Dear Sridhar, for HDPE Pipes ...
Published by Marta Dutschmann da Silva Gomes, Managing partner at WASE
Dear Sridhar, for HDPE Pipes above DN300 traditional methods aren't the most appropriate. If you can find a publishing from IWA named "Leak detection, technology and implementation" you will find technology matrices for each Pipe Material.
For HDPE Piplines, you can find that the recommended technologies for DN