Evaluating Natural Lighting as a Criterion for Healthy Spaces in Early Childhood Buildings

A healthy space is defined as a space that promotes healthy behavior, provides health support to people, and takes into consideration the health needs of sensitive groups, such as children and the elderly, and the individual's circadian rhythm, especially through the design of thoughtful natural lighting [4]. It is a supportive space for improving the quality of life, reducing stress, and enhancing mood, given that natural lighting is one of the most important health needs of its users [5]. Therefore, natural lighting is an important and primary indicator in assessing the aesthetics of architectural spaces. It has been included in LEED, WELL, and BREEAM ratings as an important indicator of health [6]. It provides physical and mental support, enhances comfort, and increases children's focus during daily activities. It also improves children's visual perception [7]. We can say that a healthy space for children is an architectural space designated for children that has sufficient natural lighting that supports the child’s physical, mental, and behavioral development.

This study adopted a quantitative analytical approach to evaluate the efficiency of natural lighting in selected architectural spaces within early childhood environments. The research methodology combined architectural analysis with digital simulation techniques for natural lighting to assess its distribution and performance under different design conditions.

Architectural plans were prepared using AutoCAD software and then analyzed using Velux Daylight Visualizer software to simulate the performance of natural lighting [16]. The simulation studied the effect of window sizes, depth of space, and seasonal changes on light distribution within interior spaces, comparing them to the health standards of the theoretical framework. This led to the classification of spaces and lighting quality in the study building sample, along with proposed design treatments and solutions. This is due to the importance of window design, shape, and dimensions in the space, as well as the glass's transparency and its performance in providing natural light within the space [17].

The University of Mosul Nursery building was established in 1978 within the university campus; it welcomes children of university staff. It was renovated and reopened with support from the United Nations (UNDP). It receives children of university staff, with a capacity of 180-200 children, and this number can be increased along with the staff who care for them (Figure 1) [19].

Figure 1. Building plan, ground floor

The children’s time at the nursery is distributed from 8:30 for breakfast to 9:30, then recreational time and lessons begin at 10, then at 11 a second meal, and the sleep period is at 11:30 or 12 noon.

The building comprises two sections:

• The oval section of the building is for children aged one month to one and a half years. Each bedroom accommodates 13-15 children, and the beds measure 1 meter by 70 centimeters.
• The rectangular section of the building houses the kindergarten and nursery. Each bedroom accommodates 25 children. The beds in the bedrooms are typically bunk beds measuring 180 meters by 90 centimeters.

The research relied on coding the building's constituent spaces according to function and effectiveness within each space. Please note that the analysis will be limited to the ground floor only, as shown in Table 1. These spaces included sleeping areas, learning spaces, and dining areas. Each of these spaces was subsequently analyzed and its details clarified in detailed tables that included the shape of the space, the number of spaces on each floor, the area of the space, the orientation of the space, and the length and number of windows in the space. The research also relied on an analysis of the architectural spaces (bedrooms, learning spaces, and dining rooms) in terms of area, orientation, and lighting and ventilation openings, as follows:

1. Bedrooms (B.R)

The bedrooms are distributed across three floors with consistent sizes but varying orientations:

Area: Each bedroom measures 23.3625 m².

Ground Floor:

Model (A1/1) faces north with a 3-meter window opening onto the light well.

Model (B1/1) faces west with a 2-meter window opening onto the light well.

Models (B1/3) and (B1/4) feature southeast and east orientations, respectively, with windows ranging from 0.9 to 2 meters wide and overlooking the outside.

First and Second Floors: Each floor contains four rooms of Model (A1/1) with a consistent north orientation.

2. Learning/Living spaces (L.R)

The tables demonstrate the flexibility in using these spaces, sometimes referred to as living rooms and sometimes as learning spaces:

Standard Area: 23.362 m²

Ground Floor Layout:

There are 4 units of the model (A1/1) facing south with a 3-meter window and a view to the outside.

There are 2 units of the model (A1/2) facing north with a view of the light well.

Model (A1/3) features an extra-large window, up to 5.1 meters wide, and a south-facing view to the outside.

Corner Models (B1): These are distributed in northwest-facing directions with a view to the light well, northeast-facing directions to the outside, and southwest-facing directions with various window openings to the light well.

Repeated Floors: These include 4 units distributed between north and south-facing directions to ensure cross-ventilation or different lighting options. 

3. Dining rooms (D.R.)

The dining rooms were designed with a focus on their relationship to the exterior spaces or skylights:

Area: 23.3625 m²

Ventilation Elements:

Model (A1/1) overlooks an open shaft to the north.

Models (A1/2) and (A1/3) overlook directly to the outside (south) with windows up to 5.1 m.

Repeated Floors: The dining rooms continue to have north-facing (via the shaft) and south-facing (outside) orientations (Table 1).

Table 1. Details of the different spaces in the building

From Table 2, two types of architectural window configurations can be observed:

Regular configuration (Block A): Shown in space (D.R A1/1), which is a 3 m × 1.5 m floor plan.

Organic/curved configuration (Block B): Shown in models (B1/3) and (B1/4), where the windows take on a trapezoidal or arched shape with an area of 1.5 m × 0.9 m, or a circular shape with an area of 2 m × 1.5 m, overlooking green spaces or skylights.

Architectural note: The design is based on a nearly constant unit of area (module) for all uses, with the "sheath shape" and solar orientation varying according to the room's location in the building. The window shapes, which vary between rectangular, sectional, and circular, are illustrated as shown in Table 2.

Table 2. Shapes and dimensions of the opening

The analysis relied on the ground floor (first floor) and measured the lighting percentage, excluding the upper floors, because natural light increases on the upper floors. The AutoCAD and Flex programs were used, following these steps: Each selected nursery space was drawn using AutoCAD 3D, and the space was entered into the Flex program to measure the natural lighting. Lighting levels varied, and each space was measured at 12:00 PM. The selection of the base measurement and simulation point was based on climatic and functional considerations related to the local context of Mosul. Solar radiation intensity and daylight availability usually peak at midday. In addition, children are mainly present in the building during the morning and afternoon hours only. The chosen time represents the most suitable occupancy period, during which children are exposed to the highest level of daylight inside the building. Once on December 21st and once on June 21st, as shown in Table 3, for measuring some of the spaces.

Table 3. Analysis of the efficiency of natural lighting in the studied architectural spaces using the program Velux Daylight

• Providing natural light is essential for creating a healthy and suitable environment for children. This depends not only on the quantity of natural light but also on its quality of distribution, glare control, and its compatibility with the needs of this age group.
• To achieve a healthy environment in nursery buildings, a combination of design strategies and architectural treatments is necessary. Diffused light is the true foundation for visual comfort and eye health in children in various spaces. And here's how, clearly and systematically:

The results from the study sample building showed that variations in the amount of light reaching the spaces necessitate architectural and design solutions, such as the need to use clear windows that receive light from above, rather than directly at eye level.

Also, spaces containing rectangular windows (24-40% window to wall ratio) achieved good lighting; circular windows (16%) achieved average lighting; curved windows (7-14%) achieved poor lighting.

• The possibility of using external shading devices to block direct light and allow only diffused light.

Redesigning spaces overlooking interior areas that have shown poor natural lighting, either due to small window sizes relative to the space or the orientation of the spaces and their views towards the interior, by using glass or semi-transparent partitions that allow light to pass between rooms while maintaining children's privacy. Alternatively, using relatively larger windows facing south with the addition of horizontal blinds and light-filled shelves, and using windows facing east to provide pleasant morning light for children.

The study suggests a future use of frosted or diffused glass in sensitive areas, especially in sleeping spaces. Adopting light, white paint colors for the spaces and minimizing their reflective properties.