The use of column-tree connections is common in controlled shop environments due to their cost-effectiveness in achieving ductile welds. Field bolts are also easy to install and inspect. However. there is currently no prequalification available for these connections. https://www.bekindtopets.com/flash-grab-Viqua-F4-Ultraviolet-Water-System-Powered-by-UVMax-36-gpm-top-savings/