Genie Safety?
- Thread starterthebikingtechie
- Start date
It might seem odd I don't remember that, but it's almost 3 am and I just got back from overseeing a club show. What's rrrreally weird is that I'm not going to bother going back to check. If I contradict myself, so be it. Consistancy is the hobgoblin of small minds.
It really isn't the wheels themselves that are an issue. On a level surface, with a significant downward force, wheels don't really impact the stability of the unit in the sense we're talking about. In the same way, I think caster locks are slightly superfluous from a theoretical standpoint. Practically though, they can't hurt. If I seemed to imply that one was safer than the other, I apologize. Also, the bracing of a scaffold doesn't really matter in the scenario we're talking about. We aren't talking about structural stability, but...someone fill this in for me, please...I guess...topple stability? Geeze, it is late. If one is safer than the other, I'd imagine it's a ladder because it's top weight is centered, whereas a scaffold, with a relatively similar footprint to an a-frame on wheels, has that top load distributed. That conclusion doesn't have my stamp of approval yet, though. Maybe others would like to weigh in on this specific issue. I say ladder.
So it's a matter of height vs. footprint and weight distribution.
It all comes back to what we were talking about before and the matter of pushing any of these units with significant top loading (i.e. a person). Your dynamics are toootally thrown off when you apply a force at the bottom. It just isn't the same unit, from a physics standpoint. I just can't believe there are people out there who totally ignore this, and I'm talking the pro world. It's a matter of going through the motions and actually knowing, down to the physics level what you're doing. It's like throwing a gel up to get a color, but having no understanding of what is happening to the light when you do that. That sort of lack of understanding has a way of catching up to a person. It has to me many a time.
From single man, hydraulic bucket lift to a-frame ladder to rolling scaffold, you have to be aware that none are going to be very safe to push around. I personally don't go around doing the math on this to ensure its safety, though. Often it's a visual or gut ability to gauge it. And my gut almost always says don't. A genie lift with or without outriggers has a fairly small footprint, especially in proportion to a well extended lift and I never push that. A-Frame ladder and scaffold are safer. With both it cannot hurt to throw some sandbags at the base, just to increase your safety margin. Remember, in rigging, we use a 5-7x loading factor. There's no reason not to apply this methodology to the actual working environment. Plus, think of the practicality.
Also, scaffold is all different as are ladders, so to take a dogmatic approach is foolish. If you want to do a force diagram and acceleration calculations, all the better, but the smarter way is to simply not try and decrease load-in time by being unsafe.
It really isn't the wheels themselves that are an issue. On a level surface, with a significant downward force, wheels don't really impact the stability of the unit in the sense we're talking about. In the same way, I think caster locks are slightly superfluous from a theoretical standpoint. Practically though, they can't hurt. If I seemed to imply that one was safer than the other, I apologize. Also, the bracing of a scaffold doesn't really matter in the scenario we're talking about. We aren't talking about structural stability, but...someone fill this in for me, please...I guess...topple stability? Geeze, it is late. If one is safer than the other, I'd imagine it's a ladder because it's top weight is centered, whereas a scaffold, with a relatively similar footprint to an a-frame on wheels, has that top load distributed. That conclusion doesn't have my stamp of approval yet, though. Maybe others would like to weigh in on this specific issue. I say ladder.
So it's a matter of height vs. footprint and weight distribution.
It all comes back to what we were talking about before and the matter of pushing any of these units with significant top loading (i.e. a person). Your dynamics are toootally thrown off when you apply a force at the bottom. It just isn't the same unit, from a physics standpoint. I just can't believe there are people out there who totally ignore this, and I'm talking the pro world. It's a matter of going through the motions and actually knowing, down to the physics level what you're doing. It's like throwing a gel up to get a color, but having no understanding of what is happening to the light when you do that. That sort of lack of understanding has a way of catching up to a person. It has to me many a time.
From single man, hydraulic bucket lift to a-frame ladder to rolling scaffold, you have to be aware that none are going to be very safe to push around. I personally don't go around doing the math on this to ensure its safety, though. Often it's a visual or gut ability to gauge it. And my gut almost always says don't. A genie lift with or without outriggers has a fairly small footprint, especially in proportion to a well extended lift and I never push that. A-Frame ladder and scaffold are safer. With both it cannot hurt to throw some sandbags at the base, just to increase your safety margin. Remember, in rigging, we use a 5-7x loading factor. There's no reason not to apply this methodology to the actual working environment. Plus, think of the practicality.
Also, scaffold is all different as are ladders, so to take a dogmatic approach is foolish. If you want to do a force diagram and acceleration calculations, all the better, but the smarter way is to simply not try and decrease load-in time by being unsafe.
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Someone asked about moving a ladder when someone is on it. Clearly NO:
40 CFR 1926.1053 Ladders.
…
(b) Use. The following requirements apply to the use of all ladders, including job-made ladders, except as otherwise indicated:
…
(11) Ladders shall not be moved, shifted, or extended while occupied.
Ladder information is in both 40 CFR 1910.21 to 1910.30 (Subpart D – Walking-working surfaces) and 40 CFR 1926.1050 through 1926.1060 (Subpart X – Stairways and Ladders)
A general ladder safety publication:
http://www.osha.gov/Publications/osha3124.pdf
Theater work is addressed by two sets of US OSHA regulations:
40 CFR 1926 - Safety and Regulations for Construction
40 CFR 1910 - Occupational Safety and Health Standards
Theater work falls into both categories, depending on what is going on. Day to day activities are under 1910. Building a set would be 1926. Other activities (say, hanging lights), I really do not know, nor have I looked more closely at the rules and law. If you can’t find something in 1910, then check 1926.
There is overlap between 1910 and 1926, and occasionally differences, although the differences are a matter of degree and sometimes detail, rather than allowing actions under one but not the other. Perhaps the best example of a difference is that Fall protection regulations under 1926 (construction) start at 10 feet, but similar regulations under 1910 start at 6 feet.
Joe
40 CFR 1926.1053 Ladders.
…
(b) Use. The following requirements apply to the use of all ladders, including job-made ladders, except as otherwise indicated:
…
(11) Ladders shall not be moved, shifted, or extended while occupied.
Ladder information is in both 40 CFR 1910.21 to 1910.30 (Subpart D – Walking-working surfaces) and 40 CFR 1926.1050 through 1926.1060 (Subpart X – Stairways and Ladders)
A general ladder safety publication:
http://www.osha.gov/Publications/osha3124.pdf
Theater work is addressed by two sets of US OSHA regulations:
40 CFR 1926 - Safety and Regulations for Construction
40 CFR 1910 - Occupational Safety and Health Standards
Theater work falls into both categories, depending on what is going on. Day to day activities are under 1910. Building a set would be 1926. Other activities (say, hanging lights), I really do not know, nor have I looked more closely at the rules and law. If you can’t find something in 1910, then check 1926.
There is overlap between 1910 and 1926, and occasionally differences, although the differences are a matter of degree and sometimes detail, rather than allowing actions under one but not the other. Perhaps the best example of a difference is that Fall protection regulations under 1926 (construction) start at 10 feet, but similar regulations under 1910 start at 6 feet.
Joe
Heres my ten cents on the issue. I think this comes down to center of mass. When a genie lift is made, there are obviously complex formulas and all sorts of math to be able to have a bucket of some substantial mass high up in the air without it toppeling. This is probably partialy why you will not see small lightweight genies. The smallest bucket genie i could find quickly on their website goes 11.5 feet in the air and yet it weighs 1600 lbs. What this is doing is making it so that even though a person, or 500 lbs, going 11.5 ft in the air will not greatly impact the center of mass. The lower the center of mass the harder it will be to make the genie topple over. By not using the outriggers or by raising the genie onto some wheel contraption you will dramaticaly change the center of mass and many other forces as well. The ladder is deisnged such that you are greatly altering the center of mass but it distributes out through the framework of the ladder so i would imagine that putting it in a box with casters would be alright because the force required to make it move horizontaly would be great and because the casters and wooden box would transfer the weight. Ill ask the physics teacher for his oppinion when i see him next.
There are (or were) some A-frames with mfr provided locking wheelsets that I believe were designed to be wheeled while manned. One actually had a mfr's notice on the side something to the effect of "Do not move or set in motion when personnel are higher than 16 feet. Always keep on a flat smooth surface."
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