ropes used in theatres

[tivoliproduction]

not sure if this will make sense but I will see what happens... a "local" venue has a LOT of items suspended above the stage on polypropylene rope (that nasty blue stuff that has no load rating) does anybody know of any official sources of information that states this cannot be use for lifting/flying in theatres? had a quick google but to no avail.

 

any ideas?

 

hopefully this makes sense, will try and post some pics if any help.

 

russ

[Chris Higgs]

Many ropes are polyprop - even the 'sythetic' hemp is.It's all down to the mix used.

Get ropes that are made to a Standard, preferably of natural fibre (manila, hemp or sisal) where there is risk of close proximity to radiant heat (lanterns, etc).

Do not use any fibre rope where there is risk of combustion.

 

For supply, try Gleistein Ropes and speak to Julian.

[Roderick]

I think the most important part is NOT to use any ropes that aren't rated. That blue stuff may have a place in a domestic use, in a workplace you should only ever use ropes that have the documentation to show the rating. How else would you work out if it is suitable for the load?

And then there are the checks of the actual rope to make sure it isn't damaged, frayed or stretched which would reduce the rating.

 

Ropes may seem a very simple and basic tool but actually require a lot of knowledge about the right type for the right application. And that is before you start looking at the knots :P .

[Liam FitzG]

Primarily you are looking for documentation - this would be a copy of LOLER (The lifting operations and lifting equipment regulations) available from the HSE / HSA. This will state that (heavely paraphrased) all equipment used in lifting and suspension must have a SWL, and documentation stating it and an inspection schedule by competent personal.

 

As for the rope, manufacturers of rope issue a "Minimum breaking strain" for standardised ropes. They issue nothing for non standardised ropes (ie domestic and some marine applications). The MBS x Safety Factor gives you the SWL.

 

Hope this helps a little - ABTT have a very good booklet on the use of ropes in theatre.

 

Liam

[landy]

The MBS x Safety Factor gives you the SWL

 

No NO NO.

 

surely MBS divided by the safety factor = SWL (I might be wrong but I'm having a big blond day today)

[Liam FitzG]

Sorry ... I didn't mean that as a mathematical formula ... anyway it would depend whether you used a decimal or fraction for the safety factor. The point I was trying to make was that the manufacturer should supply the MBS on paper, and if they can't, the rope should not be used.

 

Liam

[Chris Higgs]

With all respect, the employer should decide on the SWL using the safety factor he sees fit (typically 8:1 for fibre ropes in theatres) based on the MBL supplied by the manufacturer.

All materials have a breaking load - is the manufacturer is prepared to provide that information for the particular rope in question?

The employer is bound to use a competent person to do this.

LOLER requires all equipment used for lifting to be strong enough for the foreseeable use of the item.

Knots, pulleys and so on are just some of the factors that will need to to be taken into account since they weaken a rope.

Many polyprop ropes would never be intended to be used for lifting, polyester may be more appropriate.