uPVC WINDOW - WATER TIGHTNESS

1
uPVC WINDOW - WATER TIGHTNESS Due to the obvious
nature of its name, this property of windows
appears to be the easiest to explain. Some
readers might already know that windows cannot
be divided into water-tight and non-water-tight.
There are as many as 10 water-tightness classes
de?ned for uncovered windows, from 1A to 9A, as
well as a special class, Exxxx where the xxxx
stands for the value of pressure greater than
600 Pa. Uncovered windows The term uncovered
window is de?ned as any window installed in a
building wall whose entire surface is exposed to
weather conditions, to include wind and
rain. Depending on the test pressure level and
the time for which the tested window remains
completely water-tight to rainwater, windows are
given appropriate designations. Consequently, in
reality, the water-tightness, also referred to
as driving-rain resistance, of a uPVC window
identi?es the
2
wind load during rainfall at which rainwater will
start penetrating the interior of the window
structure. The speci?c relation between the
pressure and the duration of exposure, and the
water-tightness class is shown in the table
below, which is prepared based on the EN 12
2082001 classi?cation standard entitled
Windows and doors. Water tightness.
Classi?cation. According to the standard,
windows which at the test pressure of 0 Pa leak
water to the interior of the window structure
after a period that is shorter than 15 minutes
are not classi?ed at all. The windows that are
the least water-tight are designated as 1A, which
means that they do not leak rainwater for 15
minutes at the pressure of 0 Pa, which means
that in regular use conditions in regions with
regular rain they leak nearly all the
time. Windows classi?ed as 9A start leaking water
into the interior of the structure only at the
pressure of 600 PA, which means that leaks may
occur in the case of rainfall at wind speeds
equal to approx. 112 km/h. Windows of very high
level of water tightness are those marked with
the E symbol, with the pressure value
provided, e.g. E 1200, which means that they
remain water-tight for at least 5 minutes when
exposed to pressure of a speci?c value (in this
case 1,200 Pa) that is greater than 600 Pa. Water
tightness is the second property of uPVC windows,
beside resistance to wind load where, the wind
pressure acting on the window is of key
importance. When selecting windows based on their
tested characteristics, one should make sure not
to treat these two properties separately. This
is particularly important with regards to the
pressure value. In nature, wind and heavy rains
often occur at the same time. One must keep in
mind that even if a window is in the highest C
class with regards to the bend in the frame on
which the wind pressure acts, the bend is equal
to 1/300 of the length of a given component. In
the case of a window that is 1 metre tall, 1/300
is equal to 3.3 millimetres. In the case of a
window that is 2 metres high, 1/300 is equal to
6.6 millimetres. Do you think that the window
will remain water-tight if such a bend
occurs? This is why the wind load resistance
class and the water-tightness class of windows
must be considered at the same time. Perhaps this
will not completely eliminate the possible
negative consequences of the elements
3
acting on the window, but it will certainly allow
signi?cantly mitigating them. For any more
information, please write us at
marketing.in_at_aluplast.net.