Sizes Of Window Openings And Room Illumination

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Sizes Of Window Openings And Room Illumination
Sizes Of Window Openings And Room Illumination

Video: Sizes Of Window Openings And Room Illumination

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The value of the light characteristic of the window

In frame buildings with strip cut walls and strip lighting, the width of the window openings determines the width of the individual inserts along the axes of the supporting structure of the frame.

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When designing buildings, the dimensions of window openings are set taking into account the necessary illumination of the premises, depending on their purpose, size, natural illumination in specific geographic conditions, the light characteristics of the window at the given ratios of the size of the room and the window opening, the light transmission of the window block, etc.

The area of ​​window openings in percentage ratios to the area of ​​the room is regulated by the “Building codes and regulations” (SNiP P-A862) and is determined by the formula.

In SNiP P-A862, a normalized value is given to. E. O. in the main premises of residential and public buildings located north of 45 ° and south of 60 ° north latitude, taking into account the obligatory regular cleaning of glasses at least 2 times a year for rooms with a low emission of dust, smoke and soot, and four times for rooms with a significant emission.

When the buildings are located south of 45 ° north latitude, the normalized value of the c. E. O. multiplied by a factor of 0.75, and for buildings located north of 60 ° north latitude by a factor of 1.2.

For example, with side illumination in buildings located north of 45 ° and south of 60 ° north latitude k. E. O. it is 0.5 for living quarters, 1 in dressing rooms and doctors' offices, 1.5 in classrooms and laboratories, classrooms, assembly and sports halls, kindergarten group rooms, dressing and laboratory rooms of medical institutions, maternity wards and 2 in operating blocks of hospitals.

SNiP permits deviations of ± 10% of the calculated values ​​k. E. O. (average or minimum) from the normalized when assigning the size of window openings.

The SNiP contains the values ​​of the total light transmission coefficient of the light opening m0. These values ​​take into account the darkening of the opening by supporting structures, the material and the construction of the binding. For example, for a single binding m0 = = 0.4, for a double one, T0 = 0.25, for a paired binding m0 = 0.3.

Thus, the light transmittance of the window opening under all equal conditions is affected by the distance between the glasses and the number of glasses. Naturally, with an increase in the number of glasses and the distance between them, the light transmission of windows deteriorates due to the absorption and refraction of a part of the light rays.

The reflectivity of the walls, ceiling and floor is taken into account by the G coefficient (SNiP). With medium tones of wall decoration, G = 3.0.

The influence on the illumination of the room of the darkening of window openings by the opposing buildings is taken into account by the coefficient k. In new construction, subject to the required gaps between the buildings, the blackout coefficient is practically equal to 1 and may not be taken into account.

The light characteristic of windows c0 depends on the ratio of the width and depth of the illuminated room B and on the ratio of its depth to the elevation H of the upper edge of the window above the conditional working plane (for example, in classrooms) or the floor (in living quarters), the value of the light characteristic c0 is given in SNiP (with a window sill height not exceeding 1.2 m).

Using these values ​​in accordance with the data of the illuminated room, it is possible to determine the value of the light characteristic of a window opening at a rounded relationship between the width and length of the room and between its depth and the elevation of the upper edge of the window. For a more accurate determination of the intermediate values ​​of the light characteristic of the window, use the interpolation method.

The value of the light characteristic of the window

Having determined the values ​​of the normalized coefficient of natural illumination e, the total coefficient of light transmission To, the coefficient of influence of reflected light G and the light characteristic of the window r0 for a given room (in the absence of darkening of the window by the opposing buildings) and substituting these values ​​into the transformed formula, we obtain the desired area of ​​the window opening.

The ratio of the area of ​​the trench opening to the area of ​​the room is 1.5511.5 = 17.4. SNiP provides for a more approximate calculation of the area of ​​the window opening:

“To determine the area of ​​window openings in the premises of residential and public buildings, as well as auxiliary buildings of industrial enterprises, in the relevant chapters of SNiP or other regulatory documents, on the basis of the requirements of this chapter, norms for the area of ​​window openings in fractions (or%) of the floor area of ​​the premises are established, in which the ratios of the main dimensions (depth, width and height) meet the instructions of the relevant chapters of SNiP or other regulatory documents”(SNiP P-L862, chapters 1 and 2, note 3).

The corresponding section of SNiP for residential buildings provides for an average rate of openings area of ​​1: 8 from the floor area of ​​the room.

The degree of illumination of the premises is significantly affected by the thickness of the outer walls and the pattern of the binding.

An increase in the width of the window slope and small divisions of the window sash with horizontal elements, especially in windows with separate sashes, sharply reduce the light transmission of the window and the illumination of the room.

You can match the split-sash window cuts in a thick wall and double-snapped window cuts in a modern curtain wall panel structure. This comparison shows that the use of window blocks with large glazing elements in modern prefabricated structures of buildings with thin outer walls made of effective materials allows, without prejudice to the illumination of the premises, to reduce the area of ​​the window opening and thereby improve the construction economy, since 1 m2 of window filling is more expensive 1 m2 of wall.

At the same time, when arranging loggias and balconies that darken the room, a slight increase in the area of ​​the window opening is justified; for this SNiP, an increase in the opening area by 2030% against the norm is provided.

The absolute dimensions of window openings are in direct proportion to the standard dimensions of window blocks, quarters in the outer walls and the gaps between the window frame and the opening slope.

The size of the window block consists of the dimensions of the sections of the elements (sashes, boxes) and glass; these dimensions are determined by the corresponding GOST and their changes are not allowed. For example, a standard double-leaf window unit 1320 mm wide with double sashes in width consists of two side sections of 85 mm each and an average (on impost) section of 130 mm. The width of the glass (multiples of 25 mm) in each casement is 525 mm, and on each side the glass enters the 10 mm wide rebate of the window frame by 7.5 mm and, therefore, the visible width of the glass is 510 mm.

Considering that the gaps between the window frame and the slope should be (for the convenience of caulking) at least 2025 mm on each side, you can determine the size according to the width of the opening in quarters and in the light (minus the size of two quarters). The dimensions of the quarter depend on the construction of the walls. For example, in brick walls, the quarter width is 65 mm, i.e. That is, a quarter of bricks, in large concrete blocks 100 mm, in panels 5060 mm.

It is necessary to take into account the gradation of the dimensions of the trench glass through 25 mm and the limiting dimensions of glass sheets at different thicknesses.

When determining the absolute size of the window opening, you should also check how the window frame fits into the opening with quarters. Here, along with the observance of the necessary gaps between the window frame and the slope, it is necessary that the frame protrudes from a quarter by no more than 2025 mm.

The height of the trench opening is determined in the same way, and the position of the upper element of the window frame must fully correspond to the position of the side elements, and the lower element of the box must be located in the opening together with the under-trench board, the thickness of which is 45 mm.

In modern construction, the height of the window opening is limited by the height of the room, the lintel and the level of the window sill, and the width of the carrying capacity of the walls.

In frame buildings with strip cut walls and strip lighting, the width of the window openings determines the width of the individual inserts along the axes of the supporting structure of the frame.

Finding the correct ratio between the height and width of window openings, taking into account the standard of illumination of the premises, is an important creative and economic task. As a rule, the height of the window opening is taken to be the same for the entire building and is determined by GOST, and the choice of the width of the opening depends on the area found by the formula: the width of the opening is the quotient of dividing the area of ​​the opening by its accepted height.

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