FIELD OF THE INVENTION
[0001] The invention relates to the field of construction, especially to window construction
elements, which reduce indoor noise contamination. More especially it relates to a
device for reducing the rain made noise level on windowsill.
BACKGROUND OF THE INVENTION
[0002] Noise made by rain can significantly act on sleep quality at night, and work and
indoor communication in the daytime. One of the most important aims of the EU guidelines
is to achieve outdoors noise level decrease till 55dB at night. (http://ec.europa.eu/health/ph_projects/2003/action3/docs/2003_08_frep_en.pdf)
[0003] There are known numerous indoor noise reduction solutions for falling precipitation
made noise on window construction elements. Described embodiments include placement
of various blinds, curtains, films, additional layer of glass, sound absorbing shields
in or around the window pane, inside or outside of the window. Unfortunately all these
constructions just decrease the noise level but do not remove its main reason - precipitation
falling on window construction elements, especially on windowsill. Unfortunately all
these constructions just decrease the noise level but do not remove it completely.
[0004] Windowsills in majority of the modem buildings, including residential buildings are
made from metal or plastic plate. Usually this plate is constructively associated
with the window frame. In such a way windowsill vibrations are introduced indoors
and often cause the resonance of window construction elements, which increases the
noise.
[0005] Rain is the main type of precipitation, which makes precipitation impact noise and
windowsill vibrations. Hail which can be reason of more intensive noise is uncommon
that is why it is not described in this case. Another known noise insulators are disclosed
in
US 5 386 702 and
US 4 508 774.
US 4 508 774 discloses all the features of the preamble of claim 1. Self-adhesive tapes are one
of the described embodiments used in construction for decreasing the vibrations made
by metal or plastic windowsill. Tapes can be stick to the bottom of windowsill during
the construction. One of the examples is offered by company "Hanno Werk GmbH & Co.
KG": http://www.hanno.com/tl_files/pdf/gesamtprospekt_bau_gb/index.html.
[0006] Unfortunately the above described solution is applicable just for metal or plastic
windowsill wherein the tape is not laid during construction. For already built buildings
this kind of tape can be used only in changing windowsills using industrial devices,
namely, the scaffolding or crane. In another situation from a safety point of view
change like this kind of works can be realized just for ground floor residents. For
the other floor residents' costs of this type of works are financially high.
[0007] Because of the above described situation solution of windowsill made vibration reduction
is needed. Preferred embodiment should be useable for windowsill, reachable from outside
without technical devices and also be adjustable for individual residential usage.
TECHNICAL PROBLEM
[0008] Technical problem is absence of a device for reducing a noise made by rain falling
on a windowsill.
SOLUTION OF THE PROBLEM
[0009] Technical problem is solved by deposition of noise and vibration decreasing coating
on windowsill.
[0010] Such a solution is possible only in creating suitable material, which can reduce
impact sound and vibrations made of raindrops falling on the windowsill. Additionally
described solution must serve for long term without degradation, not causing pollution
and fire safety issues, can be installed by residents from inside of a building.
[0011] Typical characteristics of rain must be cleared out for construction of suitable
device for lying on the windowsill. Type of rain describes several parameters including
height of raindrop falling, intensity (liters of water per square meter) and average
drop diameter. Rain classification IEC 60721-2-2 specified in Table 1 can be taken
as a reference to determine the frequency of different intensities.
Table 1. Classification of environment conditions by IEC 60721-2-2 Ed. 1.0 b: 1988
part 2: Environmental conditions in nature. Precipitation and wind.
| Rain type |
Rain intensity mm/h |
Diameter of typical raindrop |
Speed of falling m/s |
| Moderate |
up to 4 |
0.5-1 |
1-2 |
| Heavy |
up to 15 |
1-2 |
2-4 |
| Very heavy |
up to 40 |
2-5 |
5-7 |
| Extreme |
more than 100 |
>3 |
>6 |
[0012] Heavy rain parameters were used in calculations to reach the most effective noise
reduction.
[0013] Extreme rain parameters are inappropriate for noise level on windowsill calculations
because overall level of weather made noise (for example, thunder) is higher.
[0014] Efficiency of possible device can be detected by ISO 140-18:2006 standard "Measurement
of Sound Insulation in Building and of Building Elements, Part 18: Laboratory Measurement
of Sound Generated by Rainfall of Building Elements."
[0015] For this research was made device described in ISO 140-18:2006 standard. This embodiment
was tightly fixed on three sides in 5 degrees (typical windowsill angle) against the
horizon typical aluminum or polyvinylchloride windowsill by size 0.30 x 1.2 m. Water
flow against it was identical to heavy rain parameters.
[0016] Noise measurements was made for windowsill without cover and covered with different
types of 0.3 x 1.2 m size noise reducing devices.
[0017] Polyurethane foam plate with thickness 10 to 25 mm was used for noise reduction.
Preliminary experiments showed that the device with thickness less than 15 mm as well
as the increase of thickness over 20 mm do not provide adequate efficiency. That is
why 16 mm thick polyurethane foam level was used for further researches.
[0018] Size of raindrops can be from 2 till 5 mm during very heavy rain. In order to achieve
power dissipation in noise reduction device, raindrop must stuck on surface of the
device or must be broken down into several parts that get stuck in pores. In such
way raindrops with diameter to 2 mm can stuck in device pores separating surface with
diameter 1.6 to 2.2 mm without breaking down and with breaking in 1-4 parts if diameter
is up to 5 mm.
[0019] Second the most important parameter for selection of noise reduction device is density
of material. Water accumulation in material upper part can be observed in high density
wherein noise reduction effect is minimal. If material density is to small - opposite
situation can be observed - raindrops with high falling speed can break through material
layer and reach the windowsill. In this situation the best effect of noise reduction
is not reached as well. That is why the optimal noise reduction could be made by reticulated
polyurethane foam material with open pores, with average pore count 5 - 6 cm
-1, density 29 kg/m
3, hardness 2.7-4.7 kPa, durability 80 kPa, 120% (relative) elongation before breaking.
[0020] Experimentally was found that said device in the range of 100-3150 Hz can provide
around 15 dB (A) reduction in rain induced noise level, comparing with windowsill
that does not have said device.
ADVANTAGES OF INVENTION
[0021] Proposed device for noise reduction of falling rain made noise provides noise reduction
for 88 - 92% expressed as increase of background noise for 2 - 3%. Device fixation
on windowsill is easy and do not ask any special technical skills, with suitable glue
or self-sticking type. Fixation can be done in short time on any floor of the building.
Size of material can be adjustable to windowsill size during production or at the
place of usage. Material of device does not accumulate dirt, avoid plant growth on
it and is fire safe (flame retardant).
[0022] Additional advantage is that it protects windowsill from bird stay. Bird claws stuck
in the pores and complicate the taking off, so they do not get back anymore.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides a device for reduction of noise of falling rain for
metallic or plastic windowsill of window, wherein an upper surface of the windowsill
is covered (glued) by noise reduction device. As a noise reduction device is polyurethane
foam layer. Thickness of the device is about 15 - 20 mm, optimal 16 mm, amount of
pores is 5 - 6 pores on 1 cm
2, density 29 kg/m
3, hardness 2.7 - 4.7 kPa, durability 80 kPa, 120% (relative) elongation before breaking.
[0024] In optimal case polyurethane foam contains additives that avoid plant growth on it.
Material is fire safe (flame retardant). In optimal variant polyurethane foam layer
has one self-sticking layer, which keeps cover connection with metallic or plastic
windowsill for long term. Device can be industrially produced in several colors, for
different sized standard windowsills or can be adapted by cutting at the place adjusting
to windowsill size during production or at the place of usage. Installation does not
need any special technical skills, it is fast and safe, can be done from the indoor
of the building. Device traits and effectiveness is shown below described examples.
EXAMPLES
[0025] In given examples are shown efficiency of device in different conditions.
EXAMPLE 1
[0026] Measurements was made in the rural territory on daytime, comparing noise as A-weighting
average sound pressure dB (A) in frequency range 100-315 Hz 1m away from aluminum
windowsill (120x25 cm) with and without noise reduction device on open window. Results
in moderate rain are described in on Table 2.
Table 2. Noise measurements during a moderate rain.
| Daily background noise, dB (A) |
47 |
| Rain made noise, dB (A) |
53.00 |
| Difference between rain made noise and background, dB (A) |
6 |
| Noise level with noise reduction device, dB (A) |
48.1 |
| Pure noise reduction, dB (A) |
4.90 |
| Noise reduction, % |
81.67 |
| Difference between background noise and noise level with noise reduction device, % |
2.34 |
| Difference between background, dB (A) |
1.1 |
EXAMPLE 2
[0027]
Table 3. Noise measurements during very heavy rain.
| Daily background noise, dB (A) |
47 |
| Rain made noise, dB (A) |
60.74 |
| Difference between rain made noise and background, dB (A) |
13.74 |
| Noise level with noise reduction device, dB (A) |
48.4 |
| Pure noise reduction, dB (A) |
12.34 |
| Noise reduction % |
89.81 |
| Difference between background noise and noise level with noise reduction device, % |
2.98 |
| Difference between background, dB (A) |
1.4 |
[0028] Above mentioned data show the falling rain made noise on windowsill with noise reduction
device increases background noise not more than 2 dB(A). With this we can expect that
noise level in rooms will not exceed recommended 48 dB(A) limit, wherein even during
very heavy rain noise level will not exceed 48 dB(A).
INDUSTRIAL APPLICABILITY
[0029] Device can be industrially applicable for new buildings during construction, for
reconstruction of existing buildings or individual windowsill covering. Material for
described device can be industrially produced with different colors, with self - sticking
layer, what simplify the application.
1. Vorrichtung zum Reduzieren eines Lärms von fallendem Regen auf eine Fensterbank eines
Fensters, die metallisch oder aus Kunststoff ist, wobei es sich um eine netzartige
Polyurethanschaumstoffplatte handelt, wobei die Plattendicke etwa 15 bis 20 mm, optimal
16 mm, beträgt, die Dichte des Materials 29 kg/m3, dadurch gekennzeichnet, dass die Menge Poren in dem Material 5-6 cm-1 beträgt.
2. Vorrichtung nach Anspruch 1, wobei die Vorrichtung auf der einen Seite mit einer Klebeschicht
zur Bindung mit der Oberfläche der Fensterbank bedeckt ist.