Hygienic requirements to a dwelling microclimate
The Dwelling is created that the person living in it the most part of days, could have a rest, restore the forces. Thus changes in environment should not change a microclimate favorable for the person in apartment. Hence, the dwelling is intended for creation in it of artificial climatic conditions, i.e. A microclimate which set of factors is meant, such as humidity, movement and temperature of air and surrounding surfaces which, in turn, define thermal comfort.
Parameters of factors of a microclimate should correspond recommended for dwelling and to provide favorable conditions of heat exchange of the person, not breaking its normal teplooshchushchepie.
As have shown researches, in optimum temperature of air in dwelling in the winter in the conditions of the moderate and warm climate is 18-20 °s (in northern areas 21 22 °s, and in hot-18-19 °s). Air temperature in dwelling depends on temperature of external air and from work of heating devices. In order to avoid infringement of thermal balance and unilateral cooling of a body it is necessary, that a difference in air temperature across, passing from external walls to any point indoors, did not exceed 2°С, and on a vertical, between a floor and height 1,5-2 m, - 3 With difference of temperatures the person in usual clothes does not feel S.Takoj.
In an estimation of a microclimate of dwelling the temperature of an internal surface of protecting designs of a building has Great value also: walls, a floor, osteklenija. That organism heat exchange was not broke, difference of temperatures of the cooled protections and air in dwelling should make nearby 4°С. At observance of the specified temperature conditions at the adult normally dressed person in a condition of rest heat loss konvektsiej makes nearby 20, radiation (radiation)-56, evaporation of 24%, i.e. The basic way of return of heat - radiating. If the temperature of air below a body temperature, is observed mainly konvektsionnyj a way of return of heat. If the temperature of air and surrounding subjects not below a body temperature, heat return can be carried out only by evaporation.
The Second factor of a microclimate of dwelling is humidity of air to which changes the person reacts at once. That premise air was not felt as excessively dry or is superfluous damp, its relative humidity should be 30-60%.
As a rule, in the closed premises speed of movement of air is very small and is not felt as the person. But nevertheless it exists and certain impact makes. It speaks that in motionless or inactive air teplootdacha an organism is at a loss, and too mobile air increases teplootdachu konvektsiej and reduces teplootdachu radiation. For creation in dwelling of a comfortable microclimate at temperature 18-20 °s and relative humidity of 30-45% as more favorable for an organism is speed of movement of air of 0,1-0,15 km/s.
To create in dwelling comfortable microclimatic conditions, during all periods of year in cold areas it is necessary to carry out actions for the prevention and protection of an organism from cooling, and in areas with a hot and warm climate - on protection against overheating. Actions for protection against cooling concern ratsional -
noe heating, orientations of premises taking into account harmful cooling influence of dominating winds, use of a protection with big teploustojchivostju, warming of inputs, podpola, an attic, hermetic sealing of window apertures etc.
Actions for protection of dwelling from an overheat are the corresponding lay-out of apartments, through airing, the orientation of premises warning their overheating, use of verandahs, terraces and special sun-protection devices, gardening, light colouring of external protections, effective ventilation of premises etc.
Dwelling Heating. The hygienic problem of heating of dwelling consists in creation of the steady comfortable microclimate supporting thermal balance of an organism during the cold period of year. Heating should create certain level of temperature indoors irrespective of fluctuations of temperature of external air, to provide uniformity of temperature of air in horizontal and vertical directions. All these conditions are defined by heating system, quality of fuel, a regularity and sufficiency of heating.
Distinguish two kinds of heating: local (oven) and central. They differ that in the first case fuel burning is made in a heated premise in the most heating device (furnace), in the second - heat-carrier heating (waters, steam, air) outside of premises. Both systems should meet following requirements:) in regular intervals to heat up air within standard temperatures; not to be a source of pollution of premises; to be safe in the fire relation; not to create possibility of penetration of carbonic oxide in a premise.
Local heating is represented by the furnaces of a various design used for heating of one or several adjacent premises. Furnaces have special toplivnik where fuel is burnt, and smoke gases formed thus are taken away on a flue in atmosphere. Thus warmly nagretyh smoke gases it is transferred to furnace walls from which then air of premises heats up. Heating up walls of the furnace should not have temperature above 80 “With to warn podgoranie a dust and thermal radiation unpleasantly operating on the person.
Lacks of local heating are: non-uniform heating of a premise, pollution by ashes, gases, danger in the fire relation, reduction of a useful area of a premise.
Now the wide circulation has received a central heating. In comparison with local it has a number of advantages: indoors the demanded temperature of air is constantly supported, air deterioration, pollution by its products of incomplete combustion of fuel and ashes is excluded, the uniform temperature is created. There are some systems of a central heating: steam, water, radiant, air. For heating of inhabited and public buildings mainly water heating is used.
The System of the central water heating consists of a copper, pipelines and heating devices. The heat-carrier is hot water which is warmed up in a copper and on pipelines arrives in heating devices. Having given heat to the devices, the cooled water on pipelines comes back in a copper and again heats up. As at heating the water volume increases, in system the broad vessel accepting excessive volume of water is arranged. Water heating can be arranged with the top and bottom distributing. At the top distributing hot water from a copper arrives in the main pipes put in pawn on an attic, and then on struts downwards to heating devices. The cooled water from heating devices on return pipes gathers the general pipe and goes to a water-heating copper.
At the bottom distributing the main pipes planting hot water to struts, lay in a basement floor.
Heating (heating) devices - radiators - place with external walls under windows (fig. 18). It reduces the cold stream of air proceeding from windows and external walls, promotes hashing with nagretym air. Radiators should be accessible to clearing of a dust. The temperature on their surface should not exceed 80 °s. By means of radiators it is created konvektsionnyj a way otda chi heat.
The Central steam heating differs from water that instead of water hot steam which also moves in heating devices - radiators is used. Thus the temperature on a surface of radiators can exceed 80 °s, that does this system of heating of less suitable for premises as for protection against possible burns it is necessary to do special armature (wooden lattices).
More perfect system of heating considers l u-pure heating at which heat return occurs to the help of radiation. Thus warmly radiate nagretye surfaces of walls, a ceiling, a floor which heat up the hot water arriving from a boiler-house, but circulating on the pipes which have been put in pawn in thickness of concrete panels. Temperature of a surface of such panels considerably below temperature of a surface of radiators (ceiling panels have temperature 28-30 °s, wall - 40-45, basement - 25-27 “S
Radiant heating has a number of advantages in comparison with konvektsionnym (by means of radiators): return of heat by radiation decreases, more uniform temperature in horizontal and vertical directions is supported, subsidence and dust burning on heating devices is excluded, cooling possibility decreases at airing, the useful area of premises etc. does not decrease.
For heating of group of buildings quarter boiler-houses, and for heating of buildings of residential area - teploelektrotsentrali (thermal power station) are arranged. Thus in apartment houses for the household purposes water supply is usually arranged also hot.
Now the wide circulation has received air heating at which external air through vozduhopriemnik arrives in the heating chamber where heating devices - heaters are established, and then on channels moves in a premise. Cooled air leaves from premises through exhaust channels in exhaust mine.
This system of heating provides good air exchange in apartment, but a number of lacks does by its less expedient. Possibility of burning of the dust settling in channels, air pollution of heated premises by products of burning of organic substances concern them low humidity of air indoors owing to its heating in heaters.
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