Doug: Let's talk about some of the components of a personal fall arrest
system.
Start with the harness.
All harnesses are designed so that they have some
basic elements.
They must have shoulder straps, chest strap, a leg or thigh strap,
a sub pelvic or a pelvic strap, and a waist component.
The waist component is the fact that on a harness, the front becomes
the back and the back becomes the front, and it will cross over, as you'll
see once we fit the mannequin.
So we're going to fit it onto this torso and
kind of talk about some of the aspects.
Once we open it up, we take the harness off.
The easiest way to do it is to throw the harness up over the shoulder
blades, just in that kind of manner.
As we put it over like that, and then kind to of put that in a position
where it is in that upper part of the back on our body, and then check the
height of the sub pelvic strap.
Initially, you'll be able to tell whether a harness
will or will not fit an individual.
There's many different sizes, many different functions, many different elements
of a harness, but size is important.
The next step is we're going to adjust the leg straps.
Now, there are different types of buckles or connectors in
harnesses; the most common and most simplistic is what is referred to as a pass-through
buckle.
And a pass-through buckle is just that, that it will pass through
the one side, and then when we connect it, it will lock into position and
we adjust it from there.
Another type of connector shown on this harness over here, is what is referred to
as the Quick Connect.
Quick connects come in a couple different designs, but a
Quick Connect is once we have it fitted, it just quickly connects like that and
locks in.
You'll find that in chest and leg, you'll find the pass-through in
chest and leg, but another version that is very common in the market is what's
called the tongue and buckle.
The tongue and buckle, and we'll just display it on here, is nothing more than that of a
belt system, but in the legs, and the adjustments are variable and it's very easy to get it
through there and get it connected and very convenient to fit,
especially if we're working in environments where it might be where we
might wear cold-weather gear in the morning, or wet gear in the morning, and
towards the day, so it's very easy to adjust these and wear them appropriately.
Once we have the d-ring, kind of in place, it's still a little loose, we'll undo the
leg strap and we'll put it onto the torso.
Once we have the pass trough buckle, it is as simple as passing it through,
like that.
Then to tighten, lift up on here, and then pull the webbing
through that way.
Tighten it so that it gets tight to the leg.
Initially, leave a little bit of flexibility in the legs because we're going to make some
other adjustments.
The easiest way to define how we fit a harness is think of it like a piece of shrink tube.
You don't want to do it all in one area, and then do the other area.
We want to do a little on the top, a little on the bottom, little on top, and
shrink it down to the body style.
And then, once we've done one leg and we get it fairly close to being adjusted, you're
just going move to the other leg, and wash rinse repeat.
Now, once we have the legs slightly adjusted, still a little bit of loose, we're going to
move to attaching the upper part.
At that point, we're going to attach the chest strap and just assure it's connected.
The chest strap doesn't have to be so tight that it pulls in, we just need it to lay flat
across the chest.
The chest straps job is to assure that the shoulder straps don't
come off of the body, and when we fall and we fall forward, that it catches the
body and puts some of the force into the chest cavity, some into the shoulder
cavity, some into the groin and the pelvis, some into the hips.
We talked about the crossover or the hip effect, and
this is the hip effect.
Where this shoulder strap comes through and it crosses
over here, and the front crosses over here, and the idea is so that if we fall,
the forces are applied into the structural elements of the human body.
The chest strap is also what's called a minor adjustment.
You have a lot less adjustability here than you do in a torso
strap or in a leg strap.
So, we want to save this for the last part, minor
adjustment; do the big parts first.
When adjusting the torso, depending on the type of connector or adjuster, it will differ
how much flexibility or how much adjustability you might have on a harness.
And there are different types, ones that are pull-up, ones that are pulled down, some that
have roller buckles, and then other ones that might
have what we refer to as an internal adjuster or it's a loopback.
The benefit to a design of this type, is that
once we adjust it, unlike a version like this, that has a lot of extra tail, once we
tighten everything up, and even though there's devices there to tuck that tail, on
a device such as this, once we have it adjusted, there's no tail because of the design
of the tie back or loop through.
Adjusting the torso, you're going to just pull that strap through, and you might
have to move the chest strap as the harness moves on our body as we bring up
the tension into the harness.
We'll just go through and make some adjustments here.
Once we have adjusted both sides, they should be fairly
symmetrical.
You don't want to see one that's adjusted to here, and another one
up here, because that will shift how the harness fits on the body.
They should be relatively equal both in the torso as well
as in the leg straps.
As you continue to tighten up the torso, remember
you're also bringing up the leg straps in the sub pelvic strap, which is why
initially we leave them a little loose.
Once fully fitted, they should be snug to the body and only allow you
to allow a flat hand in between your leg and your leg strap, or your thigh and your
thigh strap, so that we can't fit a full fist through there.
If somebody was wearing it this loosely, it would be extremely
dangerous for them if they actually fell, because of all of that force
as the body gets picked up, like this, as we fall, those leg straps will come
up into the groin and create some very significant potential, dangerous
outcomes.
Once we have the top fitted, now it becomes those minor adjustments.
As you can see, even though the torso is a specific size, I've made very little adjustment
to the chest strap, other than adjusting it up a little
bit.
There's not a whole lot of adjustment that we want; and we want it to
basically look like the letter H, across the shoulders, and across the center.
And then make the fine tune adjustments, if it didn't bring the leg straps
up tall enough, or high enough into the body, we're just going to pull through and
get those to get nice and tight to the body so that they sit very tight, not restrictive,
but secured to the legs.
A couple final checks, once we have it fitted, if there are extra straps, assure
that you tuck them through the buckles that are generally provided on most
harnesses, so that you can slide it through.
The idea is we don't want them dangling around where they can catch
onto equipment, or other tools, or sharp objects, which can pull us or dislodge
us.
Once you tuck all of those away appropriately, depending on the
design of the harness, then we want to do the final checks.
Have the worker stretch their arms, bend over, flex, do the
things that they would normally do in a work environment, to assure that it's not
restricting them from doing what they need to do.
And then the last check is again, make sure that the D ring is in the upper part of the
back, centered in the shoulder blades, so that this is our pick point should we fall.
We don't want it low because that will make us go into
a supine or Superman position if we fall and we're suspended; we don't want
to go much more than that degree, 30 degrees is the maximum that we want to go.
With a heavier weight, it'll actually pull the D ring off a little bit, it's called
harness stretch, which is normal.
Then, we want to assure that the sub pelvic strap, this device right here, is
actually underneath the pelvis as much as possible.
We don't want to see that strap here, or even further here.
It's job is one, to help express that load, should
we fall, and create almost like a little seat.
So that force, that possible 1,800 pounds, hits us in a place
that's a little flatter, bigger footprint, instead of taking it in a sharp object.
One thing to remember, especially if you see a worker wearing the harness loosely, is that
in a fall, we are accelerating; and OSHA is very specific about the amount of force that
is allowed to be applied to the body in a fall arrest scenario, and that number is 1,800
pounds.
Whether you actually do the mathematics, you're an engineer, or you're just a human being,
1,800 pounds of force, whether you've felt it before or not, one can assume, can have
some significant damaging effects to the human body.