When the massive AquaDom aquarium in Berlin burst in late 2022, killing 1,500 fish inside it and causing extensive damage to a surrounding building, officials called in plastics experts to try to explain what happened.
The 28 million euro AquaDom structure was supplied by Grand Junction, Colo.-based Reynolds Polymer Technology Inc., which claims to be the only company in the world that designs, engineers, casts, thermoforms, fabricates and installs cast acrylic panels for aquariums.
The aquarium was installed by partner company International Concept Management Inc. in December 2003 at the Radisson SAS hotel in Berlin.
This 15.85-meter-tall, 11.08-meter-diameter cylindrical aquarium used 41 PMMA panels and 16 on-site bonds. It was in the Guinness Book of World Records as the largest cylindrical aquarium in the world.
According to the building's owner, Hamburg, Germany-based Union Investment Real Estate GmbH, the outer PMMA cylinder wall thickness was 22 centimeters at the bottom and 18 centimeters at the top.
The AquaDom made international news when it ruptured at 5:45 a.m. on Dec. 16, 2022. One million liters of salt water destroyed the hotel lobby, breakfast area, reception and elevators. RTL TV station speculated that the cause could have been the temperature difference between nighttime atrium air at -9° C and the water at 26° C.
In order to establish insurance claims, Union Investment commissioned an investigation in January 2023 by Christian Bonten, the head of the Stuttgart, Germany-based IKT plastics technology institute. Bonten came to IKT in 2010 from bioplastics compounder FkuR in his hometown of Krefeld, having previously been responsible for polystyrene business and the Designfabrik at BASF in Ludwigshafen, Germany.
Bonten said in an Oct. 11 report that outer cylinder damage by sabotage, incorrect cleaning agents, seismic vibration or cold atrium winter air were unlikely. The cast PMMA didn't show any weakness. Union Investment stated: "Forensic investigation provides clues to causes of damage, but no conclusive evidence."
Possible causes identified by Bonten included an effect of an adhesive bond drying or base area notches during a 2019 renovation.
"No clear evidence for possible causes can be derived from existing documentation and much elaborate forensic examination," he said.
Bonten's team couldn't determine where the first fracture or crack occurred in the 26 outer panels, or whether a seam opened or if a slow crack growth started from stress by notch at the base, "even though calculations showed it is theoretically conceivable."