Norm-based screening

Practice-based criteria are intended to capture the actual corporate behaviour and not just the corporate commitments. As for policy-based criteria, the practice-based ones are generally aimed at capturing human rights violations by companies. This specific type of exclusion is also sometimes called norm-based screening. 

Surfactant testing and reagent screening can be performed in a variety of ways. The simplest and most common technique used in the petroleum industry is the standard blender test [7]. Other test methods [4] include Ross-Miles foam height test, flow loop testing, capillary foam testers, contact angle measurements, tensiometers and actual field evaluations. Due to its low cost, easy duplication and ability to be used in the field, blender testing has become the norm in the industry for foam based fluids. 

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