60 of 74  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Sludge pipes : Stainless steel 1.4404 (section inside the  buildings)  CHP – Boiler – hot and cold water piping  : Stainless steel 1.4404  Discharge, overflow and drainage pipes  : Corrugated PE, Reinforced concrete, box  (for pipes with diameter > 1600 mm)  Service water pipes : HDPE (PE100) or PPRC Sewage pipes inside the buildings : HDPE PE100  Chemical Lines : HDPE, PP The following flow velocities for the each individual media shall be used.  Pipe Velocities 3_Vol3_d4.3_Section 3_Plant Description_GIR_rev08  Media  Velocity  Wastewater  Gravity flow   0.6 m/s at average flow  Pressure flow   2.5 m/s at maximum flow  Sludge  Gravity flow   0.6 m/s at average flow  Pressure flow   1.8 m/s at maximum flow  Biogas  3.5 m/s at maximum flow  Compressed air  for DN    600   12 m/s  for DN300 – DN600  10 m/s  for DN 75 – DN250   8 m/s 