Which factors affect the shock absorption of loose safety materials such as gravel, wood chips or bark mulch?

According to EN 1177, the shock absorption of loose safety materials such as gravel, wood chips or bark mulch is significantly influenced by moisture, compaction and temperature. An adequate layer thickness is also crucial to ensure effective fall protection. Since loose fills like gravel or wood chips can become dirty, weathered or decompose, it is important to regularly check, top up or replace them to maintain the required safety level.