There are three types of industrial lighting: natural, artificial and combined.

· natural illumination of premises with sky light (direct or diffused) penetrating through light openings in the external structures of buildings;

· artificial lighting with electric light sources;

· combined lighting, in which natural lighting, which is insufficient according to the norms, is supplemented by artificial lighting.

Visible radiation (light) is the radiation that strikes the retina of the eye and can cause a visual sensation. Light is a part of electromagnetic radiation with a wavelength of 0.38 to 0.78 microns.

Lighting quantities that determine the performance of industrial lighting are based on an assessment of how they feel to the human eye. There are quantitative and qualitative indicators of lighting.

Quantitative indicators

To quantitative indicators include: luminous flux, luminous intensity, illumination, brightness, reflection coefficient.

Luminous flux (F)- the power of the luminous flux of radiation, estimated by visual sensation by the human eye. The dimension of the luminous flux is lumen (lm).

Light intensity (J)- spatial density of the light flux in a given direction, i.e. luminous flux per solid angle ω in which it is emitted

Candela (cd),

Where ω solid angle in steradians (cf).

Illumination (E)- the density of the luminous flux on the surface illuminated by it, the luminous flux, referred to the area of ​​the illuminated surface S, measured in m 2, provided that it is evenly distributed over the surface, when the source light falls on it perpendicularly

.

Brightness (V)- is a light quantity directly perceived by the eye. It is determined by the ratio of the luminous intensity in a given direction to the projection area of ​​the radiating surface onto a plane perpendicular to the direction of radiation

.

The values ​​of the maximum brightness values ​​on the working surface.

Surface reflectance r characterizes its ability to reflect the light flux falling on it. It is determined by the ratio of the reflected light flux to the incident

Values ​​of the coefficient (r) for surfaces of various nature.

Qualitative indicators

To quality indicators illumination include: background, contrast of the object of distinction with the background, glare index, illumination pulsation coefficient, discomfort index.

Background- the surface adjacent directly to the object of distinction on which it is viewed. The background is considered light if the reflection coefficient P is greater than 0.4; medium at P = 0.2...0.4 and dark if P is less than 0.2.

Object contrast with background K Photometrically measured brightness difference between two zones. It is determined by the ratio of the absolute value of the difference between the brightness of the object and the background to the brightness of the background:

The contrast is considered large when K is more than 0.5 (the object and background differ sharply in brightness), medium at K = 0.2 ... 0.5 (noticeably different) and small if K is less than 0.2 (slightly different).

Blindness index 2 (P)- criterion for assessing the blinding effect of the lighting installation, determined by the expression

P \u003d (S - 1) 1000,

where S is the glare coefficient equal to the ratio of the threshold brightness differences in the presence and absence of glare sources in the field of view.

Normalized values ​​of the coefficient R.

Illumination ripple factor (Kp)- criterion for assessing the relative depth of fluctuations in illumination as a result of a change in time of the luminous flux of gas-discharge lamps when powered by alternating current, expressed by the formula

where Emax, Emin, and Esr are the maximum, minimum and average values ​​of illumination for the period of its fluctuation, lux, respectively.

The main task of industrial lighting is to maintain illumination at the workplace that corresponds to the nature of visual work. Increasing the illumination of the working surface improves the visibility of objects by increasing their brightness, increases the speed of distinguishing details, which affects the growth of labor productivity. When organizing industrial lighting, it is necessary to ensure a uniform distribution of brightness on the working surface and surrounding objects. Looking from a brightly lit to a dimly lit surface forces the eye to readjust, which leads to visual fatigue and, accordingly, to a decrease in labor productivity. To improve the uniformity of natural lighting in large workshops, combined lighting is carried out. The light color of the ceiling, walls and equipment contributes to a uniform distribution of brightness in the field of view of the worker.

Industrial lighting should ensure the absence of sharp shadows in the field of view of the working person. The presence of sharp shadows distorts the size and shape of objects, their distinction, and thereby increases fatigue, reduces labor productivity. Particularly harmful are moving shadows, which can lead to injury. Shadows must be softened, using, for example, lamps with light-diffusing milky glasses, in natural light, using sun protection devices (blinds, visors, etc.).

To improve the visibility of objects in the field of view of the worker, there should be no direct and reflected glare. Glitter is an increased brightness of luminous surfaces, causing a violation of visual functions (dazzle), i.e. deterioration in the visibility of objects. Glitter is limited by a decrease in the brightness of the light source, the correct choice of the protective angle of the lamp, an increase in the height of the suspension of lamps, the correct direction of the light flux to the working surface, as well as a change in the angle of inclination of the working surface. Where possible, shiny surfaces should be replaced with matt ones.

Illumination fluctuations in the workplace, caused, for example, by a sharp change in the mains voltage, cause re-adaptation of the eye, leading to significant fatigue. The constancy of illumination over time is achieved by stabilizing the floating voltage, rigid mounting of fixtures, and the use of special circuits for switching on gas-discharge lamps.

When organizing industrial lighting, you should choose the required spectral composition of the light flux. This requirement is especially essential to ensure correct color reproduction, and in some cases to enhance color contrasts. Optimal spectral composition provides natural light. To create the correct color reproduction, monochromatic light is used, which enhances some colors and weakens others.

Lighting installations must be convenient and easy to use, durable, meet the requirements of aesthetics, electrical safety, and must not be the cause of an explosion or fire. Ensuring these requirements is achieved by using protective grounding or grounding, limiting the supply voltage of portable and local lamps, protecting lighting network elements from mechanical damage, etc.

Introduction

Properly designed and rationally executed lighting of industrial premises has a positive psychophysiological effect on workers, improves efficiency and safety, reduces fatigue and injuries, and maintains high efficiency.

When illuminating industrial premises, natural lighting is used, created by direct sunlight and diffused light of the sky and changing depending on the geographical latitude, time of year and day, degree of cloudiness and transparency of the atmosphere; artificial lighting created by electric light sources, and combined lighting, in which natural lighting, which is insufficient according to the norms, is supplemented with artificial lighting.

The main task of industrial lighting is to maintain illumination at the workplace that corresponds to the nature of visual work. Increasing the illumination of the working surface improves the visibility of objects by increasing their brightness, increases the speed of distinguishing details, which affects the growth of labor productivity.

Combined lighting is allowed for industrial premises in which visual work of I and II categories is performed; for industrial premises under construction in the northern climatic zone of the country; for rooms in which, according to the conditions of technology, it is required to maintain stable parameters of the air environment (areas of precision metalworking machines, electroprecision equipment). At the same time, general artificial lighting of the premises should be provided by gas-discharge lamps, and the illumination standards should be increased by one step.

The purpose of this work is to review and study lighting and its characteristics.

Main lighting characteristics

Quantitative indicators

The sensation of vision occurs under the influence of visible radiation (light), which is electromagnetic radiation with a wavelength of 0.38 ... 0.76 microns. The sensitivity of vision is maximum to electromagnetic radiation with a wavelength of 0.555 microns (yellow-green color) and decreases towards the boundaries of the visible spectrum.

Lighting is characterized by quantitative and qualitative indicators. Quantitative indicators include:

- light flowФ - part of the radiant flux, perceived by a person as light; characterizes the power of light radiation, measured in lumens (lm);

- luminous intensity J - spatial density of light flux; is defined as the ratio of the light flux df, emanating from the source and uniformly propagating inside the elementary solid angle dШ, to the value of this angle; J \u003d df / dSch; measured in candelas (cd);

- illumination E - surface density of light flux; is defined as the ratio of the luminous flux df uniformly incident on the illuminated surface dS(m 2), to its area: E \u003d df / dS, measured in lux (lx);

- brightness L surface at an angle b to the normal is the ratio of the luminous intensity dJb emitted, illuminated or luminous surface in this direction, to the area dS projections of this surface onto a plane perpendicular to this direction: L\u003d df / (dScosb), measured in cd * m -2.

Qualitative indicators

For a qualitative assessment of the conditions of visual work, indicators such as background are used. , contrast of the object with the background, pulsation coefficient of illumination, index of illumination, spectral composition of light.

Background - it is the surface on which the discrimination of the object takes place. The background is characterized by the ability of the surface to reflect the light flux incident on it. This ability (reflection coefficient p) is defined as the ratio of the light flux reflected from the surface F neg to the luminous flux Fpad incident on it; p == Phot/Fpad. Depending on the color and texture of the surface, the values ​​of the reflection coefficient are in the range of 0.02 ... 0.95; at p>0.4, the background is considered light; at p = 0.2...0.4-average and at p<0,2-темным.

The contrast of the object with the background k - the degree of distinction between the object and the background is characterized by the ratio of the brightness of the object under consideration (points, lines, signs, spots, cracks, risks or other elements) and the background; k = (L op -L o )/L op considered large if k>0.5 (the object stands out sharply against the background), medium at k==0.2...0.5 (the object and the background differ noticeably in brightness) and small at k<0,2 (объект слабо заметен на фоне).

Illumination ripple coefficient kE- this is a criterion for the depth of fluctuations in illumination as a result of a change in the luminous flux over time

KE=100(E max -E min)/(2E cf);

where E max, E min E cp - maximum, minimum and average illumination values ​​for the oscillation period; for discharge lamps ke= 25...65%, for conventional incandescent lamps k E ? 7%, for halogen incandescent lamps K E = 1%.

Blindness Rho - criterion for assessing the blinding effect created by the lighting installation,

Po=1000(V 1 /V 2 -1),

where V 1 and V 2 are the visibility of the object of distinction, respectively, with screening and the presence of bright light sources in the field of view.

Shielding of light sources is carried out using shields, visors, etc.

Visibility V characterizes the ability of the eye to perceive an object. It depends on the illumination, the size of the object, its brightness, the contrast of the object with the background, the duration of the exposure. Visibility is determined by the number of threshold contrasts in the contrast of the object with the background, i.e. V=k/k pop , where k pore - the threshold or smallest contrast distinguishable by the eye, with a slight decrease in which the object becomes indistinguishable against this background.

Light has a complex corpuscular-wave nature and is part of the optical region of the spectrum. Visible radiation of the optical spectrum includes radiation with a wavelength from 0.38 to 0.78 microns. In this range, waves (monochromatic light) evoke a color sensation. For hygienic assessment of lighting, the following indicators are used:

Luminous flux F - part of the radiant flux, perceived by a person as light, characterizes the power of light radiation, measured in lumens (lm).

One lumen is the luminous flux emitted by a point source with a luminous intensity of 1 candela (cd) in a solid angle of 1 steradian (sr).

Light intensity J - spatial density of the luminous flux, defined as the ratio of the luminous flux DF (lm) , coming from the source and uniformly propagating inside the elementary solid angle DW (steradian), to the value of this angle, is measured in candelas (cd):

Solid angle - the part of space contained within a conical surface. It is measured by the ratio of the area cut out by him from a sphere of arbitrary radius to the square of the latter.

Illumination E - surface density of the luminous flux, is defined as the ratio of the luminous flux DF (lm), uniformly incident on the illuminated surface, to its area D S(m 2), measured in lux (lx):

One lux is the illumination of 1 m 2 of the surface when a luminous flux of 1 lm falls on it.

Brightness L surface at an angle a to the normal - the ratio of the luminous intensity D J a(cd), radiated by the illuminated or luminous surface in this direction, to the area D S(m 2) the projection of this surface, onto a plane perpendicular to this direction, is measured in cd / m 2:

where a – the angle between the direction of light intensity and the vertical.

One cd/m2 is the brightness of a uniformly luminous flat surface radiating in a perpendicular direction from an area S = 1 m 2 the power of light in 1 cd .

Brightness is a value directly perceived by the eye. With constant illumination, the brightness of the object is greater, the greater its reflectivity.

Daylight ratio(KEO) – the ratio of natural illumination created at some point of a given plane inside the room by sky light (direct or after reflections) to the simultaneous value of external horizontal illumination created by the light of a completely open sky; expressed as a percentage:

Where E B - illumination at a point inside the room, created by the light of the part of the sky visible through the light aperture, lx; E n - illumination at the same time outside the production room, created by uniformly scattered light of the entire sky, lx.

object of distinction- the smallest element of the object under consideration or a defect that must be distinguished in the process of work (for example, a line, a sign, a thread, a spot, a risk, a crack, a symbol, etc.).

Background - surface adjacent directly to the object of distinction on which it is viewed. It is characterized by a reflection coefficient depending on the color and texture of the surface.

Reflection coefficient r is defined as the ratio of the light flux reflected from the surface Ф ref to the light flux incident on it Ф pad:

The reflection coefficient values ​​are in the range of 0.02…0.95. r > 0.4 - the background is considered light; r \u003d 0.2 ... 0.4 - average; r< 0,2 – темным.

Contrast of object with background k – the degree of difference between the object and the background
characterized by the ratio of the brightness of the object under consideration (points, lines, risks or other elements) and the background:

k> 0.5 is considered large (the object stands out sharply against the background);

k= 0.2…0.5 – medium (object and background differ noticeably in brightness);

k < 0,2 – малым (объект слабо заметен на фоне).

Illumination ripple coefficient k E- criterion of the depth of fluctuations in illumination as a result of a change in time of the luminous flux of the used light sources:

Where E max , E min and E cp - the maximum, minimum and average values ​​of illumination for the oscillation period. k E = 15 – 65% for gas discharge lamps;
k E= 7% for conventional incandescent lamps; k E= 1% for halogen lamps.

Illumination ripples occur due to the supply of light sources with alternating voltage. They are of particular importance when using low-inertia light sources, which are fluorescent lamps. Pulsations of illumination on the working surface not only tire the eyesight, but can also cause inadequate perception of the observed object due to the appearance of the stroboscopic effect.

The small value of the ripple coefficient for incandescent lamps is explained by the large thermal inertia of the filament, which prevents a noticeable decrease in the luminous flux of the incandescent lamp F ln at the moment the instantaneous value of the AC mains voltage passes through 0
(Figure 3.1).

At the same time, gas-discharge lamps (including fluorescent lamps) have low inertia and change their luminous flux F ll almost in proportion to the amplitude of the supply circuit voltage. Standard values k E for gas discharge lamps are presented in table 3.1.

To reduce the pulsation coefficient of illumination, fluorescent lamps are included in different phases of a three-phase electrical circuit. The lower right curve of Figure 3.1 shows the nature of the change in time of the total luminous flux created by three fluorescent lamps 3F ll, included in the first case in one phase (phase A of the network), and then in different phases of a three-phase network.

CLASSIFICATION OF INDUSTRIAL LIGHTING

Depending on the light source, industrial lighting can be of two types: natural, created directly by the solar disk and diffuse light of celestial radiation, and artificial, carried out by electric lamps.
By design features, natural lighting is divided into:
lateral, carried out through windows in the outer walls;
the upper one, carried out through aeration and rooflights, openings in the coatings, as well as through light openings in places of height differences in adjacent spans of buildings;
combined, when side lighting is added to the top lighting.
Artificial lighting is provided in rooms where there is not enough natural light or to illuminate the room during those hours of the day when there is no natural light.
According to the design, artificial lighting can be of two types - general and combined, when local lighting is added to the general lighting, concentrating the luminous flux directly at the workplace.
General lighting is divided into general uniform lighting (with a uniform distribution of the luminous flux, excluding the location of the equipment) and general localized lighting (with the distribution of the luminous flux, taking into account the location of the workplaces).
The use of one local lighting inside buildings is not allowed.
According to the functional purpose, artificial lighting is divided into the following types: working, emergency, special.
Working lighting is mandatory for all premises and in illuminated areas to ensure normal operation, the passage of people and traffic. Emergency lighting is provided to ensure minimum illumination in the production area in the event of a sudden shutdown of working lighting.
Emergency lighting to continue work should be arranged in cases where the sudden shutdown of working lighting (in the event of an accident) and the associated disruption of normal maintenance can cause an explosion, fire, poisoning of people, prolonged disruption of the technological process, disruption of facilities such as power plants, control rooms, water supply pumping units and other industrial premises where work stoppage is unacceptable.
The lowest illumination of working surfaces that require maintenance during emergency operation should be 5% of the illumination normalized for working lighting with a general lighting system, but not less than 2 lux inside buildings.
Emergency lighting for evacuation should be arranged in places dangerous for passage, in stairwells, in industrial premises with more than 50 employees. It should provide the least illumination in the premises, on the floor of the main passages and on the steps of at least 0.5 lux, and in open areas - at least 0.2 lux. Exit doors of public premises, in which more than 100 people can be located at a time, must be marked with light signals-indicators.
To continue working, emergency lighting fixtures are connected to an independent power source, and lighting fixtures for people evacuation are connected to a network independent of working lighting, starting from the substation switchboard.
For emergency lighting, only incandescent and fluorescent lamps should be used.
Special types of lighting include: security, duty. For security lighting of sites of enterprises and emergency lighting of premises, if possible, a part of the lamps for working or emergency lighting should be allocated.

1. Main lighting characteristics

1.1. Quantitative indicators

The sensation of vision occurs under the influence of visible radiation (light), which is electromagnetic radiation with a wavelength of 0.38 ... 0.76 microns. The sensitivity of vision is maximum to electromagnetic radiation with a wavelength of 0.555 microns (yellow-green color) and decreases towards the boundaries of the visible spectrum.

Lighting is characterized by quantitative and qualitative indicators. Quantitative indicators include:

- light flowФ - part of the radiant flux, perceived by a person as light; characterizes the power of light radiation, measured in lumens (lm);

- luminous intensity J - spatial density of light flux; is defined as the ratio of the light flux df, emanating from the source and uniformly propagating inside the elementary solid angle dШ, to the value of this angle; J \u003d df / dSch; measured in candelas (cd);

- illumination E - surface density of light flux; is defined as the ratio of the luminous flux df uniformly incident on the illuminated surface dS(m 2), to its area: E \u003d df / dS, measured in lux (lx);

- brightness L surface at an angle b to the normal is the ratio of the luminous intensity dJb emitted, illuminated or luminous surface in this direction, to the area dS projections of this surface onto a plane perpendicular to this direction: L\u003d df / (dScosb), measured in cd * m -2.

1.2. Qualitative indicators

For a qualitative assessment of the conditions of visual work, indicators such as background are used. , contrast of the object with the background, pulsation coefficient of illumination, index of illumination, spectral composition of light.

Background - it is the surface on which the discrimination of the object takes place. The background is characterized by the ability of the surface to reflect the light flux incident on it. This ability (reflection coefficient p) is defined as the ratio of the light flux reflected from the surface F neg to the luminous flux Fpad incident on it; p == Phot/Fpad. Depending on the color and texture of the surface, the values ​​of the reflection coefficient are in the range of 0.02 ... 0.95; at p>0.4, the background is considered light; at p = 0.2...0.4-average and at p<0,2-темным.

The contrast of the object with the background k - the degree of distinction between the object and the background is characterized by the ratio of the brightness of the object under consideration (points, lines, signs, spots, cracks, risks or other elements) and the background; k = (Lop-L o)/L op considered large if k>0.5 (the object stands out sharply against the background), medium at k==0.2...0.5 (the object and the background differ noticeably in brightness) and small at k<0,2 (объект слабо заметен на фоне).

Illumination ripple coefficient kE- this is a criterion for the depth of fluctuations in illumination as a result of a change in the luminous flux over time

KE=100(E max -E min)/(2E cf);

where E max, E min E cp - maximum, minimum and average illumination values ​​for the oscillation period; for discharge lamps ke= 25...65%, for conventional incandescent lamps kE? 7%, for halogen incandescent lamps K E = 1%.

Blindness Rho - criterion for assessing the blinding effect created by the lighting installation,

Po=1000(V 1 /V 2 -1),

where V 1 and V 2 are the visibility of the object of distinction, respectively, with screening and the presence of bright light sources in the field of view.

Shielding of light sources is carried out using shields, visors, etc.

Visibility V characterizes the ability of the eye to perceive an object. It depends on the illumination, the size of the object, its brightness, the contrast of the object with the background, the duration of the exposure. Visibility is determined by the number of threshold contrasts in the contrast of the object with the background, i.e. V=k/k pop , where k pore - the threshold or smallest contrast distinguishable by the eye, with a slight decrease in which the object becomes indistinguishable against this background.

20. Indicators characterizing the quality of workplace lighting.

The main quality indicators of lighting are ripple factor ,index blindness And discomfort ,spectral composition Sveta.

The amount of illumination must be constant over time so that eye fatigue does not occur due to re-adaptation. A characteristic of the relative depth of illumination fluctuations as a result of a change in the time of the luminous flux of light sources is the coefficient of illumination pulsation Kp. Ripple factor characterizes the change in the luminous flux of a discharge light source over time with a frequency of 100 Hz when powered by an industrial frequency current. Prolonged exposure to pulsed light leads to visual fatigue, increased fatigue, headaches, etc. The closer the ripple factor is to zero, the better. Russian standards allow a ripple coefficient of not more than 10-15% for residential and public buildings.

Kp (%) \u003d 100 (Emax - Emin) / 2Esr,

where Еmax, Emin and Еср are the maximum, minimum and average values ​​of illumination for the period of its fluctuation.

Restrictions on spectral features , more precisely - on color reproduction, are superimposed only if we are talking about performing high-precision visual work. Correct color reproduction is provided by natural light and artificial light sources with a spectral characteristic close to that of the sun.

There should be no direct and reflected glare in the field of view. Glitter - increased brightness of luminous surfaces, causing a violation of visual functions (blindness), i.e. deterioration in the visibility of objects. Direct glare is associated with light sources, reflected glare occurs on a surface with a large reflectance or reflection in the direction of the eye. Evaluation criterion blinding of the action created by the lighting installation is the glare indicator Ro, the value of which is determined by the formula

Rho = (S - 1) 1000,

where S is the glare coefficient equal to the ratio of the threshold brightness differences in the presence and absence of glare sources in the field of view.

Evaluation criterion uncomfortable brilliance, which causes discomfort with an uneven distribution of brightness in the field of view, is an indicator of discomfort.

The quality of natural lighting is characterized by the coefficient natural light (KEO). It represents the ratio of natural illumination, created at some point in a given plane inside the room by the light of the sky, to the value of the external horizontal illumination, created by the light of a completely open sky; expressed as a percentage.

Quantitative indicators include: light flow ,the power of light ,illumination And brightness .

The part of the radiant flux, which is perceived by human vision as light, is called luminous flux F and is measured in lumens (lm).

Luminous flux Ф - the flux of radiant energy, estimated by visual sensation, characterizes the power of light radiation.

The unit of luminous flux - lumen (lm) - is the luminous flux emitted by a point source with a solid angle of 1 steradian at a light intensity of 1 candela.

The luminous flux is defined as a quantity not only physical, but also physiological, since its measurement is based on visual perception.

All light sources, including lighting devices, radiate a luminous flux into space unevenly, therefore, the value of the spatial density of the luminous flux is introduced - luminous intensity I.

The power of light I is defined as the ratio of the light flux dФ, emanating from the source and propagating uniformly within an elementary solid angle, to the value of this angle.

The unit of light intensity is the candela (cd).

One candela is the intensity of light emitted from a surface of 1/6 10 5 m 2 of total radiation (state standard of light) in the perpendicular direction at the solidification temperature of platinum (2046.65 K) at a pressure of 101325 Pa.

illumination E is the ratio of the luminous flux dФ incident on the surface element dS to the area of ​​this element

Lux (lx) is the unit of illumination.

Brightness L of a surface element dS at an angle relative to the normal of this element is the ratio of the luminous flux d2Ф to the product of the solid angle dΩ, β of which it propagates, the area dS and the cosine of the angle?

L = d2Ф/(dΩ dS cos θ) = dI/(dS cosθ),

where dI is the intensity of the light emitted by the surface dS in the direction θ.

Reflection coefficient characterizes the ability to reflect the light flux falling on it. It is defined as the ratio of the light flux reflected from the surface Fotr. to the flow Fpad falling on it.