The jump test is possibly not an accurate test either. If my 135 #' is doing the jumping, I would not be too impressed with the quality of the impact. There are those who may be on board the FOG who are more than double my weight. for them to do the jumping might be overkill for certain constuctions.
When ever i bought scaffold planks (Mason contractor so planks needed to have some flex but not break qualities) I would specify what their use and that if not of good enough strength, i would send them back. For planking, i used only spruce, as it had the qualities need for the heavy loading and they were lighter weight than D-fir. When delivery was made, i would tell the driver I was going to unload by myself and would check each and every plank. If they did not meet my test, the entire load was going back.
My test? First i would check for knots. If there were knots (in spruce planks, there were almost always a few knots, but some i knew from experience were ok while others could be dangerous.) The ones I considered to be dngerous were either put aside for return or, if the driver siad they were ok, I would tell him either they go back or i test hem. If they did not meet my test, he had to either take them back or do whatever he liked with them. I would place one end of a plank on the ground and the other on the truck body. I would them jump up and down at the center of the span. If the plank held up, it was good to stay. If it did not hold up, it was the driver's problem. In the days when i was masoning, i was considerable better shape than i am now and weighed in at about 155 #'s. I would jump three times. The first time I did this, I did break a couple of planks and told the driver to take the whole load back
About an hour later, the owner of the biz called me on the site phone. he was melting the phone lines, but after about five minutes of his yelling, and my, of course, verrryyy calm speaking :
,we finally arrived at an understanding. I never, in the next thirty or so years, got another bad load of spruce planking from that company.
A few years later, i was working for a builder who did outweigh me by nearly 2x (nearly 300#') my weight. My help was unlaoding some of my planks that had been around a while and even tho covered with cement, were still strong. Every time we loaded, either I, or my site foreman, would test the planks or, if obvios problems, would shorten for odd job use or go into the form lumber pile. When my helper arrived of the site with the load of scaffold lumber, the nearly 300# builder told him the planks need to be tested. My helper told him I had already tested them to my satisfaction. The builder said he had to be sure and set each end of a plank on a saw horse, climbed up to the middle of the plank and jumped just . i don't think any 2x10 (the size of spruce planking) could have stood that punishment and of course, each plank snapped. Needless to say, the builder and i had a few words about that little episode.
It does make a little difference who is doing the jumping [scratch chin]
Tinker
