1. What is Room Cavity Ratio?

Definition: The Room Cavity Ratio (RCR) is a unitless number that describes the proportions of a room in terms of its height, length, and width.

Purpose: It's primarily used in lighting design to determine how light will interact with room surfaces and to calculate light loss factors.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RCR \) — Room Cavity Ratio (unitless)
• \( H \) — Room height (meters)
• \( L \) — Room length (meters)
• \( W \) — Room width (meters)

Explanation: The formula accounts for the relationship between room height and its floor dimensions, which affects light distribution.

3. Importance of Room Cavity Ratio

Details: RCR helps lighting designers:

• Determine appropriate light fixture placement
• Calculate utilization coefficients
• Estimate light loss factors
• Design efficient lighting systems

4. Using the Calculator

Tips: Enter the room dimensions in meters. All values must be greater than 0. Typical RCR values range from 1 (large, low rooms) to 10 (small, tall rooms).

5. Frequently Asked Questions (FAQ)

Q1: What's a typical RCR value?
A: Most offices have RCR between 3-5. Classrooms are typically 4-6, while warehouses may be 1-3.

Q2: How does RCR affect lighting design?
A: Higher RCR means more light is absorbed by walls, requiring more luminaires or higher output fixtures.

Q3: Can RCR be used for non-rectangular rooms?
A: For irregular rooms, use equivalent length and width that would give the same floor area.

Q4: What's the relationship between RCR and ceiling cavity ratio?
A: CCR is calculated similarly but uses the height from luminaires to ceiling rather than floor to ceiling.

Q5: Why is the constant 5 used in the formula?
A: The 5 comes from the standard calculation method in lighting engineering to normalize the ratio.