When to Replace Birdcaging Wire Rope?

[TJScalzo]

Hi everyone, this is my first post here so I apologize if I've missed anything or should be posting this elsewhere.

I was recently hired as the "general theatre technician" (one-person department) for a high school with a good number of different venues, each with their own quirks. There hasn't been anyone in the position for a number of years, so I am now responsible for all of these spaces without any explanations of their specific technical systems. I have been getting acquainted with the spaces and discovering how everything works on my own for the past couple months.

I have just discovered that the two large pendant lights over the audience in one of the venues are each supported by a single line of wire rope attached to hand-cranked winches. When I flew them in to replace their light bulbs, I observed a couple instances of bird caging on the lines. Looking at the system as a whole, it seems at least one of the winches wasn't aligned correctly with the guide pulley above, so the wire rope has been wound around the drum unevenly for a number of years.

Based on my relatively limited rigging experience, all of these factors are cause for concern and the wire rope should be replaced at the very least. Ideally, the whole winch system would be reconsidered and/or rearranged to allow the line to wind onto the drum evenly. However, as we're nearing the end of the school year, I have been told that my department doesn't have the budget to have a vendor come in anytime soon.
I was able to submit a work order to have an electrician and a carpenter from the city come and look at it. Although they admitted that rigging wasn't their areas of expertise, they both didn't seem too concerned since there's no visible fraying or breakage. They didn't feel the need to elevate this to an emergency safety concern.

I've attached images of the bird caging as well as the winch system and pendant light.

I have always believed that being overcautious is better than someone getting hurt. I originally believed this was an emergency that needed to be fixed as soon as possible, but in this situation I'm outnumbered. I just got out of college. I'm still proving myself as a theatre professional at this school. The city employees didn't think that this was an issue, so I'm questioning my rigging knowledge and how serious of a problem this actually is.

How much of an immediate concern should this be? Does anyone have suggestions of professional riggers or rigging companies in Connecticut that could come do an inspection? If replacing this rigging system got added to a list of big budget items for next school year, would that timeline be okay?

These pendant lights will probably only have to fly up and down once every couple of years to replace their light bulbs. It's entirely possible that this was the first time they were moved in the last decade. The pendants are probably at least 400lbs each and are hanging directly over the audience. I'm in a position where I could push for the emergency removal/replacement of these pendants and their rigging, but I don't want to cause a huge fuss if it's not that serious.

I apologize for such a long post. Any advice would be much appreciated. Thank you in advance.

 

[dblack]

You've got a tough gig and beautiful pendants. You are right to be concerned, they should absolutely be addressed. They probably won't fall tomorrow. When I see one item in a venue like this, I start to look at other things too. Equipment damage due to age and/or low maintenance is contagious.

For inspections at secondary schools, a subsidy program exists...
Also a search engine for participating firms.
https://www.usitt.org/rsi

 

[StradivariusBone]

Coming from a venue that had zero access to houselights, it's nice that someone took the time to make a system to accomplish that relatively safely. It kinda looks like the winch drum bend radius is too small and might be causing it to unwravel, especially if the pendents are indeed that heavy. I agree with what's been said, it probably won't fail immediately but once steel deforms it no longer is at the original strength so you're definitely right to be concerned.

 

[Van]

Good that it's a Thern winch. That picture of the Idler/Mule/ whatever, block on the wall looks like the anchors facing the camera are failing and the mount is pulling away from the wall?!? Personally I'd want to see that pulley replaced, have the fleet angles addressed, and the wire rope replaced. If no one has been in your position for a while push, extremely hard, for a full rigging inspection by a reputable company.

 

[TJScalzo]

You've got a tough gig and beautiful pendants. You are right to be concerned, they should absolutely be addressed. They probably won't fall tomorrow. When I see one item in a venue like this, I start to look at other things too. Equipment damage due to age and/or low maintenance is contagious.

For inspections at secondary schools, a subsidy program exists...
Also a search engine for participating firms.
https://www.usitt.org/rsi

Thank you for the link to the subsidy program. It looks like the spring deadline just passed, but I'll keep it in mind for the fall.

Coming from a venue that had zero access to houselights, it's nice that someone took the time to make a system to accomplish that relatively safely. It kinda looks like the winch drum bend radius is too small and might be causing it to unwravel, especially if the pendents are indeed that heavy. I agree with what's been said, it probably won't fail immediately but once steel deforms it no longer is at the original strength so you're definitely right to be concerned.

I appreciate the way you phrased this. Every time I tried to explain why the bird caging was concerning, the city employees were dismissive since there weren't any broken strands.

Good that it's a Thern winch. That picture of the Idler/Mule/ whatever, block on the wall looks like the anchors facing the camera are failing and the mount is pulling away from the wall?!? Personally I'd want to see that pulley replaced, have the fleet angles addressed, and the wire rope replaced. If no one has been in your position for a while push, extremely hard, for a full rigging inspection by a reputable company.

I've attached some close-up photos of the block above the winch. It seems like it was unevenly sunk it into the drywall when it was installed. I haven't noticed any loose anchors when flying the pendant, but I guess it would need to have all tension on the line released to know for sure if it has pulled away from the wall. I'll keep an eye on it as well as the wire rope.

I wasn't aware of the term "fleet angle" before. It's good to know there's a way to describe how centered the wire rope is with the winch drum. I will definitely pursue a full rigging inspection to catch anything else that may be wrong in these spaces.


Thank you all for your advice on this! I'm glad to hear it's not an overreaction to want to fix this system.

 

[kicknargel]

Question: are the damaged areas of cable in play while the pendant is in it's standard position (only exposed when flown in for service)?

I do think it unlikely that this would suddenly catestrophically fail from this state without further observable wear. And it's much less likely to fail while hanging statically, rather than while being cranked when presumably no one would be in harm's way.

You could increase confidence by adding a redundant safety line until the system can be maintained.

 

[Crisp image]

To fix or at least reduce the fleet angle the winch should be moved closer to the wall. This would also reduce the leverage on the wall bracket fixtures connecting it to the wall. If when the cable is wound on the drum with the pendent at full height the damaged cable is as least 3 full turns on the drum (and it is neat and tidy) the stress on the damaged section would be minimal due to the friction of the wraps on the drum. It still needs to be replaced to ensure safety standards are maintained.
Regards
Geoff

 

[egilson1]

First, I commend you on your astute observation. Good catch.

Second, the bird caging you see is not uncommon on manual pile on winches like these. We see it all to often on applied electronics manual crank up winches (or boat trailer winches for the matter). It's usually caused but the wire rope not wrapping back and forth on the drum, which on tis style of winch is operator error in terms on not watching the wire rope as it wraps onto the drum. The fleet angle is certainly not making that task any easier.

BUT, there is another potential culprit. The block groove looks to be WAY oversized for the wire rope diameter which could be allowing the wire rope to flatten out when it travels along the sheave. This would also cause the wire rope to open up as in the photos. So I would recommend swapping those out for a block with the matched groove size to the wire rope diameter.

And finally, I'm based in Boston and do a lot of work in CT. We can certainly look at the option of me coming down to evaluate what's going on in person.

Regards,
Ethan

 

[TJScalzo]

Question: are the damaged areas of cable in play while the pendant is in it's standard position (only exposed when flown in for service)?

I do think it unlikely that this would suddenly catestrophically fail from this state without further observable wear. And it's much less likely to fail while hanging statically, rather than while being cranked when presumably no one would be in harm's way.

You could increase confidence by adding a redundant safety line until the system can be maintained.

To fix or at least reduce the fleet angle the winch should be moved closer to the wall. This would also reduce the leverage on the wall bracket fixtures connecting it to the wall. If when the cable is wound on the drum with the pendent at full height the damaged cable is as least 3 full turns on the drum (and it is neat and tidy) the stress on the damaged section would be minimal due to the friction of the wraps on the drum. It still needs to be replaced to ensure safety standards are maintained.

From what I can tell, the damaged areas of cable are buried beneath layers of other cable when the pendant is at the ceiling. Whether it's 3 full turns that are neat and tidy is harder to say. I tried my best to motivate the cable to wrap evenly when I flew it out, but the high fleet angle made that very difficult. Adjusting the placement of the winch would help immensely.

 

[TJScalzo]

First, I commend you on your astute observation. Good catch.

Second, the bird caging you see is not uncommon on manual pile on winches like these. We see it all to often on applied electronics manual crank up winches (or boat trailer winches for the matter). It's usually caused but the wire rope not wrapping back and forth on the drum, which on tis style of winch is operator error in terms on not watching the wire rope as it wraps onto the drum. The fleet angle is certainly not making that task any easier.

BUT, there is another potential culprit. The block groove looks to be WAY oversized for the wire rope diameter which could be allowing the wire rope to flatten out when it travels along the sheave. This would also cause the wire rope to open up as in the photos. So I would recommend swapping those out for a block with the matched groove size to the wire rope diameter.

And finally, I'm based in Boston and do a lot of work in CT. We can certainly look at the option of me coming down to evaluate what's going on in person.

Regards,
Ethan

I suppose it's good to know that this kind of thing isn't unexpected on a winch system like this one. I tried my best to make the the cable wrap evenly when winding it up most recently, but from how difficult the fleet angle makes that, I wouldn't be surprised if whoever did this before me did not care to try.

I hadn't considered the groove size of the block and the wire rope's diameter being mismatched. There are many elements of this system that don't make sense. For another thing, the cable simply disappears into a roughly cut hole in the drywall with no guide or protection from friction making the hole bigger.

I appreciate your insight on this, Ethan! We worked together briefly when I was at Emerson and I should have thought to reach out directly. I just sent you an email.

 

[dblack]

A bit of reunion here, I see.

Ethan, I worked a bit with you at ALPS.

TJ, I think I recall your face in the back hall of the Maj. I PM'd Christmas Celtic Sojourn for years.

 

[egilson1]

A bit of reunion here, I see.

Ethan, I worked a bit with you at ALPS.

TJ, I think I recall your face in the back hall of the Maj. I PM'd Christmas Celtic Sojourn for years.

Dan Black? Is that you?