FOH Bars - Ladder required

[rooftop]

May I just say the main reason for the guys wanting "hooks" is not to hang the ladder off the bar, but simply to stabilise the top end of the ladder to stop it sliding laterally along the bar. Admittedly this is unlikely with a good modern ladder, but it has happened to one of our guys on our old ladder (which is now out of service).

 

Maddison, what is that funky hook called? It looks like it could slide in the end of the stiles and presumably be bolted/welded in place?

 

QUOTE (rooftop @ 26 Aug 2009, 8:57 AM)

Our FOH LX bars are about 3 metres high and fixed solidly to the concrete roof.

 

I would want "solidly" qualified before hanging people off the bar, which is what is effectively happening.

 

There is no intention of hanging anyone off the bar.

[Maddison]

Maddison, what is that funky hook called? It looks like it could slide in the end of the stiles and presumably be bolted/welded in place?

 

They appear to be called Scaffold Ladder Hooks. I just ran a google image search and found it from this New Zealand site which looked similar to things that I've seen at the top of hooking ladders I've used.

[hadyn.williams]

What do you attach it to?

How do you rescue someone who is dangling?

 

I'm not totally sure on the specifics as I've never used the system and I'm not harness trained in any way. I think the reason for the fall arrest is that should you slip off the ladder sideways (you would possibly be leaning slightly to one side to rig a lantern to the side of the ladder) the only place for you to fall is down onto one of the seats in the stalls...

I think a fall arrest lanyard is used which is connected to a 'mini-block' which is then attached to the 'horse shoe' rail above the circle. The same bar that the ladder is hooked on to and where the fixtures are rigged.

I don't know the specifics of rescue but I would presume they're is a rescue plan which may involve pulling the person back in over the circle edge - I don't know though. I'll try and find out more about it when I'm next there in a few weeks.

 

Fall Arrest and mobile ladders generally don't go together very well, because you can't clip on until you're up the ladder, and you'll have to unclip to descend.

It's not a big ladder, probably only a couple of metres, so you don't have to go far before you can reach to clip on, but you need to go higher to be able to lift a lantern to rig. But I see your point.

[TomHoward]

I would want "solidly" qualified before hanging people off the bar, which is what is effectively happening.

There is no intention of hanging anyone off the bar.

There will be stresses applied to the bar though, and in the event of the bottom of the ladder losing friction with the floor (in the event where it would usually slip out) it would seem to me that there may be a large proportion of the load of the ladder applied to the bar. I'm not an expert in this specific field but the potential would be enough to worry me - I personally would assess exactly how 'solid' this bar is, and what reasonable forces could be applied to it before using it as part of stabilisation for access equipment.

[rooftop]

I repeat; there is no intention of this happening. The bottom of the bar is effectively footed as it stands in the aise between rows of tiered seating. The seat, or the step in the floor stops the ladder from going anywhere. The top of the bar is fixed at either end to the structural building pillars (such that the force exerted on the bar by the ladder is in turn exerted on the pillar by the bar. The middle of the bar is fixed at several points to the roof.

 

PleaseI am only interested in experiences and suggestions for successfully securing the tops of ladders. We will leave the hypothetical argument about "are the bars strong enough" to the company that installs / load tests our rigging. Okay? :P

[benash]

We will leave the hypothetical argument about "are the bars strong enough" to the company that installs / load tests our rigging. Okay? :P

Point taken. But I can't resist...

 

I would want "solidly" qualified before hanging people off the bar, which is what is effectively happening.

There is no intention of hanging anyone off the bar.

There will be stresses applied to the bar though, and in the event of the bottom of the ladder losing friction with the floor (in the event where it would usually slip out) it would seem to me that there may be a large proportion of the load of the ladder applied to the bar. I'm not an expert in this specific field but the potential would be enough to worry me - I personally would assess exactly how 'solid' this bar is, and what reasonable forces could be applied to it before using it as part of stabilisation for access equipment.

I agree. It has to be said, though, that in a case where the person's weight has been taken largely by the bar, the ladder has failed (by tipping/slipping or breaking) and if it hadn't been attached to the bar the person would now be on the ground. If it were me I'd rather take the chance that the bar is strong enough rather than being assured of a fall to ground.

[TomHoward]

What about an appropriately welded American stye trigger clamp, something like a suitably rated version of the Doughty Twenty Clamp? As well as giving an inital hook this option would also allow you to secure the ladder if you were working for long periods of time.

 

(Again as long as the bar is suitable to lean against.)

 

Edit to remove specific suggestion of Doughty Twenty Clamp, the weight (20kg per clamp) is too low.

[benash]

What about an appropriately welded American stye trigger clamp, something like a suitably rated version of the Doughty Twenty Clamp? As well as giving an inital hook this option would also allow you to secure the ladder if you were working for long periods of time.

 

I won't comment about whether that clamp is suitable or whether a locking clamp is really necessary/appropriate. Anyway, if you were to attach clamps to the top of the ladder and then just hook the clamp against the bar you end up in a situation where if the clamp fails the ladder falls. I would highly doubt that Doughty would ever recommend their clamps to be used in such a situation so if you were to go down that road and it fails, it's on your head. Probably best to use something that is designed for the job or else you're off to get something certified for that application (big dollars). If you're big on locking clamps, it might pay to have a look and see if scaffolders use anything that fits the bill.

[david.elsbury]

The bottom of the bar is effectively footed as it stands in the aise between rows of tiered seating. The seat, or the step in the floor stops the ladder from going anywhere. The top of the bar is fixed at either end *snip*

I have a question.

The only time I have used an extension ladder with hooks, it has been on a clear stage. Therefore if the ladder is extended to say, 10 feet, the angle may be 45 degrees from vertical. If the ladder is extended to 11 feet, the angle will be shallower. If the ladder is only extended to 8 or 9 feet, the ladder will be closer to vertical- or even not touching the floor.

 

So if I read the above statement correctly, the feet of the ladder are sitting on (effectively) a large set of steps with seating on. This means that if the ladder is hooked onto, say, FOH bar number 1, you can only adjust the angle in 1 foot increments by sliding the ladder up or down. Except that in this case, what if the ladder was half a foot too short? You can't move the seats, you can't extend the ladder because otherwise it won't lock, and you can't poke the top of the ladder over the bars as you normally would, because your hooks won't make contact with the bar and achieve what you want.

 

Or if we look at it another way... if you get a custom made ladder with the hooks in the correct place for your FOH # 1 bar, for the ladder to be at a 45 degree angle... is that ladder going to suit for your FOH #2, or #3 bars? Are they exactly in 1 foot (or whatever) increments? Will you have to have a seperate ladder for each FOH bar? You see where this is going?

 

In my opinion there is nothing wrong with having someone who is paying attention footing the ladder.

 

My 2c ;)

David

[rooftop]

All the FOH bars are at the same height from the floor. All the seats / aisles are in the same position relative to the bars. Therefore, one ladder will indeed fit all ;)

 

I will look into the scaffolder's clamps/hooks (thanks for the suggestions), but I had hoped there would have been an off-the-shelf theatrical solution.

 

My thoughts were that the hooks would be fitted two or three rungs down from the top of the ladder, so that

 

a) the ladder extends beyond the top of the bar, for extra safety, and

b) the ladder can still be used as a freestanding ladder against a wall when necessary (without the hooks fouling the wall)

[Chris Adam]

I'm not going to say wether I think that solution is right or wrong. That's for you to decide, but.....

 

That sounds like a total pain in the hoop to get right. Mount them too low and they will end up taking a proportion of the weight. Mount them too high and they wont be hooked over the bar. Same would apply if the angle was different from normal (ie if there's a seat mount in the way at one point so you have to go in front of it.) Make the angle too steep and the hooks will be too high. Make the angle too shallow and there will be weight put on the hooks. Also, if the ladder does slide sideways (even a little bit) pressure and weight would be put on ONE of the hooks, that it may or may not be able to withstand. If it breaks, more damage could be done (and a finger of blame could suddenly be pointed in your direction).

 

Sounds like you have a challange there, but if 99.9% of venues around the UK don't need to hook their ladders on to the bar, then it may be a challenge you don't need.

[rooftop]

Well, as you say, there is obviously not a common need for such gizmos.

 

Unfortunately, [speaking as a manager], sometimes staff get an idea in their head and they won't let go... and then expect you [the manager] to rustle up the answer in your lunchbreak. So I said I'd investigate ladder hooks, and the fairly conclusive answer from this thread is that they are not commonplace.

[Jiff]

Before anyone asks, the rigging element is pretty minimal as the techs tend to stick to the same LX rig apart from the odd special. It's just the focussing, gels and gobos that changes per event.

 

 

And you can do that with 3 points of contact on the ladder?

[rooftop]

And how would you do it?

[johnlinford]

Before anyone asks, the rigging element is pretty minimal as the techs tend to stick to the same LX rig apart from the odd special. It's just the focussing, gels and gobos that changes per event.

 

And you can do that with 3 points of contact on the ladder?

 

Three points of contact is for when climbing a ladder, not while working at the top of it.