Download - Engineering Surveyor

Sewers and drains: junctionsEstablishing locationWhen setting-out junctions for sewers and drains, the normal procedure is: show the plan location of each junction on a Sewer Information Sheet (and Site Information Sheet asappropriate) express the location of each junction in terms of the numbers of pipes to be placed from a given manholebefore the junction, or the number between junctions measure up the position for later fitting of saddle connections.Note: Specifications often require that the pipe built into the manhole and the next pipe be short pipes to avoidexcessive bending load on the pipe. In the example opposite, the first junction is placed after five pipes (twoshort and three full) and there are three full pipes to the second junction.Estimating angle estimate angle of junction in plan and specify type of junction required on information sheet estimate the angle of each junction in section and classify as flat, medium or steep as shown provide foreman and ganger with copy of the information sheet to begin work.Note: If angles are difficult to determine, seek the supervising authority’s agreement to use saddle connections.Marking before backfilling mark junctions before backfilling for ease of constructing trenches and for making connections measure the ‘as laid’ location of each junction by taping from the inside face of the nearest downstreammanhole record position on ‘master copy’ of Sewer Information Sheet.CIRIA C70959