Simulations of the hallways on Levels 1 to 4 in Blocks A and B, as well as the main lobby on Level 1 of Block C, were carried out based on the official FTKE building plan. The analysis considered key lighting characteristics, including the color rendering index (CRI) and color temperature of the existing fixtures [20] . For each space, the most suitable lighting configuration was recommended to ensure compliance with the minimum illuminance levels specified in the MS1525 standard [21] . Details of the initial lighting systems for the hallways and lecture halls in Blocks A, B, and C are presented in Table 1 .

Once the lighting fixture is selected, the DIALux Evo software will be used to simulate the number of fixtures required to meet both the minimum recommended lux levels and the maximum allowable lighting power as specified in the MS1525 standard [22] . The simulation will be based on the average illuminance values calculated by the software. Key parameters considered in the analysis include the achieved average lux level (lx), illuminance uniformity, total power (W), total annual energy consumption (kWh/year), and overall energy efficiency [23] . Once all parameters are met, the best lighting configurations with lower power consumption for the hallway are simulated and proposed [24] . Adhering to these guidelines is crucial to prevent eye strain, headaches, and stress. Moreover, proper lighting promotes better health, which in turn boosts productivity and satisfaction [25] . In addition to the amount of electrical current used, the average light level achieved at the work plane also needs to be considered. MS 1525 specified the work plane lux level for hallway and lobby must be at least 100 lux. The annual operating hours and total annual power consumption are also calculated. For this study, the operating hours are assumed to be nine hours per day, five days per week, over fifty-two weeks per year [21] .

According to the simulation results, the new improved lighting configuration system used the least amount of power while meeting all technical requirements. To support its economic viability, an economic analysis is conducted using the TNB tariff for medium voltage commercial buildings (Tariff C1), as shown in Table 2 . The total annual power usage is multiplied by 36.5 sen per kWh to calculate the total cost in Ringgit Malaysia (RM) [26] .

The annual operating hours, assuming nine hours per day, five days per week, and fifty-two weeks per year, are calculated using Equation (1). The total annual power consumption is determined using Equation (2) [27] .

$\begin{array}{l}\text{Annual operating hours}\left(\text{hours}\right)\\ =\text{Daily operating hours}\times \text{Weekly operating days}\times 52\text{weeks}\end{array}$(1)

$\begin{array}{l}\text{Total annual power consumption}\left(\text{W}\cdot \text{h}\right)\\ =\text{Total power consumption}\left(\text{W}\right)\times \text{Annual operating hours}\left(\text{hours}\right)\end{array}$(2)

The areas covered in Block A encompass the hallways of all four levels. To meet the required lux levels as per the MS1525 standard while minimizing power consumption, these areas were designed using DIALux Evo software. Figures 2-5 presents the simulation results for current (before) and the proposed (after) lighting configurations for the hallways (levels 1 - 4), while Table 4 presents the technical analysis of these configurations.

Referring to Table 4 , the proposed lighting configurations for hallway levels 1 and 2 reduced to 9 luminaires per level, compared to the current configuration, which employs 13 luminaires per level. It is shown that the proposed lighting configurations use a fewer number of luminaries while meeting the MS1525 standard of 100 lux for these areas. This change reduced the average lux for hallway level 1 from 149 lx to 104 lx and for level 2 from 147 lx to 103 lx, reducing the total power usage from 208 W to 144 W and annual consumption from 400 kWh/year to 277 kWh/year. On the other hand, for the hallways on levels 3 and 4, the number of luminaires was reduced from 16 to 10 each. These reductions caused the average lux levels to drop from 178 lx to 106 lx for level 3 and from 174 lx to 104 lx for level 4. As a result, the total power usage was reduced from 256 W to 160 W for both level 3 and level 4. The annual energy consumption further decreased from 524 kWh/year to 308 kWh/year for hallway level 3 and from 523 kWh/year to 308 kWh/year for hallway level 4.

Case study 2 focuses on the hallways across all four levels. The lighting design for these hallways was designed using DIALux Evo software to meet the required lux levels as per the MS1525 standard while minimizing power consumption. Figures 6-9 illustrate the simulation results for the existing (before) and proposed (after) lighting configurations for Block B, covering levels 1 to 4, while Table 5 presents the technical analysis of these configurations.

According to Table 5 , the proposed lighting configurations for the hallways on levels 1 and 2 reduced the number of luminaires from 12 to 9 per level. Despite using fewer luminaires, the proposed design still meets the MS1525 standard of 100 lux for these areas. This adjustment lowered the average lux levels from 179 lx to 106 lx on level 1 and from 178 lx to 106 lx on level 2, resulting in a reduction in total power usage from 192 W to 144 W and a decrease in annual energy consumption from 370 kWh/year to 277 kWh/year. Similarly, for the hallways on levels 3 and 4, the number of luminaires was reduced from 16 to 10 per level. This led to a decrease in average lux levels from 173 lx to 109 lx on level 3 and from 169 lx to 107 lx on level 4. Consequently, total power usage dropped from 256 W to 160 W, and annual energy consumption was reduced from 493 kWh/year to 308 kWh/year per hallway.

The Block C covered the main lobby of FTKE only. Figure 10 provides a comparison of the lighting setups of the new and existing lighting configuration systems in order to achieve the minimum lux level according to the standard while minimising power consumption. Table 6 provides a technical comparison between the new and existing lighting systems.

The main lobby of FTKE in block C originally had 45 luminaires, but after reconfiguration to comply with the MS1525 standard of 100 lux, the number was reduced to 22. This adjustment led to a significant decrease in the average lux level, dropping from 235 lx to 115 lx which in turn reduced the total power usage from 720 W to 352 W, and annual power consumption from 1782 kWh/year to 678 kWh/year

Following the simulation results, the total annual power consumption was compared to assessing the electricity costs between the current technique and the proposed technique of the lighting system. Table 7 shows the total electricity bill saving in Ringgit Malaysia (RM).

Table 7 provides a detailed comparison of the annual energy consumption between the current configuration and the proposed configuration across various locations within blocks A, B, and C at FTKE. In Block A, the energy consumption for all four hallway levels decreased from 400 kWh/year to 277 kWh/year for Levels 1 and 2, 524 kWh/year to 308 kWh/year for Level 3, and 523 kWh/year to 308 kWh/year for Level 4. Similarly, in Block B, the energy consumption for all hallway levels dropped from 370 kWh/year to 277 kWh/year for Levels 1 and 2 and 493 kWh/year to 308 kWh/year for Levels 3 and 4, respectively. The most significant reduction occurred in Block C’s lobby, where energy consumption decreased from 1782 kWh/year to 678 kWh/year. Overall, the total annual energy consumption was reduced from 5355 kWh/year to 3018 kWh/year, leading to a decrease in the annual electricity bill from RM 1954.58 to RM 1101.57. This resulted in a total electricity bill saving of RM 853.01 per year.