Ladders – So Simple, So Misused
I’d already decided to write about ladder safety, when, lo and behold, March was, you guessed it, Ladder Safety month. It is also Brain Injury Awareness month and the third week is National Drug & Alcohol Facts week. And there are a bunch of others, too.
In the context of ladder safety, I could see how brain injury could be related, if you fall on your head, for instance. I can see how drugs or alcohol can increase the chances of a ladder mishap. Let’s be candid, some craft beverage manufacturers are a little loose on the rules around tasting the product during work hours.
I’m a big fan of rules of thumb. (There’s a rabbit hole of an idiom, did it really have to do with spousal abuse?) I digress, a rule of thumb is, a quick maxim or measurement that expedites work. With ladders, there are many, and they all help you use the ladder properly and safely.
These rules to apply every time you use a portable ladder:
- Inspect the ladder before each use.
- Keep ladders from degrading in sunlight or coming into contact with chemicals.
- Secure the footing of the ladder.
- When in doubt, have a coworker support you and the ladder.
Ladders are designed to be safe when we stay within a region of stability. There are lots of forces working on the ladder that can displace it. There is your weight bearing straight down. This is called the gravitational vector – I just like saying it out-loud, makes me feel smart.
That force pushes the ladder to the ground, too, and if the ladder is on a slippery surface or leaning up at too shallow of an angle, the base of the ladder will not have enough friction and will want to slide away from what the ladder is leaning against. This is called the translational force. You can learn more about the physics on this YouTube video, or just take my word for it.
And then there is whatever activity we are performing on the ladder. Do we have our hands full? Are we exerting force doing the task that also puts a force against the ladder system?
If we lean way out to one side we add a second translational force to push the ladder sideways. The physics gets messy here, because we go from the relatively tame subject of static physics to the complex subject of dynamics. Trust me, you’ll probably fall if you lean out.
Keeping ourselves in the right position on a ladder is akin to the stability triangle discussed in forklift safety. We have to stay within a space that keeps us and the ladder pointing straight down with gravity to the greatest extent possible.
There are handy rules to keep you in the stability zone of ladders, here are some favorites:
- Three points of contact. Always have at least three points of contact on the ladder. That could be two feet and a hand, or two hands and a foot (as when climbing), or even two feet and your belly pressed into a rung. Use your head, but don’t use your head as a third point of contact!
- The belt buckle rule. Always keep your belt buckle between the two vertical rails (stiles) of a ladder. This will help keep the ladder from slipping out to one side.
For extension ladders:
- The four to one rule. For extension ladders that are leaned against a structure, the vertical height to the point of ladder contact should be four times the distance of the base of the ladder from the structure. This is about a 75° angle and it will feel quite steep.
- The three-foot (or three-rung) beyond rule. When you intend to climb off the top of an extension ladder, place it with at least three feet extending above the point of contact. This gives you something to hold on to getting on or off the ladder.
For step ladders:
- A-frame ladders should always ‘face’ the work surface, never be set up parallel to it. Leaning left or right from a step ladder risks the ladder sliding away from you.
- Never use the top step and the very top of a step ladder to stand on. Think of it this way, you no longer can possibly have three points of contact.
If the laws of science aren’t enough to change your behavior on ladders, how about the laws of probability?
Ladder safety violations consistently rank in the OSHA Top 10 Citations list. Ladder mishaps result in over 130,000 emergency room visits per year and over 300 trips to the morgue. The CDC estimates that 43% of fall fatalities in industry involved ladders. Falls are the second most frequent cause of on-the-job death after transportation accidents. Learn more at the Ladder Institute.
And the kicker, what month should Ladder Safety month really be? December. That’s when homeowners fall from ladders while setting up their holiday lights.