Trilight Apex

[TomLyall]

After a quick search I cant find anything on this on here... and so...

 

which way SHOULD trilite be hung, apex up or apex down?

 

what are the advantages and disadvantages of each?

 

are there any important safety/loading factors that affect this?

 

personally, from a purely practical point of view and not knowing alot about rigging I would say apex down as I prefer rigging lights on a single bar, and also as you can then run cables along the top.

 

Tom

 

Im only asking out of interest and to see peoples opinions, so obviously all manufactuers instructions should be followed and work completed by a competent rigger. :** laughs out loud **:

[j_b]

After a quick search I cant find anything on this on here... and so...

 

which way SHOULD trilight be hung, apex up or apex down?

 

what are the advantages and disadvantages of each?

 

are there any important safety/loading factors that affect this?

 

personally, from a purely practical point of view and not knowing alot about rigging I would say apex down as I prefer rigging lights on a single bar, and also as you can then run cables along the top.

 

Tom

 

Im only asking out of interest and to see peoples opinions, so obviously all manufactuers instructions should be followed and work completed by a competent rigger. :** laughs out loud **:

<{POST_SNAPBACK}>

 

I assume you mean trilite, by opti

 

On the opti website: which is here they list tables indicating the loading figures for a given span, but don't mention the orientation. Further in the catalolgue, they list corners suitable for use 'apex up' or 'apex down'. This indicated to me that they intend their truss to be used in either configuration.

 

Slick triangular truss (here), for example, they used to quote different figures for apex up or apex down - which is fine, as structurally is is different, and therefore the load rating is different. On the new version of slick triangular, it is the same same, I wonder if they have just wanted to be able to give out less information, i.e. minumise the danger of someone using the weaker apex down configuration and using the higher apex up figures for the loading, however I'm sure someone out there will put me to rights if this is not the case - I just design within the limits I'm given!

 

For your information: Slick litebeam:

 

MkI 6m CPL Apex down: 101kg

Mk II 6m CPL Either orientation 244kg.

MkI 6m CPL Apex Up: 213 kg

[gareth]

All the diagrams, illustrations, etc. on the Opti website appear to indicate that apex-down is the order of the day. Apex-down is how I've always used Trilite, and it seems to make much more sense than the alternative. (Think about it - if you hang it apex-up, then hang a couple of moving lights on one of the bottom chords, it's just going to twist the whole thing around.)

 

HOWEVER - if you're at all unsure of the correct orientation for Trilite, a quick e-mail or phone call to Optikinetics should provide you with the answer.

[TomLyall]

Thanks for the information, and yeah I did mean trilite, spelling, aparently including product names, isn't my strong point!

[Brian]

From a purely structural point of view, both are valid. Each configuration will behave differently and you will need to understand these differences to be able to safely use the truss. The method of suspension will also greatly affect the strength and behaviour of the total system.

 

Any loading figures given by the manufacturer will apply to one configuration unless they place safe and quote the lowest figure.

 

If in doubt, as Gareth said, talk to the manufacturer.

 

For instance, when triangular trusses are used as the roof of a building they are normally used as a simple beam. Here the top members are in compression and the bottom oneareis in tension. Pipe in tension is stronger than pipe in compression and hence you tend to want more pipe at the top, hence point down.

[Martin]

Pipe in tension is stronger than pipe in compression and hence you tend to want more pipe at the top, hence point down.

<{POST_SNAPBACK}>

 

I always thought it was the other way round.

[Brian]

Pipe in tension is stronger than pipe in compression and hence you tend to want more pipe at the top, hence point down.

<{POST_SNAPBACK}>

 

I always thought it was the other way round.

<{POST_SNAPBACK}>

Pipe in compression has a nasty habit of buckling.

 

[EDIT]

I supose that a pipe only in compression will be stronger than one in tension, it's just that the failure mode is buckling.

[slim_mcslim]

I have always gone for hanging the truss how I have needed it in the past.

 

Generally I have hung point down, because it makes loading easier, but sometimes when I have to put a lot onto a truss I put it point up, and just manually balance the load between the front and back of the truss.

 

According to the Opti website, their loading charts are based on hanging the truss point up, and evenly loading both lower tubes.

 

And I just thought that I would leave you with this HAWSAW picture from lite structures.

[andy_s]

How's this for confusion - one person says that the Opti website indicates apex-down, and another person says that it says apex-up. Surely you can't both be right? Is there anyone who really knows the answer out there?

[gareth]

How's this for confusion - one person says that the Opti website indicates apex-down, and another person says that it says apex-up. Surely you can't both be right?

 

Hey, don't take my word for it - my post was based purely and simply on the fact that, in the literature on the Opti website, the vast majority of the photos and diagrams seem to show the triangular variation of Trilite in an apex-down orientation. Nowhere could I see any text which specified that an apex-up or apex-down arrangement was the preferred way of using the product, and at no point did I say or imply that the content of my post was to be taken as being the 'right answer' to the question being asked here.

 

As I said, the only way to get a reliable answer is to give the manufacturers a call and ask them the question (nothing on this forum should be taken to be a reliable answer to this question unless you can be sure that it's come directly from a representative of Opti).

 

 

According to the Opti website, their loading charts are based on hanging the truss point up, and evenly loading both lower tubes.

Slim, could you please post a URL for the page which gives this information?

[paulears]

since litestructures sell and hire their corner components in both apex up and down configurations, it's a fair guess that they are quite happy with both.

 

I've often hung their astralite with apex in the middle - when a single flown span was needed - working on the specs for bi-lite hung vertically. This is especially useful when using doughty clamps with hanging rings, and a modest load - there is enough load to let one side hang vertically.

 

As for the interesting photo showing someone climbing with no sign of safety equipment - perhaps a little unusual for a public website, but I bet there are few of us who haven't actually done this. I'm willing to say that I have. (I could also mention that apex down is much more comfortable if anyone hypothetically sat on the top)

[andy_s]

How's this for confusion - one person says that the Opti website indicates apex-down, and another person says that it says apex-up. Surely you can't both be right?

 

Hey, don't take my word for it - my post was based purely and simply on the fact that, in the literature on the Opti website, the vast majority of the photos and diagrams seem to show the triangular variation of Trilite in an apex-down orientation. Nowhere could I see any text which specified that an apex-up or apex-down arrangement was the preferred way of using the product, and at no point did I say or imply that the content of my post was to be taken as being the 'right answer' to the question being asked here.

 

As I said, the only way to get a reliable answer is to give the manufacturers a call and ask them the question (nothing on this forum should be taken to be a reliable answer to this question unless you can be sure that it's come directly from a representative of Opti).

 

 

According to the Opti website, their loading charts are based on hanging the truss point up, and evenly loading both lower tubes.

Slim, could you please post a URL for the page which gives this information?

<{POST_SNAPBACK}>

 

 

sorry Gareth - I didn't mean anything personal - I've looked at the website and would agree with your reading of it - it certainly shows most of it apex down, but the joiners appear to give you many options, including apex in or out. My point, and perhaps I expressed it a bit tersely, was that it seems to be possible to look at the website and come away with apparently contradictory theories. You are quite right to point out that, as it says on the opti website, for detailed information, contact the manfacturers directly.

[smeggie]

ummm, how bizzare - the slick/trilite kit I've used on the ground [i.e. ground support] always used it with apex up.

when it's flown I have always known it to be hung with the rear side flat . then again, we have never loaded it that heavily.

[colinmonk]

Jus to be pedantic, it would only twist apex up with a moving light on it if it was a straight run... If it was a box then there would be no movement, and the benefits would be more room to hang conventional fixtures on.

 

In all seriousness though, if you have any questions over which way to hang a truss, contact the manufacturers and ask them, they are the only people who can give you a true answer regarding their product.

[TomLyall]

at risk of getting into a long discussion about safety and stuff...

 

colin you say that it would not twist if you had a square of trilite etc, does this not imply that it is placing parts of the truss under great strain?

 

anyone who knows more care to elaborate?