When is it necessary to replace the porous filter for CPTu tests? December 06, 2025 14:34 Updated The sintered bronze porous filters are single-use and must therefore be replaced after each test. Related to CPTu Piezocone S-CPTu Related articles When is it necessary to replace the saturated test ring with grease for CPTu tests? When is it necessary to replace the tip (Qc) and the friction sleeve (Fs) of the piezocone? What is the correct procedure to prepare a P-C series piezocone in order to perform a test? What is an encoder and what is it used for during CPTu and S-CPTu tests? What are porous filters or filtering elements for CPTu tests?