plate test ?

[weldinwes]

Good Evening

The guys that will be taking the test will be tested on 1” thick x 8” long plate without backing strip. They will have strong backs on them and when the front side is welded they will either grind or gouge the back side and weld it. The will use Lincoln Welding Machines with wire feeders with E71T-1 wire, wire size 0.045” with Argon/CO2 75/25 gas, metal will be preheated 100°F. if there anything that is need please feel free to contact me.

This is email i got from hr.
my question is if there's no back up strip is it an open root? And wth is strong backs?