This British Standard, a section of the BS 812 series, describes methods for determining the flakiness index of coarse aggregate.
Aggregate particles are classified as flaky when they have a thickness of less than 0.6 of their mean sieve size. The flakiness index of an aggregate sample is found by separating the flaky particles and expressing their mass as a percentage of the mass of the sample tested. The test is not applicable to material passing a 6.30 mm BS test sieve or retained on a 63.0 mm BS test sieve.