Slip Testing of Tarmac Surfaces

Pendulum Slip Testing on Tarmac Surfaces: Ensuring Safety and Performance

Introduction

Slip resistance is crucial for maintaining safety on roadways and pedestrian areas, especially when surfaces are wet. Pendulum slip testing is a widely recognized method for assessing the slip resistance of various surfaces, including tarmac. This blog explores the process, significance, and best practices of pendulum slip testing on tarmac surfaces.

What is Pendulum Slip Testing?

Pendulum slip testing involves using a specialized device, often referred to as a pendulum tester, to simulate foot traffic and measure the slip resistance of a surface. The tester swings a rubberized foot (known as a slider) over the surface and measures the friction generated during the test. The results are expressed in terms of a ‘Pendulum Test Value’ (PTV), which indicates how slippery a surface is under specific conditions.

Why Test Tarmac Surfaces?

Tarmac, commonly used in roads, driveways, and car parks, can become slippery due to rain, ice, or the accumulation of debris. Ensuring that tarmac surfaces meet slip testing safety standards is essential to prevent accidents. Pendulum slip testing testing helps:

1. Assess Safety: Determine if the surface provides adequate grip for vehicles and pedestrians.
2. Comply with Regulations: Many organisations such as the Highways Agency have regulations that mandate slip resistance testing to ensure public safety.
3. Guide Maintenance: Identify surfaces that may require resurfacing or treatment to improve slip resistance.

The Testing Process

1. Preparation: Ensure the surface is clean and free from contaminants. Slip testing should be conducted under controlled conditions, ideally including when the surface is wet, to mimic real-world scenarios.
2. Equipment Setup: Position the pendulum tester on the tarmac surface. The tester consists of a swinging arm with a slider, typically made from a specific rubber compound, that contacts the tarmac.
3. Conducting the Test: The tester swings the arm down, allowing the slider to make contact with the surface. The force required to stop the pendulum is measured, giving a PTV score.
4. Multiple Tests: For accuracy, conduct multiple tests across different areas of the surface to account for variability in texture and condition.
5. Data Analysis: Analyze the PTV scores. A higher PTV indicates better slip resistance. Values below a certain threshold (commonly 55 or 36) may be deemed unsafe.

Interpreting Results

• High PTV (36 and above): Indicates good slip resistance, suitable for wet conditions.
• Medium PTV (25-35): May require caution, especially in wet weather.
• Low PTV (below 25): Suggests a high slip risk; consider maintenance or resurfacing.

Best Practices for Effective Slip Testing

1. Regular Testing: Conduct slip resistance tests periodically, especially after significant weather events or surface alterations.
2. Document Conditions: Record weather conditions during testing (e.g., temperature, humidity) for context.
3. Professional Assessment: Consider hiring professionals with expertise in pendulum testing for accurate results and recommendations.
4. Follow Standards: Adhere to recognised testing standards, such as BS 7976 and EN 13036-4, to ensure reliability and compliance.

Pendulum slip testing is an essential process for evaluating the safety of tarmac surfaces. By understanding and implementing this testing method, property owners, civil engineers, and safety bodies can significantly enhance safety for all users. Regular assessments not only ensure compliance with regulations but also foster a proactive approach to surface maintenance, ultimately preventing accidents and promoting safer environments.