dead hung battens: recommendations?

I have looked around and have seen a number of methods, some look strong, some pretty questionable. ours are questionable. We have 3 electrics, 2 borders, 2 long light fixtures (not sure what to call them), two projections screens. 360 degree photo below; there have been some additions to this since it was taken, including two more electrics.

Ceiling is plaster and wire mesh (built in the 30's by the WPA) above that giant I beams running along the US/DS axis. We have good access to above the ceiling. Whats there now is 1/4 aircraft cable with wire rope clips, looped around the I-beam and a loop on the end on the batten. Spacing is pretty wide. The borders actually are hung on what appears to be manilla or hemp rope up to an ancient pully system to mule blocks. Likely from the 50's. Yea, I know.

So running from the beam to the batten, what combination of cable, chain, hardware or what-not would you recommend, or do you use?

Thanks in advance...

Backus Community Center Stage, International Falls, 360 degree image

Rigging is not for beginners!

The solution should come from someone that can look at ALL the factors and devise a safe method. We don't have all that information and so can't really say what would or wouldn't work. You need an experienced contractor willing to put their professional liability insurance and reputation up against your and your child's lives. An experienced theatrical contractor might be hard to come by up there, but many travel the country doing exactly this sort of work. Flying one man (ETCP preferred,) in to supervise is not a huge expense when it's literally a life and death situation.

With that in mind: I feel I can tell you there are manufactured batten clamps, beam clamps, shackles, turnbuckles and such (rated for the loads needed) that most folks use. Many hardware store products are NOT suitable. There is a controversy over chain type: https://www.controlbooth.com/threads/questionable-rigging.38314/#post-332013, just to give you a feel for the issues. If you have a lot to do then aircraft cable (properly 'wire rope') is often cheaper. Any method done without knowledge and skill is just asking for trouble. Amateurs treading where the experts disagree is another level of crazy.

Most battens are made of 1.5" ID (1.9"OD) schedule 40 iron pipe and supported every 10'. I hope yours are made this way, but I've also seen some thin tubing used that isn't even structurally rated. I'm not fond of much of what I can make out in the photo. I like to design to 25lbs per foot with 100lbs point load between supports or at ends. That will hold most lighting and scenery loads you are likely to consider. Those are numbers your contractor can use to make a safe space.

Another issue is the roof. I would hope that the original design allowed for some theatrical loads, but they may have considered a few curtains too small to bother with calculations. Those strip lights are pretty minimal but modern lighting can be quite heavy. LED tend to come with large heat sinks and conventionals aren't made from sheet metal much anymore. It takes a structural engineer to determine how much can hang from the building. You have serious snow and wind load issues so a local would be best. I wouldn't add anything to that set up without a good look at the building and probably an engineers stamp on the plans.

I'm sorry to go all doom and gloom on you. There is too much that can go wrong and even liability issues with CB posting rigging instructions on the open web. If I've gone too far the mods will erase me - and I'm OK if they just want to erase details.

You have been very helpful and have given me food for thought. Thank you!

RickR pretty much pegged it.

My thought was nothing gets hung till a certified structural engineer takes a look at the existing roof structure.

Ultimately you can't hang anything without knowing the roof will stay up.

If you then draw up a plan for what you think you need and/or will end up with in the future, in terms of lighting and scenic needs, the engineer can tell you how to proceed.

You might check with the city or county engineering department about your concerns.
I assume the venue belongs to one of those entities.

It also looks like you might have sprinkler pipes in that area. You would definitely need to speak with the city/county engineering departments, and a call to the fire marshal wouldn't hurt either. The last thing you want is to get them all installed, and then have the fire marshal claim that something is obstructed.