Applies to QESTLab, QEST Web App (QWA)

Types of Particle Size Distribution Tests

Particle Size Distribution (PSD) tests can be classified, on the basis of the method used, as either direct or indirect tests.

Direct Tests

Direct PSD tests are those that use laboratory sieves to mechanically “measure” the particle sizes present. This is the most common form of PSD test likely to be encountered. Tests of this type are commonly referred to as “Sieve Tests” or “Sieve Analysis Tests”.

Test methods for determining the amount of fines present, by washing a sample over a single sieve, are a sub-group of this type of PSD test. Example

Indirect Tests

Indirect PSD tests are those that typically rely on Stokes Law to estimate the particle sizes. PSD tests of this type include:

• Hydrometer tests

• Pipette tests

• Decantation tests

• Centrifuge tests.

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