Lighting Truss Suspension

[parcan2009]

Hi All,

 

I am a lighting designer, and I am currently working on a new nightlcub installation.

 

This installation is within an old warehouse, where they have cross girders. I am looking to suspend multiple truss' across the length of the warehouse.

 

I am unsure of how to suspend the rig. I am looking at daughty engineering under the girder clamp section (see below) are these clamps normally used on such installations?

 

http://www.doughty-engineering.co.uk/cgi-b...showprod_T28870

 

http://www.doughty-engineering.co.uk/shop/67/index.htm

 

What would be the best way to suspend a rig in this situation? There are 15 cross sections of steel girders. I am looking to install directly below and also inbetween the girders. There are no cross steels supporting the roof that I can suspend from on an axis for weight distrobution.

 

Any comments would be much appreciated!

 

Many Thanks,

 

Russ

[Jivemaster]

The safe way to hang a rig starts with a structural engineer's appraisal of the load bearing limits of the structure, unless you have good drawings with SWLs marked on them.

 

After that you must design a rig and calculate all the loads in trusses and their hangers, taking into account the dynamic nature of some (typ moving light) loads.

 

You certainly do NOT just go up and hang clamps on beams.

[parcan2009]

The safe way to hang a rig starts with a structural engineer's appraisal of the load bearing limits of the structure, unless you have good drawings with SWLs marked on them.

 

After that you must design a rig and calculate all the loads in trusses and their hangers, taking into account the dynamic nature of some (typ moving light) loads.

 

You certainly do NOT just go up and hang clamps on beams.

 

Hi there,

 

I have had a structural engineer do an assessment and all steels are capable of the loading required. I was tempted to employ a rigging company, but I have good experience in rigs as I am an electrical engineer by trade with buildings and structures.

 

I am just trying to figure out the best way to rig the equipment. I will be using standard square truss, and I intend on using steel cable to suspend from the girders.

 

Can you reccomend any sites that show examples, and also any companys that supply this type of equipment.

 

I am able to drill the structural steel, so I can put in eye bolts, but I'd prefer to stay away from this and use girder clamps. Basically I am looking to suspend between the structural steels, which would mean the steel wire needs to be applied at an angle, and I'm concerned to weather if not the girder clamps can be used with sheer loads aswell as torque loading.

 

Would wraping the steel wire around the girder with hook an eye bolts be good enough? Or would I need something that is more solid?

 

I am also tempted to suspend from standard lighting bars down to a triangular truss, as I could impliment a unistrutt system.

 

I am also going to be installing a complete led video system into the roof space, suspended via unistrutt.

 

Any comments and advice would be much appreciated. I am still at the design stage, so anything would assist me!

 

Many Thanks,

 

Russell

[ImagineerTom]

As part of the ultimate owners insurance requirements, and indeed your own professional indemnity insurance you'll be expected to be able to show that this job was designed/installed by a compitant person. The very fact you are having to ask these questions (very VERY basic questions in the world of rigging) establishes that you are not a compitant person so after doing all the work you'd have to get an expert in to check it all over. Save yourself a lot of time, money, hassle and problems by just getting an expert in now. You don't have to sub-out the whole job but please do at least have an EXPERT design and spec the system even if you subsequently install it yourself (to their spec and tollerances) as if you get this wrong lots of people get very badly hurt.

[kerry davies]

Hi and welcome;

being a newbie and not having given any details on your profile, not even what country you are in, it would be counter-productive for anyone here to respond other than to say get an expert in to advise you.

 

Basically you are asking for technical and safety advice on an open forum and anyone giving this without some idea of to whom they are giving it and under what circumstances would be a little unwise. Besides some of these guys get paid for this level of advice, it's their livelihood.

[david.elsbury]

I don't think you are likely to get answers on an internet forum, where might I add you have no idea who is giving you this advice- a 15 year old schoolkid, or a 25 year-experience pro rigger.

 

Furthermore, I agree with Kerry, we have no idea at all where you are, what laws may apply to rigging overhead structures such as a permanant rig, who you are, what you have experience in (other than the fact that your name is Russell and you are a "lighting designer").

 

If we give advice on here telling you how to do it and something terrible happens such as the rig collapsing, what are you going to say in court- I got advice off an internet forum?

 

If you get advice from a professional, who is experienced in this area, they will have the liabilty insurance to cover their back if anything goes wrong.... they will also have the experience and training to know what works, and what doesn't...

 

I am no rigger... but I do know that it's a little more than throwing stuff up in the roof and hoping for the best...

 

:(

[Ynot]

All of the cautionary comments made thus far are right on the button.

If you take time to read some of the posts here - especially in the safety forums - you'll see that as a rule we (that is those of us with more than fleeting experience in the industry) will have a tendency to jump on anyone either asking about or recommending potentially unsafe practices. This isn't because we're kiljoys, but because we have a genuine desire to make sure that anyone attempting this sort of thing does so as safely as possible. That may be by ensuring quality posts in replies, condemning poor advice from teens who think they know the answer because they saw it on telly, or - as in this case - recommending that the poster seeks proper advice from a qualified professional as we can't always advise on what we can't physically see.

 

Occasionally this can come across as being over-zealous when several people pounce on an individual, but at the end of the day advice given here could easily be quoted in a court should you make a serious error and attempt to mitigate your position by saying 'The Blue Room said it would be fine...'

 

Sorry if this doesn't help your question, but I fear you're going to have to spend some cash (or that of your client) to make sure you get this right. And if you've already quoted the client a figure for doing this job without including enough to cover proper assessments for the hanging points and methods, then I suspect you're going to see whatever profit you expect to make on this deal disappear rather quickly - on this and potentially other safety related items.

 

Bottom line is that if you're not experienced as an installation tech, then you're NOT the right man for an installaion job........

[chrismca09]

Personally I'd get the pro boys in to come in design and rig. They will be able to give a complete specification to suite your needs and give the best way of suspending your truss. I am worried about the load you wish to be hanging from the roof structure, You have just stated that you "have had a structural engineer do an assessment and all steels are capable of the loading required" this means nothing! what about the maximum load you can get off of this particular structure? What about what your hanging off the rig its self? have you taken into account the self weight of the truss system? Rigging company looks to be the way forward in my eyes....

[paulears]

Probably also worth noting that as it's a new venture, the owners will have to arrange insurance cover, and as new clients the insurance company will require them to have evidence stating the safety elements.

 

As you are providing items like truss, you will have to tell them what the maximum load will be - not for what you put on it, but for what others in the future will put on it. This comes up all the time. People post asking what load can be hung of XYZ truss they have found in a venue new to them. The answer is always 'have a look at the paperwork'. If there isn't any, the next answer is always to ask a structural engineer - so we're back at the necessity to have one involved. It need not be very expensive. Large form roof steelwork will be rated at far more than you need in many cases. Certainly when I've done projects like this, I always use a proper engineering company. My way of doing it is to get them in to attach drops of some kind to the building, and then rate those. One project recently involved a 100 year old theatre that had been demolished, apart from the original steelwork, and then re-built in modern materials around the original structural elements. I wanted to hang 17m of 4 chord truss (Litestructures was the one chosen). The load would be video monitors, some lighting and loudspeakers. Distributed load fine for the truss - but how many drops - quite long ones, from a curved massive girder - ornate and highly visible? All it took was a phone call to the engineers, an explanation of what I wanted to do, and the loads. A photo of the steelwork and an emailed diagram showing the point loads on the truss, and they made two visits to the site. First was because from my photos, they knew the brackets would have to be specially fabricated, the second was to fit them and just leave the cables for me to terminate to the truss fittings with hardware they supplied. Their paperwork was simple - and with the truss already quite full, there is still plenty of spare capacity if needed in the future.

 

Could I have done all this myself? Simple answer is no. I suspect the loading figures they supplied were not calculated at all - they were simply a vastly downrated guesstimate based on their knowledge and experience. These kind of firms are used to dealing in huge weights, nothing to do with just our industry - cranes, ships, industrial power stations - that kind of thing. They told me that the roof steelwork is massively over engineered, especially now that the actual building is probably half the weight of the original, and all these beams are now doing is supporting their own weight - the new roof being almost insignificant, being modern aluminium. I have no way of having this information, so I can't provide documentation saying it's safe, but the engineers can. Trying to do it yourself in this case has to be a two stage process. Simply inform your clients that a structural engineer needs to be involved to provide certification, then find one who can just do the bits you can't. Most will be quite happy. If you can't find one, PM me and I'll pass on the details of my one, if you are in the UK. Lastly,

Moderation:

Most members know, but new ones may not be aware, that the editing feature auto locks after a preset time. Just after you have posted you can go back and edit your posts. However - there is no way of removing posts. If members post something that then gets awkward after reading a newer one, it's considered poor forum etiquette to go back and remove the content. If you do need to do this because you've said something stupid or just plain wrong - then if the editing period has not expired, take it out - BUT LEAVE AN EXPLANATION so people reading the ones that follow can understand what happened. David replied and included some comment that without the original post make no sense (which I removed, sorry David). This doesn't really work. It's also worth remembering that once the time lock engages, you cannot edit anything - so always worth thinking before pressing the final button!

[SJEvents]

Hi All I'm new to this blue room thing... but I would love for some ideas on how to hang a 2m section of trilite truss at least 600mm lower than the existing single pole lighting bar. What would I need to so this... strops? shackles? etc.....

Cheers Sam

[david.elsbury]

Your best bet, if you are unsure, is to contact a qualiified and/or experienced rigger and to employ them to either train you to do so, or come and do the work for you.

 

Edit: I think my post above to the first OP sums it up pretty well, in fact. Quoted for reference:

 

I don't think you are likely to get answers on an internet forum, where might I add you have no idea who is giving you this advice- a 15 year old schoolkid, or a 25 year-experience pro rigger.

 

Furthermore, I agree with Kerry, we have no idea at all where you are, what laws may apply to rigging overhead structures such as a permanant rig, who you are, what you have experience in (other than the fact that your name is Russell and you are a "lighting designer").

 

If we give advice on here telling you how to do it and something terrible happens such as the rig collapsing, what are you going to say in court- I got advice off an internet forum?

 

If you get advice from a professional, who is experienced in this area, they will have the liabilty insurance to cover their back if anything goes wrong.... they will also have the experience and training to know what works, and what doesn't...

 

I am no rigger... but I do know that it's a little more than throwing stuff up in the roof and hoping for the best...