The value of safety factor, taking into account

The value of safety factor, taking into account

dustiness of the room and contamination of lamp

The room

The safety factor К_з

In natural lighting

In artificial light

Vertically

Obliquely

horizontally

Gas discharge lamp

Incandescent lamp

1. Industrial spaces with the contents in the air;

 

 

 

 

 

а) over 5 mg/m³ dust, smoke, soot

1,5

1,7

1,7

б) from 1 to 5 mg/m³........................

1,4

1,5

1,8

1,8

1,5

в) less than 1 mg/m³.........................

1,3

1,4

1,5

1,5

1,3

2. Spaces of public and residential buildings...........................................

1,2

1,4

1,5

1,5

1,3

 

The index space is calculated by the formula:

,                                     (3.4)

where А – the length of the room, m; B – the width of the space, m; H_l – suspension height of the lamp above the work surface, m.

When we received the result of the calculation luminous flux by the formula (3.3), we choose the nearest standard lamp. It should be noted that the luminaire LL may have more than one lamp that is n can be equal to
2 or 4. In this case the luminous flux group LL should be reduced to 2 or 4 times.

Light and electric parameters of some of the most widely used lamps are given in table 3.4.

The utilization factor of luminous flux of lamps is determined according to SNiP 23-05-95, depending on the type of lamp, р_f, р_w and index i in the following way:

 

i

η

0,28...0,46

0,34...0,57

0,37...0,62

0,39...0,65

0,40...0,66

 

Table 3.3

The approximate value of the coefficients

the reflection of the walls and ceiling

 

The nature of the reflecting surface

The reflection coefficient

Whitewashed ceiling, whitewashed walls with the windows closed by white curtains

Whitewashed walls of the unfinished windows, whitewashed ceiling in wet spaces, clean concrete and light wood ceiling

Concrete ceiling in the dirty spaces, wooden ceiling, concrete walls with windows, walls are covered with light wallpaper

The walls and ceiling in spaces with a large amount of dark dust, solid glass with no curtains red brick, wall with dark wallpaper. The estimated dark surface or a dark floor.

Table 3.4