Glossary

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Sewer rehabilitation

The term sewer rehabilitation denotes a number of methods for rehabilitating wastewater pipelines. The purpose is to seal pipes against ingress of groundwater and egress of wastewater, to restore structural stability, and/or to stop corrosion. Trenchless sewer rehabilitation, or no-dig methods, describes methods that do not require opening the surface to be opened along length of the sewer. This reduces construction time, cost, and environmental impact. The methods can be used for sewers with nominal widths from DN 100 to DN 5000 (standard diameter in mm). Trenchless sewer rehabilitation accounts for about 50% of the sewer rehabilitation market. Trenchless sewer rehabilitation is divided into three process categories: Repair, renovation, and renewal. The pipe lining method is a renovation process. Renovation methods are used for locally constrained, repetitive, and extensive damage. The process can be used to work a single conduit (sewer section between shafts) or on several adjacent conduits in one go. Processes requiring workers to enter the sewer are used only in larger dimensions (> DN 1000 mm). Pipe lining and relining methods are the best established renovation processes, with a market share of about 30% in trenchless sewer rehabilitation. Again, two basic processes can be distinguished, heat-curing and UV-curing. In the heat-curing process, resin-soaked felt hoses are inverted (rolled) into the sewer using steam or hot water. The chemical curing reaction of the resin is initiated by the heat of the water or steam. In UV processes, glass-fibre hoses are pulled into the sewer and inflated with compressed air. The chemical reaction is initiated by UV light emitted by a robot moving along the length of the liner on the inside. UV-curing processes account for about 55% of the market in pipe lining. Our process is the leading technology for trenchless sewer rehabilitation for diameters from DN 150 to DN 1000. The Brandenburger winding process exceeds all requirements and sets the gold standard for mechanical stability, chemical resistance, and leak tightness. With a share of about 35%, Brandenburger is the market leader for UV-curing processes. However, there is still plenty of room for development.

Short-term bending stress

Just as with the determining of the modulus of elasticity, the "three-point bending test" for determining the short-term bending stress in accordance with ISO 178/ ISO 11296-4 is applied and indicates how the material retains its dimensional strength under various external influences.