The objectives of fracture control for pipelines include:

Maximise the likelihood that a defect will remain stable and not progress to a rupture; this is achieved by providing adequate toughness in both the pipe body and the longitudinal weld (fracture initiation control).
Ensure that brittle fracture can never occur by providing sufficient toughness in the steel at the minimum temperature the pipe will encounter (brittle fracture control); the drop weight tear test is used to assess whether fracture at the minimum design temperature is brittle or tearing (ductile).
Ensure that a ductile fracture will be arrested rather than propagating, again by providing sufficient toughness (tearing fracture control); toughness for tearing fracture control is assessed by the energy absorbed in the Charpy impact test.