For artificial lighting of premises, incandescent lamps and gas-discharge lamps are used.
Incandescent lamps are simple to install, cheap and easy to use. However, they convert only 2.5...3% of consumed energy into luminous flux and are sensitive to voltage fluctuations in electrical network, distort color reproduction, enhancing yellow and red tones with a lack of blue and violet parts of the spectrum. The industry produces various incandescent lamps: vacuum NV (their power usually does not exceed 40 W), gas-filled NG, bi-spiral with krypton-xenon filling NBK, etc.
Building codes and regulations provide for the use of gas-discharge lamps as the main light source due to their following advantages: significant luminous efficiency, 2...4 times higher than that of incandescent lamps; efficiency; favorable spectrum composition; longer standard service life, amounting to 6000... 12,000 hours versus 1000 hours for incandescent lamps.
Gas-discharge (fluorescent) lamps are tubes or flasks with electrodes located inside, filled with an inert gas or mercury vapor. When skipping electrical discharge Ultraviolet radiation occurs through gas or metal vapor, incident on the phosphor layer that covers the inner surface of the lamp. The phosphor converts ultraviolet radiation into visible light. By selecting the composition of the phosphor, you can achieve luminous flux desired color. There are low-pressure gas-discharge lamps, inside of which a certain vacuum is created during the manufacturing process, and high pressure.
Symbol for low pressure fluorescent tubular lamps for general lighting deciphered as follows: L - luminescent; B - white; D - daytime; E - natural; C - with improved color rendering; TBTS - warm white with very good color rendering; T - with a three-component mixture of phosphors having a narrow-band emission spectrum; R - reflex; K - red; G - blue; F - yellow; 3 - green; P - pink; M - modernized; 2 and 7 - a distinctive feature of the lamps from the base model; 10, 15, 18, 20, 30, 36, 40, 65, 80 - rated power in watts.
High-pressure lamps make it possible to create significant levels of illumination at relatively low energy costs. They are used for outdoor lighting and in high rooms in the presence of dust, smoke or soot in the air. The most commonly used lamps are DRL (mercury arc fluorescent) lamps or their variety - DRVL (mercury tungsten arc fluorescent lamps), the disadvantage of which is the enhancement of green and blue tones. Therefore, in cases where distortion of color perception is unacceptable, preference is given to DRI type lamps (mercury arc lamps with metal iodides), which have corrected color.
The disadvantages of gas-discharge lamps, in addition to color distortion, include: the presence of a stroboscopic effect, noise from ballasts and poor ignition of low-pressure lamps at low air temperatures (the technical specifications provide for the operation of low-pressure tubular fluorescent lamps in the temperature range of 10...55 ° C).
A device consisting of a lamp and lighting fixtures is called a lamp. A light source is installed in the lighting fixture to distribute the light flux in the desired direction, protect the eyes from the shine of the luminous surface of the lamp and protect the lamp from contamination or moisture, as well as to ensure electrical, fire and explosion safety.
The degree of protection against glare of a lamp is characterized by the protective angle a between the horizontal and the line connecting the filament to the opposite edge of the reflector (Fig. 20.2). As a rule, α ≥ 27°.
The industry produces approximately 25...30 various types lamps for incandescent lamps and about 200 for fluorescent lamps (Fig. 20.3). Depending on the distribution of the luminous flux in space, luminaires of direct, diffused and reflected light are distinguished. In luminaires for fluorescent lamps there is predominantly direct light distribution, while in luminaires for incandescent lamps it is predominantly direct and diffuse.
Direct light luminaires emit at least 90% of the total luminous flux into the lower hemisphere. They are used in rooms with dark ceilings and walls, which emit a lot of dust, soot, and various fumes (feed production workshops, forges, etc.). They give quite sharp shadows. Lamps with predominantly direct light, emitting 60...90% of the total luminous flux into the lower hemisphere, are installed in rooms with ceilings and walls that reflect light well. They give quite soft shadows.
Diffused light luminaires emit 40...60% of the total luminous flux into each hemisphere. They are used in rooms where it is necessary to create high levels of diffused light illumination, as well as in office and domestic premises with light walls and ceilings.
Rice. 20.2. Scheme for determining the protective angle of a lamp a:
a - lamp with incandescent lamp; b - lamp c fluorescent lamps
Lamps of predominantly reflected light emit 60...90% of the total luminous flux into the upper hemisphere. Reflected light luminaires emit at least 90% of the total flux into the upper hemisphere.
Lamps with fluorescent lamps are most often multi-lamp. They can be of direct light (types OD, ODR), predominantly direct light (types ODO, ODOR, SLD, SHOD) and diffused light (type PVL).
Combined systems use local lighting fixtures designed to create high levels of illumination in a limited area work surface. When installing such systems, the following conditions must be observed:
Rice. 20.3. Lamps:
a — “Universal” (direct light); b—type PU-200; c - PU-100; g - type VZG (explosion-proof, gas-filled); d — “Deep emitter” (direct light); e - "Lucetta" (scattered light); g— “Milk ball” (scattered light); h - ceiling PSH; and - type OD (suspended open daylight with solid reflectors); /s - type PVL (dust-proof, fluorescent) for which general lighting lamps must provide at least 10% of the illumination of the working surface provided for this type of work. For local lighting in order to eliminate the stroboscopic effect, incandescent lamps are usually used.
The design of lamps depends on their purpose. In open luminaires, the lamp is not separated from the external environment, but in closed luminaires, the lamp and socket are separated from the external environment by a shell without sealing. Used to illuminate damp rooms saturated with water vapor, moisture-proof lamps have a housing that can withstand the effects of moisture, and its design ensures the tightness of the input wires, socket and lamp. Explosion-proof luminaires prevent the occurrence of sparks. To illuminate rooms with high dust concentrations, dust-proof lamps are used.
The type of lamps is determined by eight groups of signs consisting of three letters and numbers. The structure of the symbol for lamps and irradiators is as follows:
Here 1 is the light source (one letter); 2 - method of installing the lamp (one letter); 3 - purpose of the lamp (one letter); 4 — series number (two-digit number within 01...99); 5 — number of lamps (number); 6 — lamp power, W (number); 7 — modification (three-digit number within 001...999); 8 - climatic version and placement category (letter and number).
The explanation of the letter designations of the luminaires is given in Table 20.2.
20.2. Letter designations of lamps and irradiators
|
Light source |
Designation reading |
Installation method |
Designation reading |
Application area |
Designation reading |
||
|
Incandescent lamps: |
|||||||
|
general purpose |
Hanging |
Industry private enterprises |
|||||
|
lamps (mirror and diffuse) |
Ceiling |
Mines and shafts |
|||||
|
quartz halogen |
Wall mounted |
Society military buildings |
|||||
|
Fluorescent lamps: |
|||||||
|
straight tubular |
Tabletop |
Residential (domestic) |
|||||
|
curly |
Floor and crowning |
Premises |
|||||
|
erythematous |
Built-in |
||||||
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K category: Electrical questions
How do luminaires with fluorescent lamps work?
The PVL-1 lamp is designed for two fluorescent lamps with a power of 40 W at a voltage of 220 V. The main parts of the lamp: body, reflector, opal glass diffuser and suspension unit. In the upper part of the housing there is a two-lamp starting and regulating device 2 type 2UBK-40/220 for starter ignition of lamps. The lamp is suspended on cables or rods.
Rice. 1. FM-60 lamp: 1 - body; 2 - cartridge; 3 - protective flask
Rice. 2. Lamp SKhM-100: 1 - reflector; 2 - cartridge; 3 - body; 4 - head; 5 - suspension
The PVLP-2 X X40 lamp is designed to work with two 40 W fluorescent lamps. Its components are: housing 2, reflector 5, diffuser 3 and suspension unit 4. Control gears are located in the housing.
Rice. 3. Lamp PNP-2ХУ0: 1 - diffuser; 2 - body; 3 - cartridge
The ODR-2X40 lamp (Fig. 15) consists of a reflector, a body, a suspension and a screening grille. A two-lamp ballast of type 2UBK-40/220 for starter ignition of fluorescent lamps is mounted in the housing. To illuminate the ceiling and upper part of the walls, holes are made in the reflector of ODO and ODOR lamps, through which 10...15% of the light flux of the lamps is directed to the upper hemisphere. The suspension unit allows you to place the lamp on a pipe, cable or rod, as well as place lamps on the main lighting box in any quantity. Figure 16 shows the electrical circuit of the ODR-2X40 lamp.
Rice. 4. Lamp PVL-1: 1- body; 2-ballast control device; 3 - suspension unit; 4 - reflector; 5 - diffuser
Rice. 5. Lamp PVLP-2Х40: 1 - ballast; 2 - body; 3 - diffuser; 4 - suspension unit; 5 - reflector
Rice. 6. Lamp ODR-2X40: 1 - reflector; 2 - body; 3 - suspension unit; 4 - grill
Rice. 7. Electrical diagram of the ODR-2X40 lamp
Page 16 of 17
Table 4. Characteristics of lamps
Type of lamps |
Lamp power, W |
Lamp weight, kg |
Suspension method |
||||||
Lamps for lighting rooms with normal conditions environment: with incandescent lamps: |
|||||||||
NSP01Х100/D23-01, “Astra-1” |
Hanging lamp with enameled direct light reflectors, designed for local and general lighting |
||||||||
NSP01X100/B20-04 |
|||||||||
"Astra-2" |
|||||||||
"Astra-3" |
|||||||||
NSP01Х200/Б20-05 “Astra-22” |
|||||||||
with fluorescent lamps: |
Pendant lamp with screening grilles and removable panels for predominantly direct light |
On the ceiling or on rods, installed in a line |
|||||||
Pendant lamp with screening grids |
On a pipe, cable or rods |
||||||||
with DRL lamps: |
|||||||||
SD2DRL-250-2 SD2DRL-400 |
Pendant lamp with diffuse reflectors |
On 3/4" pipe or mounting profile |
|||||||
Lamps for lighting rooms with harsh environmental conditions: |
|||||||||
with incandescent lamps: |
|||||||||
NSP21-100-001UZ |
Pendant lamp with enamel reflectors |
On a hook, 3/4" pipe or mounting profile |
|||||||
NSP21-200-003UZ |
|||||||||
NS P21-200-005UZ |
|||||||||
NPP02-100-001-002UZ |
Ceiling and wall |
||||||||
NPP02-100 003UZ |
|||||||||
NSP01X100/D5-3-02 |
Direct light pendant lamp with enameled reflectors |
||||||||
"Astra-11" |
|||||||||
NSP01Х200/D5 3-03 |
|||||||||
"Aster a-12" |
|||||||||
Direct light fixture with reflector, dustproof |
|||||||||
Predominantly diffused light dustproof luminaire |
|||||||||
Pendant lamp with plastic housing |
|||||||||
Direct light pendant lamp with aluminum reflectors |
|||||||||
The agricultural lamp is completely dust-proof |
On dowels or screws |
||||||||
with fluorescent lamps: |
|||||||||
Hanging and ceiling lamp with fiberglass housing with diffuse reflector for rooms with chemically active environments |
To the ceiling using brackets or on rods |
||||||||
Continuation of the table. 4
Type of lamps |
a brief description of |
Lamp power, W |
Lamp weight, kg |
Suspension method |
PVLM-1 Х80 PVLM-2Х80 PVLM-2Х10 |
Pendant and ceiling luminaire with direct and predominantly direct light without reflector |
Individually on rods |
||
PVLM-DR-2X80 (1VLM-DR-2X40 |
Pendant and ceiling luminaire of direct and predominantly direct light with diffuse reflectors with screening grid |
|||
Pendant lamp with diffuser |
||||
Luminaires for hazardous areas: |
Luminaire with increased reliability against explosion |
On 3/4" pipe using flange or mounting profile |
||
N4BN-150-U 1 without reflector VZG-200AM VZG/V4A-200M |
Pendant lamp Same |
150 |
For 3/4" pipe |
Rice. 27. Lamps:
a - “Astra-1”, “Astra-11” (“Astra-12”): b - “Astra-22”, “Astra-23” (“Astra-2”); c - -PPD (PPR)-100: g-NSP OZH60-01UZ; d-NCBN-150; e - LDOR-2Х40 (LDOR-2Х80); g - PVLP-2Х40; 3 - PVLM-2X80; i-PVL1-2X40
For lighting, a variety of lamps with incandescent lamps, fluorescent lamps, and DRL lamps are used. A brief description of some types of lamps (Fig. 27) used for lighting agricultural production facilities is given in Table. 4.
Hanging lamps on a hook is used for lamps weighing up to 10 kg. The lamps are hung on a hook using a ring or bracket. In rooms without increased danger, hooks are not grounded, but insulated.
When cabling, it is most convenient to install luminaires on a mounting profile, since it ensures fastening of the luminaire and laying of the cable in the descent section.
OCCUPATIONAL HEALTH AND FIRE SAFETY
Occupational safety and health issues fire safety occupy a paramount place in any organization, regardless of the type of activity. Special attention requires the activities of the organization, and in in this case industrial safety testing laboratory, where almost all types of hazardous production factors are present.
Occupational safety – a system for preserving the life and health of workers in the process labor activity, which includes legal, socio-economic, organizational and technical, sanitary and hygienic, treatment and preventive, rehabilitation and other measures.
Occupational health and safety management in the laboratory is carried out by the manager, and to organize labor protection work, a “Occupational Health and Safety Department” is created.
5.1. Calculation of artificial lighting and placement of lamps
To maintain high performance, reduce fatigue, injuries and increase efficiency and safety, it is necessary to correctly design and rationally implement the lighting of industrial premises.
When calculating artificial lighting, the main task is to determine the required electrical power lighting installations in order to create the desired illumination in the room.
Having calculated artificial lighting, the issues of choosing a lighting system, light source, lamps and their placement, standardized illumination and calculation of lighting using the luminous flux method must be resolved.
Selecting a lighting system
General or combined lighting systems are used in industrial premises for all purposes. The general lighting system is divided into uniform and localized lighting, the choice between them is made taking into account the type of activity and location production equipment. If production requires precise visual work, then it is recommended to use a combined (general and local) lighting system.
Selecting light sources
Currently, the following light sources are used for artificial lighting:
Incandescent lamps;
Gas discharge lamps.
As a rule, gas-discharge lamps are used for general lighting. They have a longer service life and are more energy efficient. Fluorescent lamps, which are distinguished by the spectral composition of visible light, are widely used and used:
White (LB);
Cool white (LCB);
Warm white (LTB);
Daylight(LD);
Natural light (LE).
If the letter “C” is added at the end, this means that “de-luxe” phosphor is used, which has improved color rendition, and the addition of “TsTs” means “super deluxe” phosphor, which has high-quality color rendition.
Lamps of the LB type, compared to other types, are used most often; lamps of the LHB, LD and LDTs types are used when there are increased requirements for color reproduction, and lamps of the LTB type are used when correct color rendering is necessary human face. The main characteristics of fluorescent lamps are given in Table 5.1.1.
also in industrial lighting In addition to fluorescent gas-discharge lamps (low pressure), high-pressure gas-discharge lamps are used, such as DRL type lamps (mercury arc fluorescent), which are used to illuminate rooms with a height of 7 to 12 meters.
Table 5.1.1 . Main characteristics of fluorescent lamps.
Incandescent lamps are used in cases where it is impossible or impractical to use gas-discharge lamps.
Selection of lamps and their placement
In order to select the type of luminaires, the conditions of the production environment should be taken into account, economic indicators and lighting requirements.
To reduce glare, luminaires with a protective angle or with light-diffusing glass are selected. If it is necessary to reduce the reflection of glare, lamps with diffusers are used, and in special cases lamps are made in the form of large diffuse surfaces, shining with reflected or transmitted light.
If it is necessary to illuminate high-lying surfaces, lamps are used that have sufficient luminous intensity in directions adjacent to the horizontal, and sometimes above the latter.
Of exceptional importance is the creation of sufficient brightness of the ceilings and walls of the illuminated room. Therefore, if these surfaces have a good reflectance coefficient, it is advisable to use lamps with predominantly direct or diffused light, and when special requirements to the quality of lighting - also predominantly reflected or reflected light.
For fluorescent lamps, lamps of the following types are more common:
Open two-lamp lamps (OD, ODO, ODOR, OOD);
Dust- and moisture-proof lamps (PVL);
Ceiling lamps.
Open two-lamp luminaires are used in rooms with normal conditions, with good reflection of light from the ceiling and walls. But it can also be used in cases of moderate humidity and dust.
PVL lamps are used in some fire hazardous areas; the lamp power is 2x40 W.
Ceiling lamps are used for general lighting of closed, dry rooms, with a lamp power of 10x30 W (L71B03) and 8x40 W (L71B04).
The main characteristics of luminaires with fluorescent lamps are given in Table 5.1.2.
Table 5.1.2. Characteristics of some lamps with fluorescent lamps.
To place lamps in a room, you need to know the following indicators:
H – room height;
h c – distance of luminaires from the ceiling;
h n = H - h c – height of the lamp above the floor, height of the suspension;
h p – height of the working surface above the floor;
h =h n – h p – design height, the height of the lamp above the working surface.
To combat glare and ensure favorable visual conditions in the workplace, requirements are being introduced that limit the minimum height of luminaires above the floor. These requirements are given in Table 5.1.3.
L is the distance between adjacent lamps or rows. If the distances along the length (A) and width (B) are different, then they are designated L A and L B.
l – distance from the outer lamps or rows to the wall.
Table 5.1.3. Least permissible height suspension of lamps with fluorescent lamps.
Optimal distance l It is recommended to consider L/3 from the outermost row of lamps to the wall.
The most effective way is to evenly place the lamps in a checkerboard pattern and along the sides of the square (the distances between all lamps are equal both between the rows and in the row)
Fluorescent luminaires, when evenly spaced, are usually arranged in rows parallel to the rows of equipment. If the level of standardized illumination is high, then the rows are arranged continuously, with the lamps connected to each other at their ends.
The optimal location of lamps is determined by the value l = L/h. If this value is excessively reduced, this will lead to an increase in the cost of lighting installation and maintenance, and an increase will lead to sharply uneven lighting. Table 5.1.4 shows the values of l for various types of luminaires.
Table 5.1.4. Optimal location lamps.
5.1.4. Selection of standardized illumination
SNiP 23-05 – 95 “Natural and artificial lighting» normalizes the illumination values of working surfaces, the choice is made depending on the characteristics of visual work. These requirements are given in Table 5.1.5.
Table 5.1.5. Illumination standards in industrial workplaces with artificial lighting
| Visual work category | Visual work subcategory | Contrast of subject with background | Background characteristics | Artificial lighting | ||||
| Illumination, lux | ||||||||
| With general lighting system | ||||||||
| Total | including from the total | |||||||
| Highest precision | Less than 0.15 | I | A | Small | Dark | 5000 4500 | - - | |
| b | Small Medium | Medium Dark | ||||||
| V | Small Medium Large | Light Medium Dark | ||||||
| G | Medium Large " | Light « Medium | ||||||
| Very high precision | From 0.15 to 0.30 | II | A | Small | Dark | - - | ||
| b | Small Medium | Medium Dark | ||||||
| V | Small Medium Large | Light Medium Dark | ||||||
| G | Medium Large " | Light Light Medium | ||||||
| High precision | St. 0.30 to 0.50 | III | A | Small | Dark | |||
| b | Small Medium | Medium Dark | ||||||
| V | Small Medium Large | Light Medium Dark | ||||||
| G | Medium Large " | Light « Medium |
Continuation of table 5.1.4.
| Characteristics of visual work | Smallest size object of discrimination, mm | Visual work category | Visual work subcategory | Contrast of subject with background | Background characteristics | Artificial lighting | ||
| Illumination, lux | ||||||||
| With a combined lighting system | with general lighting system | |||||||
| Total | including from the total | |||||||
| Medium accuracy | St. 0.5 to 1.0 | IV | A | Small | Dark | |||
| b | Small Medium | Medium Dark | ||||||
| V | Small Medium Large | Light Medium Dark | ||||||
| G | Medium Large " | Light « Medium | - | - | ||||
| Low accuracy | St. 1 to 5 | V | A | Small | Dark | |||
| b | Small Medium | Medium Dark | - | - | ||||
| V | Small Medium Large | Light Medium Dark | - | - | ||||
| G | Medium Large " | Light « Medium | - | - | ||||
| Rough (very low precision) | More than 5 | VI | Regardless of the characteristics of the background and the contrast of the object with the background | - | - |
5.1.5. Calculation of general uniform illumination
The calculation of general uniform artificial lighting is carried out using the luminous flux coefficient method, which takes into account the luminous flux reflected from the ceiling and walls.
The luminous flux is determined by the formula:
F = E n ×S×K z ×Z / (n×h),
E n – standardized minimum illumination, lux;
S – area of the illuminated room, m2;
K z – safety factor (according to table 5.1.6);
Z – coefficient of minimum illumination (ratio E avg /E min);
n – number of lamps;
h - luminous flux utilization factor, %.
Table 5.1.6. Safety factor for luminaires using fluorescent lamps.
The luminous flux utilization coefficient h depends on the height of the luminaire h, the type of luminaire, the reflection coefficients of the walls r c and the ceiling r n. Luminous flux coefficient shows what fraction of the lamp flux hits the illuminated surface.
Reflection coefficients are assessed subjectively (see Table 5.1.7), and the room index is determined using the formula:
Table 5.1.7 . The value of the reflection coefficients of the ceiling and walls.
Table 5.1.8 shows the values of the luminous flux utilization factor h of luminaires with fluorescent lamps, where the combination of reflectance coefficient and room index is most often found.
Table 5.1.8. Luminous flux utilization factors of luminaires with fluorescent lamps.
| Lamp type | OD and ODL | ODR | ODO | ODOR | L71BOZ OL1B68 | AOD and SOD | PVL - I | ||||||||||||||||
| rn, % | |||||||||||||||||||||||
| r s,% | |||||||||||||||||||||||
| i | Utilization rates, % | ||||||||||||||||||||||
| 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,25 1,5 1,75 2,0 2,25 2,5 3,0 3,5 4,0 5,0 |
Thus, having calculated the luminous flux Ф and knowing the type of lamp, using Table 5.1.1 you should select a standard lamp that is close in calculated values, then you can determine electrical power the entire lighting system.
In cases where the required luminaire flux is outside the range (-10 ¸ + 20%), then it is necessary to either adjust the number of luminaires n, or change the height of the luminaires.
When calculating fluorescent lighting, instead of the number of lamps n, the number of rows N is substituted into the formula, and F should be understood as the luminous flux of lamps in one row.
The number of lamps in a row N is determined as
where Ф 1 is the luminous flux of one lamp.
5.2. Calculation of artificial lighting and placement of lamps in the premises of the industrial safety testing laboratory in the construction of IKBS MGSU.
Calculations of artificial lighting will be made according to the method described above.
Selecting a lighting system.
It was decided that the production premises of the testing laboratory will be equipped with a system of general uniform lighting. This decision was taken taking into account the characteristics of the type of activity of the laboratory and the types of testing equipment located in the premises. The operating principle of the testing equipment is based on remote control processes, which minimizes human participation in testing and does not require increased visual attention during testing.
Selecting a light source.
The production premises of the testing laboratory have dimensions: H = 6 m; A= 36 m; H=18 m.
Taking into account the size of the production premises, service life and for reasons of energy saving, fluorescent gas-discharge lamps of the LD-40 type were chosen as the light source. Since the test methodology does not require increased requirements for color rendering, lamps of the LD-40 type in this case are able to fully ensure the preservation of high staff performance. Lamps of type LD - 40 have high luminous efficiency, long service life (up to 10,000 hours), good color rendering and low temperature.
According to SNiP 23-05-95 “Natural and artificial lighting”, the work carried out can be classified as category IV, "V" subcategory works (medium contrast on a light background). In accordance with the selected category of visual work, the lowest illumination of the working surface E min is taken to be 200 lux.
It is proposed to use lamps of the ODR type, since the room is intended for direct testing, which means that normal conditions must be maintained.
- Determination of the safety factor.
The safety factor KZ takes into account the dustiness of the room and the decrease in the luminous flux of lamps during operation. For production premises testing laboratory with gas-discharge lamps selected KZ = 1.8 (rooms with average dust emission)
- Determination of the minimum illumination coefficient Z.
The minimum illumination coefficient Z characterizes the unevenness of illumination. It is a function of many variables and is most dependent on the ratio of the distance between luminaires to the design height (L / h).
When placing luminaires in a line (row), if the most favorable L/h ratio is maintained, it is recommended to take Z = 1.1 for LD type lamps.
- Determination of luminous flux coefficient η.
To determine the luminous flux utilization factor h, find the room index i and expected reflection coefficients of room surfaces: ceiling r p and walls r with.
According to table 5.1.8 for this room we accept: r p = 50%, r c = 30%,
- Calculation of room index i.
The room index is determined by the formula:
A, B, h – length, width and estimated height (height of the lamp hanging above the working surface) of the room, m.
,
H– geometric height of the room;
h sv– overhang of the lamp, we accept h St = 0.5 m;
h p– height of the working surface. h p = 1.0 m.
We get h= 4.5 m. and room index i= 2.7.
Luminous flux utilization factor h: yes complex function, depending on the type of lamp, room index, reflectance of the ceiling, walls and floor.
Using Table 5.1.8, we find by interpolation h = 61%.
The illuminated area is accepted equal area premises:
S = AB = 1296 m2.
Distance between lamps L defined as:
L=1.1×4.5=4.95 m.
The value of l was determined from Table 5.1.4 and was taken equal to 1.1 for types of ODR lamps. Thus, we calculate the number of rows of lamps in the room:
N b =18/4.95=3.64.
Number of lamps in a row:
N a =36/4.95=7.27.
We round these numbers to the nearest larger N a =7 and N b =4.
Total number lamps:
N= N a × N b =7 × 4=28.
Along the width of the room, the distance between the rows is L b = 4.5 m, and the distance from the outer row to the wall is taken to be 0.5 L = 2.25 m. In each row, the distance between the lamps is also taken to be L a = 4.95 m, and the distance from the extreme lamp to the wall will be equal to 0.5L = 2.48 m.
Luminous flux utilization factor in fractions of a unit.
We finally accept N = 28, a multiple of 4 lines of 7 lamps.
Thus, when using lamps of type LD - 40, four in each lamp, the number of lamps required to ensure normal illumination is N = 28
Related information.