Funke develops customised solution for rainwater retention system in Witzenhausen

Funke Kunststoffe GmbH was engaged as a construction partner for the installation of a special rainwater retention system (RRA) on the premises of DS Smith in Witzenhausen in northern Hesse. This system has to withstand enormous point loads as it is located under a car park that is also used as a storage area. 

Funke developed a customised solution for this, in which additional DN/OD 200 support pipes were installed in the D-Raintank 3000® and D-Raintank 3000 smallbox® elements. DS Smith, a leading provider of sustainable packaging, is pursuing an environmentally conscious strategy with this system, in which only clean roof rainwater is channelled into surface waters. 

Increased stability thanks to special design 

In order to cope with the enormous loads caused by forklift trucks and storage loads, DS Smith decided against a reinforced concrete solution, which would have been too costly. Instead, the engineering firm Oppermann recommended the Funke system, which is equipped with stable PVC-U elements and four load-bearing columns. 

To fulfil the special requirements, Funke added central support tubes in each system element to further increase the load-bearing capacity. The system comprises four layers of D-Raintank 3000 smallbox® elements in the outer area and a combination of three layers of D-Raintank 3000® and D-Raintank 3000 smallbox® elements in the centre. 

Efficient handling and reliable support 

The lightness of the plastic elements and their manageable dimensions made installation considerably easier, which site manager Niklas Bachmann from the contractor Küllmer GmbH emphasised positively. Funke employee Martin Ritting was on hand to advise the construction crew, which further optimised the process. 

The installation of the elements was sealed with a special layer of filter fleece and plastic sealing sheets to protect them from damage. Additional flushing pipes ensure the filtering of solids and enable easy cleaning. 

DS Smith has thus implemented a future-proof and climate-resilient solution for rainwater management that also offers flexibility in operating procedures. 

(Source: Funke Kunststoffe GmbH)