulbs for lighting . This common error occurs because of the misleading information about the technological life, which usually leads to possible disappointment for the clients.
With this article we will try to explain about the important things you need to know in regard to the warranty of the energy saving light bulb when buying one.
One of the huge benefits of the energy saving light bulbs offered on the market is their longer exploitation period as compared to the normal incandescent light bulbs, which have a normal life of 1,000 hours.
The lifetime for most CFL energy saving light bulbs of 6,000-15,000 hours, and the new LED energy saving light bulbs have a life of 50,000-100,000 hours. In most cases, the producers give warranty information in years, but this is calculated for 2.7 hours use of the lamp daily, which is about 1,000 hours per year.
Since most CFL energy saving light bulbs have a life of about 10,000 hours, their producers claim that their products have a 10 year life. This is how some retailers try to mislead their clients by convincing them that this is the warranty period of the energy saving CFL or LED light bulbs. This is far from reality though, because if light bulbs are used for 6 hours daily, then these 10,000 hours will pass in about 5 years. If you use the light bulbs for 24 hours a day, then the period is about 1 year.
This is why you should be careful when you see an energy saving CFL light bulb for which the retailer claims to have more than 1 year warranty and for the LED energy saving bulbs of more than 5 years. This means that the retailer has given an unrealistic warranty period, longer than that given by the producer, which could possibly lead to problems with eventual claims for defective products.
Another important factor which you need to keep in mind are the warranty conditions, because often times they may make it impossible for a defective product to be returned to the shop and a claim to be made.
Stay alert for such absurd requirements like keeping the original packing or with the new energy saving light bulbs to be installed by a professional electrician for example.

New requirements for lamps and lighting products' packaging

Why does the marking on all packaging of lighting products changing?

From September 1st 2010, a new EU directive was implemented.
According to its requirements, all lighting products must be marked first and foremost according to their lumen output, and the previous requirement for a comparison in watts to the ordinary incandescent light bulbs (which made light by heating a metal filament wire to a high temperature until it glows) remains a secondary requirement.
This measure became necessary, to avoid the confusion of customers, when choosing the lamps and lighting products for their needs. With the introduction of new types of lighting products, produced by different technologies, it has become more difficult for the customers to their informed choice of the necessary power of the lighting products for their particular needs.
As a result of the new directive, all lighting products on the market must be marked mainly according to the Lumen output (their light flow intensity). It must be clearly marked on the packaging, with a larger font than the one for the comparison to the older incandescent light bulbs in Watts.
This new measure also has a goal to eliminate the speculative manner of the marking made by certain producers under the older requirements. For example, many of them abused the fact that the older light bulb of 100 watts, depending on the producer or the technology used for their production, had an output of about 1,000-1,450 lumens, and for comparison, they marked the lower figure of 1,000 lm, which usually is the same as that of the energy saving 20w lamps.
With the adoption of the new rule, now the upper boundary figure of the lumen output will be used (about 4,000 lm), and as a result, the energy saving 20w lamps of 1,200 lm, which used to be marked as: 20w=100w now need to be marked as 20w=88w for example.
With these changes, comes the new requirement to mark the content of Mercury (if there is such), as well as the time necessary for the lighting products to reach 60% of their maximum power (which usually is marked from 5 to 30 seconds) . Also, the number of times the lighting product can be switched on and off has to be clearly marked (it is usually somewhere between 5,000 and 10,000).
Here are several examples, which will help you quickly get acquainted with their characteristics when you are buying lighting products in the future.
The old 100w light bulbs have: 1,100-1,450 lm output and can be substituted with 20-23w energy saving lamps with about 1,200-1,400 lm or with 10-15w LED lighting products with a 1,000-1,500 lm output.
The lighting products with old marking will be available at the market until all quantities are sold, so do not be worried if you see the same products marked with the same lumen, but with different watts .

Light – what we don’t know about it

Light is an electromagnetic radiation, visible to the human eye only within the wavelength of 400-700 nm.
This electromagnetic radiation is measured according to the following three dimensions:

- Light luminance intensity (perceived by the human eye as the light intensity), it is measured in cd (Candela – Latin for candle). Here are several examples:
Ordinary candle = 1 cd
Ordinary 100W lamp = 100 cd
Energy savingCFL bulbs of 20W = 100 cd
Enery saving LED lamps of 5W = 30 cd

- Wavelength (perceived by the human eye as the color of the light), in accordance with its wavelength, the human eye perceived the light in different colors.
Here are the different colors depending on the light’s wavelength:

red ~ 700–630 nm
orange ~ 630–590 nm
Yellow ~ 590–560 nm
green ~ 560–490 nm
blue ~ 490–450 nm
violet ~ 450–400 nm

-Light polarization – the polarization of the light is not visible to the human eye, but can be viewed through various types of filters.

There are several more measurement units used for the measurement of the various aspects of light, and everything associated with lighting and illumination:

- The intensity of the light flow (how much light is contained in one area) is measured in Lumens (lm). Here are several examples:
Ordinary candle = 11 lm
Ordinary 100W lamp = 1100 lm
Energy saving 20 W CFL bulbs = 1100 lm

- the color temperature is measured in K (Kelvin) degrees – these degrees show the temperature which is needed to heat an absolute black body (this is a theoretical object, which doesn’t exist in the natural world) in order for it to emit light in the same color. Here are several examples:
Ordinary candle: 1900 K
Ordinary lamp: 2700K
Energy saving CFL bulbs: from 2700 to 6500 K
Midday light: 6500K

- Illuminance is measured in Luxes (lx). When we spread 1 ml of light on an area of 1 sq.m., from a distance of 1m, then its illuminance is 1 lx.
The high quality lamps and lighting products are always marked with the amount of Lumens of their light flow, as well as the light color.