Well, in spite of the above suggested references, I looked over the ladder and OSHA stuff and still can't find anything useful for my situation, other than affirming that I should keep to using 2x10 planking, 6 ft long, for heavy-duty (75#/ft) use (OSHA 1926 Subpart L App A).
I'm stuck at the point of finding a way to diagonally brace a vertical support for the table member of the furniture. My latest scheme was to make some sort of adjustible struts which could support the system furniture table, then procede to work off that table surface, or extend a strut up even higher for support of a plank. The design of the vertical strut, and some 1/4" steel offset link for coupling an extra elevation strut to the under-table support strut is easy. The bracing isn't!
Basically it comes down to this. You wouldn't put one end of a plank on a step-ladder rung, and support the other end on an extension ladder, right? So, likewise, supporting a plank on a vertical bracket located at the system furniture wall would be equivalent to supporting the plank on an extension ladder! Hence, I need diagonal bracing. This makes it all very cumbersome. If I end up with too many parts and pieces it becomes impracticable for occasional service work in a multi-story office building. It would be so much simpler to just hang brackets on the top edge of the furniture walls to support/secure the plank. Too bad the system furniture walls are constructed so flimsily. Keep in mind that I'm trying to cope with working around a cubicle space packed with books, computer stuff, file cabinets and all sorts of under-the-table cords and outlet, space heaters, trash containers and foot support stools...where I have to get in and get the job done without disrupting things for longer than an hour, if possible! [Linked Image]