WO2016001471A1

WO2016001471A1 - Acoustic insulation screens with artificial plant covering

Info

Publication number: WO2016001471A1
Application number: PCT/ES2015/070521
Authority: WO
Inventors: Leandro Victoria Navas; Aurelio Arenas Dalla Vecchia
Original assignee: Universidad De Murcia
Priority date: 2014-07-03
Filing date: 2015-07-03
Publication date: 2016-01-07
Also published as: ES2555668A1; ES2555668B2

Abstract

The invention comprises a novel type of acoustic insulation screen with an artificial plant covering having considerable acoustic benefits, which improves acoustic insulation and the acoustic absorption coefficient in relation to other monolithic acoustic screens built with various materials that are incompatible with the landscape, providing integration of noise barriers into the natural surroundings.

Description

ACOUSTIC INSULATION SCREENS WITH VEGETABLE COVER

ARTIFICIAL

DESCRIPTION

Object of the invention

The present invention consists of a new mode of sound insulation screen used to reduce noise levels caused by the traffic of different means of transport (automotive, rail, etc.) and other industrial and recreational activities.

Increasingly, on certain roads near populated areas, we can see a large number of acoustic screens made of different materials installed: metal, concrete, lightened concrete, methacrylate, wood, etc. All of them have an overall exterior appearance for each of the sides seen that are not integrated into the environment. In the best case we find another type of acoustic screens made with a natural vegetal covering that provides them with a better appearance and that improves their appearance and integrates them into the environment. However, these screens require continuous maintenance, as they are like vertical gardens with needs for irrigation, fertilization, pruning, etc.

The acoustic screens object of the invention are manufactured with an artificial vegetal covering that gives them an aesthetic appearance that makes them landscape compatible with the natural environment where they are installed, with a high coefficient of acoustic absorption and a good insulation coefficient.

Technical sector

Acoustic barriers in construction, on roads and on railway lines. Background of the invention and state of the art The environmental noise caused by traffic and industrial and recreational activities is one of the main environmental problems and is the origin of a growing number of complaints. The Fifth European Community Program for environmental policy and action in 1993 began to correct this situation and included a series of basic objectives with respect to noise exposure to be achieved in the year 2000. Another proposal to revise the Fifth program (Decision No. 540 / 1996 / EC of the European Commission of 4 November 1996 on the revision of the Community Program for policy and action in the field of environment and sustainable development) developed initiatives to reduce noise with actions aimed at meeting these objectives.

The first step to develop this program was reflected in "The Green Book of the fight against noise" of the European Commission, aimed at stimulating public debate on the future approach to noise policy. The green paper reviews the global noise situation and the community and national measures adopted so far and establishes an action framework that will improve information and examine future options for noise reduction from various sources. As a result of these demands and to this day, acoustic barriers have been installed in numerous infrastructures as an effective way to reduce the environmental impact they cause, especially roads and train tracks.

The social pressure on noise is getting the adoption of noise control criteria recommended by WHO and the OECD being generalized. One of the solutions in which more work is being done in recent years is in the development of acoustic screens, since it has been demonstrated that it is an effective method to reduce the sound impact caused by such infrastructure in the means of propagation.

Regarding the state of the art, it must be said that in the current market there are companies that have developed innovative designs of screens or acoustic barriers that, in addition to complying with the necessary specifications for this type of shielding, minimize the environmental impact by using industrial waste and other recycled materials in its manufacture. With all this it is tried to obtain that in no point of the inhabited zones next to a Road or railroad track the following noise levels are exceeded (equivalent sound pressure level LAeq.):

The day = 65 dB (A)

LAeq, night = 55 dB (A)

On the other hand, it is worth mentioning the documents that have been located related to this invention:

Patent-1 (FR2806108A1, Perrin Roudil Richard, 10.09.2001) in which a sound-absorbing wall with a decorative plant structure is described. Describe how this structure is fixed on a sound absorbing wall built for this purpose.

Patent-2 (KR20090005902A, MUN KWANG HO et al., 14.01.2009) in which an artificial grass cover is described on a wall that separates the houses from the road with road traffic to isolate them from noise.

Patent-3 (DE4136444A1, BALSAM AG, 13.05.1993) in which the structure and mode of manufacture of an artificial turf for sports fields is described.

Patent-4 (US5912442A, NYE et al., 06.15.1999) where a structure constructed with two perforated sheets and an intercalated layer of honeycomb is described. This structure is intended to reduce acoustic vibration in buildings that are in environments with high noise levels.

Description of the invention

The procedure described below is intended to obtain a new acoustic insulation screen that has high absorption and sound insulation coefficients in accordance with the European standard (Sound absorption standards UNE-EN-1793-1, and acoustic insulation UNE-EN-1793-2) and highlights its pleasant aesthetic appearance that facilitates its integration into the natural environment once installed. For this, the behavior has been analyzed as acoustic absorbent materials of continuous artificial plant coverings, such as those of "artificial grass", although they may have another type of plant design such as cypress leaf, boxwood leaves, or others. For this, the acoustic absorption coefficient of different samples of continuous artificial plant cover has been measured.

Comparative measures have been carried out using different dimensions and textures of artificial plant coverings, verifying that the manufacture of screens with continuous artificial plant cover considerably improves the absorption and insulation coefficients with respect to the best parameters of other acoustic screens. In the case of high acoustic absorption coefficient screens, the average absorption coefficient of a perforated metal sandwich screen with rock wool insulation increases, from a value of 0.70 to a value of 0.75. In the case of screens with low noise absorption coefficient, you can increase it by multiplying its value by three (for example, increase the average absorption coefficient of an unperforated sandwich screen from a value of 0.27 to a value of 0.64). In the case of a rigid plastic screen reflecting methacrylate increases its absorption coefficient from 0.06 to a value of 0.31; something similar happens in the case of concrete screens. In the case of a steel pole, its absorption coefficient increases from a value of 0.07 to a value of 0.30. Figure 5 shows the bar diagram related to the distribution of the acoustic absorption coefficient as a function of frequency, for the perforated sandwich screen cited with artificial plant cover. As far as the sound insulation measure is concerned, the installation of the artificial plant cover increases the sound reduction (transmission losses) by a value of about 6 dB, with respect to the screen on which it is installed, depending on the conditions in which that the artificial vegetation cover be applied. Figure 6 shows the distribution of sound insulation values as a function of the frequency for the same screen with artificial plant cover. It has also been proven that the installation of the artificial plant cover, which resembles a ridge profile known as "Thnadner" but with absorbent properties (Esteban David Olmos Cancino / 'Evaluation of the loss of insertion of an acoustic barrier applied in a linear project ", PhD Thesis, University of Valdivia, 2002), significantly reduces (between 1dB and 3 dB according to the geometric characteristics of the artificial plant cover used) the acoustic diffraction generated in the edge of the screens, which contributes to increase the insulation rate of them.

As a structure on which to apply the artificial plant cover, it is possible to use both concrete panels made of light aggregates, and "sandwich" panels of self-supporting sheet metal, with a core of insulating material (rock wool or others), or any other type of monolithic panel.

These panels must be supported laterally by vertical posts, preferably metal, which can be of Gray-HEB, UPN, IPN or other profiles, joined or welded to anchor plates to fix them to the ground. The profile of these posts has a double "U" geometry that acts as a slide in the assembly of the panels, and as a support, these being fitted between each pair of posts. When lining the panels with artificial plant cover, a strip or strip must be left unlined on each side edge of the panels to be able to move them and insert them without difficulty between each pair of posts. The width of the unlined strip or strip depends on the depth of the "U" of the profile. To avoid an acoustic bridge that decreases the effectiveness of the screens, the posts should be lined with the artificial plant cover on both sides, as well as the side parts that are visible. The artificial plant cover of the posts must have a thickness less than those of the panels to avoid a step in the roof and achieve a visual effect of continuity on the screen surface.

In addition, the upper part (ridge) of the panels and posts must be lined by the artificial plant cover to achieve a reduction in the transmission of diffraction sound at the upper edge, to increase its resistance to weather agents and to mimic to a natural hedge thus achieving maximum integration in the environment.

The artificial plant cover is formed by a continuous base or tapestry of an elastomeric thermopolymer such as EPDM (ethylene propylene diene) or others and a surface that mimics grass or any other plant belonging to the plant kingdom made of a thermoplastic such as polyethylene and / or polypropylene . Fibers or artificial plant elements are sewn to the tapestry or base of the cover that on the back of it are formed longitudinal seams that protrude in a low-relief of a few millimeters. It has been experimentally proven that by practicing holes in the base of the green roof in the area of the streets that are formed between the longitudinal seams, the absorption coefficient that this green roof gives to the screen where it is fixed is considerably increased.

These materials that form the artificial plant cover together with the distribution and height (greater than or equal to 3 cm) of the artificial plant fibers or elements give the whole of the acoustic screen resistance to vandalism attacks such as "graffiti" paintings, since it prevents its fixing and highlighting, in addition to contributing to the improvement of the aesthetic and acoustic properties of the support panel; It also gives them other properties such as: high resistance to abrasion, wear and weather agents; a working temperature that ranges between -40 ° C and 120 ° C; high chemical inertia being resistant to pollutants and corrosion; UV resistance; color fastness; Fire resistance, not spreading the flame.

Description of the figures

Figure 1: Section view of two sound absorbing screens with artificial plant cover, assembled using machi-female edges.

Figure 2: enlarged perspective view of the back of a piece of the base of the green roof where the longitudinal seams and the holes made in the streets between seams are distinguished.

Figure 3: perspective of the sound absorbing screens supported with the posts and anchor plates.

Figure 4: overall perspective of a sound-absorbing screen with artificial plant cover.

Figure 5: Bar chart relative to the distribution of the acoustic absorption coefficient as a function of the frequency (for thirds octave values from 100 Hz to 5000 Hz), for the sandwich display with artificial plant cover.

Figure 6: Graph relative to the distribution of the sound insulation index or transmission losses in decibels, as a function of the frequency per octave, for the sandwich display with artificial plant cover. Reference List

1. Artificial plant cover.

2. Machi-female.

3. Core of insulating material.

4. Base of the vegetation cover.

5. Longitudinal seams.

6. Holes made in the base.

7. Vegetable fibers.

8. Artificial plant cover.

9. Post.

10. Anchor plate.

Preferred Embodiment of the Invention

The manufacture of these acoustic screens consists of two phases: 1) Mechanical treatment of the base of the artificial plant cover and 2) fixed of the artificial plant cover on the surface of the panels and the posts that support them.

1) Once the appropriate artificial plant cover is selected and acquired, it must have perforations in the base that supports the artificial plant cover fibers, which increase the acoustic absorption coefficient of the panels on which they are applied. These holes will be made in line between the seams presented by the base of the artificial plant cover on the back.

The realization of these holes can be carried out either during the manufacture of the base of the artificial plant cover, or prior to installation in the panels. Different geometries and sizes of the holes have been tested, as well as the distance between them, being a good configuration formed by circular holes of diameter "d" 2 mm≤ d≤ 4,5 mm separated from each other a distance "s" of 0.5 cm≤ s ≤ 3 cm.

2) Once the type of panel on which to fix the artificial plant cover has been manufactured, its dimensions are measured, as well as the dimensions of the posts on those that will be housed. From the measurements obtained, the artificial vegetal cover is cut with the exact dimensions to cover the lateral surface of the two sides of the panel, but leaving the two bands or lateral strips of the panels that will be housed inside the "U" uncovered "of the posts. For the panel located at the top of the screen, a single piece of artificial plant cover covering both sides and the upper edge will be cut.

In addition, the artificial plant cover will be cut with the dimensions of the faces seen from the posts, so that it also covers the top of it. This cover will have a thickness less than the cover of the panels, so that the surfaces of the panel and the posts are flush. In this way two effects are achieved, one aesthetic, because a visual continuity of the acoustic screen is obtained when the post is hidden from view and, another functional, because it prevents the post itself from acting as an acoustic bridge and propagating the sound to the back of it. That is to say, sound attenuation and insulation is achieved not only in the panels but also in the vertical fastening posts.

Once the artificial plant cover of the required dimensions is cut, it is glued onto the faces of the panel using a polyurethane adhesive. Figure 1 shows the artificial plant cover 1 adhered to both sides of the panel, the machi-female joint 2 between two panels and the core of insulating material 3. The union of the artificial plant cover to the panel is made at the seams of the back of the base of the cover, because the seams protrude from the rest of the cover on the back, therefore being in contact with the panel where they are to be fixed and it will be at those points of contact where the adhesive is applied. These seams together with the holes and the continuity of the base or tapestry create cavities (Helmholtz resonators) that contribute to improve the sound absorption coefficient and the sound insulation index of the panel.

In figure 2 it represents an enlarged view of the back of a piece of green roof on whose base 4 a line of holes 6 has been made in the middle of the streets formed by the longitudinal seams 5 that fix the vegetable fibers 7 to the base or tapestry . When the panels are finished and the posts are installed on the ground, the panels are fitted by the top of the posts until reaching the desired height, placing on the top a panel that has cover in addition to the two faces, the edge higher. Figure 3 shows the panels with plant cover 8, assembled on a pole 9, fixed to the ground with anchor plate 10. Finally, the artificial plant cover strips are fixed with adhesive to the faces seen from the posts, so that are completely covered.

In its case, it is also advisable to cover the protective base of concrete or other materials on which the acoustic screens rest and which can reach a height of about 70 cm. If this base is not covered, the overall acoustic absorption coefficient of the entire acoustic barrier decreases considerably. Figure 4 shows a joint view of the finished acoustic screen. Figures 5 and 6 graphically represent the sound absorption coefficient and the sound insulation index measured with the measurement system of the impedance tubes.

Finally, it is necessary to highlight the differences of this invention with those described in the documents that have been related in the state of the art section:

Regarding the document cited as Patent-1, it should be said that it is not described that the plant cover has sound-absorbing capacity, the absorbent capacity is made by a plastic foam. Its absorbent and sound insulating capacity is not quantified. In this invention the artificial plant cover is fixed on a wall or panel, whether or not sound absorbing. The tapestry that forms the basis of our artificial plant cover is continuous with longitudinal seams that form a low relief on the back of the plant cover. When performing the perforations in the middle of the streets formed by these longitudinal seams, longitudinal and continuous resonance chambers are formed that absorb the sound; This composition gives the wall where sound absorbing properties are fixed.

In the document cited as Patent-2 describes an artificial grass cover that is fixed on the walls of a wall but makes no reference to the Vegetable cover receive some treatment, to absorb sound, as is the case with our invention. Nor is its sound absorbing and insulating capacity quantified.

The document cited as Patent-3 describes the manufacture of an artificial turf for sports fields, where the few holes that are made on it have the sole functionality of draining the water so that it does not flood. Without its distribution being established, it lacks dimensions in diameter and separation.

And finally, the document cited as Patent-4 describes a structure to reduce acoustic vibration based on the concept of Helmholtz's cavity where the response of the structure to induced acoustic vibrations in the frequency range between 10 and 1000 is quantified Hz. Its absorption and sound insulation behavior in the frequency range of 80 to 5000 Hz is not studied as established by current regulations. Our invention uses Helmholtz cavities, but with the difference that the arrangement of the holes in the cover of the vegetation cover is original and decisive to obtain a high absorption capacity and is a totally different procedure to that described in this document.

Claims

1. Acoustic shielding system for reducing noise levels on roads, highways, highways, railways and their environments; characterized in that it is constructed by applying an artificial plant cover (1) fixed on the faces or surfaces of monolithic panels; said artificial cover is based on a tapestry (4) that has longitudinal seams (5) protruding from the back of the tapestry and in the spaces formed between said seams, perforations (6) are made with predetermined distances between holes.

2. Acoustic shielding system according to the preceding claim, characterized in that said artificial cover is based on a continuous tapestry.

3. Acoustic shielding system according to the preceding claims, characterized in that the perforations of said base consist of circular holes of diameter "d"; 2 mm≤ d≤ 4.5 mm; separated from each other a distance "s"; 0.5 cm≤ s≤ 3 cm.

4. Acoustic shielding system according to the preceding claims, characterized in that the artificial plant cover covers the front, rear and upper sides of the vertical fixing posts of the panels.

5. Acoustic screening system according to the preceding claims, characterized in that the artificial plant cover covering the panels also covers the upper part (ridge) thereof.

6. Acoustic shielding system according to the preceding claims, characterized in that the artificial plant cover covers the sides seen from the posts.

7. Acoustic screening system according to previous claims, characterized in that the artificial plant cover is formed by a base of an elastomeric thermopolymer such as EPDM (ethylene propylene diene) or others and a surface that mimics grass or any other plant belonging to the plant kingdom made of a thermoplastic such as polyethylene and / or polypropylene.

8. Acoustic screening system according to previous claims, characterized in that it can be used by installing it on dividing walls of urban plots, sound-absorbing screens on roads and rail lines, and the walls that constitute the medians of motorways and highways.

9. Acoustic shielding system according to previous claims, characterized in that it can also be used by installing it on the walls or baseboards that serve as the basis for the support of the screens.

10. Use of the acoustic shielding system to obtain "anti-graffiti" surfaces on the screens or walls where it is applied.