Croatians are serious about their sport: the Arena Zagreb is the capital’s newly built 15,000-seater stadium, home to national games of football, hockey, handball, athletics, basketball and many other sporting competitions in addition to concerts, exhibitions, fairs and conventions. Built in 2008 in order to welcome the 2009 World Men's Handball Championship, the arena is built to the latest specifications and, most importantly, has a flexible seating configuration and rapid ‘turnaround’ between events. The specifications of the arena also aim to provide home and visiting sides with the highest levels of comfort that could be expected from an international venue: spacious changing rooms are equipped with powerful shower facilities that faultlessly provide hot running water to the many dozens of players who may use them at any one time. The engineers selected ACV’s word-leading combination of a HeatMaster 201 with a Jumbo 1000 hot water tank. Known around the world for its uniquely reliable and powerful production of hot water, this pair produces over four tonnes of hot water in the first ten minutes of operation and nearly nine tonnes of hot water in an hour of continuous flow. Such power is not the unique preserve of large arenas: the floor area required for the HM 201 and Jumbo 1000 is a very modest 2.5 m2. With a modern design and facilities like that, it’s no wonder that Arena Zagreb won the Structural Design of the Year award at the 2009 World Architecture Festival.