Experimental investigation of the governing vibration excitation mechanism in wastewater pipe systems

Structure-borne sound of waste water pipe systems often dominates the noise from sanitary installations in buildings. The drain pipe system is composed of several pipe elements, (1) straight cylindrical section, (2) inlet (T-joint), and (3) bend. When water flows through a pipe system, the vibration is excited by the water fall at the inlets and the bend, and by the turbulent water flow adhering to the inner wall of the pipe elements. The vibration is transmitted to building elements via fixing elements like pipe clamps. This study aims to experimentally investigate the dominant vibration excitation with reference to the flow rate. The physical arrangement of the pipe system is based on the set-up given in standard EN 14366-1, and further modified in order to focus on single excitation source. A total of five different pipe arrangements were tested with four different flow rates. The vibration response of the pipe was evaluated in terms of the blocked force at the fixing point on the wall. The experimental results indicate that the dominant excitation source is dependent on the flow rate. The significance of the flow-induced force on bend increases with the flow rate.