This Technical Report specifies procedures for validating characterization methods for physical properties of sludge.This Technical Report is applicable to sludge and sludge suspensions from:- storm water handling;- urban wastewater collecting systems;- urban wastewater treatment plants;- treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271/EEC);- water supply treatment plants.This method is also applicable to sludge suspensions from other origin.