The use of green constructions as a means of reducing the noise pollution

. The main problems of a modern world are increased energy consumption, greenhouse gas emissions, urban runoff, and the urban heat island effect.They caused by buildings. Another urgent issue – noise pollution. These problems negatively affects human physical and psychological health. The soliton of the problems is a green construction. The article provide the analysis of the modern green wall technologies, a detailed look at the different vertical greening systems, their benefits and disadvantages, and how each of these systems reduce noise. The result revealed that there is no universal gardening system, it should be selected individually. In terms of noise reduction, hydroponic systems with green wall panels are the most noise-reducing systems. We evaluate the indicators of the effectiveness of green wall systems and select the rational solutions for integrated greening systems of buildings, compare existing technological solutions with innovative solution, patented by the authors. The result is presented by the development of technology with modular green systems, which will expand the practice of technological design, experimental construction and renovation of buildings, to improve the quality of the urban environment through rational construction and technological solutions and appropriate work methods.


Introduction
In the modern world, the problem of preserving the ecologically favorable environment is rising abruptly due to the accelerated growth of the urbanization: the lack of green spaces in large cities, global warming, increased noise pollution, deteriorating air quality, extensive consumption of electricity and water are the consequences of mindless mass development of territories.These above-mentioned aspects negatively affect people, worsening their physical and psychological health.For example, according to the results of a WHO study, excessive noise exposure impairs hearing, develops cardiovascular diseases, reduces human productivity and even the standard of living by 10-12 years; dirty air provokes the development of lung cancer, acute respiratory diseases.One of the most effective and aesthetic ways for modern cities to improve the microclimate is the introduction of green architecture.In a large number of countries around the world, buildings with vertical are beginning to be erected, both apartment buildings, hotels, and offices and government buildings, decorated with a wide variety of plants.
The human body is a complex ecosystem and requires three basic things to live a full life: food, water and oxygen.As you know, a person can live 2-3 weeks without food, 5-7 days without water, but only 2-3 minutes without oxygen.Therefore, it is oxygen that is the most important factor in human existence.But the rapid development of society and civilization leads to a reduction in oxygen in the atmosphere.This is especially true in large metropolitan areas, where a huge number of production machines are concentrated, which are the main producers of carbon dioxide and absorbers of oxygen.It is in megacities that there is a constant lack of oxygen.In this regard, a very important task is the development of green spaces in urban areas.But this, unfortunately, is associated with certain difficulties, namely the lack of sufficient space for laying out parks and green areas.Therefore, the development of vertical gardening of cities today is one of the priority areas for the development of urban infrastructure, which is given great attention all over the world.
Due to the identified problem, one of the tasks of modern design is the construction of buildings and structures using technologies that help protect the environment and reduce the negative impact on people.
Many countries have taken a course towards environmentally friendly construction -national projects are being adopted (the National Project "Ecology" in Russia); laws: in San Francisco in 2017, a law was adopted, according to which new buildings must be designed with green roofs.There is also a system of fines and criminal penalties is introduced, for example, for "Crimes against the environment" in Germany, you can get a term of three years in prison.Italian scientists Bevilacqua P., Mazzeo D. and Arcuri N. were carried out the experiments with the thermal assessment of the green roof systems [1][2][3].Furthermore, the technological and organizational parameters of optimal roof base solution were studied by V.D. Tho [4].
There are many systems of international standards and criteria are being developed to assess the environmental friendliness of buildings, such as LEED (USA); BREEAM (UK); DGNB (Germany); Green Star (Australia); CASBEE (Japan); Minergie (Switzerland).These rating systems are a set of quantitative and qualitative indicators characterizing the level of comfort, energy efficiency and environmental friendliness of buildings.Green Certified Buildings: Acros Cultural Center (Fukuoka, Japan), Torre Reforma (Mexico City), The Edge (Amsterdam, Netherlands), Shanghai Tower (Shanghai, China).Following the principles of sustainable construction, which are described in these standards, will lead to economic benefits and reduced energy consumption.
For example, a LEED Gold certified US Treasury building saves more than 1 million dollars of US taxpayers a year through smart and integrated strategies to reduce energy and water consumption.Use of greening systems on the territory and buildings is one of the methods of green construction, which allows you to use a small space for good purposes effectively.Greening of walls does not incur large construction costs, is available in most parts of the world, is easy to operate and, most importantly, is very effective.
The study in Japan [5] found reductions in heat flux about 50% per year, and work in Ottawa [6] found a 95% reduction in annual heat gain.The research in Madrid showed that green roofs reduced the cooling load on an eight-story residential building by 6% during the summer [7].
In these environmentally friendly systems, plants act as natural biofilters, because they have the ability to change the chemical composition and ionize air molecules, as well as absorb and reflect sound waves, increase air moisture, and act as heat insulators.Thus, green spaces help to improve the microclimate of premises, increase sound insulation and air quality, and solve the problem of lack of green living areas.Moreover, vertical landscaping is a way to diversify and improve the architectural appearance of buildings.Landscaping systems are successfully used in many countries of the world, for example, One Central Park (Sydney, Australia), Bosco Verticale (Milan, Italy), Robinson Tower (Singapore), Parkroyal Collection Pickering (Singapore).There is a lot of research on the use of plants in construction.The purpose of this work is to compare different vertical gardening technologies to identify the most convenient system to operate and design, as well as the most noise-insulating coating for using it in in industrial premises.
To achieve this goal, the following tasks were solved: -consider different landscaping systems; -identify the pros and cons of each of them according to certain criteria; -evaluate the noise-absorbing characteristics; -determine the most soundproofing system.

Materials and Methods
In this study the methods of comparative analysis of the various options for vertical greening systems were applied.Based on the results of comparison of these systems, the choice of the best option was made according to the following parameters: availability in the organization, ease of use and reduction of noise impact.This study also provides a detailed description of the structure of green wall systems.
Depending on the system, the main components of green walls can be: plants, substrate, supporting elements around which plants grow, and a system of pipes and pumps that delivers water and fertilizer.According to the principle of operation, modern wall landscaping systems are: felt -hydroponic systems; modular -using a substrate and container technology -planting in pots (figure 1).Hydroponic green wall systems can be either modular containers or large panels.The systems are installed via brackets that sit out from the load-bearing wall (or a stand-alone structure) to create an air gap between the wall (or other structure) and the backing sheet of the green wall system.In a hydroponic system, an inert growing medium is provided to which the plants physically anchor, such as a horticultural foam, a mineral fibre or a felt mat.These materials can act as a water retentive sponge, although the more they soak up the heavier the system becomes.The advantage of the hydroponic system is that there is no structural decay of the growing medium, no salt build up from fertilisers and nutrients are supplied in a precise and controlled manner.Over time, plant roots grow and ramify through the entire system to create a very robust network [8].The example of such a system is the Trio Apartments in Sydney; The Athenaeum Hotel in London and the B3 Hotel Virrey in Bogota.
Modular green wall systems can be substrate-based systems use substrate-holding containers made of plastic or metal.The substrate is packed directly into the empty container or placed in a water permeable, synthetic fibre bag.The containers are connected together and anchored to the wall or to an independent, structurally secure metal rack or framework.Alternatively, plastic or metal growing containers can be hung on a metal grid fixed to the wall.Individual growing containers can be removed for maintenance or replanting.Most substrate-based systems are designed for automatic irrigation, just like the hydroponic green wall systems.The green wall system, designed and patented by the authors is shown on the Figure 2. The growing medium in these systems provides a structure to support the plant and facilitates water, air and nutrient access, decreasing the need for constant management associated with hydroponic systems.However, over time the reserve of nutrients will be exhausted and there can be a build-up of salts in the growing medium.Traditional potting mix is not a suitable substrate for green walls.This type of landscaping system allows you to diversify the types of vegetation, not limited to vertical climbing plant species.
In urban areas, where there is a lack of space for planting trees, shrubs and laying out lawns, the use of climbing plants in vertical gardening plays a huge role.Thanks to climbing plants, it is possible at low cost to obtain a high aesthetic effect in a fairly short period of time.Vertical gardening in the conditions of dense development of high-rise buildings in modern megacities is often the only way to bring green plants closer to the interior.Such plants have high qualities: a variety of forms, bright color of flowers, the presence of dense foliage and even fruits.For example, such a plant as a liana creates various patterns on the facades of buildings and structures due to the intricacies of its branches.In order to appreciate the full effect of such plants, it is necessary to understand that creepers are not a variety of plants, but a life form.Such plants can be both annual and perennial, ornamental and fruit.Naturally, for the vertical gardening of megacities, perennial species of these plants are used, a feature of which is the colorfulness and picturesqueness of the leaves.In the spring-autumn period, these plants have a rich and dense leaf shape, the flowering of such plants lasts a long time.The vegetation has hanging branches with dense foliage and a tiled surface.The rich abundance of colors of flowers, the presence of juicy fruits, as well as the magnificent appearance of such plants created by a sharp movement up and out of the elastic stems creates an undeniable advantage.
The most popular type of vines are Jacqueman's woolly or purple clematis; climbing roses; Chinese wisteria, floribunda rose variety; curly honeysuckle Telman.For use in vertical gardening, such types of vines as Engelman's girlish grapes have found wide application; girlish grapes or ivy, common ivy; ivy Colchis; climbing hydrangea.These plants have high decorative qualities, thanks to which they are able to easily climb along the walls of houses without special adaptations.But lianas are used not only for vertical gardening.Some creepers have found application in the decorative design of slopes.They are a type of ground cover plant.These include common ivy, Colchis ivy, climbing hydrangea.
Clematis (clematis) and climbing roses tend to have a variety of varieties and species.They bloom profusely and spectacularly during almost the entire growing season.This allows to create combinations that are distinguished by spectacular flowering over an extended period of time.As the long-term experience of specialists in the field of urban planning shows, the use of a diverse range of plants to model a successful landscape is completely optional.
It is also necessary to note the special value of climbing plant systems.They have not only high-quality systems of plants, but their main functions in vertical gardening are also decorative design of objects, disguise of individual small structures, design of playgrounds and recreation areas.But the most important thing is the creation of special microclimatic conditions, namely, an increase in relative humidity, the creation of shade, and a decrease in the radiation background.
Among the most famous buildings of this type are the Acros building in Fukuoka, Japan; Solaris and Parkroyal in Singapore.The basis of the structure in the container green systems is the supporting waterproof metal frame, which is divided into three types: frame grid, built-in frame rack, portable frame rack with guides.An irrigation system is fixed directly on the frame itself.This system is a huge network of hollow pipes, and pots with soil substrate, in which the plants are subsequently planted.For each pot, a personal irrigation tube is placed to supply water and fertilizer.As a rule, this irrigation system is connected to the water supply and sewerage system [9].

Results and Discussion
To identify the most noise-absorbing system, we have made a request to manufacturing companies to provide us with data, how exactly their greening systems reduce the noise level.
The measurements were made in the AIRO Acoustics Laboratory (UKAS accredited testing laboratory No. 0483) of the sound absorption of three configurations of Biotecture Living Wall System.Measurements of sound absorption, Sound Absorption Coefficient (as), were conducted in accordance with British Standard BS EN ISO 354 [10].Single figure ratings of sound absorption performance, known as the Weighted Sound Absorption Coefficient (aw) and Sound Absorption Class, are derived from these measurements in accordance with British Standard BS EN ISO 11654 [11].The specimen comprised the Biotecture Living Wall System, which was installed for test directly over the floor of the reverberation chamber to cover an area of 3.00 m x 3.60 m thereby satisfying the area and aspect ratio requirements of BS EN ISO 354.
The system included a 15 mm thick Palight Board (550 to 700 kg/m3) which was used as a waterproof backing and mounting board.This was overlaid by a geotextile drainage layer, with aluminium fixing rails, drip-lines and cover strips at 450 mm centres.40 Biotile Panels with 600 x 450 mm modular dimensions were clipped into the fixing rails in a 5 panel long x 8 panel high array.Each Biotile Panel consisted of a 3 mm plastic framework with a 55 mm thick Grodan growing medium of 75 kg/m3 Rockwool mineral wool.The front face of each Biotile Panel was sub-divided into 16 cells by the plastic framework with each cell including a pre-cut 50 mm diameter removable plant plug (figure 3). 1. Biotecture living wall system with fully planted panels (test no.L/3360/1) The panels were wet with an average moisture content of 60 to 70%, and were fully planted with 640 plants of a mixed perennial plant selection.Photograph No. 1 shows the planted system installed for the test.2. Biotecture living wall system with dry panels (test no.l/3360/2) The panels were dry, did not include plants but did include the removable Grodan growing medium plugs.Photograph No. 2 shows the un-planted system installed for the test.3. Biotecture living wall system with wet un-planted panels (test no.l/3360/3) The panels were wet with an average moisture content of 60 to 70%, did not include plants but did include the removable Grodan growing medium plugs.Photograph No. 2 shows the un-planted system installed for the test.The sound absorption of a specimen is measured under diffuse field conditions where sound is incident upon the specimen from all directions.The specimen is installed directly over the floor of a purpose to build the reverberation chamber.The chamber rests on resilient mountings to give it good acoustical isolation from the building exterior.In order to give a good diffusion of the sound field, the walls are non-parallel, the ceiling pitched and twenty randomly suspended diffuser panels are included with a surface area of 37.2 square metres.
A steady sound source with a continuous spectrum in the frequency bands of interest is used to drive an omnidirectional loudspeaker which is located in the chamber.The reverberation times of the chamber are determined using the interrupted noise method with three decay measurements made at each of four microphone positions for each of three loudspeaker positions to obtain a good average at each of the one-third octave intervals from 100 Hz to 5000 Hz as prescribed in the Standard [10].The test is conducted with the specimen installed within the chamber, and also in the absence of the specimen and any associated framework.
Sound absorption coefficient (αs) of the parameter is calculated using the following formula: where: V is the volume of the empty reverberation chamber (m³); S is the area of the test specimen (m²); T1 is the mean reverberation time of the empty reverberation chamber (seconds); T2 is the mean reverberation time of the reverberation chamber with the test specimen installed (seconds); m1 and m2 are the power attenuation coefficient at T1 and T2 calculated according to ISO 9613:1993 [12]; c1 and c2 are the velocity of sound.
Noise reduction data was provided by Biotecture, the British company that specializes in creating living green walls.This company uses hydroponic systems technologies, which is why they are the most detailed in this study is presented in the Table1.This table shows the sound insulation coefficient of hydroponic systems in three possible states.Thus, we were ensured the safety of industrial premises by reducing the noise impact through the use of green walls.Many scientists have conducted research on green technologies and their impact on both outdoor and indoor microclimate [13][14][15][16][17][18].The arrangement of green systems on the rooftops and walls of buildings is a way to improve the quality of the urban space.The wide range of benefits is associated with green systems, including performed technological systems with organizational structures, reduction of the airborne noise and energy cost savings by 40% [19][20][21][22][23][24][25].Technological benefits of modular construction for high-rise buildings in urban green infrastructure were studied [26][27][28][29][30][31].This study examines the rational technological parameters and a comparative assessment of the technological efficiency of green wall systems based on test methods, research of their calculated absorption parameters.There is unique investigation because it has not been fully explored.Today smart green wall solutions have become increasingly popular in recent times for their environmental, technical and aesthetic benefits.At the same time, existing green wall technologies can be difficult to operate.Innovative green technologies will also bring great environmental benefits and help mitigate negative impacts in the conditions of mass urban development.The purpose of this study is to understand which types of the green walls can serve as a health defense mechanism from incessant noise for people, as well as which of systems are the most beneficial to use.Three different landscaping systems were considered: felt, modular, container.Based on the results of the analysis, we found out there is no system of vertical gardening, which would be the only universal system for all cases, each of the systems has its own pluses and minuses.

Conclusions
Also using the data provided to us by Biotecture, we found out which systems are the most noise-absorbing.In the industrial buildings, the problem of noise pollution is more acute, so we suggest using greening systems in order to reduce noise levels, improve air quality and create a pleasant, lively atmosphere that will have a positive effect on the employees of the enterprise.
Thus, the results of this study are as follows: -various solutions of green wall systems are considered and analyzed; -compiled a comparative characteristic of these systems; -the most environmentally friendly and efficient landscaping options have been identified; -the most noise-absorbing systems have been identified.

Table 1 .
The comparative characteristics of Biotecture's green wall systems.