In ancient times, light was perceived by people as a phenomenon that depended on the will of higher beings ... Today it is no secret to anyone how to control this radiation, what is its essence, how to calculate artificial lighting.
The lack of light rays leads to a significant decrease in working capacity, deterioration of well-being and to a decrease in mood. In this regard, the important point is the correct, in compliance with hygiene requirements, placement and connection of lighting devices. For enterprises, it will be beneficial to purchase energy-saving equipment for both indoor and outdoor areas.
Lighting characteristics
In the wavelength range of 380-780 nm, the electromagnetic radiation of the optical spectrum becomes visible. It can be characterized by the following values:
1. Luminous flux (this is part of the optical radiation perceived by man as light). The unit of measure is lumen. In calculations, it is designated as F.
2. Light intensity (this is the density of the light flux in space lying in the direction of the axis of the solid angle). It is designated as I,
but measured in candelas.
3. The solid angle (this is the part of the space that is located inside the conical surface). Measured in steradians. Designated by W.
4. Illumination shows the value of the surface density of the light flux. Its unit is luxury, and is denoted by E.
5. Brightness is the surface density of the light intensity of a surface that lies in a given direction. This flow is measured in candelas per square meter and is denoted by L.
6. The blindness index (P) is a criterion for the glare of light devices.
7. The criterion for the pulsation of illumination (Kp), measured in percent, is used to assess the relative depth of fluctuations in illumination.
8. The indicator of discomfort (M) is used as a criterion for evaluating discomfort brilliance, which causes a feeling of pain in the eyes when inhomogeneous placement of bright spots in the field of view.
Measuring instruments
To determine the illumination, various light meters are used. For example, the Yu-116 device allows you to calculate this parameter created by an incandescent lamp and natural light. The light meter is used to control illumination in agriculture, transport, industry and other fields.
To measure other values, such as brightness, ripple, analog-to-digital devices are used. An example of these is the ARGUS-07 heart rate monitor-luxmeter. The principle of its action is to convert the luminous flux, which is created by extended objects, into an electrical continuous signal proportional to illumination. Then it is converted into a digital code displayed on an electronic scoreboard.
Types of lighting in production
If the room is illuminated only by lamps, floor lamps, lamps, that is, artificial light, then such lighting is called artificial. It is necessary to create comfortable working conditions, normal operation of buildings and territories. It can be divided into the following types:
- Working.
- Security.
- Emergency
- Attendant.
The first is used to illuminate offices, work places outside the building. The second and fourth type of lighting is turned on during off hours, and the third distinguishes emergency exits, various safe moments. Artificial lighting can be general, in which the lamps are placed evenly in the upper area of the office, or combined. In the second case, local lighting is added to the general, which is created by lamps located near the workplace.
The next type of industrial lighting is natural. Here, too, several types can be distinguished: lateral, upper, combined. The first is when sunlight enters the room through light openings in the exterior walls. In the second, the light passes through openings in the walls at elevation points of the building or through lights. The third type combines overhead and side lighting. This type of lighting is especially necessary in rooms with the constant presence of a large number of people.
The combined form of lighting is a combination of natural and artificial. It is used in special cases when works from the first to the third category are performed, if space-planning decisions for construction are necessary or when the feasibility study is confirmed by calculations.
Norms of types of lighting
When choosing the values of the parameters of norms, you need to rely on SNiP "Natural and artificial lighting." In this case, the illumination of the premises is regulated by its minimum permitted level, based on the characteristics and type of visual work performed (ZR). There are three types of missile defense:
- The first includes activities in which you do not need to use optical devices. The object of distinction in this case may be at different distances from the eyes.
- The second allows the use of optical devices when performing work. The reason lies in the very small size of the object in question, which is not perceived by the eye.
- The third includes works in which it is necessary to perceive information from the screens. This type has special requirements for the organization of lighting.
In coordination with SNiP "Natural and artificial lighting", the following characteristics of visual work without the use of optics can be distinguished: discharge, subdischarge. The first is formed in connection with the size of the object of discrimination, and the second - from a combination of contrast and lightness of the object of discrimination with the background. For each characteristic, the illumination, the index of illumination, the ripple coefficient and its own methods of calculating artificial lighting are normalized.
If the lighting in the room is natural or combined, then for the discharge of ZR the coefficient of natural illumination is given. It is the ratio of natural light to a set amount of external horizontal illumination, which is created by the light of the open sky.
When natural lighting is lateral and one-sided, a minimum KEO value occurs at a point located at the intersection of the vertical plane of the section of the room and the conditional functional surface at a distance of 1 m from the wall farthest from the light openings. If the lighting is top or combined, then the calculations take the average value of the coefficient at the points located at the intersection of the vertical section plane of the room and the working surface.
Calculation of artificial lighting
The first point in this matter will be the selection of the type of light source. It is also necessary to determine the lighting system and the corresponding norm. The second item will be the placement in the office of the selected lamp and the calculation of lighting at certain points. And finally, the last item will be the determination of the unit power of the lamps. The choice of a light source is carried out according to the following rule: economical discharge lamps are used in rooms with an air temperature above ten degrees, with high requirements for color rendering quality and a minimum degree of injury. If there is no natural light in the office and precise work is performed, then fluorescent lighting is used. If it is necessary to use and calculate LED lighting, then it should be remembered that lamps of this type do not have a stroboscopic effect, that is, the light goes on constantly. Therefore, it is important to carry out the correct calculation of the ripple coefficient in order to exclude high brightness.
When determining the lighting system, it is necessary to take into account the efficiency of the combined light system, as well as its hygiene (uniformity and brightness of the light flux). When office equipment is not evenly distributed, localized lighting is used. The determination of the type of luminaire must be approached, taking into account the rules for the dispersion of brightness in the field of view of workers, as well as depending on the state of the air.
For a clearer light distribution, a lighting circuit is created. It can be of several types: simple (connecting a small number of fixtures connected to one switch), intercom (connecting two independent groups of light sources that are controlled at one point), bidirectional (turning on and off from two points), commutator (control by two switches in two directions, and one in one direction).
The calculation of the lighting of the workshop should take into account the following parameters: determining the type of light sources and lamps, their calculation and proper distribution in space, determining their power and power supply. In addition to the items listed, it is necessary to pay attention to the types of visual work, environmental conditions, how working equipment is located, the number of employees, emergency lighting.
Power density method
Calculation of artificial lighting in this way allows you to carry out an approximate calculation of the lighting of the production room with a uniform distribution of fixtures. The power of one lamp is calculated by the formula:
Pl = PyS / pl
Where Ru denotes the specific power of the lamp, the value of which is in the directories. The specific power depends on the type and placement of lamps and fixtures, the characteristics of the room being lit, as well as on the height of the suspension. The value of S shows the floor area, and PL - the number of lamps. Results are usually rounded up.
Luminous flux or utilization method
In this way, the calculation of production lighting is carried out in cases where the illumination of the working surface is specified. The method is not used for localized external and local lighting, if the working surfaces are not horizontal, as well as in the calculation of directional concentrated light flux.
Calculations are carried out according to the formula:
F = En SZK / Nη
Where F is the light flux; En - normalized illumination; S is the floor area; N is the number of lamps; Z is the minimum power coefficient; K is the safety factor; η - coefficient of use of light rays of lamps.
According to the value of the luminous flux, a luminaire is selected, which may differ from the calculated value in the range from -10 to +20 percent. If the difference is greater than the permitted boundaries, then the number of fixtures is regulated.
Point method
The method is used to determine the light rays of lamps in cases where the reflected light is unimportant. The method is used for any location of the illuminated surface and fixtures. The method is based on the ratio of the dependence of the illuminance of the surface (E), which is created by a point source of light, on the distance to the surface (r), the angle of incidence of the beam (a) and the light intensity (I):
E = I cos α / r 2
The calculation of the lighting of the workshop, and specifically the lighting installation, includes several stages:
1. Finding the minimum normalized illumination.
2. Selection of the type of light source. Determination of the type of fixtures and their placement in the workshop.
3. Highlighting control points with the least conditional illumination on the office plan.
4. At control points, calculations are made according to the conditional illumination. The subsequent calculation of the lighting of the production room is based on the point with the lowest conventional illumination.
5. Using the lookup tables determine the factors of additional illumination and margin.
6. Find the luminous flux of the lamps. According to the results, a standard lamp is selected.
7. Determine the power of the lamp and the entire light installation.
We give the following example of lighting calculation: in the problem, the height h = 4 m, the safety factor k = 1.5, the additional illumination coefficient u = 1.2, and the normal illuminance Emin = 75 lux are given. It is necessary to determine the lighting with working surfaces near the walls with UPD lamps.
Since the luminaries of this type have a deep light distribution, for them λ = 1. The distance between the light installations will be 4 m, and from the extreme lights to the walls - 1 m. We place the control points A, B (with the lowest illumination) on the plan and calculate the distance from them to the projections of the nearest lamps (d). The next item will be the determination of the conditional illumination and finding the point with the least illumination. According to the data, we calculate the value of the luminous flux of the lamp, its difference with the standard value, and also find the lighting.
Calculation of general lighting when working with computers
When an employee’s activities are related to a personal computer, special rules must be followed when installing lighting. In this case, the eye experiences a double load, as it perceives reflected light from the keyboard and documents, as well as direct from the monitor.
The room should have artificial and natural lighting, with a KEO coefficient of at least 1.2%. It is necessary that the working surface with computers is oriented laterally to the light openings for the penetration of natural light. The calculation of the artificial lighting of the room is carried out relative to the general uniform light incidence system. Direct brilliance is limited from light sources (the brightness of windows, lamps and other luminous surfaces is not more than 200 cd / m2), and reflected is regulated by the correct choice of lamps and positions of functional places depending on the basis of light (brightness of glare on the screen is not more than 40 cd / m 2 ).
In artificial lighting, fluorescent and compact fluorescent lamps must be used as light sources. If the premises are industrial or public in nature, then metal halide lamps can be used. Luminaires must be with shielding gratings and diffusers.
Street Lighting Solutions
Street lighting carries the important task of combining external sections into a single whole, plays the role of an assistant to safety and orientation in space, and also brings an aesthetic touch to the decoration of cities. Lighting equipment for this type of lighting must be selected depending on the features and status of the objects. They can be turned on automatically or using the dispatcher. There are several types of street lighting:
- Flooding. The essence of the method is to install and aim floodlights. It is used for illumination for protective purposes of the adjacent territories.
- The general. This method includes uniform distribution of fixtures of the same type. It is ideal for lighting paths, parks, areas where people and cars move.
- Marking. In this type of street lighting fixtures are located along the selected lines and shapes. It is used to create visual contours, emphasize relief, highlight the direction of roads and pedestrians.