Friday, June 26, 2009

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.

Tuesday, June 23, 2009

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.

Monday, June 22, 2009

Toe busters!

Here is a metal strip that was intended to cover the transition from a sprung wood stage floor to the adjacent tile on concrete floor.Here you can see a side view of the metal showing how it has become bent and sticks up into the travel path.
Here is a floor pocket that was not properly installed and is resting upon the stage floor deck instead of being set flush with the wood surface.

Friday, June 19, 2009

And you really can't do this !

The earlier post about blocked exit corridors was just the beginning of this subject. This is probably one of the most dangerous and common problems I find in theatres. IF THE PATHWAY LEADS TO AN EXIT DOOR - THEN IT MUST BE KEPT CLEAR! Also note the broken emergency light and burned-out EXIT sign lamp. This door was at stage left.
This vestibule was at a house left leading from the audience chamber to the outside exit. This vestibule was also feed from the stage by doors on the left (barely visible in the picture). It had a table, chair, and loudspeaker cabinet all in the travel path.

Wednesday, June 17, 2009

And when she gets there she knows...

She's climbing a stairway with no hand railings.Not just one like this, but two! One each side of the stage. And note the 'no contrast' step nosings and slick surfaces, too!

Tuesday, June 16, 2009

You can't do that!

Aisles and corridors along the exit route must be kept clear of obstructions (this means tables, chairs, junk, more junk, and anything else that would or could impede the flow of people out of the building in the event of an emergency).

Monday, June 15, 2009

Great signs

Such a simple concept, but missed by many - label the door to the electical room.

Sunday, June 14, 2009


Standardized set pieces for One Act Play competition need love, too! Drop them and they break. The next thing that might break is the actor using it. Don't just toss them into trucks, trailers, and storage rooms. Always inspect and repair before use! Look closely, and you can see that the lower 1x3 stabilizers both have knots in them and they are cracking. Yet another failure mode in progress.

Student stagehands take note: These things are heavy and shouldn't be moved by one person - You can hurt your back by lifting too much.

You should also be wearing ANSI standard steel-toed OSHA approved work boots (PPE). If you drop a piece like this on your foot it can do a lot of damage if you are wearing flip-flops, sandals, or tennis shoes.

And lastly: This is another good reason to be wearing leather gloves (PPE) when you are moving these things -- they can have nails, staples, tacks, and splinters that can really rip you up.

Saturday, June 13, 2009


Just because there is a flat spot somewhere doesn't necessarily mean it's available for storage. Storing stuff, particularly heavy stuff, on a ledge over a doorway is just not a quality decision. Stuff moves, it gets snagged, it shifts, it rolls -- the next thing you know: you wake-up in an ambulance with your noggin' throbbin'. And here you have to lean out over a railing on a spiral staircase to get to the 'stuff'. A geat opportunity for a fall, too!

Wednesday, June 10, 2009

Burning Stones

This was a truly excellent design for a stone wall. From the audience seating it really did look like rocks in a great wall. Up close, I was able to see how it was made: Each 'stone' was made from a brown paper lunch sack with wadded-up newspaper inside. They were glued to a piece of corrugated cardboard, and lightly accented with Krylon enamel spray paint (I saw the empty cans). There were many of these wall panels. Guess what? Not a single part was treated with any fire retardant. One spark and the whole wall would have gone up in flames! Location: Elementary school stage.

NFPA Life Safety Code 101, paragraphs & specifically requires scenery and stage properties ('props') to be constructed of noncombustible materials.

Tuesday, June 9, 2009

It should be well hung when its wall hung.

Not everything gets rigged from above. Sometimes it is necessary to hang a cantelever load off a wall. This speaker weighs about 125 pounds and is supported from below by a steel bracket bolted to the wall, and the top is tied-back with an interesting mix of hardware.
This is a close-up of the top rigging. I could not see how the link chain was terminated to the top of the speaker. There is link chain (not rated for overhead lifting), connected to an aluminum turnbuckle (not moused, not rated for overhead lifting) via an open-ended hook at one end and an open eye bolt at the other; connected to a forged turnbuckle eye; via a stainless steel screw-pin shackle (unknown rating, but clearly not marked) that is not safety-wired (moused). The forged turnbuckle eye that was used to go through the wall should have been a sholder eye bolt with a large diameter hardened flat washer -- you can see how the base of the eye in pulled into the CMU block, possibly cracking it due the wedging forces.
When we go around to the back-side of the wall we find that the installer drilled through from the front and spalled the CMU block, then installed a mild steel flat washer and no lock-washer.
This speaker, and it brother on the opposite side of the stage, were mounted right above the walking paths of all those that came onto the stage. Also of note, although not a safety issue, was that this speaker was pointed straight-out from the wall toward a point about eight feet above the last row of seats -- whatever happened to the idea of aiming a speaker at the people? Obviously installed by someone that did not understand rigging or acoustics!

Monday, June 8, 2009

Those aren't all they're cracked-up to be.

Modern rope locks are made from formed & welded steel plates. Older ones were made with cast metal and are more prone to stress cracks, and ultimately failure. Another good reason to do an annual inspection! Never load you rope locks to more than the recommended 50 pounds - keep your sets balanced and 'in-weight'. The rope lock may be stronger, but do you really want to find-out? This is also why you don't want to use your rope locks for rope brakes -- a dynamic load like a moving set and/or counterweight carraige can place much more strain on a rope lock than you would ever imagine.

Thursday, June 4, 2009

[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.

Wednesday, June 3, 2009

Cover me !

Aside from the missing cover on this electrical box there are other interesting installation 'features':
  • The installer elected to screw into the box from the adjacent panelboard (I sure hope he killed power before he went in there!) so that there were two sharp pointed sheet metal screws protruding into the handibox about an inch or so (if you hadn't noticed, the screws that are intended to protrude into an electrical box are always blunt ended), and
  • There is no bushing through the holes connecting the two boxes, thus leaving sharp metal edges to nick the wire insulation where the knock-out was removed.
  • The source power comes into the box as a white (presumably neutral) conductor and a green (presumably line voltage) conductor, and then depart to the load as a non-standard RED (presumably neutral) conductor and a standard black line voltage conductor. Well, at least they got the NEC color coding scheme half right . . .
  • There is no dedicated ground conductor, as the conduit connections are relied upon for ground continuity. See:, and for more discussion of this topic.

Tuesday, June 2, 2009

Not to mention getting grease all over your nice clean black stagehand uniform . .

This is a motorized counter-weighted grand drape curtain system that has no guards on the chain drive. Note that the operation buttons are right UNDER the wire-guided counterweight arbor, too. You can also see that the guide wire on the left is significantly deflected from the guide spool on the arbor carraige, which indicates that the system is misaligned, thus increasing the rate of wear on the guide spool and/or the guide wire. Also, you have to lean over and reach past all of the equipment to get to the power disconnect on the wall.
Excerpt from OSHA Regulations:

1926.307(f) "Gears, sprockets, and chains" -

1926.307(f)(1) "Gears."

Gears shall be guarded in accordance with one of the following methods:

(i) By a complete enclosure; or

(ii) By a standard guard as described in paragraph (o) of this section, at least 7 feet high and extending 6 inches above the mesh point of the gears; or

(iii) By a band guard covering the face of gear and having flanges extended inward beyond the root of the teeth on the exposed side or sides. A disk guard or a complete enclosure to the height of 6 feet shall be required where any portion of the train of gears guarded by a band guard is less than 6 feet from the floor.

1926.307(f)(3) "Sprockets and chains."

All sprocket wheels and chains shall be enclosed unless they are more than 7 feet above the floor or platform.

An ANSI Standard formatted sign is also recommended:

Monday, June 1, 2009

The rain in Spain falls mainly . . .

The water scupper for the stage house roof drain was located directly above the 2400 Amp 120/240 Volt disconnect and service entrance drip loops. If you look closely, you can see that even though the drain pipe goes off to the right, there is a scupper overflow hole directly above the disconnect.

When designing a theatre is it vital that the various design trades coordinate closely both inside and out. This can prevent conduits, pipes, and ducts from crossing catwalks and rigging systems, too.