Non-fragility roof testing is used to assess whether a roof assembly can safely resist the impact of a person stumbling or falling onto it. This is particularly important for roofs formed from potentially brittle or fragile materials, or where there is uncertainty about whether the roof can be safely accessed for inspection, maintenance, or refurbishment.
Testing in Accordance with ACR[M]001:2019
The test is commonly carried out in accordance with ACR[M]001:2019 – Test for Non-Fragility of Large Element Roofing Assemblies, commonly known as The Red Book. The document is based on simulating a human impact event, rather than just applying a static roof load. In simple terms, the test checks whether the roof can arrest and retain an impact load without catastrophic failure.
The Red Book test typically involves dropping a 45 kg cylindrical sandbag from a height of 1.2 m onto selected critical areas of the roof. The impact locations are chosen to represent the most vulnerable areas, such as mid-span, near supports, edges, laps, or other details where failure is considered most likely.
Non-Fragility Roof Assessment
Following impact, the roof is assessed to determine whether the bag is retained and whether any damage, tearing, cracking, delamination, or loss of support has occurred. Under the Red Book, a roof assembly may be classified as fragile or as a Class C, Class B, or Class A non-fragile assembly, depending on its performance during one or more impact tests.
Sandberg can carry out non-fragility roof testing to assess existing roof assemblies, retained roof structures, and refurbishment projects where evidence of roof performance is required. Testing can help determine whether a roof is suitable for continued use, maintenance access, or further investigation.
