ASTM D7233-08Standard Test Method for Testing Fracture of Level Paintbrush Filaments
This test method covers a procedure for determining the number of fractures present when paintbrush filaments are bent.
This method is applicable only to monofilaments with consistent longitudinal cross sectional dimensions commonly referred to as level filaments.
The values derived are in percent fractured filaments. For example, 2 fractured out of 18 filaments tested = ²/18 or 11 %.