Enough extinguishing water with little space and effort in Ascheberg

Inserting the KS-Bluebox® elements using an aluminium crane

Klaas Alu-Kranbau GmbH manufactures trailer cranes, mobile cranes, furniture elevators and construction hoists as well as aerial work platforms and multifunctional vehicles for the fire department. "In the summer of 2022, we decided to expand a hall on the company premises by adding a 1,000 m2 canopy to create more weather-independent storage space and room for mast construction", explains Ludger Klaas, Klaas Alu-Kranbau GmbH. "In the course of applying for planning permission, we noticed that we didn't have enough extinguishing water available from the existing hydrants on the site in the event of a fire", he continues.

Extinguishing water pond too expensive

According to DVGW worksheet W 405 - which deals with the provision of extinguishing water from the local drinking water supply - a defined quantity of extinguishing water must be available for at least two hours within a radius of 300 m around the building. Against this background, it was necessary to provide an additional 200 m3 of extinguishing water in addition to the existing hydrants in the event of a fire on the company premises.

"We discussed the installation of an open extinguishing water pond, but quickly discarded it due to the disadvantages and then opted for an underground variant", recalls Simon Küter, Process Optimisation, Klaas Alu-Kranbau GmbH. "Above all, the enormous amount of space required for a pond system would have cost us much-needed space. What's more, an open pond requires regular maintenance and fencing is also necessary to prevent people from coming to harm."

The extinguishing water extraction point was also equipped with a B-Storz connection for filling (right). The vent can be seen on the left and the A-Storz connection for withdrawal in the centre

Construction designed for permanent storage

In this situation, the building owners became aware of the KS-Bluebox® from Funke, which has DIBt approval Z42.1572 for the infiltration and retention of rainwater and consists of factory-made, plastic-coated D-Raintank 3000® elements. "This variant of the D-Raintank 3000® system is not only suitable for the retention of rainwater, but also - with a view to later removal and use - for permanent storage, as in this case for the storage of extinguishing water," explains Frank Horstmann, specialist consultant for rainwater management at Funke Kunststoffe GmbH. "Various connection options ensure great flexibility, and the light weight makes handling at the installation site easy," Horstmann continues. "In addition, the possibility of shallow installation makes a significant contribution to minimising excavation work."

Different sizes, modular application options

In principle, it is possible to design them in different lengths, widths and up to three layers on top of each other. According to Horstmann, the realisable size of a KS-Bluebox® depends on the loading capacity of the transport vehicles. If required, different containers can be connected to each other on site at the installation location using pipes - as is the case on the Klaas company premises. The system at Klaas consists of four KS-Bluebox® elements measuring 12.60 m x 2.40 m x 1.80 m (L x W x H) and, minus the air cushion, has a capacity of around 200 m3 (200,000 l). As two extraction points are required in accordance with the DIN 14230 standard for extinguishing water tanks with a storage volume of ≥ 150 m³, two Funke plastic shafts DN/ID 1000 were arranged on the long sides of the system as extraction shafts. In addition, vents must be provided when using the KS-Bluebox®. These are installed at the factory with HS® pipes and extended on site. An inspection block has been integrated into each KS-Bluebox® for flushing, camera inspection and better accessibility.

The four KS-Bluebox® elements, each weighing around 3 t, were laid - two next to each other and two behind each other - in an excavation pit around 2.60 m deep on the prepared sand subgrade and connected to each other with HS® DN/OD 315 sewer pipes. A cover of 0.80 m ensures that the system can be driven over by lorries or used as a car park and is installed frost-free. All the work was completed within just one week. At the client's request, the usual A-Storz for fire engines was installed for removal and a B-Storz for filling.