The Ceiling Cavity Ratio (CCR) is a measurement in lighting design that describes the ratio of the ceiling to the fixtures . It is used to determine how light is reflected between the ceiling and the rest of the space , which affects the efficiency and uniformity of the lighting.
1. How is the CCR calculated?
The Ceiling Cavity Ratio (CCR) is calculated using the following formula:
whereby:
- = the height of the ceiling cavity (distance between the fixtures and the ceiling).
- = the width of the room.
- = the length of the room.
📌 What does this formula mean?
- A high CCR value means there is a lot of space between the fixtures and the ceiling, leading to more light loss and less efficiency.
- A low CCR value means that the fixtures are placed closer to the ceiling, resulting in more reflection and better light distribution .
2. Why is the Ceiling Cavity Ratio important?
✅ Determines the lighting efficiency → How well the ceiling contributes to light reflection.
✅ Influences light uniformity → Helps reduce shadows and dark areas.
✅ Essential for indirect lighting → Especially in offices and large halls where light is reflected from the ceiling.
✅ Used in the Coefficient of Utilization (CU) → An important factor in energy saving and lighting calculations.
📌 In rooms with high ceilings (e.g. industrial halls), the CCR is used to determine whether additional reflection or more powerful luminaires are necessary.
3. Applications of the CCR
🏢 Offices and workplaces → Optimize ceiling reflection for a comfortable working environment.
🏪 Shops and showrooms → Balanced light distribution across products and presentation areas.
🏗 Industrial buildings and warehouses → Ensures that workplaces are well lit, even with high ceilings.
🏠 Residential lighting → For modern architecture with high ceilings, CCR helps with the right lighting choice.
📌 A good CCR design prevents unnecessary light loss and improves overall lighting efficiency.
4. Difference between CCR, RCR and FCR
| Ratio | What does it measure? | Application |
|---|---|---|
| Ceiling Cavity Ratio (CCR) | Light reflection between ceiling and fixtures | Optimization of ceiling reflection |
| Room Cavity Ratio (RCR) | Light reflection between ceiling and work surface | General lighting efficiency |
| Floor Cavity Ratio (FCR) | Light reflection between floor and work surface | Assessment of light absorption through the floor |
📌 These three ratios together help to design a balanced and energy-efficient lighting solution.
💡 In short:
The Ceiling Cavity Ratio (CCR) is a key metric in lighting design that determines how light is reflected between the ceiling and fixtures . A good CCR design helps with energy savings, light uniformity, and optimal lighting efficiency , especially in offices, retail, and industrial spaces .