Arbor Day - The Last Friday Before May!

Annual  -- To do something EVERY year.  Rigging Inspections should come to mind, and although 'Arbor Day' is intended to be the day we all plant a tree, or three, it should also be a reminder that the counterweight carriages (aka: 'Arbors') in our stage rigging need love, too.

We want to look over your equipment and make sure that everything is in proper order.

• Nuts are tight.  The top and bottom rod nuts should both be checked to ensure that they are properly clamping the top and bottom arbor frames.
• The rods and back-bone are straight.
• Each cable and rope is properly secured.
• The guide shoes are clean and properly fitted to the guide rails.
• Spreader plates are spaced-along the length of the weight stack and not buried at the bottom.
• Weight locks are present, and have screws in them to allow them to be tightened-down so they can hold the counterweights from jumping out of the arbor frame in the event of a run-away and crash.
• Take the time to enumerate the arbors so they are easily identifiable regardless of what level they are positioned.
• Check to see if anyone has maybe added extraneous weights to the system . . .
There are many more things to check as a part of the rigging system, so this wasn't a complete list.

Remember: People are the most dangerous things in the theatre, so make sure that each person using the rigging system understands how to handle the weights, are secure so they can't fall over the weight loading railing, and they fully understand about using spreader plates, rope locks, and weight locking collars.  Using the tools you have properly can save lives!

KEEP THOSE ARBORS BALANCED (also referred to as: "In weight").  Train your crews to pace their work so that the fly crew (loading bridge crew) can keep-up with the ground crew that may be loading or striping a batten.  Out of balance systems can lead to run-aways, and that can really rack-up a system:

Hemp House Rigging - The 'old fashioned way'

Dawn Wilfong, 24, works the fly rail and hauls a piece of coiled rope during a performance of “A Christmas Carol.”  (c) 2010 Photo by Thomas Slusser (For The Virginian-Pilot)

Check out this great story about one of the few remaining active rope rigging houses.  http://hamptonroads.com/2010/12/behind-scenes-wells-theatre-rare-find

This wooden pin-rail is in a theatre built in Texas in the 1920's.

One of the most common scenarios this blogger sees is equipment like this that has never been serviced in 50-70+ years.  The Loft Blocks are sometimes made of dry-rotted wood or sand-cast pigiron, either of which could fail under load without notice.  The ropes need constant review and regular replacement, too, as they weaken with age and abrasion.  As you can see in the second picture, the facility operators in this building don't understand the concept of counterweighting the batten loads, so everything is stage-heavy.  The battens are dead-hauled (bull-dogged) up, and if the tie-off fails or the fly crew looses their grip, then the batten and load will will come crashing to the stage.

Other potential problems are retro-fitted belaying pins:   I've found rebar, conduit, gas pipe, broom handles, steel spikes, and other odd items used in place of the correct items.  Some hemp-house facilities are 'hand-me-down' theatres that started-out as the High School Auditorium, then was the Middle School, and is now part of the Elementary School facility.  Not only is the equipment MORE DANGEROUS, but it is located where young children not familiar with the hazard potential can pull-out the belaying pins and/or untie the rope lines.

It is extremely important that the operators and staff fully understand how the fly system works and what safety precautions must be taken when loading and operating the system.

Rollin', Rollin', Rollin' - Raw Hide! (Well, at least Raw Brain)

I found this steel microphone base up on the elevated locking gallery in this theatre. The gallery has no kick-plate around it's perimeter to keep heavy things from rolling or sliding-off onto the unsuspecting crowd below (which is a whole 'nother issue), and is about 10 feet above the stage floor.

Not setting round rolly things on edge over people's heads would qualify as a "no-brainer" to most folks. But you can never tell what somebody else might do. So, to keep from becoming a 'no-brainer' - always wear a hard hat around places like this. Pick one up at the local hardware stor or safety supply - they are less than $10 bucks and could save your life.

Lineset Numbering - It's not just for the index strip!

Here are some good examples of rigging management. Not only are the index strips and arbors CLEARLY numbered, but the batten end, loft blocks, and head blocks are also marked.

This also makes it easy to keep lineset inspection records straight during your annual safety check-up.

Round and round we go . . .

Occasionally we'll run into these in really old facilities. Although quaint and historic, they are really dangerous. These are round counterweights. Note that there is no top clamp, and nothing to keep them from sliding off of the center rod. They really belong in a stage equipment museum display, not on a stage.

[Wire] Rope Terminations at Arbors

This picture shows a single purchase cast iron arbor top plate. The wire ropes are not supported by thimbles allowing them to deform and separate strands under load. Additionally, only one wire rope clip was used for termination, in lieu of the required minimum of two. Some of the "Crosby" clips (u-bolt cable clips) are installed backwards with the dead (unloaded) end of the cable run under the saddle (Remember: "Never saddle a dead horse").

The fiber hauling line does not have a thimble either, which acts to buffer the abrasive casting finish against the rope surface. Here is a picture of an arbor bottom plate with a plastic rope thimble (they are also available as a metal type):

This is a very old wire guided arbor with extended eye bolts for attachments (again, no thimbles to reduce the point-load on the rope bending point). You can also see that the top plate is tilted showing that the arbor has been racked and is skewed diagonally.

Here is the top of a double-width arbor (carries two stacks of weight). Again, no thimbles. It appears that the installer tied a clove hitch and then terminated the cable with just one wire rope clip. I don't know where the loose nut (partially hidden) that was laying on top of the arbor top plate came from . . .

And here is a the top of a new arbor that is properly terminated. Note that the load lines can be disconnected without cutting the cable. This makes them much easier to work on and replace if necessary. You can also see how the wire rope cables are not deformed as they bend around the thimble. Also of note is the safety wire (mousing) on the screw-pin shackle to keep it from coming apart. It's unknown why the front-most line was attached with a shackle when the other lines were looped around a through-bolt.

Ladder, ladder, on the wall . . . how many ways can you make me fall?

This ladder may have been 'legal' when it was installed (probably circa 1951), but it doesn't meet today's ANSI / OSHA standards.

For starters, access is on a platform that is about 8 feet above the stage (not visible, but off to the left of the ladder). There is no railing along the edge of this platform. To correct this situation (other obstacles to come, stay with me), a safety railing would have to be installed to protect the worker on the platform, then a cage would have to be installed to enclose the ladder. Since the ladder is almost adjacent to the railing, additional guards would have to be installed between the top of the railing and the bottom of the ladder cage so that the worker could not fall over the railing as they climb the ladder.

Note that there is also a wire-guided line set intruding into the climbing space of the ladder.

The next thing that is encountered is the opening through the proscenium wall. A platform is required here so that the worker can enter the door without hanging off of the ladder.

• Side note: The door was found open, thus violating the fire wall integrity. This door is a 'shorty' - its only about 48-50" tall. They built them that way to meet the square footage requirement for penetrations through the fire wall. Curious, as there never was a fire curtain installed to separate the stage and house - why would they worry about the size of the fire door?
• Second side note: On the other side of the fire door there was a light switch to illuminate the attic catwalk, but if you didn't know this, you would enter in the dark to find a 2 foot wide catwalk that turns immediately left. This catwalk has no guard rail or toe boards, beyond which was about a 20-25' drop down into an interior wall void that goes all the way down to the auditorium floor level. If you fell down in there they wouldn't find you until your body started to stink-up the place. Don't fall in on the last day of school - you'll be there all summer! Did I mention that all of this was fully accessible to the students?
• Third side note: There was no grab-rail or anything to get a hold upon as you climb off the ladder into this 'shorty' door way - you have to reach in blindly and get a grip on anything that you can feel for - that was scary. Climbing back out of the door to get on the ladder was 'fun', too!

So, assuming you have added the requisite landing at the attic access door level, you now have to get up to the gridiron level. The existing ladder over-hangs the access door opening on the right, and runs into the headblock beam on the left. Time to re-group and think this over.

Plan B: Lets put the ladder to the right of the door, far enough off-stage that you can go past the electrical conduits with the proper clearance. This way we don't need the railing-to-ladder-cage filler panels, and we get out of the way of the wire-guided line set. We would have two platforms: One at the access door level, and one at the gridiron level. Of course, both platforms will require proper railings.

When you connect the platform to the gridiron you find that there is no railing along the headblock beams. (Imagine climbing the existing ladder, working your way around the off-stage headblock beam, over the loft well between the headblock beams, only to find that the gridiron was built with 2x6's set on-end with about 6" gaps between them. So much for having a good footing and a 'non-combustable' structure . . .)

Oh yeah, did you notice that there was NO loading gallery? Need to add one of those, too. Looking at the picture you can see that a loading gallery floor would likely encroach into the platfrom area for the attic access door. Dang! Wuddle we do?

We could use all motorized line-shaft rigging, but that is a fairly expensive solution. The saving grace is that the facility is now a 6th-grade only school that does not have a theatre arts program. The wire-guided rigging system was pretty well shot, and all the drapes need replaced, so the movable rigging will probably all go away and the battens will be dead-hung. The facility still needs a proper ladder access to the attic and gridiron, but at least it won't need a loading gallery, too.

One last note: Did you see that 2x4 fluorescent light fixture bolted to the bottom of the wood 'gridiron' joists? There were about a dozen of those that need to be serviced . . .

Weight, weight, don't tell me...

Why is it that EVERY rigging system I see has loose, missing, or missapplied weight locking collars? These are the easiest thing in the world to use! My advice: Check, check, and re-check. If your fly crew won't use them, dismiss them from the fly rail.

The weight lock collars at the left are 3-4 feet above the top counterweight, and the ones on the right are probably 15-18" up.

That won't keep the counterweights in-place should you have a stage-heavy run-away. The arbor hits the top stop and inertia lets them keep on going . . . until gravity overcomes the flight pattern and it comes crashing down to the floor below; probably bouncing and boinging off of the adjacent metal, rope, and cables all along the way. Talk about an uncontrolled and unpredictable ballistic missile!

Here is what can happen when the weight hits the floor:

The force of the impact broke-off a 2" thick piece of steel! Imagine what would happen if it struck someone on the way down! Even an OSHA required ANSI standard hard-hat wouldn't help you.

Of course, stacking the weights on top of the weight locking rings won't help either . . .

So what else could we do wrong? How about no thumb-screws in the locking collar . . .

Or maybe use a U-Bolt to clamp the weights in place (note the rear clamp has slid down into the back fork of the weight).

Counterweight Locking Collars.

Use 'em!