Fly System Warning System

[gafftapegreenia]

I didn't say that a safety plan was a bad idea, just that the Code Red system was ineffective and convoluted. As someone who HAS experienced a run away, there is little enough time to shout "HEADS" before its all over. (And let me tell you, you do NOT want to see a run away. Seeing a brick fly past someone's head just narrowly missing them will shake you to the core. Do everything you can to prevent runaways.) Being attentive to ones environment, such that you say, hear the screaming of the lift lines as the batten starts coming in, is just as effective as yelling "HEADS".

I do fully support a show emergency plan stating that all the lights come up, the curtain comes in, and whatever other unique circumstances your theatre may demand as suggested by the others.

Now what can make runaways even more fun is when the arbor crashes and bricks fall off of it, in this situation the runaway lineset can then go back in the opposite direction.

And WHY ON GODS GREEN EARTH has a school ever been built without a loading rail? I've seen, and worked in, schools that only have a lock rail. I will NEVER understand it. Sure its cheaper to build but is it really that cost effective once one considers all the pain and potential for disaster that exists from operating a system without a loading rail? I was lucky enough to go to a school that had a mid rail and loading rail and even not having a mid rail feels like a bad idea.

Yet they just keep building schools without loading rails.

 

[MNicolai]

The scary thing with counterweight systems is that you can get a domino effect of problems. Let's say you've hung a 250lb loudspeaker array from a batten and you've done it via one length of chain between the loudspeakers and the batten. Let's say the speaker stack falls because of a bad link in the chain or an undersized shackle. Here's what happens:

Step 1: Initial Catastrophic Failure -- the shackle fails, the loudspeaker array crashes to the floor.

Step 2: Newton's 3rd Law -- the arbor now weighs 250lbs more than the load on the batten, arbor comes crashing in and the batten goes shooting upward.

Step 3: When the batten hits the grid, or when the arbor hits the floor, the two separate from each other because of damaged lift lines and the pipe comes crashing to the floor.

The opposite type of failure is possible which is where the batten is suddenly too heavy for the arbor. Let's say you've got something heavy hung from a batten and it's all the way at the grid. While it's at the grid, some putz starts taking bricks off of the arbor because they thought they were told to empty Line #7 instead of Line #17. They have really good rope locks, so they get 200lbs of bricks off before the rope starts to slip through the rope locks and the realize their error.

Step 1: Putz removes bricks from wrong arbor making the arbor 200lbs lighter than the arbor. The rope slips through the locks and the batten comes crashing toward the floor while the batten goes upward.

Step 2: The arbor hits its upper limits with A LOT of force and the screws at the top of the weight stack weren't tightened down so while the arbor stops moving, bricks are propelled upward from the arbor, leave the arbor, and start showering downward to the stage floor.

Step 2a: We can assume the arbor and/or lift lines are damaged enough that the arbor itself starts falling toward the floor.

Step 3: The bricks that were propelled out of the arbor start hitting other arbors and lift lines of adjacent line sets on the way down. Now three or four other arbors start crashing to the floor and lift lines damaged, the battens also start dropping to the floor.

Step 4: The bricks, battens, and debris hit people on the way down if they haven't already.