raise / lower truss

[andrewb]

I have a lighting truss that is 17m long and 5m wide. The building has a 24 foot hight ceiling and I need some kind of way to lower and raise the truss for bulb changes etc. Some kind of automatic winch. Any companies that I might try? this project will be installed across the pond if that helps.

 

thanks

[Jivemaster]

Few of us will be familiar with your federal and state regs, but raising and lowering a rig that size would be a major lifting operation in the UK. Even if you were to fit out with motorhoists then the rig must be secured at height with steel bonds so you will always need to access the rig at height.

 

Please tell us what prevents the use of access equipment Tallescope, scaffold tower etc, or roof level walkways. You would need - in the UK - fastenings for personal fall arrest equipment.

[andrewb]

 

Few of us will be familiar with your federal and state regs, but raising and lowering a rig that size would be a major lifting operation in the UK.  Even if you were to fit out with motorhoists then the rig must be secured at height with steel bonds so you will always need to access the rig at height. 

 

Please tell us what prevents the use of access equipment Tallescope, scaffold tower etc, or roof level walkways. You would need - in the UK - fastenings for personal fall arrest equipment. 

<{POST_SNAPBACK}>

 

 

Sorry, forgot to mention specifics.

 

1) the floor below it is at all different slanted levels so scaffolding would be near impossible.

 

2) the space between the roof and truss will not allow for a walkway. We have already had a moment with the building designers over this if you know what I mean.

 

3) the room is extremely cluttered on the floor so any large equipment used to reach the truss is out.

 

k, so winching is out. Is there anyway of attaching a rope ladder of sort that could be lowered on command? Fastening equipment is no problem. We actually already have that build into the ceiling for specific purposes.

 

thanks for the help

[mikienorth]

Andrewb;

I have seen truss that moves regularly without having to remove a steel safety bond each time it came in or out.

Load arrestors were used, one for each motor point, not too clear on the rest of the information, I'm not a rigger, but each truss peice was rather long, and hung on 3 1T Lodestars, which were, for them, inversely mounted, that is, motor up.

 

My venue has a peice of truss 24 feet long by 6 feet square cross section flown above the seating/orchestra pit. This is on a motor winch in the roof, which raises and lowers it on 5 wire ropes. This has no steel safetys to detach every time we just press a button on a pendant and in it comes. It has a total SWL of 1T, of which half is the truss and rigging, so we can hang 500KG on it.

 

The Bierhubeli in Bern, Switzerland has a truss system above its stage as a permanent installation, that lowers to floor level for you to rig onto.

 

My point is, this is not particularly uncommon, I am sure other theatres in the UK have a similar arrangement to ours, and we have all seen or know of a dynamic truss in shows. Others will have a system like the swiss one. They are just examples I have first hand knowledge of.

 

This kind of thing can and is done, I just hope someone else on here can suggest how to you because I can't.

 

Try contacting the people who installed the truss, but then you probably have already. Try contacting rigging companies in the US, Or theatrical engineers. Or, as an absolute last resort for advice, factory crane companies. Large manufacturing plants have overhead cranes, which is essentially what you need.

[Jivemaster]

Tallescopes and scaf towers have been custom made for raked stages in the UK. Dont exclude chainhoists but as a 17x5 metre truss will need several hoists means must be provided for ensuring the truss is correctly and uniformly lifted. The load being correctly distributed while the lifting occurs Annual service and inspection of the lifting equipment must be possible for UK regs. Even cable management for power and control must be designed so that all cables can move the full truss lift without strain or abrasion

 

I still suspect that even a totally custom access tower to current safety regs would be a cheaper option, and incur less continuing expense.

 

In the UK a system that couldnt be maintained as you describe would be the start of a formal complaint against the designer/architect, -- the rig should have a life beyond the first lamp failure.

[Nick512]

One solution already mentioned here is using chain hoists, ie loadstars,Verlinde ect... the number of these will be determined by the type of truss and weight to be lifted and/or rigging points available.

 

for a permanent install these can be inverted so motor stays fixed to rigging point and only chain moves, this is much neater and cabling is easyer.

 

as for safteys, you could do it two ways which are all fine in uk. 1. use load arrestors and 2. use double braked motors. both eliminate the need to access truss at high level.

 

the safety laws in the US weren't as strict up until the justin timberlake truss collapse, now its worth checking in the state that your operating in as all are different..

 

my only concern with this idea is your venue hight as you will loose up to 1m for the motor hight unless you can have them rigged above the ceiling which would be ideal. you would also need some sort of cable management system, such as kevlar runners for the motor chain.

 

I have a good contact in New York, who runs a rigging/fabrication company, message me if you need it.

[eenie]

I have a lighting truss that is 17m long and 5m wide. The building has a 24 foot hight ceiling and I need some kind of way to lower and raise the truss for bulb changes etc. Some kind of automatic winch. Any companies that I might try? this project will be installed across the pond if that helps.

 

thanks

<{POST_SNAPBACK}>

 

 

Ok Here it is. 17mt x 5mt is not an especially big Rig but does need thinking of. Despite some of the answers you have received, you can lower the grid using chain hoists, load the equipment and raise the truss. It all depends on how you are using the truss. If, for example, you are using it as a mother grid then you would normally operate it by lowering the grid, attaching any hoists for lifting equipment to the grid, raising the grid, dead hanging the grid with intermediate steels, for example ( this would increase the loading capacity ), then raising equipment onto the grid. The raising and lowing of the grid is design so you do not have to use access equipment or else whats the point of using chain hoists. You should not using PPE fall arrest equipment to attach to the truss, or tallascopes & scaffold towers for that matter. They are not designed to take the shock load that is applied by a falling person under an circumstance. Their are specific products on the market that can be used with fall arrest if you wish.

 

The usual thing is, number of hoists needed depends on truss type, loading etc. You can use load arrest systems, dbl brakes if you wish but it depends on the national regulations, venue requirements etc. For example dbl brakes are not law in the UK but are in Germany.

 

If you contact Total Structures in the US tel + 1 805 676 3322 they would be able to help you will all aspects that you would need.