Even people who are far from lighting technology are well aware of the basic parameters that lighting in an office must meet: a color temperature of about 4000 K, an illumination of at least 400 lux. Such parameters were taken as a basis in our country back in the 1980s. Then they made it possible to find a compromise between not the highest technical capabilities and the health of employees. In addition, they responded to the realities of the existing socio-economic system. Time has passed, and today office lighting requires a completely different approach.
Workplace illumination
Let's start the revision of the requirements for office lighting with the seemingly simplest parameter - illumination. According to SP 52.13330.2011 "Natural and artificial lighting", the norms for the level of illumination are tied to the size of the objects to be distinguished and their contrast relative to the background. There is no direct requirement of 400 lux for office work, this parameter is necessary if you work with documents printed in size 10 and larger, and there is no need to determine the authenticity of the document. This is quite consistent with the reality of 30 years ago, when it was not customary to write individual provisions in contracts in small, hard-to-read type, and falsification of documents was not widespread. However, this is completely unsuitable for modern business and government agencies.
The European standard DIN 5035 establishes a minimum illumination level in an office of 500 lux, which is already closer to modern realities. But do not rush to accuse Russian standards of being archaic. If you strictly follow the method for determining the minimum illumination prescribed in SP 52.13330.2011, then, if necessary, read what is written in the contracts in small print or determine by eye the authenticity of signatures, seals and forms, the requirements turn out to be even stricter - at least 600 lux. It is this kind of coverage that should be in the office of a top manager and any other employee, on whose signature major contracts depend. But in what our set of lighting rules is still lagging behind the European standard, it is that it does not set parameters for offices like openspace. From the point of view of visual comfort, the situation in openspace is more complicated than in offices with the usual cabinet system. DIN 5035 requires that the illumination in workplaces in them be at least 750-1000 lux, depending on the reflectance of the ceiling, walls and partitions. In our country, openspace offices have become widespread only since the end of the 2000s, so they do not yet appear in the domestic regulatory framework. However, the overwhelming majority of openspaces are converted factory halls, therefore, the minimum illumination, using the norms for industrial premises, can be roughly estimated. The resulting minimum value varies between 750-1250 lx, which is in line with European standards.
So, in modern conditions, the illumination level of a workplace in an openspace office should be at least 750 lux, and in a separate office - at least 600 lux. But the solution to the problem of increasing illumination at the workplace is not limited to installing lamps with a high luminous flux or increasing the number of light sources. There are other important factors to consider. Otherwise, an increase in the level of illumination will not only not increase labor productivity, but will have the opposite effect.
Visual comfort
Even if the pulsations of the light flux are clearly not visible, they are nevertheless perceived at a subconscious level by the human brain. This manifests itself as increased fatigue, irritability, etc. A person perceives pulsations of the luminous flux with frequencies up to 400 Hz. At the same time, for inexpensive luminaires, including LED ones, significant pulsations are characteristic at a frequency of 100 Hz.
In Russia, SP 52.13330.2011 sets the maximum level of pulsation of the luminous flux for rooms where intense visual work is carried out at the level of 10%. But in the event that work at the computer is going on in the illuminated room, then the sanitary standards SanPiN 2.2.2 / 2.4.1340-03 "Hygienic requirements for personal computers and work organization" come into effect, limiting pulsations at the level of 5% … A significant part of ultra-budget LED luminaires do not comply with this norm. Nevertheless, even this limitation is relevant for the previously accepted illumination level at the workplace of 400 lux.
The higher the illumination level, the stronger the person reacts to the pulsations of the light flux. Let's give such an illustrative example. In the 1970s, televisions were produced that did not give a very bright picture - to watch programs, you had to close the curtains during the day and turn off some of the lamps in the room in the evening. But then for a comfortable viewing, a vertical frequency of 50 Hz was quite enough (with such a frequency the image flickered on the screen). In the 1990s, TVs began to display brighter images and the frame rate was raised to 100Hz to avoid flickering. Finally, modern TVs can be watched even when bright sunlight hits the screen, but you have to increase the frame rate up to 200 and even up to 400 Hz.
The same is the case with lighting. The brighter we illuminate the workplace, the less ripple should be. Unfortunately, for an illumination of 600 lx and above in relation to offices either in Russia or abroad, there are no specific recommendations for the pulsation coefficient of the luminous flux. There are only expert estimates, according to which for a modern office with its total computerization and high level of illumination, the coefficient of pulsation of the luminous flux should not exceed 1-3%. So while you have to be guided by a simple rule - the less, the better.
The luminous flux ripple factor depends on the parameters of the luminaire power supply (driver). This unit has a rather complex design, even if the manufacturer buys it on the side, a certain "scientific school" is needed to make the right choice. That is why zero or close to zero values of the pulsation coefficient of the luminous flux are obtained, as a rule, when a company that has extensive experience in producing all kinds of electronic devices (for example, LG, Philips, Verbatim) is taken into the production of an LED lamp. The most striking example of this is German Esylux company, which, before starting the production of LED luminaires, has accumulated vast experience in the creation of intelligent lighting control systems. As a result, the Esylux Nova LED luminaires have a zero level of pulsation of the luminous flux.
Another problem associated with increasing light levels is the dazzle effect. The simplest way to reduce the level of visual discomfort is a milk diffuser. This option is used in some cases - for example, when lighting medical institutions. But for offices, it is hardly applicable. The milky diffuser significantly reduces the luminous flux, which reduces the energy efficiency of the luminaire. In addition, with a ceiling height of more than 3 m, a luminaire with such a diffuser will shine to the sides, but not to the workplace.
In extra-budget luminaires, a “crushed ice” diffuser is often used, which provides high energy efficiency in combination with the cheapness of the material, since high-precision machines are not required for its production. But such a diffuser is not able to direct the light mainly to the workplace, and the aesthetic solution of the diffuser leaves much to be desired.
The most suitable type of diffuser for an office luminaire is microprismatic. It consists of a large number of miniature prisms that ensure optimal light distribution. Several variants of the device of microprismatic diffusers are known, differing in the shape of the prisms and the order of their arrangement. The most successful for visual comfort, although the most difficult to manufacture, is the Crystal version, which is used, in particular, in some modifications of Esylux Nova luminaires.
Natural and artificial lighting
A room where people are constantly located should receive sufficient light from the street, except for those cases when it is technically impossible to do this. Why is this necessary, if with the help of modern energy-efficient lighting devices it is possible to provide the required level of illumination? The reason is that natural light, penetrating into the room, allows the body to "adjust" its biorhythms for a certain time of day. That is, the window in the office space not only provides additional light, which allows partly to save energy, but also serves as a kind of "communication channel" with the outside world, ensuring the correct functioning of the employee's body.
When there is enough daylight to illuminate a room, we talk about natural light. If the light from the lamps complements the street light, this is called combined lighting.
Excerpts from the Federal Law of December 30, 2009 N 384-FZ "Technical regulations on the safety of buildings and structures"
Article 23. Requirements for the provision of lighting
1. In premises located in the above-ground floors of buildings and structures with permanent residence of people, natural or combined, as well as artificial lighting should be provided, and in underground floors - artificial lighting sufficient to prevent the threat of harm to human health.
2. In the premises located in the above-ground floors of buildings and structures, in which, according to the conditions for the implementation of technological processes, the possibility of natural lighting is excluded, artificial lighting should be provided, sufficient to prevent the threat of harm to human health.
The penetration of light into a room from the street can be expressed in terms of the coefficient of natural light (KEO). This coefficient is equal to the ratio of the natural illumination created at some point on a given plane inside the room by the light of the sky (direct or after reflections) to the simultaneous value of the external horizontal illumination created by the light of the completely open sky. The KEO value is separately normalized for natural and combined lighting, as well as in cases where light from the street enters the room from above or from the side. The normalized KEO value for combined lighting is much lower than for artificial lighting. Hereinafter, we will operate with data for the most common type of natural lighting - side lighting.
SP 52.13330.2011 recommends that there should be natural light in rooms where people are constantly present. This is a healthier option. For offices with a cabinet system, the minimum KEO value is 1%, for openspace there is no norm, but the closest option is “design rooms of design bureaus”, for which the KEO value is set at least 1.2%.
The emergence of office buildings with all-glass walls in large cities creates the illusion that there are no problems with natural light. But, in fact, there are problems, moreover, they are only getting worse. Firstly, not all companies are located in the "crystal palaces". Often, there are simply no glass buildings in convenient locations for an office - for example, in the historic center of the city. Old factories with small windows are used for offices. Secondly, because of the dotted building, the advantages of large windows are leveled. What is the benefit of glass walls if they are overlapped by an adjacent building? And, thirdly, even with a good location of the office center in the city, the light will not penetrate into the depths of the large openspace.
As an exception, SP 52.13330.2011 allows, if it is impossible to realize natural lighting due to the appropriate space-planning solution, to use combined lighting. Then KEO should be at least 0.6% for the cabinet system and at least 0.7% for the "design rooms of design bureaus".
In fact, in modern conditions, such an "exception" has become a common practice. This does not contradict the current rules, but it is not useful for the health of personnel, because the experts determined the norm for KEO at least 1–1.2% as a result of serious research. In addition, there are rooms with exclusively artificial lighting. Let's say meeting rooms are a space where employees are occasionally. Such premises may not have windows at all, and this does not contradict the norms. Also, windows may not be in those factory halls where they interfere with the production process.
In these cases, the so-called biodynamic lighting will help the staff to maintain health and high productivity, which changes the spectrum of lighting depending on the season and time of day, so that it matches natural time as much as possible. The most advanced biodynamic lighting system is SymbiLogic, developed by Esylux. This system is implemented in some LED luminaires of the Esylux Nova series. These luminaires are designed to be embedded in Armstrong or plasterboard ceilings. In the event that there is no possibility to embed the luminaire into the ceiling, the Esylux Alice surface-mounted ceiling luminaire with SymbiLogic support will do.
Easy to install and manage
Luminaire advantage Esylux Nova with SymbiLogic system - ease of installation and system management. Luminaires are combined into sets (sets), 4 pieces each, which include two Master devices and two Slave devices. The DALI protocol is used for control, but no special controller is required - the control device is built into the Master luminaire with a presence sensor. Another Master type luminaire does not have a presence sensor and is used as a data router. 220 V power is supplied to Master type luminaires, control signals and power to Slave luminaires are transmitted via two CAT5 cables with RJ-45 interface. Any electrician can install the system; for this he does not need to study network technologies. If necessary, the joint work of two sets is possible.
The system is configured from a mobile device (smartphone or tablet) via the Bluetooth interface. In this case, the mobile device must support Bluetooth 4.0 or higher. The system is capable of operating both in the mode of automatic change of the spectrum of illumination, and in the mode of manual adjustment. In the latter case, it can be controlled using a conventional two-button wall switch: one button controls the brightness, the other controls the color temperature. The presence sensor automatically turns on or off the lighting when an employee is present or absent from the workplace.
The “self-sufficiency” of Esylux Nova luminaires does not prevent, if necessary, to include them in the “smart home” system. It is possible to connect the system via the DALI interface with other luminaires, as well as to control the system via DALI. In the future, it is planned to ensure the integration of luminaires with building management systems in order to obtain statistical data on the presence of employees in certain places of the office. This opens up opportunities for a more rational use of office space.
Among the ideas for the beneficial use of recessed luminaires with adjustable color temperature, one can note not only offices and high-tech industries, but also, for example, clothing stores. Trying on a weekend suit or evening dress requires a certain amount of lighting to match the time of day that the garment is supposed to be worn. For this purpose, fitting rooms are equipped with lighting that can simulate a particular time of day. To create the desired effect, simply press a button.
The benefits of biodynamic lighting are clear. But how can the investment in this technology be justified? A set of Esylux Nova lamps made in Germany costs significantly more than, say, lamps from Chinese manufacturers. However, Esylux Nova guarantees the longevity of the products. The die-cast metal housing provides efficient heat dissipation and therefore the stability of the LED parameters. Thanks to a high-quality power supply, the estimated lifespan of the entire luminaire (not just LEDs) is 50,000 hours. This is why Esylux gives Nova a five-year manufacturer's warranty. This time is quite enough for biodynamic lighting not only to pay for itself, but also to bring impressive profits.
And for those who want to test the effect of biodynamic lighting, Esylux offers a program "TEST DRIVE HUMAN CENTRIC LIGHT".
Alexey Vasiliev
