Instruction for installation of manholes:  HDPE manholes need a well compacted bedding and sidefill made with fine grain loose soil       « Versione Italiana HDPE corrugated pipes Company Quality and environment Products Presentation Conduits Drainages Sewage Manholes . Price-list Branches Art and culture News Contacts How to reach us Privacy Map and guide Restricted area Manufacturer of polyethylene manholes. HDPE manholes easy to install. Sewer manholes, absorbing manholes, moulded base manholes perfect tightness even when the pipe is misaligned   Manholes  |  Manholes installation INSTRUCTIONS FOR INSTALLATION Like the flexible pipes, the PE manholes need a well compacted bedding and sidefill made with fine grain loose soil (coarse sand and fine gravel). This bedding must be accurately compacted to limit the settlement on the surface surrounding the manhole and compaction can be easily obtained using simple equipment for compaction.  Besides, the use of loose soil for the trench backfill eliminates the risk of road surface expansion and shrinkage due to the water content variation (variation of the groundwater levels) which is the main cause of road surface strain. back to Manholes Industrie Polieco - M.P.B. S.r.l. Structured polyethylene pipes for conduits, sewer and drainage systems Palbox Industriale S.p.A. Management and coordination ex-art. 2497 of Civil Code: Industrie Polieco-Mpb S.r.l. Polyethylene pipes for pressure system (water, gas and sewer system) Internet partner: Sigla.com [www.sigla.com]