The CSB confirmed that the vessel that launched into the Faultless Linen building, killing four people, was a vertical condensate storage tank, technically referred to as the SCR or semi-closed receiver. The SCR at Loy-Lange Box Co. in St. Louis, Mo., provided the condensate or hot water to a steam generation and supply system supporting a corrugated box manufacturing process. That process was being started up on the morning of the incident. Initial visual examination suggests that the bottom pressure boundary of the SCR failed.
According to initial calculations performed by CSB investigators, the SCR contained about 510 gallons of water and was operated at about 330°F and 100 psig. The SCR itself is roughly 20’ to 25’ tall, 3’ diameter and 3,000 lb.
When the vessel failed, the hot condensate jetted from the bottom, converting from hot water to steam. The power of the jet of water rapidly turning to steam broke the vessel loose from its piping attachments and fastenings, propelling it through the internal structure and roof of the building. The downward force of the steam launched the 3,000-lb vessel with a speed of about 120 mph about 425’ into the air. The SCR remained airborne for over 10 seconds.
The structural integrity of both buildings is still being assessed. Protocols to remove the SCR from the Faultless building are also being developed.