1. What is DDA Ramp Gradient?

The DDA (Disability Discrimination Act) ramp gradient calculation determines the slope percentage of accessibility ramps. It ensures ramps meet accessibility standards for wheelchair users and people with mobility impairments.

2. How Does the Calculator Work?

The calculator uses the DDA gradient formula:

Where:

• \( \text{DDA Ratio} \) — The ramp ratio expressed as 1:run (e.g., 1:12)
• \( \text{Gradient %} \) — The resulting slope percentage

Explanation: The formula converts the DDA ratio into a percentage gradient, making it easier to understand and verify compliance with accessibility standards.

3. Importance of DDA Compliance

Details: Proper ramp gradients are essential for wheelchair accessibility, safety, and legal compliance. Steep gradients can be dangerous and difficult to navigate for people with disabilities.

4. Using the Calculator

Tips: Enter the DDA ratio as a single number (e.g., for 1:12 ratio, enter 12). The calculator will automatically compute the corresponding gradient percentage.

5. Frequently Asked Questions (FAQ)

Q1: What is the maximum allowable DDA ramp gradient?
A: Typically 1:12 (8.33%) for maximum rise, with 1:20 (5%) preferred where space permits.

Q2: Why is gradient percentage important?
A: Percentage gradients provide a standardized way to measure slope steepness and ensure compliance with accessibility codes.

Q3: How do I measure DDA ratio in the field?
A: Measure the vertical rise and horizontal run. Ratio is calculated as run divided by rise (e.g., 12:1 run-to-rise = 1:12 ratio).

Q4: Are there different requirements for different ramp types?
A: Yes, requirements may vary for approach ramps, landing areas, and turning spaces. Always consult local building codes.

Q5: What about ramp landings and handrails?
A: Landings are required at top, bottom, and turns. Handrails are typically required for ramps steeper than 1:20.