Lamp Safety Bond

[gherriott]

Just a quick question....I want to hang two lamps on a vertical piece of scaffold bar that is coming down from the grid, almost like a boom. What is the best way to secure the lamp, because attaching a safety bond around the lamp and scaffold will do absolutely nothing as if the clamp fails, the whole lot will just slide off the bottom of the pole.

 

Thanks

 

Greg

[dbuckley]

I do this fairly often, I basically use a few safety lines "in series" one round the bar at the top, through the clamp, down to the highest lamp. Then go from lamp to lamp. The safeties I keep tight so if anything lets go the drop distance is only an inch or two.

[Ynot]

If the lantern is anything heavier than a par can I wouldn't recommend clamping stratight to the vertical with a hook clamp anyway - use a boom arm, or a short length of scaff perpendicular to the upright.

Then the safety can go around the boom/scaff.

[dbuckley]

I assumed the OP was asking the question from the point of the scaff clamp failing, which is always my worry, even though it's never happened and I've been dropping verticals from bars for years. Doesnt make me any less careful though.

 

Using short lengths of scaff horizontally is also recommended practice from my perspective, even for parcans, which is mostly what I put on the drops; its just less hassle than tightning up a hookclamp and hoping it holds. For proper luminaires you need to do that really for burning angle considerations.

 

Dropped verticals are not the perfect booms, but they sure are a convenient compromise.

[david.elsbury]

You can also put a safety bond through the pipe. (Or, a wire drift and shackles, depending on what's around)

[Ynot]

I assumed the OP was asking the question from the point of the scaff clamp failing,

Actually, I read

I want to hang two lamps on a vertical piece of scaffold bar that is coming down from the grid, almost like a boom

as he was wanting to use the hook clamp direct onto the vertical.... CAN be done with par cans, though not recommended.

[J Pearce]

As David says, a good way to do it is to run a steel drift down the pipe, then back up through all the yokes; with both ends of the drift being fixed to a suitable load bearing point in the roof.

 

This safeties the whole assembly, though obviously make sure your lanterns are vaguely point-in-the-right-direction focussed before doing this, as it limits a lanterns movement on the yoke.

[StevieR]

Have a look at this - Doughty Boom Arm. These are available with integral safety points.

[Martin]

If I'm using a standard boom arm then I usually clamp the loose hook clamp next to the boom arm to keep it with the unit, so it can go straight back on come the get-out. This also serves as a handy point to clip the safety on to.

[GregB]

A hook clamp on a boom is a no no in my book. I have invested lots of hard cash (for a small theatre) in trigger clamps.

Hanging any fixture off angle with a hook clap is bad news, the weight of the fixture tends to damage the barrel.... Half-couplers/trigger clamps definitely the quick route to safe hanging. While your there hanging your vertical boom run a safety steel through the vertical and back over the fixing point (a nice heavy duty one). this may then double as a line you could clip lamp safty bonds too.

[Neil Hampson]

The problem with this is other than lanterns with axial lamps, the lamp is burning horizontally, which they are not designed to do. I agree that this will not affect a Parcan, or an SL/S4 but any other lantern is not designed for sideways operation. The lamp life will be severly reduced and the lantern is likley to overheat as the convection airflow designed to deflect heat through the top of the lantern.

 

Also on another point. when you use a boom arm with an integral eye for a safety bond, what is used as a safety against the failure of the boom arm itself?

[GregB]

Sorry Niel not quite sure I follow.

Like previous post:

a good way to do it is to run a steel drift down the pipe, then back up through all the yokes; with both ends of the drift being fixed to a suitable load bearing point in the roof.

this is basically what I'm saying.

With regard to the lamp orientation it doesn't matter which way the clamp hangs, the lamp can be turned on the clamp to be the right-way-up and pointing in the right direction.

[Tomo]

With regard to the lamp orientation it doesn't matter which way the clamp hangs, the lamp can be turned on the clamp to be the right-way-up and pointing in the right direction.

Not so - if you clamp directly to the vertical bar, then the yoke of the fixture ends up at 90 degrees to the way it was designed to hang.

This means that airflow through the lamphouse is at 90 degrees to the original design.

 

In many fixtures this doesn't matter, but in some it does!

[GregB]

Turn the Yoke 90deg. Am I missing something???

apart from:

the way it was designed to hang.

I really can not see the problem with the yoke on a lamp being at 90 degrees from the bar just because the bar has moved from horizontal to vertical plain. Providing the joke is stong enough to take the load of the lamp in that oriantation, (lets face it most kit is pretty robust) what's the worry?

[Tomo]

I could do with diagrams for this!

 

Anyway:

Grab a lantern - a Cantata is good for this, as it's boxy and has clear airflow baffles on the lamphouse.

You'll see that when hung 'normally' the sides of the yoke and lamphouse are vertical, and the baffles on the Cantata are on the top.

Cooling airflow is nominally vertically upwards, via any baffles etc

Depending on how it's focussed, the airflow is either out the back or front of the lamphouse, or out of the 'top' of the lamphouse - or somewhere between these.

 

If you clamp it to a vertical boom, the sides of the yoke are now horizontal.

This means that the airflow is now out of the side of the lamphouse - hence the possible problem.

As you adjust focus, you can tip the back or front of the lantern towards the vertical - but you aren't likely to point it straight up or straight down!

 

To be honest, it's getting to be academic as most modern fixtures burn happily in any orientation anyway.

Some older stuff doesn't like it though.