Impact of Innovative Lighting Strategies on the Performance of Workplace Environment

Abstract

Innovative lighting layouts ILS is crucial in the office environment, with a significant impact on occupants’ well-being, visual quality, and saving energy consumption. A technical understanding of light sources and performance is vital in lighting design. Open office lighting settings varies from small areas based on light quantity, fixed approach (recessed/suspended), and layout, affecting illuminance lx-level and visual quality. This study evaluates minimalist lighting conditions and identifies the most efficient solution for uniformity in a workspace. It focuses on specific zones (accent light seating zone, task area, and circulation zones). Considering many factors, such as luminaire type, layout distribution, and quantity, influence illuminance levels and visual quality. The aim is to establish various innovative lighting layouts for multiple tasks in an open office, and identify key factors enhancing illuminance levels, distribution uniformity, and energy efficiency. This work utilizes Dialux-evo 10 simulation software to develop various strategies using different minimalist luminaires shapes, quantities, and layout distributions within an existing office in Masdar City, UAE to improve visual workspace performance. Two-strategies have created, analyzing current conditions and evaluating proposed lighting concepts by installing various artificial lighting types and designing different layouts for each workspace independently. The results emphasize the importance of different factors such-as light efficacy and fixed lighting approach in achieving required illuminance levels. The visual impact of each workspace is influenced by lighting uniformity, color, and distribution, a CRI of 80 or higher is preferred for accurate color representation. The type, quantity, and arrangement of luminaires play a crucial role in the overall visual outcome. The linear arrangement with batwing-shaped distribution Scenario-C achieves an acceptable illuminance level of 565lx, resulting in a reduction of approximately 10.9% compared to the regular arrangement of the base case.

1 Introduction

Since people spend majority of their time indoors, approximately 90% on average, with 36% of that time usually spent at work. Spending more time indoors reduces our exposure to beneficial light effects, leading to inadequate nutrition from natural daylight to support our biological, emotional, and visual needs (PHILIPS 2021). Prioritizing pleasant indoor lighting is crucial for enhancing productivity and occupant satisfaction. Lighting contributes for approximately 25% of energy consumption in commercial buildings and 15% in most homes (Alsaeid 2019). Fluctuations in light levels, known as the circadian rhythm, have a significant impact on our internal clock. Exposure to light and darkness affects hormone production, influencing our sleep patterns, alertness, mood, memory, and performance (Greenled 2020). Recent research highlighted the potential benefits of using lighting to synchronize our body clock. Lighting design focuses on emphasizing architectural features and providing acceptable visibility for occupants. The final design must meet the visual requirements of various tasks performed by human eyes while illuminating architectural components and immediate surroundings.

The European Standard EN 12464 identifies the key photometric parameters, such as illuminance, uniformity, and glare, to ensure visual performance in indoor workplace lighting (Zumtobel 2017). To enhance indoor lighting, various approaches can be employed, including improving natural light performance, using suitable light fixtures for specific functions (e.g., bright and cool-toned lights for workspaces), employing a combination of different light sources (task, overhead, and accent lighting) to create a layered lighting effect, and installing energy-efficient lighting to achieve a balanced and comfortable environment.

2 Office Lighting

2.1 Opening Office Concept Development

In the 1960s, the Schnelle brothers created the concept of “Bürolandschaften” or office landscapes in Germany. This concept emphasized open-plan offices and encouraged two-way communication between management and staff, reflecting the human relations movement in architecture (Christoph F. Reinhart 2014). The office layout intended to facilitate interaction by physically bringing co-workers together, fostering a sense of equality. It contrasted with the Tayloristic view of offices as document assembly lines by placing everyone in an open environment. Over time, interlocking, modular furniture concepts that are grouped in tighter, highly predictable rectilinear clusters of work stations replaced the early free-form floor design. Office lighting directly affects employees’ mood, energy levels, and productivity. Insufficient light can cause tiredness and irritability, while excessively bright lighting can strain the eyes, possibly leading to migraines and disrupting the body’s natural circadian rhythms. The optimal illumination in the workspace environment promotes employee activity, creativity, energy, and a positive mindset. Nevertheless, finding the right balance between excessive brightness and inadequate lighting can be challenging (Collective 2023).

2.2 Artificial Lighting

Artificial lighting typically refers to electrically powered light sources, such as lamps, bulbs, or tubes, that can be adjusted to achieve the desired outcome. The four adjustable characteristics of light are intensity, color, direction, and movement. Each of these characteristics can be modified to impact the four main functions of illumination: setting the mood, specific focus, and ensuring visibility. In the field of architectural design, the primary categories of artificial lighting include accent lighting ( highlight specific features), task lighting ( activities like reading), and ambient lighting (overall illumination in a space) (Sholanke, Fadesere and Elendu 2021).

2.3 Interior Lighting Considerations

Several terms are used to assess lighting performance in office environment, such as efficiency and effectiveness. The lighting requirements should meet the average luminance on a horizontal plane is met while achieving the highest level of lighting with minimal power consumption (A. Bhatia 2012). To achieve appropriate illumination in an office, a combination of daylight, direct, indirect, and task lighting is recommended. Ideal lighting color temperatures for office settings include warm white, neutral white, or daylight white with a significant blue content (Dötsch 2023).

• 1. Luminaire Selection

  Fluorescent lighting is commonly used in office settings, a general lighting setup with a relatively uniform level of illumination is recommended. Modular (plug-in) wiring for fluorescent lighting fixtures utilized in office spaces to facilitate adjustments. In open office spaces, the coefficient of occupancy needs to be reduced to account for light obstruction and absorption of systems furniture partitions. It is important to consider the recommendations provided by the Illuminating Engineering Society of North America (IES) Lighting Handbook when designing for glare, contrast, visual comfort, color rendering and correction (GSA.gov 2019). Office areas require an illumination level of approximately 500 lx (30 footcandles) under cabinet task lighting. To achieve greater visual comfort and enhance glare control, it is recommended to use luminaires with wider cut-off angles. Increasing the cut-off angle will result in different light distributions on the walls, as shown in Fig. 1-a. This narrowing of the beam spread can be observed in the combinations indicated for 30-, 40-, and 50-degree angles in Fig. 1-b (Roudger Ganslandt 2009).

• 2. Ceiling Lighting

  Ceiling lighting may be the primary source of illumination in a room, particularly when the room has significant architectural features. Indirect illumination can make the ceiling typically the brightest surface in the space. High ceiling luminance can resemble an overcast sky, leading to discomfort and glare for long periods spent indoors. Ceiling wash-lights, either mounted on walls or integrated into them, are used to create effective ceiling lighting. Cove lighting, in particular, is a significant type of ceiling lighting. To prevent direct glare and achieve consistent light distribution, mounted luminaires must be positioned at an appropriate distance from the ceiling (Roudger Ganslandt 2009). Ceiling luminaires can be arranged in various ways, depending on the design concept and task requirements. Figure (1-left) illustrates 4-major point distribution designs for lighting in an office ceiling.

Fig. 1.

Right) a) Wall lighting using wash- lights, b) Luminaire selection in terms of cut-off angle. Left) Ceiling luminaires arrangement in different approaches. Source: (Roudger Ganslandt 2009)

• 3. Lighting Layout

  Many factors affect the lighting layout in a space. The lighting layout depends on specific tasks and requires arranging luminaires according to the diverse lighting needs of different areas, such as placing downlights above seating areas or using a combination of downlights and floodlights in control rooms. Luminaires should be evenly distributed for uniform lighting. The design of the ceiling form is crucial for the lighting layout. Existing ceiling grids, modules, joists, and other structural elements must be considered when designing the lighting layout. It is also important to coordinate with engineers to ensure safe installation of the cabling. Lighting distribution should not solely rely on technical considerations. The arrangement of luminaires should align with the design concept and enhance the appeal of the ceiling design. In quantitative lighting design, it is common practice to arrange ceiling-mounted luminaires to achieve uniform light distribution. A differentiated lighting with different luminaires can be created with arranged uniformly. Lighting design and effects are not directly correlated, there is no comprehensive form for lighting layouts. Lighting ceiling layout in each space is developed based on lighting tasks, technical requirements, architectural features, and design concepts. Figure 2 illustrates various design concepts for lighting distribution on ceiling surfaces derived from ERCO hand-book. Considering the point as a key design element involves using individual luminaires or compact clusters of luminaires within a spatial structure (Roudger Ganslandt 2009).

Fig. 2.

Light distribution concepts for team office space based on the ERCO handbook. Source: (Roudger Ganslandt 2009)

3 Selecting Case Study

The UAE Space Agency building was selected as case study to assess the performance of office lighting in its interior workplace. The building is located in Masdar City, Khalifa City in Abu Dhabi, UAE as shown in Fig. 3. This building was constructed to meet high standards for Estidama Four Pearls rating and LEED Gold rating criteria for sustainable building design and construction of Core and Shell projects v.3-2009 BD+C.

Fig. 3.

Geographic location analysis of the selected case study (MVC) in Khalifa City, Abu Dhabi, the UAE

4 Methodology

This work combines modeling and calculation using DIALux-evo10 simulation software Fig. 4. The initial concept involves creating specific lighting layouts using different strategies and considering selected variables. The simulation process involved iterations starting with the tracing the office plan in DIALux’s construction application and incorporating architectural details such as windows, doors, reflectance factor surfaces, and material properties. Architectural details, furniture, and electrical lighting plans from the current workspace were then added. Key step involved tracing the electrical lighting plan, identifying the types of luminaires from a catalogue, rendering the layout model, and calculating the results. The process aimed to achieve optimal lighting scenarios, meeting target illuminance levels, uniform distribution, and acceptable ambient light throughout the office. Further investigation is carried out to achieve the optimal lighting scenario and realize the target level of illumination.

Fig. 4.

FlowChart illustrating modeling simulation, & calculation of the Base Case using DiaLux-Evo10. Source: (author, 2023)

Fig. 5.

(right) Ground floor workplace office plan, electrical lighting layout-green shade, (left) Long section of selected area

5 Modeling Set-Up

5.1 Current Lighting System Overview

The selected office area is situated on the ground floor spans 367.21 m². Figure 5 presents the architectural plans, showing the layout of electrical lighting and furniture distribution for the designated working area. The office has wide south-facing glazed opening for natural light and features 48-desks and 6-circular seating tables arranged uniformly throughout the space. The existing lighting system of the office incorporates LED-luminaires for enhanced indoor visual comfort. It adheres to IEASNA 90.1–2007 standards with a proposed lighting power density of 12 W/m², utilizing efficient luminaires such as CFLs or LEDs to reduce the number of fixtures required.

The current space has modular luminaires, including 20W LED downlights near windows and 39 W LED modular recessed luminaires. The recessed luminaires have a high efficiency of up to 130 lm/W, an 8 mm aluminum frame. The luminaires easily fit into modular ceilings and feature a dirt-resistant smooth optic design. They provide effective glare control with a wide angle of more than 65°. The main characteristics of the ground floor office summaries in Table 1. Considering the current furniture layout, the simulation accurately assessed the proposed lighting distribution.

Table 1. Interior design features & properties of the ground floor-office (workspace description)

5.2 Working Plane Configurations

The study identified the main working plane in certain criteria to meet the lighting target. The office area is divided into 7-zones Fig. 6, each with specific work-plane characteristics varying heights based on setting standards. Zones-A and B are the primary work areas, while the east corner zone and front sitting area have their own lighting requirements. The remaining spaces are classified as surrounding areas. Each zone must meet the minimum target illuminance level for uniform lighting distribution and acceptable ambient light levels. Following these standards ensures a comfortable and productive work environment for the office occupants.

Fig. 6.

Working-plane configurations of ground-floor office, Activate light scene perpendicular illuminance (WP42). Source: (author, 2023)

The study calculated illuminance values for each zone individually in the initial scenario and used an Adaptive Perpendicular illuminance with a working plane height of 0.80 m (WP42) was used as the active calculation area for the entire office space in subsequent scenarios. To meet the lighting needs of the open office space, the study considered the required illuminance values for different office tasks, such as writing and reading. It adhered to the Europe standard BS EN-12464-1 to select appropriate light fixtures for the open office space (Fig. 7). The study aimed to identify specific zones; the accent light seating zone, task area, and circulation zones, to optimize lighting conditions for visual comfort and productivity of the occupants.

Fig. 7.

Settings standards & specifications considering for lighting office requirements according to: BS EN-12464-1

6 Setup Strategies

This work established two strategies: the 1^st-strategy is “Base-Case analysis,” two scenarios were conducted. The first scenario evaluated the distribution of artificial lighting in the workspace under current conditions, while the second scenario involved adjusting the distribution of artificial lighting in the reference model. The 2^nd-strategy is “New concept design,” three scenarios were implemented. Each scenario focused on installing different types of artificial lighting and designing unique distribution layouts for each workspace independently. The study utilized the adaptive perpendicular illuminance (WP42) as the active working-plane for analyzing lighting performance in all scenarios. Detailed tables were provided, describing the selected luminaires based on manufacturer’s catalog specifications. A mounting height of 2.70 m was used during the lighting design process.

6.1 Strategy One

The first strategy evaluates current lighting conditions and assesses the lighting performance of the reference model. Table 2 outlines the key features of both scenarios, including luminaire types, quantities, and distribution layouts for each type.

• a. Scenario-1 (Base Case):

  The lighting distribution design in the base-case is regular linear arrangement of two types of luminaires: recessed modular lights (57 pieces, 39 W) distributed across the entire ceiling and downlights (26 pieces, 10 W) installed in the north and front direction Table 2. This layout offers flexibility in office layout without changing the lighting design for individual workspaces, while providing even and uniform ambient lighting throughout the office space.

• b. Scenario-2 (Adjusting Base Case):

  The lighting design concept maintained similar luminaire properties to the base-case while reducing the total number of luminaires. The fixtures were relocated around the task area to achieve a different distribution layout. As shown in Table 2, scenario-2 includes 40 recessed modules (39 W) and 18 downlights.

Table 2. Description Overview of Strategy-One

6.2 Strategy Two

The second strategy focuses on creating different zones of workspaces by installing flexible lighting for individual workspaces, known as the zoned concept. This concept aims to achieve effective lighting design by meeting minimum target illuminance levels and enhancing the ambient lighting distribution in the workspace. The strategy consists of three scenarios, each with different mounting heights based on the manufacturer’s catalog. Table 3 provides an overview of each scenario, including information on the selected luminaires and their key characteristics as specified in the catalog.

Scenario-A

The lighting distribution concept includes a linear arrangement of merged linear pendant luminaires direct-indirect light fixtures mounted above the middle each task area shown in Table 3. This enhances the ambient lighting performance. There are 22 suspended luminaires with high luminous efficacy (135.6 lm/w) and a power consumption of 73 W. The front seating zones, 7 modern design Ridi spot lighting LED fixtures with a CRI of 100 and a CCT of 3000k were installed. The circulation area has 22 adjustable Endo Lighting downlights are distributed along the aisle, focusing on the accent wall.

Scenario-B

The lighting distribution aims to ensure a zonal concept, creating a modern office lighting design by combining 4-different light fixtures. Table 3 provides details on selected fixtures; minimalistic slim-line hanging lights to achieve compact groups of luminaires with flexible light types. Selected 4-types lights; linear hanged luminaires positioned at the track centered on the longitudinal axis of the desk for optimal workstation illumination. Each task area features two types of linear luminaires (Keyline and linear hanged luminaires) and a corner line light. Keyline, a Line light from Philips, offers high efficiency (up to 130 lm/W), a slim minimalistic design, high lumen output, low glare, and compliance with UGR19. It is suitable for surface-mounted, suspended, and linear applications.

Scenario-C

The last scenario has different concept among other scenarios. It employs a linear arrangement of direct/indirect luminaires mounted on the edge of the task layout. The selected LED luminaires produce a batwing-shaped light distribution, increasing the ambient lighting over the task area while minimizing reflected glare and maintaining good CRI values throughout the space. The layout includes pendant direct/indirect light fixtures for the task area, spotlight LED luminaires (14 W) for the circulation area, hanging lights (15 W GULIA) for the seating area, and recessed-mounted lights (Airam 34 W) in 6-pieces for the east zone area.

Table 3. Description Overview of Strategy-2

Table 4 provides detailed information on the selected luminaires for each scenario, as specified in the manufacturer’s catalog. Each scenario utilizes different lighting fixtures to enhance ambient lighting, increase illuminance levels, and create uniformity zones within the office space. Various factors such as (CRI), power (W), and luminous efficacy are considered. Direct/indirect luminaires are used in accordance with the (Guide 2019) to improve the overall ambient lighting system.

Table 4. Luminaires lists & properties catalogue-Strategy-1

7 Simulation Results

7.1 Stratgy-1

Table 5 shows the simulation results for the base case scenarios, including the calculation of the working plane area and energy consumption values. The office lighting achieved the minimum illuminance target of (661 lx) while consuming 4400 kWh per year. The false color-contour distribution layout revealed the need to rearrange the existing light distribution to distinguish between different zones and achieve optimal illuminance levels in each zone. In Scenario-2, the lighting performance varies from the base case, simulation results indicates that the working plane does not meet the minimum lux target (461 lx) and energy consumption increased to 3050 kWh per year due to a reduction in task lighting.

Table 5. Simulation Results and Documentation for the Base-Case Strategy-1

7.2 Stratgy-2

The working plane of Scenario-A meet the minimum lux target of (548 lx), with lower energy consumption of 3850 kWh per year compared to the reference case as shown in Table 6. The zoned concept over the task area is clearly noticeable, created a well-lit group work environment. Scenario-B also meet the minimum lux target of 516 lx, with lower energy consumption of 4100 kWh per year. The remaining circulation areas and seating areas were also well lit, as demonstrated by the false color scale. The contour false color of each zone complied with the illuminance level for circulation and task areas, with a different zoning layout distribution due to the different arrangement of compact line luminaires. Scenario-C features a wider and more expanded layout distribution of task lighting using flexible batwing luminaires. The working plane in Scenario-C achieves the minimum lux target (565 lx), with energy consumption of 3900 kWh per year, lower than the reference case.

Table 6. Simulation Results and Documentation for Proposed Strategy-2 I Three-Scenarios

This study determined the most effective lighting solution for uniformity in workspace. Table 7 summarizes the final simulation results of entire scenarios. The research offers valuable insights for creating effective lighting strategies in offices, ensuring adequate illuminance, uniform lighting distribution, and acceptable ambient light levels to optimize lighting conditions in an open office.

Table 7. Final summary & comparison results

8 Conclusions

Innovative lighting strategies enhance lighting performance, occupant well-being and efficient energy consumption in offices. Optimal artificial lighting design is crucial for achieving the desired illuminance levels. The study identified specific zones (accent light seating zone, task area, and circulation zones) and ensuring minimum target illuminance levels, uniform lighting distribution, and acceptable ambient light levels to optimize lighting conditions in an open office space. Considering many factors such-as luminaire type, layout distribution, and quantity influence illuminance levels and visual quality. Different lights in open office layouts require various settings compared to typical small area. The comparison between the base case and proposed scenarios reveals significant differences in light distribution contour over the task area. Base case has the highest lux-level 661lx but accounts the highest energy consumption 4400–6850 kWh/year due to high quantity of luminaires with 39 W power for each, while Scenario-2 achieves the lowest energy consumption but failed to meet the required lux level by 461lx. The 2^nd-strategy of 3-scenarios focused on choosing a flexible light generating different layouts distribution over the task workspace to enhance the overall results, light distribution and reduces energy consumption. Each alternative solution switched the current- recessed lights of the base case with new minimalist light type suspended lights varies in power, shape, CRI ranging (85–100) and high luminous efficacy. Task lighting was majority suspended at different heights with direct/indirect light and high efficiency up to 120 lm/W. The linear arrangement with batwing-shaped distribution Scenario-C achieves an acceptable illuminance level of 565lx, resulting in a reduction of approximately 10.9% compared to the regular arrangement of the base case.

Many factors such as luminaire type, mounted light approach, quantity, layout distribution, and luminance efficacy influence illuminance lx-level and visual quality. Higher luminance efficacy leads to better visual conditions, energy efficiency, and lower energy consumption. Considering multiple factors is crucial for designing lighting systems that achieve optimal energy consumption and visual performance. Noticeable differences appearance and visual impact of each scene are influenced by uniformity, color, distribution, and lighting. Key factors affecting overall visual scene outcomes are the type, number, arrangement, and layout distribution of luminaires. Final results revealed that various LED luminaires with different characteristics could create flexible lighting layouts. Designing a workspace lighting system involves considering illuminance, color temperature, CRI, and energy efficiency. Appropriate illuminance levels depend on function and area size. Color temperature affects the warmth or coolness of light; lower temperatures (2700 K–3000 K) create a warmer, yellowish light and higher temperatures (4000 K–5000 K) create a cooler, bluish light. A CRI of 80 or higher is preferred for accurate color representation.