ND WSE lt / ND WSE hd Water Retention Elements
Water storage and retention elements made of polypropylene for surface drainage and water buffering used in the Nophadrain Systems for intensive green and trafficable roofs. Due to the special design, the water retention elements can also be used on inverted roofs. The elements can be combined with flow restrictors (e.g. ND AFC-200) for the suitable regulation of drainage.
| Product | ND WSE lt Waterretention Element |
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| Material | polypropylene (PP) 100% recycling material |
| Open volume | approx. 95% |
| Open surface | 63% |
| Durability | 50 years |
| Dimensions | approx. 0.6 m x 0.6 m x 100 mm* |
| Compressive strength | > 400 kN/m² (for standard height 100 mm) |
| Weight per piece | > 2.4 kg (for standard height 100 mm) |
| *Available in other heights on request | 50, 80 and 150 mm (table below) |
| ND WSE hd Waterretention Element |
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| polypropylene (PP) 100% recycling material |
| approx. 95% |
| 63% |
| 50 years |
| approx. 0.6 m x 0.6 m x 80 mm* |
| > 1,050 kN/m² (for standard height 80 mm) |
| > 2.1 kg (for standard height 80 mm) |
| 50, 80 and 150 mm (table below) |
Applications
Both series are designed for the use under heavy structures on roofs without fall and are therefore suitable for temporary storage or water buffering of excess water caused by possible discharge restrictions into the sewerage system due to e.g. heavy rain.
The elements of both series are available in different heights. The required amount of water buffer can be achieved by choosing the right build-up height; provided that the water buffer is in compliance with the local building regulations. To establish targeted definitions of the discharge volume the appropriate throttle system can be combined with an adjustable flow control system (e.g. ND AFC-200) can be combined with a water retention build-up.
The ND WSE hd Water Retention Elements are suitable for SLW60 and due to its high compressive strengths the appropriate system for the use under traffic areas. The elements of the ND WSE lt series are designed for SLW30 and therefore suitable for the use in intensive green roofs and light trafficable (pedestrian) areas. With increased demands on the water supply to the vegetation, products of the ND WSE lt series can also be used for permanent water buffering.
For protection of the waterproofing membrane, ND TSF-100 Slip and Protection Sheet has to be placed underneath the ND WSE lt / hd Water Retention Element. In case of an inverted roof the ND TSF-100 has to be exchanged by the ND 100sv Drainage System. As filter layer, the ND FV-300 Filter Geotextile has be used.
Accessories
The products from the ND WSE series need to be interlocked with special connectors in order to assure best force transmission. For the ND WSE elements with heights of 50 and 80 mm use the Connector Small; for heights 100 and 150 mm use Connector Large. Recommended quantity: for ND WSE-lt: 6 connectors per m2; for ND WSE-hd: 12 connectors per m2 (available per bag (50 pieces)).
*Other heights available on request:
Standard height for ND WSE lt is 100 mm and for ND WSE hd 80 mm.
| Product | Dimensions | Compressive strength (kN/m²) | Weight (per piece) |
| ND WSE-50lt | approx. 0.6 m x 0.6 m x 50 mm | approx. 500 | approx. 1.5 |
| ND WSE-80lt | approx. 0.6 m x 0.6 m x 80 mm | approx. 500 | approx. 2.0 |
| ND WSE-100lt | approx. 0.6 m x 0.6 m x 100 mm | approx. 400 | approx. 2.4 |
| ND WSE-150lt | approx. 0.6 m x 0.6 m x 150 mm | approx. 400 | approx. 3.4 |
| Product | Dimensions | Compressive strength (kN/m²) | Weight (per piece) |
| ND WSE-50hd | approx. 0.6 m x 0.6 m x 50 mm | approx. 1,050 | approx. 1.6 |
| ND WSE-80hd | approx. 0.6 m x 0.6 m x 80 mm | approx. 1,050 | approx. 2.1 |
| ND WSE-100hd | approx. 0.6 m x 0.6 m x 100 mm | approx. 700 | approx. 2.5 |
| ND WSE-150hd | approx. 0.6 m x 0.6 m x 150 mm | approx. 500 | approx. 3.5 |