some opinions please

[Impact Pete]

I'm looking at flying a 3m scaff bar to support 4 x 3 kilo led fixtures, the beam luckily enough is a very overengineered 10" x 4" girder brace. (it is not an I beam just solid.

 

I don't want over the top rigging as this is a permanent install but it has to meet safety requirements and so I was wondering what people might do in this situation, It has to look neat and tidy and using an ali scaff tube with fixtures and cabling will not weigh more than 30kilos in total.

 

Have thought about getting fixed steel engineered straps using 1/8" steel made up but if there is something off the shelf it would make more sense, would of been easier with an I beam..

[Brian]

...just solid.

I assume you mean it's a box section not that it's solid.

[Impact Pete]

...just solid.

I assume you mean it's a box section not that it's solid.

 

Yep meant box section, not as in 10" x 4" solid steel! I think the walls would buckle under the weight!

[Brian]

Boxbolt.

 

Basically it's a rawlbolt but for use on steel.

[Modge]

Boxbolt.

 

Basically it's a rawlbolt but for use on steel.

Rivnuts http://www.memfast.co.uk/ would be of interest in a similar context then. They do need a special tool (quick search spotted one for £13 on ebay) to put them in, but for fixing things to metal they are very useful. You're left with a threaded hole in your choice of size up to at least M12.

[Seano]

Is the top of the beam exposed?

If its slingable, I'd probably sling it.

Eg: PVC coated 4 or 6mm steel wire rope sling, closed into a basket with a single (bolt) anchor shackle, with a SWR drift if required.

Personally, I prefer not to drill holes in structural steelwork if its easily avoidable, not least of all because its hard work.

 

While the load you're putting on the lighting bar is very small, how certain are you that nothing more substantial will ever be rigged on it?

I think I'd prolly want the bar to be able to support rather more substantial lighting fixtures than the wee LED thingamabobs you're putting in - if you hang it, they will come! ;)

 

edited to clear up a typo

[jonathanhill]

Sling it with a poly wrapped steel if you can. To ladder beam if possible. See Seano's post. He speaks truths.

[Impact Pete]

Is the top of the beam exposed?

If its slingable, I'd probably sling it.

Eg: PVC coated 4 or 6mm steel wire rope sling, closed into a basket with a single (bolt) anchor shackle, with a SWR drift if required.

Personally, I prefer not to drill holes in structural steelwork if its easily avoidable, not least of all because its hard work.

 

While the load you're putting on the lighting bar is very small, how certain are you that nothing more substantial will ever be rigged on it?

I think I'd prolly want the bar to be able to support rather more substantial lighting fixtures than the wee LED thingamabobs you're putting in - if you hang it, they will come!

 

edited to clear up a typo

 

Hi I feel the same I'm not going to drill into a big beam, as for the bar I will put a load rating sticker on it and make sure that is listed in the paperwork, also it is very doubtful that anyone would put anything else on it as the venue is not production based. But you never know!

 

A concurrent post has been automatically merged from this point on.

 

Sling it with a poly wrapped steel if you can. To ladder beam if possible. See Seano's post. He speaks truths.

 

I like that idea mainly as the top of the ladder can go right up to the beam leaving bottom easier to hang off and giving a lower drop which might be required

[ImagineerTom]

just to correct #5 - rivnuts are NOT structural, generally not rated and I personally wouldn't stand under anything that's being held up by them. They're intended to be used in paneling situations where the overall shape and sheer volume of them used, combined with the "non critical" nature of use means it's not an issue.

 

In short, they're for cosmetic situations only.

[Modge]

just to correct #5 - rivnuts are NOT structural, generally not rated and I personally wouldn't stand under anything that's being held up by them. They're intended to be used in paneling situations where the overall shape and sheer volume of them used, combined with the "non critical" nature of use means it's not an issue.

 

In short, they're for cosmetic situations only.

Really?

Not what I was hold (obviously or I wouldn't have repeated it). I'll pass that along to some one who seemed to think otherwise.

[ImagineerTom]

They're basically a pop rivet - there's a token amount of pull strength they have but it's nothing compared to the 10ton+ sheer strength anything held up by an M12 would be expecting

[Matthew Robinson]

Boxbolt.

 

Basically it's a rawlbolt but for use on steel.

Rivnuts http://www.memfast.co.uk/ would be of interest in a similar context then. They do need a special tool (quick search spotted one for £13 on ebay) to put them in, but for fixing things to metal they are very useful. You're left with a threaded hole in your choice of size up to at least M12.

 

Isn't that just a tap? In which case, would it not be better to get a tap set of a suitable size?

[Pete McCrea]

A rivnut is a cross between a rivet and a nut ( see what they did with the name there? Clever.....) basically you drill a hole, insert the rivnut, then apply the tool. The tool pulls the threaded portion of the rivnut upto the back of the material, like a rivet, leaving a flange on the outer edge of the material and a compressed section then thread at the rear. Used by Da Lite et al on fastfolds screens where the legs screw into the frame, and by Unicol to get threads into their brackets. There is no actual tapping of the original material, so ifs not like taking a tap and die set to the steel box section.

[Impact Pete]

I think I could use http://www.ac-et.com/shop/view.asp?id=VIRS21B&cat1=3 around beam and attach a http://www.ac-et.com/shop/view.asp?id=DOT32100&cat1=3 to the ali scaff bar, would rather get hold of some white slings as would look better.

Then I guess an additional steel safety.

 

Still looks like a temp install though, wanted it more tidy on the beam but really don't want to drill any holes in it.

[jonathanhill]

I would use a poly wrapped wire rope drift round the beam. Someone lovely like Rope Assemblies would be able to make a bespoke drift for you. I would also use a badger clamp on the bar (which I would swap for ladder beam). If you are that worried about the aesthetic, could you not wrap the sling/strop in some calico?