Designers use lighting layers to create a comprehensive lighting plan for a space. These layers include:

Task Layer: Provides focused illumination for specific activities, such as under-cabinet lighting in a kitchen.
Focal Layer: Highlights particular features, like a fireplace, drawing attention to them.
Ambient Layer: Offers general background lighting that affects the overall brightness of the space.
Decorative Layer: Adds visual interest and style through ornamental lighting elements.
Daylight Layer: Utilizes natural sunlight to enhance the space.

By combining these layers, designers achieve both aesthetic appeal and functional efficiency in lighting design.

The Lighting Specification Process

Lighting architect outlines the steps for creating a quality lighting specification package. Performance specifications detail both the quantifiable and qualitative aspects of a lighting product, often accompanied by product data or manufacturer catalog sheets. This allows for broader product consideration and more competitive pricing.

Specification Preparation: Lighting specifications must be continuously updated to match project milestones and design changes, ensuring clarity and accuracy for proper bidding. This involves evaluating products, preparing lighting calculations, obtaining quotes, and coordinating design details throughout various project phases.

Team Communication: Lighting affects every part of a building, necessitating extensive coordination with a diverse team, including architects, interior designers, and engineers. Effective communication is crucial for integrating design changes and maintaining accurate specifications.

Review Process: After finalizing specifications, the process includes bidding, reviewing shop drawings, samples, and mock-ups to ensure compliance with performance criteria. Mock-ups and reference projects help verify product characteristics.

Substitution Considerations: Substituting fixtures is generally discouraged due to potential issues with performance, design compatibility, and overall lighting effect. Proper fixture selection involves careful planning and coordination to avoid discrepancies.

Interior lighting service refers to the installation, maintenance, and management of lighting systems within buildings and vehicles. The primary function of interior lighting service is to ensure that lighting within a space is effective, efficient, and meets the needs of the occupants. Here’s a breakdown of its key functions:

1. Illumination: The most basic function is to provide adequate light for visibility and activities within the space, whether it’s a home, office, or vehicle interior. Proper illumination enhances comfort, productivity, and safety.

2. Aesthetics: Interior lighting can be used to enhance the visual appeal of a space. This includes creating ambiance, highlighting architectural features, and setting the mood for different activities.

3. Safety and Security: Adequate lighting helps prevent accidents by ensuring that all areas are well-lit, reducing the risk of trips, falls, and other hazards. In security-sensitive areas, lighting can deter intruders and ensure visibility for surveillance systems.

4. Energy Efficiency: Modern interior lighting services focus on energy-efficient solutions, such as LED lighting, which reduces energy consumption and lowers utility costs while maintaining optimal illumination levels.

5. Customization and Control: Advanced lighting systems allow for customization and control, such as adjusting brightness levels, changing color temperatures, and automating lighting schedules to match the needs of the occupants.

6. Compliance with Regulations: Interior lighting services ensure that the lighting systems comply with local building codes and regulations, particularly regarding safety standards and energy efficiency requirements.

Overall, interior lighting service plays a crucial role in enhancing the functionality, safety, and aesthetic appeal of indoor spaces.

4.1.1.Aims of Good Lighting

Good lighting is necessary for all buildings and has three primary aims. The first aim is to promote work and other activities carried out within the building; the second aim is to promote the safety of the people using the building; and the third aim is to create, in conjunction with the structure and decoration, a pleasing environment conducive to interest of the occupants and a sense of their well-being.

4.1.1.1.Realization of these aims involves:

a) careful planning of the brightness and colour pattern within both the working areas and the surroundings so that attention is drawn naturally to the important areas, detail is seen quickly and accurately and the room is free from any sense of gloom or monotony;

b) using directional lighting where appropriate to assist perception of task detail and to give good modeling;

c) controlling direct and reflected glare from light sources to eliminate visual discomfort;

d) in artificial lighting installations, minimizing flicker from certain types of lamps and paying attention to the colour rendering properties of the light;

e) correlating lighting throughout the building to prevent excessive differences between adjacent areas so as to reduce the risk of accidents; and

f) installation of emergency lighting systems, where necessary.

3.1 There are several reasons why specialized lighting systems might need to be installed in certain buildings to ensure illumination in case the regular lighting supply fails. Emergency lighting can be classified into three distinct categories, each tailored to serve a specific purpose.

3.1.1 Escape Lighting

Escape lighting is necessary in most types of buildings in order to enable the occupants to leave the interior safely in the event of an emergency.

3.1.2 Safety Lighting

Safety lighting is necessary in those situations where the failure of the normal lighting could place people in danger. The danger may relate to the operator, as in the use of a circular saw or the handling of hot metal, or to others, as in an operating theatre.

In order to prevent panic and enable help to be summoned, safety lighting should always be provided in lifts(elevators).

 3.1.3 Standby Lighting

Standby lighting is provided in buildings where it is decided that, for reasons other than safety, work or activities should be continued in the event of failure of the normal lighting. 

Note that escape and safety lighting are enforced by law in some countries. Standby lighting, on the other hand, is not generally covered by official regulations.

4.2.1 Illuminance

Illuminance refers to the amount of light that falls on a specific surface, which is an important factor in evaluating the effectiveness of a lighting installation. In most environments, this surface is the primary area where activities are performed, often called the “working plane.” For example, in an office, the working plane might be the surface of desks where tasks like reading or writing occur. The level of illuminance on this plane directly impacts how well these tasks can be performed and also affects the overall visual quality and ambiance of the space. Proper illuminance ensures that the space is both functional and visually appealing.

4.2.2 Recommendations on Illuminance

4.2.2.1  Scale of Illuminance

Illuminance levels are essential in determining how well we can see and perform tasks in different environments. For instance, to simply recognize facial features in a room, the light needs to produce a luminance of about 1 candela per square meter (cd/m²). This level of luminance is usually achieved with a horizontal illuminance of around 20 lux, which is considered the minimum requirement for non-working areas, such as corridors or waiting rooms.

When adjusting lighting, a noticeable change in brightness usually requires a difference of about 1.5 times the current illuminance level. This factor is used to create a recommended scale of illuminance levels, which ensures both functional lighting and comfort in various settings. The recommended scale of illuminance includes the following levels: 20, 30, 50, 75, 100, 150, 200, 300, 500, 750, 1000, 1500, and 2000 lux, with higher levels used in more demanding environments, like workspaces or operating rooms.

4.2.2.2 Illuminance Ranges

Lighting requirements can vary greatly depending on the specific conditions of different spaces or the activities performed within them. Because of this variability, it’s often more practical to recommend a range of illuminance levels rather than a single fixed value for a particular type of interior or activity.

Why a Range of Illuminance?

• Varied Conditions: Different rooms or areas used for the same purpose might have different lighting needs. For instance, two offices doing similar work might still need different lighting levels due to differences in room size, wall color, or furniture arrangement.
• Task Variability: Even the same activity might require different lighting depending on specific factors like the importance of accuracy or the contrast of the materials being worked with.

How the Range Works

• The illuminance range is typically defined by three steps from a recommended scale (e.g., 20, 30, 50, 75 lux, etc.).
• Middle Value: This is the standard or recommended level of light for most situations within the range.
• Higher Value: Use this when:
  • The task involves low contrast or dark surfaces, making it harder to see.
  • Mistakes could be costly or difficult to fix.
  • The work requires high precision.
  • Increased productivity or accuracy is essential.
  • The person performing the task has reduced vision.
• Lower Value: Use this when:
  • The task involves high contrast or bright surfaces, making it easier to see.
  • Speed and precision are not critical.
  • The task is performed infrequently.

Application of the Values

• The recommended illuminance levels are provided in a table, which helps to match the lighting needs with specific tasks and activities.
• These values are based on experience, practical use, and the need to balance good lighting with energy efficiency.
• The table values are “service values,” meaning they represent the average light level maintained over time.

Reference Surface

• The illuminance level should always be measured on a “reference surface.” For work-related tasks, this is usually the working plane (like a desk or countertop).
• In some cases, the reference surface could be specific areas like the task zone or might be angled differently if the task isn’t performed on a horizontal surface.
• For general lighting, like in hallways or ambient lighting, the reference surface could be the floor, wall, or another relevant area.
• It’s important to clearly specify which surface is being used as the reference when measuring and setting lighting levels.

This approach allows for flexibility in lighting design, ensuring that the space is well-lit according to its specific needs while also being energy efficient.

4.3 Luminance Distribution on Major Room Surfaces

Luminance distribution refers to how light is spread across different surfaces within a room, and it’s crucial for achieving effective and comfortable lighting. Here’s what to consider:

1. Luminance of Tasks and Surroundings: The lighting should be sufficient not just on the surface where tasks are performed (like a desk or work area), but also in the areas around it. This helps ensure that the entire workspace is well-lit and that there are no dark spots that could hinder visibility or create discomfort.

2. Reflectance of Surfaces: Different surfaces in a room—such as the ceiling, walls, and floor—reflect light differently. Surfaces with high reflectance (like white or light-colored walls) will bounce more light around, potentially reducing the need for higher illuminance levels. Conversely, surfaces with low reflectance (like dark-colored walls) absorb more light, which might require more intense lighting to achieve the desired brightness.

3. Glare Prevention: Glare occurs when light is too intense or poorly directed, causing discomfort or visual impairment. To prevent glare:

   • Control Light Fixtures: Use fixtures that diffuse light evenly and avoid directing intense light sources directly into the line of sight.
   • Manage Window Light: Use blinds, shades, or frosted glass to control the amount of natural light coming through windows and reduce glare from direct sunlight.

In essence, a well-balanced luminance distribution ensures that light is effectively spread throughout the room, enhancing visibility and comfort while avoiding issues like excessive brightness and glare.

4.3.1 Luminance Distribution in the Task Area

When setting up lighting for a task area, it’s important to manage the brightness of both the task surface and its immediate surroundings to ensure good visibility and comfort. Here’s how it works:

1. Task Luminance vs. Surrounding Luminance: The area where you are performing a task (like a desk or workbench) should be brightly lit compared to the surrounding area. Ideally, the brightness (luminance) of the surrounding area should be lower than that of the task itself. It’s recommended that this surrounding luminance be at least one-third of the luminance of the task.

2. Reflectance Ratio: The reflectance of the surfaces around the task (such as the wall or table edge) should be between 30% and 50% of the reflectance of the task surface. For example, if the task surface is very bright, the surrounding surfaces should be somewhat less bright to maintain good contrast and prevent visual discomfort.

This setup helps to ensure that the task area is well-lit, making it easier to see and perform tasks, while the surrounding areas are dimmer, reducing glare and improving overall visual comfort.

4.3.2 Luminance of Ceilings, Walls, and Floors

This section focuses on how the brightness of the ceilings, walls, and floors (referred to collectively as peripheral surfaces) should be managed in relation to the lighting of the task area to ensure good visibility and comfort.

1. Luminance in Peripheral Vision: The brightness of the areas around your main work area (like the ceiling, walls, and floor) should be at least one-tenth as bright as the task area. This helps maintain a visual balance and prevents the surroundings from feeling too dark compared to the task area.

4.3.2.1 Reflectances and Illuminances

To achieve a balanced and comfortable lighting environment:

1. Ceiling Reflectance and Illuminance:

   • Reflectance: The ceiling should have a high reflectance, meaning it should be able to bounce back a lot of light. This helps in reducing the contrast between the light fixtures and the ceiling, making the ceiling appear brighter and less stark.
   • Illuminance: To avoid the ceiling looking too dark, the lighting level on the ceiling should be at least one-tenth of the lighting level on the task area. This ensures that the ceiling remains adequately lit, complementing the main task lighting.

2. Illuminance Ratio:

   • The ratio of the lowest to the average level of light in the space should not be less than 0.8. This means that the difference between the brightest and darkest areas of the room should be within a certain range to avoid extreme contrasts.

3. General Area Illuminance:

   • The average light level in general areas of a working interior (like the rest of the room) should be at least one-third of the light level in the specific task areas. This helps maintain consistent lighting throughout the space, avoiding areas that are too dark compared to where tasks are performed.

4. Adjacent Interiors:

   • The difference in average illuminance between adjacent rooms or areas should not exceed a ratio of 5:1. This ensures that lighting levels are consistent across different spaces, avoiding stark contrasts that could be jarring or uncomfortable.

In summary, these guidelines help ensure that lighting is evenly distributed and visually comfortable throughout a space, balancing the brightness of different surfaces and maintaining consistency between different areas.