Below ground drainage systems installation guide

1 CI/SfB( )In6 OCTOBER 1999 OUIG4 Below ground drainage SYSTEMSINSTALLATION GUIDECONTENTS PAGEB elow ground drainage SystemsResources and Planning4 Transport4 Handling4 Storage5 installation Notes6 Excavation6 Bedding6-7 Backfill Sequence8 Pipe Protection8-9 installation of TwinWall Pipes10-11 OsmaDrain SystemContents12 installation Information13-34 Osma UltraRib SystemContents35 installation Information36-45 Wavin TwinWall SystemContents46 installation Information47-49 Below ground drainage SystemsTesting50 Safety50 Maintenance50 General Information51 Acceptance52 Abbreviations52 Below ground drainage SYSTEMSC ontents3 Below ground drainage systems installation GUIDET able 1. Size of Block BundlesNominal Number ofDimensionsWeightPipe3m/6m lengthsin mmper bundle kgSizeper bundleheightwidth3m6mOsmaDrain1105072511 45246492160258651035230460 Osma UltraRib15024655970158304225127309701733 273009966970227 Wavin TwinWall1503311801000-2972251411801000-2 35300811801000-264 RESOURCES AND PLANNINGThe main contractor, or sub-contractor.

2 Needs no special equipment or are responsible for checking lay-out drawings to ensure they are correct so thatexpensive site alterations do not have to bemade after may make up OsmaDraincomponents such as gully assemblies off-siteand in clean working conditions - particularlywhen components have solvent welded made from PVC-U and/or HDPE arelightweight between one sixth and one tenththe weight of equivalent clay , care must be taken duringtransport, handling and BundlesGenerally, pipes are delivered pre-packed inblock bundles of standard quantities. In thesebundles, pipes are held by straps and Pipes and FittingsWhen vehicles with a flat bed are used fortransporting loose pipes, make sure the bed isfree of nails and other pipes throughout their length.

3 Loadpipes so that they do not overhang the vehicleby more than one load pipes with larger diameters andthicker walls before those of smaller diametersand thinner walls. Pipes should always be liftedoff the vehicle, not dragged, thus avoidingdamage to the sure vehicles have adequate sidesupports at approximately 2 metre spacings,and that all uprights are flat, with no sharpedges. Secure pipes during are supplied in cardboard boxes orplastic 1. Transport of loose pipesHANDLINGA lways be careful to avoid damage whenhandling pipe. Cold weather reduces theirimpact strength, so take extra care whenhandling pipe in wintry unloading block bundlesmechanically, use either nylon belt slings or forklift trucks with smooth forks.

4 Metal slings, hooksor chains must not come into direct contact withthe and unload loose pipes by hand andavoid using skids. When loose pipes have beentransported one inside the other, always removethe inner pipes not drop or drag of block bundlesBELOW ground drainage SYSTEMSR esources and Planning, Transport and Handling4 Below ground drainage systems installation GUIDEBELOW ground drainage SYSTEMSS torageSTORAGEB lock BundlesStore block bundles on a reasonably flatsurface free from sharp projections likely todamage the bundles can be stored up to threehigh without extra side supports or bearers. Inaddition, block bundles will remain free standingwhen care when removing pipes frombundles as the straps are under considerabletension and may flail when of loose pipes on the groundFigure 4.

5 Storage of loose pipes on bearersLoose PipesStore loose pipes on a reasonably flatsurface free of sharp projections. Provide sidesupports at least every 2 metres. Thesesupports should preferably consist of battensat least 75mm wide (see Figure 3.)Ideally, loose pipes should be uniformlysupported throughout their entire length. If this isnot possible, place timber supports at least75mm wide at 1 metre maximum centresbeneath the pipes (see Figure 4).Stack pipes of different size and wall thicknessseparately. If this is not possible, stack pipeswith larger diameters and thicker walls underthose with smaller diameters and thinner pipes should be stacked withthe sockets protruding and placed atalternate not stack pipes more than seven layersin height or above a maximum height of fittings supplied in plastic bags awayfrom direct fittings have to be stored outside in theirplastic bags, open the bags to prevent abuild-up of above storage requirements apply tothe United Kingdom climatic conditions.

6 Intropical climates reduce the stack height andstore pipes and fittings under cover or in Ringsa) OsmaDrainWhere applicable, OsmaDrain 110mm and160mm sockets are supplied complete witha captive ring ) Osma UltraRibSealing rings are supplied either loose withpipes and fittings or pre-fixed in the case ofInspection Chamber and Manhole Basesand are included in the ) Wavin TwinWallSealing Rings are supplied loose with pipesand fittings if required, all pipe and fittingprices are exclusive of ring seals, and musttherefore be ordered separately. Rings should be stored in their originalpackaging away from strong sunlight orweathering. They should never be placed onthe end of the pipes which are being ground drainage systems installation GUIDE2m2m or 7 layers maximum1m spacing maximum75mm bearing widthINSTALLATION NOTESThe information included on this page isbased on the recommendations given in BS5955: Part 6: 1980 Code of Practice for PlasticsPipework ( installation of unplasticized PVCpipework for gravity drains and sewers), BS8301: 1985 Code of Practice for BuildingDrainage, Water Industry Specification (WIS), No4-08-02 (Specification for bedding and sidefillMaterials for buried Pipelines) and British Boardof Agr ment Certificate Nos 87/1835: 89/46,89/2268, 90/2563 and 91 and backfill must be of the correctspecification.

7 Excavated as-dug material maybe suitable (see BS 5955: Part 6: 1980 for as-dug suitability tests), otherwise a non-cohesivematerial is required (see Table 2).EXCAVATIONIt is important to take precautions againsttrench collapse. Do not open trenches too far inadvance of pipe laying. Support the sides oftrenches that are deeper than metres. Keeptrench widths as narrow as practicable but notless than 300mm wider than the pipe diameter, 150mm clear each side of the pipe to allowproper compaction of the for Manholes andInspection ChambersAdditional excavation is necessary for:a. Traditionally constructed OsmaDrain/Osma UltraRib 750mmManhole BasesOsmaDrain and Osma UltraRib 250mm /300mm / 450mm diameter Shallow / Multi-Base /Universal Inspection Chambers need noadditional excavation other than that required fornormal drain and Osma UltraRib pipeslaid on trench bottomWhere the as-dug material is suitable,* thebottom of the trench may be trimmed to formthe pipe bed (see Figure 5).

8 *Suitable material is defined as granular material in accordance with the recommendations of BS 5955: Part 6: 1980 Appendix A, having maximum particle sizes notexceeding those as detailed in Table 2. Small depressions should be made toaccommodate pipe or fitting socket. After thepipe has been laid these should be filled carefullyensuring that no voids remain under, or around,the and Osma UltraRib pipes laid on trench bottomBELOW ground drainage SYSTEMSI nstallation Notes, Excavation and BeddingBELOW ground drainage systems installation GUIDE6 Table 2. Processed Granular Bedding and Sidefill Materials for Flexible Pipe BoreNominal maximum particleMaterial Specification(mm)size (mm)see nominal single sizeOver 100 to 1501510 or 14mm nominal single sizeor 14mm to 5mm 150 to 3002010,14 or 20mm nominal single sizeor 14mm to 5mm graded or 20mmto 5mm - Aggregates conforming to BS 882, air-cooled blast furnace slag conforming to BS 1047, orlightweight aggregates conforming to BS 3797 are suitable as processed bedding and sidefill As-dug backfillTrench bottom trimmed and loosened to form ground drainage SYSTEMSB edding continuedWhen the formation is prepared, the pipesshould be laid upon it true to line and level withinthe specified tolerances.

9 Each pipe should bechecked and any necessary adjustments tolevel made by raising or lowering the formation,ensuring that the pipes finally rest evenly on theadjusted formation throughout the length of thebarrels. Adjustment should never be made bylocal packing. When the formation is low anddoes not provide continuous support, it shouldbe brought up to the correct level by placingand compacting suitable and Osma UltraRib pipeslaid on processed granular beddingWhen the as-dug material is not suitable, alayer of suitable processed granular materialmust be spread evenly on the trimmed trenchbottom. The trench should be excavated toallow for the thickness of granular beddingunder the barrels. The trench formation shouldbe prepared, the bedding placed and the pipeslaid in accordance with BS 5955: Part 6: 1980and BS 8301: and Osma UltraRib pipeslaid on a 50mm minimum processedgranular the case of 110mm/160mm OsmaDrainand 150mm Osma UltraRib pipes, where the as-dug material can be hand trimmed byshovel and is not puddled when walked upon, a50mm depth of bedding material may be this case the material must be nominal 10mmsingle-sized aggregate (see Figure 6).

10 OsmaDrain and Osma UltraRib pipeslaid on a 100mm minimum processedgranular the as-dug material cannot be handtrimmed by shovel and is puddled when walkedupon, or, when pipes are to be laid in rock,compacted sand or gravel requiring mechanicalmeans of trimming, or, in very soft or wetground, the bedding should be a minimum of100mm of processed granular material inaccordance with Table 2 (see also Figure 7). Below ground drainage systems installation GUIDE7 Figure and Osma UltraRib pipes laid on 50mm minimum of processed granular materialFigure and Osma UltraRib pipes laid on 100mm minimum of processed granular materialFirst 300 mm of backfill selected to be free fromstones exceeding 40 mm (unless processed granularmaterial extends 100 mm above pipe crown).First 300 mm of backfill selected to be free fromstones exceeding 40 mm (unless processed granularmaterial extends 100 mm above pipe crown).