Table 1 of
DIN 18 055
Groups according
to the pressure
|
Groups according to the pressure pressure |
A |
B |
C |
D |
Experimental pressure |
150 |
300 |
600 |
|
Corresponding to wind strength |
7 |
9 |
11 |
Special regulation |
The building height in meter (approximate
value)
|
8 |
20 |
100 |
|
1)
The groups according to
the pressure are included in the
list of the pressure inventory
2)
According to Beaufort scale
3)
Group D includes windows that
are expected to bear extraordinary pressure |
What is K – glass like? /Low emission glass/
K- glass goes by the name of low emission glass. It is transparent glass with
crystal white reflectiveness and high sun and
heat protection. When K –Glass is used in sealed glass package this enhance
the heat insulation capability of the package and thus the level of the heat insulation is almost equalized to the
level of PVC profiles. In this way
the water condensation on the glass surface is avoided. There is a Titan
coating on one of the sides of K – Class. This titan layer is resistant to
mechanical and chemical treatment. As Titan belongs to the group of precious
metals it can change its properties only under extreme conditions
(e.g. vacuum environment and temperature above 700 °C). K – Glass converts the short
rays into long rays and so the heat absorbed by the coated glass does not travel across the air gap to the outer pane and the cold outside world. Instead the coating reflects the heat back into the room. K – Glass lets the heat from
the sun through (UV / 280-380 nm/ – 3%; visible part /380-780 nm/ – 44%; IR /780-2500nm/ - 53%),other amount of the heat reflexes and
another absorbs. The glass does not let sun rays over 2500nm. through. The rays emitted from the electric and fire –burning heating appliances are over 10 000nm. The glass does not let them trough but
absorbs amount of them. K – Glass has good insulation properties (from 1.4 w/ì2 Ê - 1.7 w/ì2 Ê.) . Unfortunately it can not solve the
problem with the humidity in the premises.
Indoor humidity:
Premises are
constantly being moistured. There are different reasons for this occurrence
-
humidity due to new building construction
-
humidity caused by cooking and other domestic activities
-
humidity caused by men and
animals especially when they breathe;
-
humidity caused by water vapor in bathrooms,
laundry, etc.
-
moisture on the surface of building components (water vapor condenses and produces visible water or "condensation)
According to the physical laws water vapor condenses and produces visible water or "condensation”
Condensation
is caused by:
- Insufficient indoor ventilation;
-
Insufficient heat insulation of the outer walls of
a building;
-
Structural building defects;
-
Inexpedient human actions e.g. inappropriate operation regime of the heating system;
-
Wrong heating system
– improper place of the
heating appliances;
The following table shows indoor separation of
moisture
Moisture sources |
Amount of moisture
(gr. per hour)
|
Man |
low activity
|
30-60 |
medium activity
|
120-200 |
hard work
|
200-300 |
bathroom |
bath
|
~ 700 |
shower
|
~ 2600 |
kitchen |
cooking
|
600 - 1500 |
Approximately per day
|
100 |
Indoor flowers |
e.g. violets
|
5 - 10 |
Indoor plants |
e.g.
India
rubber plants
|
7 - 15 |
Excess and
prolonged humidity can cause the following unpleasant effects:
-
condensation stains on
the walls behind the furniture and in the corners. After a
period of time these stains can lead to the occurrence of mod;
-
steamed
up windows of the bathroom, kitchen, bedroom;
-
condensation on the walls under the windows
Relative humidity : the term describe the amount of water vapor that exists in a gaseous mixture of air and water. The warmer the air
the more humidity it can absorb. The opposite is also relevant – the colder
the air the less humidity it can absorb.
For example: if the temperature of the air in 1m3 is 20°C the maximum amount of water vapor
can be up to 17,5 gr. The same amount of air with a temperature of 0°C can absorb only 5gr. water. In practice this
means: if 1m3 20°C air is
cooled up to 5°C water vapor condense
and the content of water drops in the air is 12,5 gr.
Cold air is always “dry air”! It is said that in
autumn when the relative humidity is very high and air temperature is around
0°C the windows should not be opened
in order to avoid indoor humidity. Of course that is wrong attitude. From the
example mentioned above it is clear that when the air temperature is 0°C and the relative humidity is 90% the air absorbs only 4gr./m3 water. If that air is warmed up to 20°C it can absorb (17,5 – 4) = 13,5gr. more water in order to reach its 100% humidity. It is obvious that the excess indoor humidity can be
reduced only by effective ventilation.
Heating:
Improper
place of heating appliances and insufficient ventilation can be the main
reasons for moisture damages. Unfortunately we use the short- time heating
which means that the premises are heated only when they are occupied. For
example when we leave the room in the morning we turn our home heating down
to minimum, in the evening we turn it up. In such condition the temperature
of the surface of walls is always very low. Condensation on
the walls and windows occurs when warm air reaches the cold walls. It is recommended
that the room temperature even in premises that are rarely used must be 16 - 17°C. It is difficult for the warm air to reach the
corners and wall bends of a room so condensation is
liable to occur on these parts of the room. One of the reasons for
condensation on the walls under the windows is the insufficient window
infiltration.
The purpose of ventilation is:
Gases, odour, moisture and harmful substances
are responsible or human health and well – being. That is why the purpose
of ventilation is:
-
to provide fresh air for healthy living
-
to avoid the occurrence of mould and condensation
stains by providing sufficient air circulation
-
to provide sufficient amount of fresh air if there
are opened fireplaces
Various possibilities for ventilation:
The required amount of fresh air for a
person per hour is 10 – 25m3. It
means that the air in a 30m2 premises with a height of 2,5m2 which is
occupied by three people who need about 60m3 air, must be changed 0,8 times per hour. Since this air exchange cannot be achieved
when windows are closed other actions must be done.
Forced natural
ventilation: by this method of ventilation the windows are fully opened for about
10 min. in order to provide air exchange. This method makes sense as the
surface of the walls, carpets and furniture keeps its
temperature. These surfaces do not need reheating. The air of the room is reheated
for relatively short time
|
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