Showing posts with label Wire rope termination. Show all posts
Showing posts with label Wire rope termination. Show all posts

Tuesday, August 13, 2013

Risk Management for Rigging from ProSoundWeb

Andrew Martin, the originator of ATM Flyware, wrote a good guide for managing your show rigging assets in the March 28, 2013 edition of ProSoundWeb.  The article provides a short overview of Risk Management Guidelines and provides a series of example graphics to show you specific points of concern to watch-out for.
Example of SpanSet / Round Sling Inspection Points
The article can be found here:  www.prosoundweb.com/article/hanging_out_risk_management_for_rigging

Monday, July 1, 2013

Cirque du Soleil suffers tragic loss of performer during show accident

MGM Grand, Las Vegas, Nevada - Saturday, June 29, 2013.   In a yet-to-be-explained equipment failure, one of the aerial performers in Cirque du Soleil's fell about 50 feet from above the show's massive 3-axis moving stage into the forestage pit during the fight scene at the end of a performance.  The pit is nearly 4 stories deep.  Sarah Guyard-Guillot, 31, mother of two, came loose from her safety cable and disappeared into pit unexpectedly.  The show was halted, the audience informed that they could obtain replacement tickets for a future show, and were dismissed.  The show has been suspended indefinitely pending an investigation into the root cause of the accident.  Guyard-Guillot, mother of two young children, was pronounced dead at a hospital late Saturday night.  It is reported that her safety harness was intact with her costume when she was recovered from the accident site.  She was a trained acrobat and aerialist, originally from Paris, France.  She had performed in the industry for about 22 years.
Sarah Guyard-Guillot  1979-2013

This is the first performance-related death that the troupe has experienced in over 30 years of show production.*  Guyard-Guillot was one of the original performer's in the show when it opened in 2006, and had performed the show since then.

An extremely through and rigorous safety program is entrenched in the companies' culture, so this has been shock to those that work the shows in a tight-knit group.  Cirque's safety managers have been very transparent and informative by sharing their safety culture and knowledge at numerous industry events like the annual USITT convention, LDI convention, and UNSCA's Entertainment Innovation Conference.

The death comes at an unfortunate time for the circus, a reportedly $1 Billion (US) company which employs 5,000 people globally, including 2,000 at its headquarters in Montreal, Canada.  Cirque maintains around 19 touring productions in operation worldwide, yet has recently reduced it's workforce and is trying to reign-in its expenses.

Cirque du Soleil's founder, Guy Laliberté, said in a statement:  "I am heartbroken. I wish to extend my sincerest sympathies to the family. We are all completely devastated with this news.  Sassoon was an artist with the original cast of KÀ since 2006 and has been an integral part of our Cirque du Soleil tight family. We are reminded, with great humility and respect, how extraordinary our artists are each and every night. Our focus now is to support each other as a family. " 

A thorough write-up about this incident can be found at Jim Hutchison's Jim On Light site:
www.jimonlight.com/2013/07/01/tragedy-at-ka-in-las-vegas-sarah-guyard-guillot-falls-to-her-death-during-final-fight-scene

Local news coverage:
www.kctv5.com/story/22726807/spectator-on-cirque-death-i-thought-there-was-a-net

www.lasvegassun.com/blogs/kats-report/2013/jun/30/cirque-suffers-another-accident-artist-falls-ka-mg

~*~*~*~*~*~*~*~
* In 2009, a Cirque performer died in Montreal after sustaining head injuries from falling off a trampoline during training. Oleksandr Zhurov, who was 24, hailed from the Ukraine and was known as Sacha. There also have been several injuries during Cirque performances in the last decade. Actors have been hurt during performances of "Zumanity" in Las Vegas, Nevada; "Corteo" in Portland, Oregon; and "La Nouba" in Orlando, Florida.

The same night as the deadly fall during , Cirque's newest show, "Michael Jackson: ONE," held its opening night performance at the Mandalay Bay Resort and Casino in Las Vegas. That production experienced its own trouble the previous week.

On Wednesday, June 26, 2013, Cirque reported that an acrobat taking part in one of the final preview performances suffered a mild concussion after slipping through slack rope in the show's "Stranger in Moscow" scene. That performer, who is expected to return to the production, missed a protective pad below the actors and landed hard on the stage.
~#~#~#~#~#~#~#~#~#~#~#~#~
FOLLOW-UP
OSHA FINES CIRQUE DU SOLEIL AND MGM GRAND
FOR PERFORMER'S DEATH AND OTHER CONCERNS

2013-10-29  - Nevada OSHA has finished its investigation into the death of Sarah Guillot-Guyard, the Cirque du Soleil performer who fell 94 feet during the climactic scene of Ka on June 29, 1013 and later died.  OSHA determined that accident happened when the wire rope she was suspended from broke. According to the report, the wire rope “was severed due to the rapid ascent of the performer, ultimately causing the rope to be freed from the sheave/pulley and scraping against a shear point.”  OSHA officials cited Cirque du Soleil with six proposed citations and more than $25,000 in fines and MGM Grand with three citations and a $7,000 fine.  Cirque du Soleil and MGM are appealing the fines.

One of the citations for Cirque du Soleil includes a failure to “protect or prevent Ka employees from striking an overhead grid during the Ka show at the Ka Theater.” Reporting for the Las Vegas Sun, John Katsilometes wrote that “This matches reports from those familiar with the Ka staging and fatal incident that Guillot-Guyard did hit the metal grid over the stage as she ascended high above the Final Battle scene, which jarred the rope connecting her to her harness.” Katsilometes also reported that Cirque du Soleil will be appealing the fine:

    In a statement that also referenced Cirque’s internal review of the incident, [Cirque du Soleil spokeswoman Rene-Claude Menard] said: “Cirque du Soleil completed an exhaustive review of its safety policies and procedures in the wake of the tragic accident involving Sarah. We have redoubled our efforts to ensure the overall diligence and safety of our performers and crew. We have received and reviewed the OSHA citations. We have initiated the appeal process as part of OSHA’s administrative protocol. Safety always has been the top priority for Cirque du Soleil, its performers and crew members.”

On the KTNV website (www.jrn.com/ktnv/news/Cirque-du-Soleil-MGM-Grand-cited-in-KA-performers-death-229744241.html), Krista Hostetler listed the citations OSHA has proposed. They are:

Summary of Cited Violations

Cirque du Soleil:
- NRS 618.375 (1): A General Duty Citation was issued because the employer did not protect or prevent KA employees from striking an overhead grid during the KA show at the KA Theater. $7,000 proposed penalty.

- The first part of the General Duty Citation was issued because the employer did not provide proper training for the KA Battle Spearman Warrior employee involved in the accident in the use of equipment and tasks used in the Ka show, battle scene at the KA Theater.

- The second part was issued because the employer had a Fall Protection Program with construction requirements that do not apply to theater settings because the KA Theater is regulated by Nevada OSHA general industry standards. $7,000 proposed penalty.

- 29 CFR 1910.132: This citation was issued because the employer did not properly assess the workplace for hazards that required personal protective equipment at the KA Theater, including opensided floors, bloodborne pathogens and other potentially infectious materials, pyrotechnic dust cleanup, and not finalizing a hazard assessment for the performers. $7,000 proposed penalty.

- 29 CFR 1910.132: This citation was issued because the employer did not certify that a workplace hazard assessment had been performed and did not include the date the hazard assessments were conducted. $0 proposed penalty, grouped with the proposed citation above.

29 CFR 1904.32: This citation was issued because the employer did not include on the OSHA Form 300 Log of Injury and Illnesses, the object or substance that directly injured or made a person ill, which prevented a trend analysis and kept the employer from recognizing and conducting employee training involving recurring injuries in accordance with Nevada Revised Statute. $3,300 proposed penalty.

Nevada Revised Statute 618.379: This citation was issued because the employer removed equipment from a fatality site on June 29 before Nevada OSHA authorized the dismantling and removal of the equipment (38 feet of wire rope that was attached to the victim at the time of the accident). $935 proposed penalty.

MGM Grand Hotel & Casino:

- NRS 618.375: This General Duty Citation was issued because MGM Grand employees were exposed to hazards due to deficiencies in the Cirque du Soleil Fall Protection Program with construction requirements that do not apply to theater settings because the KA Theater is regulated by Nevada OSHA general industry standards.

- 29 CFR 1910.132: This citation was issued because MGM Grand employees were exposed to hazards due to the deficiencies in Cirque du Soleil hazard assessments for the KA Theater that included opensided floors, bloodborne pathogens and other potentially infectious materials and pyrotechnic dust cleanup. $7,000 proposed penalty.

- 29 CFR 1910.132: This citation was issued because MGM Grand employees were exposed to hazards due to deficiencies in the Cirque du Soleil hazard assessments because Cirque du Soleil did not certify that a workplace hazard assessment had been performed and did not include the date the hazard assessments were conducted. $0 proposed penalty, grouped with the proposed citation above.
 

Wednesday, April 24, 2013

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:

    Monday, January 21, 2013

    Have we learned nothing?

    The festival season starts early in the south, and Mardi Gras is one of the first events we see set-up for numerous stages and shows.  Outdoor festival stage canopies have proven to present opportunities for accidents because they have large surfaces that can be caught by side winds and uplifting plow winds.  To counter-act the forces developed by gale-force winds, event riggers rely heavily on large ballast weights to tie-off canopy structures in an attempt to anchor the framework to the ground.


    These ballast weights work well if they are massive enough for the predicted winds and effective 'sail area' presented by the canopy roof and side walls.  If they are too light, the ballast weights will just be dragged across the ground and bulldoze a path of their own.  Slippery grass, or dirt that turns to mud, just act as a lubricant to free the ballast weights up for sliding in the event of a downpour, so anchoring or pinning the ballast weights to keep them from moving is also part of a good rigging plan.  (The ballast weights shown above were not pinned or anchored to prevent sliding)

    Wind is not a steady-state event.  You know that.  It gusts.  It starts and stops.  It changes direction.  It generally whips everything around a bit as it works it mayhem.  For this reason, we need to use secure connections on the guy wires for the ballast weights and stabilizing X's that are used to stiffen the structures against parallelogram movements.  If you don't, a gust of wind can slack the line, unhook the conenction(s), and you loose all anchoring in the blink of an eye.


    As you can see above, the anchor ties used in the blocks in the first picture are common ratcheting tie-downs in the trucking industry, and they only have a open hook at the load securing end.  This may be de rigueur for the transport industry, but it's a no-go for event safety.  If the wind gets to blowin' and this bad boy comes loose, it could rip the flesh right off of someone unlucky enough to get in it's flailing path.

    So, it was bad enough to see the above tie-down terminations at almost every corner of the stage, but then I looked further up the anchor line and found this:


    Each anchor line had two possible points of failure.  Three stages and a major cable bridge over the street, all in close proximity, four to eight anchor blocks secured in this manner for each one, and two possible failure points per securement.  All of this within a city block of a major open waterway (read: obstruction-free wind-path).  Personally, I don't like those odds.

    The City is relying on the Event Producers to Employ Staging Subcontractors that will erect facilities that will be safe for the (possibly highly intoxicated) general public to hang-out around and potentially be leaning-on, climbing on, or even messing with.  Plan for the worst, and you may have a chance of having an incident-free event, but if you leave opportunities for failures in the system like are shown above, be ready to pay the piper (or at least the plaintiffs).

    Follow-up to commenter:
    If you are going to use ratchet-straps to secure anything (subject to load rating), then utilizing products that have a self-closing clip is highly recommended.  Here is a picture of that type of ratchet and clip:


    It is also recommended to have a wire rope safety cable that runs in parallel with this, preferably one that is only slightly longer than the final tensioned length of the ratchet strap.  This can prevent a total release of the system should the ratchet strap fail.  Fabric based straps and slings are subject to weakening due to abrasion, minor cuts, and rot.  Straps exposed to sunlight have shortened lifespans due to the exposure to UV light which weakens the fibers.

    Friday, March 30, 2012

    Show me a little tail, please

    The crimp oval on the left is done with a bit of the cable exposed above the metal, as it should be.

    On the right, we have one that came-up a bit short.  To get full strength out of the crimp it must be compressed down around ALL of the cables.

    Copper crimp ovals are preferred over aluminum ovals due to reports of cracks and splits in the softer aluminum.  Check your cable terminations regularly to see that they holding-up and were done correctly.
    Common tool manufacturers for compression fittings are:
    Also notice the split link used to connect the chain back to itself.  This device is not rated for overhead lifting and, therefore, should not be used for stage rigging.

    Wednesday, February 2, 2011

    RigCalc for smart phones and on the web

    D2 Flying Effects are riggers that fly people and things.  They are also pretty savy programmers, too.  At their web site you can find RigCalc and a bevy of other software tools for making life on the fly rail easier.

    They also have a Rigging Math Primer online at: www.d2flying.com/riggingmath/

    There are a bunch of really handy online calculators at: www.d2flying.com/RigCalc.html

    The smart phone app looks like this (2 of 4 screens shown):



    A really handy app for stackin' steel bricks.
    If they add a batten loading calculator to get the needed weight it will be great.

    Just $9.99.  Where to get it: http://www.androidzoom.com/android_applications/productivity/rigcalc_qmvr.html

    Also available for the iPhone and Blackberry with links at: http://www.rigcalc.com/
    Other related blog entries:

    http://theatresafetyblog.blogspot.com/2010/03/in-god-we-trussed-all-others-pay-499.html
    http://theatresafetyblog.blogspot.com/2009/12/jr-clancy-releases-irigging-application.html
    http://theatresafetyblog.blogspot.com/2010/06/arena-rigging-app-for-iphone.html

    Tuesday, June 8, 2010

    Arena Rigging App for the iPhone


    OK, you can use it other places you need a bridle, too (except horseback riding).  It's still handy, just as long as you use it on the ground and don't try to use your iPhone while straddling an iBeam.  Keep that loose stuff ON THE GROUND!  It's also handy for checking your ability to do these calculations IBM -(It's Better Manually) for the ETCP Rigging Tests.

    Where to get it:  http://www.bridleapp.com/

    Other related blog entries:
    http://theatresafetyblog.blogspot.com/2010/03/in-god-we-trussed-all-others-pay-499.html
    http://theatresafetyblog.blogspot.com/2009/12/jr-clancy-releases-irigging-application.html

    Friday, April 9, 2010

    Get a grip - a really tight grip

    Tools for crimping compression ovals onto wire rope cable can be, shall we say, a bit unwieldy at times.  Actually, almost always.  An if you are not built like a linebacker, they can flat wear you out if you have dozens - nay hundreds - of crimps to perform.  Enter a really workable solution from Nicopress:  The
    Nicopress® Model 5606.  Much cooler than Luke Skywalker's Light Saber (but only because you can actually own one of these).



    Features:
    • One hand operation; lightweight & slim
    • Visible orange weather resistant housing
    • Audible bypass when predetermined pressure is achieved
    • Crimping jaws can be opened mid-cycle to adjust connection
    • Crimp cycle time:  Less than 6 seconds
    • Battery charge time: Less than 1 hour, about 250 sleeves for 1/4" wire rope can be compressed per charge.
    • Jaws rotate 360 degrees for ease of use in confined spaces.
    • Weight: 6.75 lbs. with Lithium Ion Battery
    • Dimensions: 20.5" L x 4" H x 2.5" W
    • Wire Rope Die Sizes: 3/64" thru 5/16" diameter

    The top button (thumb) initiates the crimp action, and the bottom button releases the jaws.

    Interesting side note:  The crimp dies for 1/4" wire rope only require two compressions, unlike the hand tool's three, so when you are doing inspections, and find fewer crimps, it doesn't necessarily mean that it was done wrong, but instead it may have been done with a different tool / die than what you are accustomed to seeing.

    Info at:  www.nicopress.com/products/toolh-wr-5606

    Thursday, April 1, 2010

    Getting NOT Kinky - Fire Curtain Release Perimeter Line

    If you have a Fire Curtain in your theatre, then part of that protective system is a fire control line that surrounds the Fire Curtain perimenter on three sides (stage left, top, & stage right) and has fusible links that will separate should there be a fire in the immediate vicinity of the Fire Curtain.  That line must be a small diameter (3/8" fiber rope or 3/32" diameter 7x19 wire rope) cable so that it bends easily and move freely through the pulley blocks at the corners of the Fire Curtain.  Ref: 2010 NFPA 80, Section 20.7.3.2.

    The bend radius of the cable is known as the D:d ratio.  This represents the ratio of the pulley sheave diameter (D) to the cable diameter (d).  The for 7x19 stranded wire rope the recommended D:d ratio is 51:1, so the recommended sheave diameter for 3/32" diameter cable is 51 x 3/32, which equals 153/32, or about 5".  The minimum ratio is 34:1, which is means that a 4" pulley is typically used as they are commonly available.  Ref: American Iron and Steel Institute "Wire Rope Users Manual, 2nd Edition", Table 9.


    In the picture above we have a variety of design issues:

    • The cable is 1/8" diameter plastic-coated wire rope.  It is a bit larger diameter than the required 3/32", so it would require an even larger sheave, about 6".  As you can see, the pulley is only about 1-1.5" diameter, or about 1/4th the required size.  This can cause the cable to 'take a set' and get a kink in it so that it doesn't want to move freely through the sheave.  I've seen wire rope as large as 1/4" diameter used with pulleys like this - and they definitely take a set after resting immobile for years on end.

    • The cable's plastic jacket might melt and gum-up the works should there be a fire - not good.

    •  Although this rigging point isn't bearing a significant load, it's still jsut bad juju to use pot-metal dime-store clothes-line pulleys, twisted-link 'dog chain', and quick-links to string stuff up.  Man-up and install it right with load-rated equipment - after-all, this is a Fire Curtain System, not just a trick-line for a one-act play!
    Test your Fire Curtain System every 90 days. Ref: 2010 NFPA 80, Section 20.7.1.3.
    Have your Fire Curtain System Inspected Annually.  Ref: 2010 NFPA 80, Section 20.9.1.

    Friday, March 26, 2010

    In God we Trussed - all others pay $4.99

    Xtreme Structures (Sulphur Springs, Texas) (http://www.xsftruss.com/)  has introduced a new iPhone app called iTruss.  It provides simple weight calculations for trusses with various loading configurations.  It's always good to check your load calculations thoroughly.  Nobody wants to call an aMbulance.

    Also see the TheatreSafetyBlog entry for the iRigging app:

    Wednesday, December 9, 2009

    J.R. Clancy releases iRigging Application


    It's always good to have rigging information at your fingertips - it sure beats guessing or digging in your tool box for that chart of numbers. J. R. Clancy has turned its popular rigging slide rule tool into a free iPhone application. Installers and users of theatre stage rigging should find this handy. The new application delivers instant information in English and metric (SI) units.

    iRigging provides wire rope data, including: minimum sheave diameter; cable breaking strength; and recommendations for quantity of cable clips, wire turn-back for cable clips, proper torque for cable clip bolts, and Nicopress sleeve crimp quantities. Other data includes: allowable fleet angles, uniform and midpoint batten loading, arbor capacity, weight of counterweights, recommended working loads for equipment, motor current, stage ropes, and weight of stage fabrics.

    The tool is free and currently available at Apple App Store.

    More information about J. R. Clancy is available at www.jrclancy.com. As of this date there is no information available about the iRigging application on their web site.

    Note: The app does not include iCommonSense, so you have to provide that yourself. It does feature standard GIGO* operation, though.

    * Garbage-In yields Garbage-Out

    Have fun with it, just don’t be an iDiot and drop your iPhone from the iGrid – it might hit someone in the iHead. Has anyone released the iLanyard to keep this from happening?

    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.

    Thursday, May 14, 2009

    Wire rope cable termination gone wrong - very wrong


    (Sigh) What can I say that this picture doesn't? Obviously, the proper way to terminate a wire rope was not in this person's skill set. Good intentions mean little if someone gets injured due to a rigging failure.

    • Know your load.
    • Know your cable strength.
    • Know how to apply a safety (design) factor for live loads vs static loads.
    • Know the efficiency (derating) of the termination method (Crosby's are different than Nicopress).
    • Know how to install a cable thimble.
    • Know how to terminate it for maximum safe load carrying capacity.

    If you use cable clips ("Crosby's"):

    • Know how to install them ("Never saddle a dead horse" means don't install the forged cable grip over the unloaded tail of the cable).
    • Know how many you need.
    • Know the spacing required.
    • Know the torque of the bolts/nuts and use a torque wrench to achieve it.

    If you use crimp-on sleeves ("Nicopress"):

    • Know how to install them.
    • Know how many you need.
    • Know the spacing required.
    • Know which axis of the compression oval is to be crushed (crimped).
    • Know how to check and adjust the crimping tool so the die properly siezes the compression oval.
    • Use a Go / No-Go gauge to check your finished crimps.

    {Photo courtesy of 'Curiousbrandt' on Flicker}