Summary
Demolish the existing DA tray spray head through the roof of the existing CUP plant. Add new isolation valves on the low-pressure steam and boiler feed water lines to allow for continuous operation of the temporary DA, during removal of the tank spray head. Install the owner-provided tray spray head on the existing tank, along with owner-provided safety relief valves. After installation of the spray head, extend the doghouse structure above the roof and add an additional upper-level platform around the tray head to allow for future maintenance, as well as providing access from the roof. See attached file.