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APS testing guideline

An important on-site test is conducted by the IKT institute for subterranean infrastructure. The leak test is performed as follows: A sample section of about 30 x 20 cm is inspected by an independent expert. The IKT checks the leak tightness of three samples as shown in the images. The red drop consists of local utility water and should have a diameter of about 45 mm. The evaluation is based on the passage of testing liquid through all three sample sections. The two possible results are TIGHT and NOT TIGHT.

Burst lining

Burst lining describes a trenchless rehabilitation procedure by which the old pipe is destroyed and displaced by a hammering burster. In the same course, a new plastic or steel pipe of equal or greater diameter is drawn in.

Composite materials

A composite material is a composite that is made up of two or more components and that features other material characteristics than its individual components. Our Brandenburger Liner is such a composite material; consisting of resin and ECR glass.

Corrosion resistance

The corrosion resistance describes the durability of a material against decay (Lat. corrodere = corrode, erode, gnaw away); it is measured for liners by their resistance against decomposition due to chemical or aggressive substances in the wastewater and the sewer atmosphere.

Darmstadt abrasion resistance test

The Darmstadt abrasion resistance test is a test procedure in accordance with DIN EN 295-3 for examining the abrasion resistance of a liner or wastewater pipe and is part of the approval procedure for national technical approval of the DIBt. A half-shell is filled with pebbles, sand and water for the test and the application range is simulated by 200,000 tilting movements.

ECR glass

ECR glass (E-glass Corrosion Resistant) is an especially corrosion-resistant glass and, unlike the more commonly used E-glass, is not attacked by acidic or base environments. This makes it well suited for use in the aggressive environments of the wastewater sewers.

Flushing test

In the flushing test, a liner's flushing resistance is tested under defined conditions. Flushing resistance is required because sewers are flushed regularly for cleaning and removal of obstructions. A hose with a flushing nozzle is pulled through the lined pipe. Dirt is flushed from the sewer with high-pressure water. In the past, the "Hamburg model flushing test" was used. In this test, the liner was subjected to 30 flush cycles from a flushing head with eight 2.6 mm nozzles and a water pressure of 120 bar. If the liner was undamaged afterwards, then the test had been passed. Since about 2 years ago, the test is conducted according to DIN 19523. This test can be done in the laboratory. Its principal difference from the Hamburg-model flushing test is that not the pressure but the jet energy density is the critical parameter. The liner is exposed to a jet energy density of 330 W/mm², which corresponds to a pressure of 90 bar at a flow of 280 l/minute. If the liner shows no signs of damage after 60 cycles, then the test has been passed and the liner can be installed. In addition to the Hamburg-model flushing test and the test according to DIN 19523, there are other national tests like the Quik flushing test in Switzerland. In addition to high pressure and numerous flushing cycles, this test also adds gravel to the flushing water to increase the abrasive effect.

Guide pulley set

The guide pulley set is an installation aid to ensure the reliable and careful drawing in of the liner through the shaft and past several angles into the conduit to be rehabilitated.

Heat exchanger surface

A heat exchanger surface can find application in the base area of the Brandenburger Heatliner. This adsorbs the residual temperature of the wastewater and utilises it for the heat pump.

Impact strength

The impact strength describes is the ability of a material to absorb shocks and impacts without breaking.


Impregnation is the impregnation of solid or porous materials with a liquid or viscous substance. The impregnation for the Brandenburger Liner is the combination of polyester or vinyl ester resins with the ECR glass fibre composite.

Liner flexural strength

If it is too low, then the liner has insufficient load capacity and may break under less than its rated maximum load. This characteristic is measured in a three-point bending test, just like the modulus of elasticity.

Liner installation

A hose carrier soaked with a reactive resin is drawn into the sewer and pressed against the sewer wall through inflation with compressed air. A chemical reaction in the resin turns the hose into a stable, load-bearing inner lining. The technology is completely trenchless and requires no digging whatsoever. The flexible liner hoses are typically applied using existing inspection shafts in the sewer. The special characteristics that set the Brandenburger liner system apart from other pipe lining types are: • Use of seamlessly wound liners made of glass fibre laminate webs
• Unique saturation of the raw materials before the production of the pipe liner with UV-reactive UP resin         (possibly with addition of peroxides for the variation "hybrid curing" for larger wall thicknesses over 10         millimetres)
• Drawing in the liner on a protective foil and form-fitting expansion using compressed air
• Curing of the liner using precisely dosed UV exposure ("BLUETEC® technology").


If exposure to municipal wastewater is a factor, then a group 3 (DIN 18 820 T1) or type 1140 (DIN 16 946 T2) is generally used. For aggressive industrial wastewater, e.g. containing alkaline solutions and/or with high temperatures, the GFRP composite is impregnated with a special vinyl ester resin. This resin corresponds to group 5 in accordance with DIN 18 820 T1 and type 1310 in accordance with DIN 160946 T2. Both resins are compliant with the international standard DIN EN 13121. The polyester resin is categorised as group 4, the vinyl ester resin as group 7a.

Reversible heat pump

Reversible heat pumps are employed not only for heating, but also for cooling buildings. The Brandenburger Heatliner is an example of how the residual heat of the wastewater is exploited for heating buildings or for warming up water and for withdrawing warmth from room air and to dissipate it to the wastewater via the heat exchanger surface in the summer.

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.

UV light-curing technology

UV light-curing technology is generally understood as a process in which a chemical curing process is triggered using UV radiation. The patented Brandenburger pipe lining process is based on this UV light-curing technology. In order to cure the liner, a UV light chain meeting the specific requirements is pulled through the liner which is already installed in the old pipe and erected by pressurised air. The resin contained in the liner material reacts to the UV radiation and cures completely within the briefest time.

Wrapping technology

The wrapping technology describes the unique patented production mode of the Brandenburger Liner. The previously impregnated glass fibre composite is wound around a transparent inner foil at a defined speed and appropriate winding angle. State-of-the-art mechanical engineering and quality standards ensure that the liners retain their dimensional strength and also feature an excellent durability over many years.

Young's modulus

Pipe liners are exposed to a variety of loads, e.g. groundwater, road traffic, or the pressure of the earth. They need to be designed accordingly and have sufficient load capacity. The Young's modulus is a key mechanical characteristic in this regard. It is measured by means of a three-point bending test on construction site samples. The measured Young's modulus (or modulus of elasticity), is compared with the specification. In formulas, it is abbreviated as  E . A greater Young's modulus means that the material resists deformation more. A component made of a material with a high Young's modulus (e.g. steel) is therefore rigid; a component made of a material with a low Young's modulus (e.g. rubber) is flexible. What does this mean for our purposes?The glass mats we use are designed to fulfil the load capacity requirements in the cured liner. ADV 75 for instance has a Young's modulus of 7500 N/mm².