This document specifies a method to determine the compressibility of sludges, conditioned or not.This document is applicable to sludges 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 and sludge suspensions of other origin.