From 0 to 250 Cubic Meters in Only 8 Hours – HOBAS Tank Secures Potable Water Supply in Lower Austria

The market town of Karlstetten lies in the Mostviertel region of Lower Austria on the southeastern edge of a hilly area, Dunkelsteinerwald. Set in idyllic countryside about 10 km from the provincial capital of St. Pölten, it is home to over 2,000 people - with the figure steadily rising in recent years. As there are no lakes for swimming in the immediate vicinity, many homeowners in Karlstetten have their own pools that they fill every year beginning of summer. This caused considerable shortages in the potable water supply in recent years, making an extension to the water network essential, especially in view of the rising population figures.

 

To increase capacity, the investor opted for a HOBAS Potable Water Tank. The professional advice provided by HOBAS Experts, the prefabricated units for a rapid installation, and the fact that the tank’s capacity can easily be increased soon convinced the customer. The municipality of Karlstetten decided on a tank with a capacity of 250 cubic meters, which can be increased to 320 cubic meters to cater for future needs. In concrete terms, the tank consists of a 12-meter-long valve chamber and three 21-meter-long potable water chambers. There is also a connection for a fourth future chamber if required.

 

HOBAS Potable Water Tanks are manufactured to comply with the very strict legal requirements of the destination country. The standards they meet in Austria are ÖNORM B 5161, ÖVGW PW 407, and GRIS GV 14. This means that HOBAS Potable Water Tanks are entitled to bear the quality mark GRIS W 1.277.

 

In addition, HOBAS has its own quality standards which are even stricter. “When it comes to potable water supplies, we simply do not compromise. We are talking about people’s health here and only the highest standards are good enough for us,” says Doris Strohmaier, managing director, making the HOBAS Group’s position very clear. And this commitment is taken seriously: each raw material used in producing the pipes, each process step, and each part bought in is carefully documented, must be certified for potable water, and can be traced at any time afterwards. Extensive tests on the pipes and fittings as well as exact records of transport and installation ensure that the client receives excellent quality and the local population can rely on a safe supply of impeccable potable water.

 

HOBAS Experts have a wealth of experience with potable water tanks under their belts and can provide clients with support in all areas from planning through design to installation. The tanks are prefabricated at the factory and thanks to their well thought out modular design they can be quickly assembled on site without any special equipment. Fabrication from order release to loading on the truck takes four to six weeks, depending on the tank size. The largest tanks supplied by HOBAS to date are around 300 cubic meters. Much larger ones are currently being planned and as far as size is concerned there are no limits. Delivery is generally just in time for installation, which does not require large storage areas or disrupt traffic. Their low weight and compact wall structure compared with other materials enable all the tank units to be transported by flatbed truck and not classed as expensive oversize loads requiring escort vehicles.

 

Contractors Held & Francke were responsible for installing the tank in Karlstetten. First they excavated a pit measuring some 24 x 9 meters and placed a layer of the standard bedding material used for HOBAS Tanks: gravel with a grain size of 8 to 16 mm. Punctually at 7:30 in the morning, the truck with the first part of the valve chamber drew up. The module with a width and height of 3 meters and a length of 6 meters was joined to the second part of the chamber using a coupling. A stainless steel door with louvers gives the water technician easy access to the chamber for carrying out any maintenance work required at a later date. As soon as the two parts of the valve chamber were connected and installation complete, work began on joining the potable water tank. At the same time, the fitter contracted started installing the interior piping and the instruments.

 

Transport of the modules was carefully coordinated: the trucks were sent off on the 380 km route from HOBAS Austria in Wietersdorf to arrive in Karlstetten just in time. As with every installation of potable water tanks, HOBAS Experts were also on site here all the time, supervising the construction work and answering the client’s questions. In addition, whenever tanks are installed HOBAS also provides the hoists and ropes needed for joining the pipes. The contractors did not therefore require any special equipment in Karlstetten. The heaviest modules were the two parts of the valve chamber - a simple truck-mounted crane was all that was needed here to lift the parts weighing 6 tons each. Within a period of only eight hours, all the parts of the potable water tank were successively delivered and installed by only four of the contractor’s men. While the tank pipes were backfilled on the outside with crushed stone the next day, the fitter finished the piping work inside the tank. The project was thus completed and the tank ready for use in only two days.

 

HOBAS Potable Water Tanks blend in with their surroundings and are only recognizable on closer inspection. In fact, the burglar-proof access door to the valve chamber is the only visible sign of the durable tank in Karlstetten. After backfilling, the excavated pit can be covered with grass or other plants. Even heavy agricultural machinery can be driven over the HOBAS Tanks made of centrifugally cast GRP pipes, unlike the GRP products supplied by other manufacturers.

 

Both the client and contractors were impressed by the quick and easy installation of the tank and professional project management on the part of HOBAS. And even visitors from abroad have expressed an interest: the mayor of Karlstetten Anton Fischer and water technician Josef Speiser recently showed a delegation from Szombathely in Hungary the modern water supply facility. The first potable water tanks were then installed in Hungary at the end of 2011.