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flying safer than ground stacking?
Posted: Mon Mar 01, 2010 12:07 pm
by RubiconProSound
I found this little blurb from the Nexo site...it has a few little tidbits I never thought about regarding ground stacking.
Ground Stacking Safety
Statistically, many more injuries occur due to unstable ground stacked PA systems than those associated with flown systems. There are several reasons for this fact, however the message is clear:
• Always survey the supporting structure upon which a ground stack is to be built. Always
look beneath PA wings to inspect the deck support and if necessary ask for the stage
scrims and dressings be removed to allow access.
• If the stage surface slopes, as it does in some theatres, ensure that the system is prevented
from sliding forwards due to vibration. This may require the fitting of timber battens to the
stage floor.
• For outdoor systems ensure that that the system is protected from wind forces which might
cause the ground stack to become unstable. Wind forces can be huge, especially upon
large systems, and should never be underestimated. Observe meteorological forecasts,
calculate the “worst case” effect upon the system prior to erection and ensure that the
system is secured appropriately.
• Take care when stacking cabinets. Always employ safe lifting procedures and never attempt
to build stacks without sufficient personnel and equipment.
• Never allow anyone, whether operators, artists or members of the public to climb onto a
ground stacked PA system. Anyone who needs to climb over 2m high should be fitted with
suitable safely equipment including a clip-on harness. Please refer to local Health and
Safety legislation in your territory. Your dealer can help with advice on access to this
information.
• Apply the same attention to all safety matters when de-stacking systems.
• Be aware that safety procedures are as important in the truck and in the warehouse as they
are at the venue.
Re: flying safer than ground stacking?
Posted: Mon Mar 01, 2010 2:01 pm
by Bill Fitzmaurice
I can believe that. Someone ground stacking is as likely as not to make the pile too high with inadequate tie downs, if any. It's tough to fly unless the venue is set up for it, and chances are better that it's not a jury rigged affair.
Re: flying safer than ground stacking?
Posted: Mon Mar 01, 2010 4:12 pm
by Dazombiewoof
Major touring acts who are flying the PA get such a discount on their tour insurance they always want one or more certified bonded riggers. I did see a flown cab take a dive to a stage once. Guy on the ground it came close to probably went home shortly thereafter, if only to change underwear. I was a very good distance away and fortuneately maintained control. Made an impression, literally and figuratively.
Re: flying safer than ground stacking?
Posted: Tue Mar 02, 2010 2:49 am
by wr_anders
Even with small stacks, I've used ratchet straps. Just always made sense.
Even when the stacks got their highest, about 12 feet, we used ratchet straps and nylon cargo nets staked deep and wide.
Good way to keep people off the speakers too.
Re: flying safer than ground stacking?
Posted: Tue Mar 02, 2010 4:53 am
by ben.in.salzburg
To what do you attach the ratchet straps when indoors or on concrete?
Re: flying safer than ground stacking?
Posted: Tue Mar 02, 2010 7:33 am
by wr_anders
ben.in.salzburg wrote:To what do you attach the ratchet straps when indoors or on concrete?
I always laid the straps on the ground, set the stack on top, then looped the end over, attached it to itself and cranked down.
Re: flying safer than ground stacking?
Posted: Tue Mar 02, 2010 8:20 am
by SoundInMotionDJ
ben.in.salzburg wrote:To what do you attach the ratchet straps when indoors or on concrete?
Indoors, I will only "ground stack" with the "ground" is a riser or stage. There is always plenty of places to attach straps on a riser. I have even driven screws into the decking of a riser to get a good place to attach a strap.
In a pinch, I have stacked on a banquet table that is flat on the ground (legs are still folded). That provided some outriggers for the stack.
With my last outdoor gig with a stack, I had the ability to strap to the support legs of a gazebo.
--Stan Graves