Как выбрать гостиницу для кошек
14 декабря, 2021
The Italian rules, such as, for example, the Commission International de I’Eclairage (CIE) recommendations, provide reference values for the parameters being able to defining the overall quality of a lighted room, e. g. the illuminance level, the daylight mean factor and the illuminance ratio.
The illuminance level should be sufficient to distinguish the details of what is wished to be observed as regards the visual task to be performed and to the required precision. The illuminance level recommended by the rules has been evolving, in the course of time, to more and more high values. Think, for instance, that the illuminance level currently considered optimal for workplaces varies from five to ten times more than the one fixed 50 years ago (e. g. General rules on the hygiene of work, Italy — 1956).
The rule UNI 10380 [8] provides, for various type of rooms, the recommended values of the mean horizontal illuminance on the work plane (taken as reference values in this paper). For libraries the maintained mean illuminance value Em equals 500 lux in the reading areas (in which the visual task coincides with the reading, study and consultation of documentary material), while it equals 200 lux in the areas provided with shelves (in which the visual task coincides with the reading of the back of the books contained in the shelves). However, the advised values should be considered to refer to artificial light and not to the natural one (with which this project is concerned). Moreover, it should be remembered that a given illuminance is considered to be comfortable not only according to the recommended values, but also depending on other factors, e. g. the colour rendition and the direction of the emitted light.
As regards daylighting, both in the Italian and foreign rules recommendations can be found, which are, in this case, provided in terms of daylight mean factor; the rule UNI 10840 [9] advises a value equalling the 3% (such value is taken as reference in this paper).
Finally, among the parameters most often used to verify the natural or artificial lighting quality inside a room there is the illuminance ratio, defined as the ratio between the minimum and mean horizontal illuminance values at the work plane. For this ratio the rule UNI 10380 [8] provide for a minimum value equalling 0.8 (such value is taken as reference in this paper).