Keywords

1 Introduction

A sustainable interior design is a design that aligns with the main sustainable design principles and strategies that aims to design a built interior environment that provides the occupants with utmost comfort, meets the safety and health requirements, and achieve the economic savings and environmental responsibility (Hayles 2015). With the huge gap between principles and the reality of practices, it has become essential to connect the designers and their designs to the core meaning of sustainable interior design; in order to achieve the social, economic, and environmental goals of the design, and enhance the overall performance of the building in terms of energy-efficiency and interaction with surrounding environment over the lifecycle of the materials. The Interior designers' role in the built environment is creating spaces that meet the needs of their clients through a process of critical thinking, research, and creative solutions. In addition to considering other aspects such as the client’s health, safety, and wellbeing as well as the environmental impact which is considered a sustainable thinking by the designer. The Life Cycle Assessment (LCA) is the method adopted by designers to achieve a longer, healthier and a considerate interior environment for the occupants (Linhares and Pereira 2017). This paper will focus on analysing the interior characteristics for a space in an educational building and proposing options for an alternative design that follows more sustainably responsible practices. The study will thoroughly explore the existing condition of the chosen space which includes layout, finishing materials, lighting, ventilation, furnishing and decoration elements. Subsequently, the proposed strategies and methods will be presented to replace the existing conditions with sustainable alternatives.

1.1 Aims and Objectives

The main aim of this paper is to create an overall environmentally friendly, economic, and socially positive spaces for occupants to enhance their comfort, productivity, performance, and social interactions.

The objectives of this research paper are the following:

  • Improve productivity and sustain the mental well- being of occupants.

  • Create an energy efficient interior environment with various strategies for cost saving and eliminating excessive energy consumption.

  • Reduce the environmental and health impacts with the proper selection for furnishing and finishing materials.

  • Aim for longevity and flexibility in the design.

2 The Case Study

The chosen site is the main lobby of the institutional building: The British University in Dubai (BUiD). The university is the first research-based, postgraduate university in the middle east with programs offered in various fields such as Business, engineering, and informatics. Additionally, the university is working in partnership with leading UK universities. Building facilities include classrooms, auditorium, student area, the writing center, and Labs.

Site Analysis

The chosen site is located in Dubai International Academic City, with coordinates of 25.1266oN, 55.4109oW. BUiD was established back in 2003 as one of many universities all in the Academic City, which was named as a serving purpose indicating the presence of all the educational institution in the area. The British University is located in an open area with great exposure to natural sunlight and wind all year. Although the city is considered a relatively new one, the educational institutions have transformed the area to an interactive one. Figure 1 demonstrates the orientation of the building and the sun path in the location as well as the site boundaries and main surroundings. The paper will be investigating one section inside the university, which is the main lobby on the first floor that includes several spaces.

Fig. 1
An illustration of the zoning plan of the university. A rectangular area has an administration room to the left with a storeroom in the top left corner, and to the right is the student area with a female room at the bottom left corner, and in between them is the reception area.

Zoning Plan

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Existing conditions

Details of the existing site conditions will be listed such as dimensions of the spaces, the finishing of the walls, ceiling and floors, lighting fixtures, and materials of the loose furniture.

The total built up area of the chosen space is about 460 m2, which include the following zones:

  • The reception zone which includes the reception counter and two waiting areas with approximately total area (96 m2).

  • Student’s zone includes activities area, female room, and a store with approximately total area (120 m2),

  • Administration zone includes open plan office area in addition to six closed offices with approximately total area (195 m2).

2.1 Drawback on Existing Conditions

Administration and reception area has no direct daylight and natural ventilation hence these areas only depend on artificial lighting and ventilation and it’s not possible for the occupants to use the space or function properly without the presence of one or both of the previously stated.

  • The design of the student area does not achieve the calm relaxing atmosphere, the used color tones for the furniture and walls are strong and alarming, the lighting is bright white and excessive which is not required for this type of space. Additionally, the furniture has non-eco-friendly materials with synthetic fabrics and tables with long processing and energy consuming manufacturing.

  • The reception design lacks the welcoming and healthy atmosphere vibe in addition to the excessive white lighting where it’s not needed. The waiting area furniture is a non-eco-friendly option since it’s made of long processed plastic which requires high energy consumption and it’s harmful for the environment and occupant’s health.

  • The lack of sufficient nature elements in all the spaces which is significant to bringing the occupants closer to nature and providing a better indoor air quality therefore enhancing their mood, productivity, and performance.

3 Methodology

The paper will use several analysis methods through computer programs for the existing conditions of the chosen space and the proposed design. Three factors will be considered during the design concept stage, namely environmental, economic, and social impacts where these impacts are directly related to achieving the desired solutions for a sustainable interior design. These factors are referenced by the ASHRAE standard which is an international standard advancing the well-being of occupants through sustainable technologies in the built environment. The interior finishing materials will be evaluated through LCA (life cycle analysis) to assess the material’s quality in terms of environmental and health impact throughout its entire life cycle starting from raw material extraction until the final stage of disposal. Additionally, an energy evaluation will be conducted for the energy consumption in the space in order to aim at reducing the amount of consumption in the proposed design using more suitable strategies for lighting and ventilation. Furthermore, a comparison is conducted between the existing design and the proposed design in order to demonstrate the areas of improvement according to the used strategies of sustainability by DesignBuilder Software.

4 Proposed Design

4.1 Sustainable Design Development

Sustainability is a concept that holds within it broad views and consideration of many other concepts that affect the human civilization and defines its interactions and relationships with ecosystems and surrounding environment, of which led many scientists to agree on avoiding entitling it to one specific meaning (Ramsey 2015). Nonetheless, it can be concluded that sustainability is the result of the environmental concern and sense of responsibility towards the planet as whole. The concept of sustainability can be simplified into “meeting the needs of the present without compromising the ability of future generations to meet their own needs” (Portney 2015, p.4). Sustainability as whole discusses sustainable ecosystems, sustainable energy, society and economy, sustainable development, environmental protection, conservation / preservation of natural resources (Farley and Smith 2020). The main distinguish is that sustainability tends to be a long-term dynamic process of all the other concepts regarding the three Es: Environment, Economic and Equity, where these three pillars of sustainability must be met and fulfilled simultaneously through protection, promotion, achieving growth and development for all at once, where no pillar is prioritized over the other, and no pillar is overshaded and neglected or sacrificed for the flourish of another. The maximum potential and yield of sustainability have yet to be achieved as the international community still lacks the awareness and perception of the importance of sustainability and its different application in all lives. The following sections discusses individually the social, environmental, and economic aspects of adopting sustainability in interior designs.

Economic Aspect

Another essential pillar of sustainability is the economy and prosperity of humans’ developments. The economic sustainability balance between the economic growth and savings and the environmental considerations and restrictions of natural resources; in order to achieve a sustainable economic growth without affecting the environmental aspects of it. The active approach is achieved through the proposed lighting system, that is 40% more efficient than the baseline (current) and is still environmentally friendly with LEDs technology. In addition, the proposed fan power in the HVAC system is more efficient and less energy-consuming, and has a smart control system that changes the fan speed according to the cooling load at that instant, which result in savings in electricity bill. The passive approach is through applying sealant on the gaps that decreases the air leakage inside the building envelope, which decreases the cooling load on the HVAC system. Additionally, decreasing the air leakage from 10 m3/m2/h which is the maximum leakage allowable from Dubai Green Building Regulation to 5 m3/m2/h which is the recommended allowable air leakage for offices and buildings according to the UK standard - ATTMA, and in addition to an extra layer to be added to the interior walls for thermal insulation promotion, decreasing the thermal losses to outdoor (unconditioned area).

Social Aspect

The social benefits of implementing sustainability in interior design are related to improvements of occupant’s quality of life, mental and physical health. These benefits can be perceived at three main topics, namely health, comfort, and satisfaction. These outcomes can be interrelated, yet they have different employment methodologies. The proposed design solutions investigated the various outcomes of health, comfort, and wellbeing which are associated with the presence of sustainable design approaches. The built environment can have negative and positive impacts on the quality of life of occupants. Some approaches such as increasing occupants’ control over indoor environmental conditions, access to natural views and daylight, higher connection with nature is likely to create positive impacts on occupant’s health and wellbeing which are closely related to their levels of performance and productivity (Benjamin 2018). Environmental Aspect: The environmental aspect is an important pillar of Sustainability, which is achieved through protection and preservation of different ecosystems, with controlled and safe interactions with human development processes, while still achieving a reasonable conservation of natural resources and utilizing them with respect to the present generation needs and avoid any excessive exploitation that might lead into accelerating their depletion, resulting in shortage of natural resources for the future generations. Generally, environmental sustainability was referred to as the “environmentally-responsible development” and the “environmentally-sustainable development” by the World Bank in 1992 when sustainability was introduced officially and implemented, where until 1995 the term was officially developed as environmental sustainability (Moldan, Janoušková & Hák 2012). The intention of adopting a sustainable interior design is to improve humans’ welfare, lifestyle and living conditions by protection the environment and its resources of raw materials and minimize the human waste (i.e., residential, agricultural, construction/commercial, …, etc.) to align it with the available natural sinks (soil, water, atmosphere) without exceeding its capacity that might lead to a reverse impact, resulting in irreversible harmful impacts on humans and different ecosystems in terms of health and safety, instead of serving its main purpose of elimination of the waste. The natural sinks are in this case consisting of two subsystems: the emitted pollution and waste absorption (Moldan, Janoušková & Hák 2012). On the other hand of the cycle, there is the sourcing side consisting of the renewable and non-renewable sources. These two subsystems are studied and analyzed of which renewable resources are promoted, investigated, and invested in with time and money, and the harmful impacts of the different stages of using nonrenewable resources are minimized, mitigated, and compensated for. Consequently, all of these approaches will lead to minimize the exploitation natural materials (Aluminum, wood, metal, …, etc.) will bring back the biological diversity and natural geometry, resulting in a clean fresh air and clean, flourished water and land resources, enhancing the human health and development. In addition, it will also improve the overall integrity of the biosystems, sustaining all the options for future generation, and maximizing the options available as whole (Ones & Dilchert 2012).

4.2 Plan Layout

Figure 1 bellow shows the space zoning for the new layout plan. The spaces were allocated according to the requirements of each space function. The administration area was placed in the area where more daylight can penetrate into the space reducing artificial light consumption as the office area requires an adequate amount of light in order to allow the occupants to properly perform their tasks. The student area was allocated in a place with less day lighting as it would be sufficient for this type of function which is mainly relaxing, socializing, and playing games. The reception area is at the center of the lobby facing the main door in order to facilitate the guidance for new visitors.

4.3 Design Specification

Walls, Floors, and ceiling finishes

The following are the finishing materials used for the walls, ceiling and flooring using sustainable approach specifications.

  • Concrete texture wall painting with low VOC

  • Modular Glass partition pre-assembled units with easy installment and removal to allow for an easy reallocation.

  • Green wall for a welcoming, warm environment in the reception area in addition to improving the indoor air quality due to the natural plantation in the wall.

  • Sustainable wood flooring boards made from recycled plastic and wood powder, non-hazardous chemicals used for installing in addition to easy installation and cost-efficient qualities.

  • Marmoleum floor covering, which is also knows as linoleum, it’s made from natural raw materials such as wood & cork dust and linseed oil. It’s a highly durable and eco-friendly product with manufacturing that uses 100% green energy.

  • Gypsum false ceiling which is recyclable and does not contain or requires the use of toxic substance for manufacturing and installment (Tables 1 and 2).

    Table 1 Wall specification
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    Table 2 Material specifications
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Furniture Selection and Specifications

Sections

Figures 2, and 3 demonstrate the proposed design simulation for the spaces which includes 3d perspectives and sections to demonstrate the height and interior elevations of the spaces.

Fig. 2
An interior view of the college. To the right are four partitioned rooms with desktops, and to the left are several seating areas with chairs, common tables indoor plants.

Section AA

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Fig. 3
An interior view of the college reception area. In the center is a reception desk with 2 chairs and a hanging creeper plant backdrop. To the right is a common room with center tables, chairs, and indoor plants. To the left is a room with 3 desktop systems.

Section BB.

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5 Analysis and Discussion

In this paper, the economic and environmental aspects have been studied and analysed separately using simulation software Design Builder and LCA analyser, respectively. Two energy models have been created: the baseline and proposed; in order to carry out a simple comparison between the initial state of the case study and the proposed interior design in terms of environmental impacts of chosen materials (i.e., finishes, flooring, furniture, and walls), and in the economic savings from the lighting and HVAC analysis.

5.1 Life-Cycle Analysis

LCA analysis was carried out in this paper to determine the environmental impacts of the proposed materials over their lifecycles, in terms of resourcing, manufacturing, transportations and operation (Krishna et al. 2017). In addition, it analyses the end-of-life cycle for the material and the disposal method, whether it consists of recycling, reusing or burial and demolishing. The flow chart below (Fig. 4) shows a simplified the materials’ main life cycle stage.

Fig. 4
A flow diagram of materials' main life cycle stages. It starts with extraction or resourcing or cultivation, transportation, refinement: grinding or crushing, production or manufacturing, transportation, layering, operation, maintenance, transportation, and disposal.

Materials’ main life cycle stages

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The environmental performance regarding the life-cycle assessment of the proposed material were studied and analyzed as shown below (Table 3).

Table. 3. Output data of pyrolysis and gasification of plastic waste
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5.2 Lighting Solution

Light-Emitting Diodes (LEDs) are an efficient lighting system that is made from semiconductors that emit light in the case of an existing electrical current flowing through the integrated microchips, causing the emission of visible light used for different application (Zhuang 2018). These lights mainly utilize the technology of LEDs for energy efficiency and savings as it uses at least 75% less energy compared to the consumption of Incandescent and Fluorescent lights. It reduces life cycle impacts and end-of-life consideration and emission and thermal release where it emits very low to no heat in its operation compared to 90% and 80% heat emission in Incandescent and Fluorescent, respectively (Gómez and Izzo 2018). Not only that, but its durability and longer lifetime of 3 to 5 times than other light. Moreover, the quality of LEDs lights is also evident in its intensity and flexibility in direction of emitted light without any necessary diffusers or reflecting medium without losing the light half through the way from the fixture (Tuenge 2013). It also comes with a wide range of colour options, which have different psychological impacts and applications. Three LEDs lights were used: Integrated LED pendant light, Integrated Grille Spotlight Downlight LED Embedded, and LED Strips Profile Aluminum Channel Aluminum Linear Lighting Profile. All three proposed lights are 100% recyclable and are manufactured from and by eco-friendly materials and processing. The proposed lighting layout is targeting 40% saving on the baseline in terms of energy consumed that is assumed to be following ASHRAE 90.1–2007, which is the minimum lighting schedule followed in UAE.

5.3 Energy Analysis

For energy analysis, two simple energy models have been created in Design Builder Simulation Software: the baseline and proposed; in order to carry out a comparison between the initial state of the case study and the proposed interior design in terms economic savings from the lighting and HVAC analysis. The four main changes that are made between the baseline and proposed cases are the following:

  1. 1.

    Lighting Schedule.

  2. 2.

    U-Value of interior wall and Insulation Thickness.

  3. 3.

    Allowable air leakage through the envelope in m3/m2/h.

  4. 4.

    FCUs fans rated power in kW.

The changes made are all summarized in the Table 4. The table shows 7.4% savings in the cooling load, which is the result of decreasing the air leakage from 10 m3/m2/h as per DGBR minimum compliance to 5 m3/m2/h as per the recommended from ATTMA. In addition, the U-value of the walls was decreased from 0.704 to 0.403 W/m2. K, Additionally, with increasing the efficiency of the fans and decreasing the power needed, less thermal heat losses were released from the fan is to the air stream. Comparisons of annual energy consumption between the base case and proposed solution are shown in Fig. 5.

Table 4 Comparison between base case and proposed solution in terms of saving
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Fig. 5
A grouped bar graph of annual energy consumption in thousands versus end-user proposed case versus base case. Coding has 31.06, 26.6, Fans-interior 5.56, 2.35. Interior lighting 12.91, 7.75, and Receptable Equipment 10.89, 10.89.

Annual energy consumption: proposed case Vs Base case

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6 Conclusion

The paper aimed to achieve various solutions through redesigning the spaces of the main lobby of the BUiD University using sustainable interior design approaches which are related to improving the occupant’s quality of life, reducing health and economic impacts that’s imposed by the traditional design while also considering the environment which is a closely related to human existence and survival. Various strategies were used in order to achieve the sustainability goals in interior spaces. These strategies included the proper analysis and selection for materials, products, lighting and colours in addition to the nature elements and day lighting that helps occupants be more connected with nature and outdoors.