Leading-edge, we would define as any place where when a worker is tied off with a fall-arrest
system and they take a fall, their lifeline, whether that's a rope lifeline, cable lifeline,
their lanyards, could strike that edge and the anchor point is going to be on one side
of the edge and the worker is going to be on the other side of that edge.
When we're working in a situation where we have a leading-edge, we have to make sure
that our arresting device stays with the workers themselves.
When we're working with a fall-arrest lanyard that means making sure that the shock pack,
the shock-absorbing device on that lanyard is always attached to the worker’s back
D ring.
The reason for that is is when we fall over a leading-edge we create a point of friction
with that pinch point that's there.
If our energy absorber is above that leading-edge towards our anchor point where that point
of friction has happened our energy is not going to transfer up to that anchor point
or to where that shock pack potentially could be, it's not going to be controlled and decelerate
it down to an acceptable level either the 1800 pounds or 900 pounds average by ANSI
and the worker could be subjected to higher arresting forces or fall forces there.
When we have the arresting device with the worker and they take a fall over that edge
it's going to function, it's going to reduce the forces that are both put on to the fallen
worker and on to that edge where the lifeline is contacting that that edge.
It has the ability to reduce how much swinging and bouncing that that lifeline has on that
edge of the same time.
We have a leading-edge and we also have leading edges that incorporate sharp edge hazards
into them.
A good rule of thumb when we're looking at something that could be a sharp edge, whether
it’s a sharp steel edge, or sharp concrete edge, anything with a radius on that edge
that's less than a number 2 pencil.
We want to start taking extra measures on that leading edge to protect against cut hazards
on that lifeline from that sharp edge.
A lot of this is being addressed through the ANSI standard.
ANSI has come up with specific standards for a leading-edge and sharp edge and come up
with specific ways for manufacturers and users to try to reduce the hazard, the cut hazards
that go along with those leading edges and sharp edges.
The ANSI sharp edge, ANSI defines a sharp edge as anything with a .0005 edge on the
steel edge.
And that's a very very sharp, that's equivalent if you think of the cut end of an I-beam that's
about how sharp that is and there are some definite hazards there when people are working
on leading edges that are sharp and don't have the proper equipment or don't have their
systems properly put in place.
We have the hazard of cutting the lifeline definitely whether it’s web or cable, we
do have cut hazards there.
There's also as we said earlier the clearance hazards that go along with that as well.
Another version of SRL that you're hearing commonly in the market is that of an SRL-LE.
LE stands for leading-edge, now that’s a specifically designed piece of equipment because
same thing as with the lanyard connected devices, we don't always have an anchorage that is
here or above and in that case, using a retractable with foot level tie-off being worst-case scenario
now we get to a condition where if this is my walking surface this is attached to an
anchor and now my D-ring is up in the air 5 foot occasionally based off of the worker’s
height and then they fall because this works like a seatbelt what happens as we're creating
acceleration on a device that's not designed to take that and worst case scenario as we
fall what will happen is it will hit this edge and create what is referred to as a shearing
effect.
This is a condition that has sadly injured numerous workers and sadly made a few of them
a fall fatality because the equipment wasn't designed to take that force in that condition
and it sheered, allowing them to continue for to whatever the lower-level was.
One of the ways that you will absolutely know that a piece of equipment is or is not designed
to be used in that configuration is of course to reference the manufacturer's instructions.
They are going to be the ones that will dictate what edges it is acceptable to use on.
However ANSI, the ones that first, ANSI committee that first instituted the leading-edge testing
requirements also mandates that the manufacturers clearly identify with symbols a retractable
that is or is not rated for leading edge.
In general, you will see non leading edge and it may be manufacturer-specific where
it has a symbol with a red X or some other marking that clearly identifies not acceptable
use, whereas if it is you will see a symbol such as this or other that will show is rated
for leading edge.
There's a lot more to that you should always investigate ensure again that we are using
the right tool for the job and just because you're working at an edge, whether it's an
unprotected side edge or leading edge you have to concern yourselves with the fact that
if in the event of the fall, the line can make contact with the edge during the progression
of the fall you consider it a leading-edge condition.
Thus having the right tool for the job versus one that could potentially shear.
However just because you are working where you have an edge and that might be the device
of choice, you will still have to consider fall calculation and fall clearance because
if you're only twelve feet up in the air and this device requires more than that of total
fall clearance you still haven't protected the worker because yes it didn't shear on
the edge but they hit the ground that's unacceptable.
Not because of the law, because your worker hit the ground.
A lot of times when we're talking leading edge or sharp edge we’re connecting our
devices at foot level.
We could be taking a much greater than a 6-foot freefall so we have to watch what our total
fall clearance is going to be when we’re working on leading edges, where we need to
anchor our devices, what the charts for those manufacture’s on fall clearance say about
the amount of distance that’s going to be needed when we're anchoring low, is that device
made to anchor right at foot level or is it only made to anchor down maybe to knee level,
what are the maximum arresting forces of that device when used in that situation.
If it is 1350 pounds where we are used to having a 900-pound device then we would have
to look at how is that going to affect the anchor points that we're connecting to as
well as the structure we're connecting to.
If we’re using certified anchor points, anything that is designed to a 2:1 safety
factor, if we designed that for 900 pounds and maybe we have an 1800 pound anchor point
that we've been using and we're now using a device that when used on a leading-edge
is going to impart 1350 pounds of force, we need to know how that's going to affect that
anchor point, how that's going to work in that entire system, how far back from the
edge we need to connect.
The further away from the edge when we’re working either on leading edge or sharp edge
the less overall fall clearance we're going to need if somebody falls and goes over that
edge.
So there's a lot that has to be looked at with leading-edge and sharp-edge.
It's up to the companies to be better educated on what leading-edge hazards they have in
their facilities or on their job sites, how they're identifying that as either a leading
edge or a sharp edge.
If we're working in the wind industry and we have a highly radiused fiberglass edge,
we probably don't have a cut hazard but we have a leading still have a leading-edge hazard.
If I'm an ironworker and I'm walking red iron tied off at foot level and I take a fall and
strike an I-beam with my fall arrest equipment, I have a leading-edge hazard, but I also have
a sharp edge hazard where I need to make sure that I’ve identified that as a potential
area where I could have a cut hazard that's there are.
Our qualified people and our competent people need to be on the lookout for these hazards
and making sure that workers are protecting themselves and using the right equipment that's
there.