Is a metal scaffold 30 feet high with a 12 by 16foot base sufficiently stable?
It is sufficiently stable in terms of proportions. The rule is that it ought not to be higher than 3 times the shortest measurement of the base. There is another applicable rule, however, that any free-standing scaffold taller than 25 feet should be supported by guys. Wire rope guys should be at least 1/4 inch in diameter.