I've heard that ladder manufacturers are supposed to make ladders safe at twice their rated rung strength (250lb ladder will hold 500lb safely). Is there any truth to this??? Just curious.
OSHA requires that ladders support 4 times their rated load, except that extra-heavy-duty ladders support 3.3 times rated load.
Here is a link that might be useful: OSHA 29CRF Part 1926.1053
Wow!!! 4 times the rated is heavy! 3.3 times it isn't light!!
I had no idea it was that way. I figure twice was good enough!