Is it acceptable to erect a scaffold slightly out of plumb or level? Why or why not?
slightly yes...but remember the higher you get the worst it gets...as in... an inch in 4 feet isnt bad, but that translates to 3 inches in 12 feet
No, they fall over or collapse when loads or stress is applied.
Depends on how high you plan or erecting it. If you are going to go many levels high, that little bit of off-level on the bottom layer, could turn into a big bit toward the top. Level it out. Doesn't take too long.
For reasons of simple Physics, you want the scaffold to be as level as possible, but be sure to erect it properly, with enough side and front/rear support to prevent toppling. As for the work surface, level is much better for purposes of your workers' balance. If you are unable to be perfectly level, due to the underlying terrain or other reasons, just ensure to minimize any issues that could create hazardous situations. I would try to keep any grade variations at less than 10% off level. In all cases, use proper safety equipment, including helmets, harnesses, and restraints, as appropriate for the situation. Good luck.
