I'm currently doing a mod on some 800 fpm armor cars and the comp tie-down's have been removed. Does anyone have any of these on their route's with the tie-down's still intact? It appears to have been a knurled roller design... These were installed in 1985. Any help would be greatly appreciated!
The purpose of tie down compensation is to make safety slide to within code limits. Not sure it was a code requirement or not. Otis used tie downs on 800 FPM and above. A 750 FPM car did not have tie downs. I was an Adjuster at Otis back in the 70's. I remember the Regional Field Engineer telling us about Armor having trouble with Safety slide. He said they did not have tie downs. You might want to get some reports from your State or City on Full Load tests for the units in question. Also check crosshead data tag & test forms to be sure speeds were not reduced.
According to code for as far back as I can find...tie-down compensation is required for over 700fpm. I've also heard of Armor issues with their design...here is a code reference regarding comp tie-down's... 2.21.4.2 Tie-Down Compensation Means. For rated speeds greater than 3.5 m/s (700 ft/min), a tie-down compensation means shall be provided and fastened to the building structure to limit the jump of the car or counterweight as a result of car or counterweight buffer engagement or safety application. The compensation means, connection, building structural members, and fastenings shall be capable of withstanding the maximum forces to which they are subjected due to car or counterweight buffer engagement or safety application with a factor of safety of not less than 2.5.
Thanks Rolly for your insight. We had to slow the cars down to 700 fpm in the mean time to pass state. Anything above 700 fpm they're required. I'm just looking for a job with the Armor setup still installed so that I can get some made up by a machine shop. That way we can put the cars back to 800 fpm.
