Masons need safe access and a few other things too. Photo: Jan Thomas

When is a Prefabricated Scaffold Frame Also an Access Ladder?

I’ve been in the safety profession long enough to remember how we used to do it 30 years ago.  And yes, we used to climb those end-frames that look like ladders.  Heck, the more agile workers climbed the cross-bracing (and some still do).

If we follow OSHA’s 1926.451(e)(6) or the less informative OSHA 1910.28(a)(2), we know that we need prefabricated scaffold access frames that have evenly spaced rungs at least 8 inches wide and not more than 16 3/4 inches tall from one rung to the next.  Where in the world do they get these dimensions from?!  ANSI standards, of course, but there is one other body of knowledge guiding us in this example.

A normal ladder has rung spacing at 12 inches on center, a rung width from 15 to 20 inches, and a tread thickness of 1 3/8.  These numbers represent our “cultural expectations” (that’s a fancy ergonomics principle).  Cultural expectations should be followed as close as possible on workplace equipment that may compromise safety, such as a ladder substitution.

Test yourself on the following examples of prefabricated scaffold frames.

Tags: ANSI, Consensus Standards, Construction Safety, Ladders, Scaffolding

This entry was posted on Monday, November 9th, 2009 at 6:10 pm and is filed under Construction, General Industry. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.