HOW IMPORTANT IS FITTING YOUR HARNESS?
STACS has been facilitating fall protection training for over 25 years. This means we’ve been in front of literally hundreds of classes and thousands of participants. It totally amazes me that we routinely observe that less than 10% of our attendees really know how to fit their harnesses.
Improperly fit harnesses can result in user injuries or even the potential for associates to fall out of their equipment.
Interestingly enough, most of those attending indicate that they’ve participated in some form of fall protection training. Apparently these sessions don’t involve properly fitting the harness!
It seems that this is symptomatic of a number of issues. Experience has shown us that many of those attending our sessions seem to underestimate the probability of actually falling. Consequently, if you don’t believe the event can happen, you tend to take the precautions for granted.
Similarly, those that work at height seem to be under the impression that if they don their harness and connect to an anchor point, they’re now safe. Many participants are baffled that we actually offer training sessions lasting 4, 8 or 16 hours. “How can you possibly talk about fall protection for that long?” This tells me that the complexity of the subject matter has been drastically underestimated.
Many have been trained to don the harness, but the quality of the fit has never been determined. They wear their harnesses to walk around in, not to fall into!
Proper harness fit involves a combination of several factors. These “post fall indicators” can include:
- D Ring Location
- Chest Strap Location
- Sub-pelvic Strap Location
- Positioning the Leg Straps
Let’s discuss each briefly:
D Ring Location:
The “post fall” location of the harness D Ring may be one of the most important considerations with respect to fit. The final location can be a combination of improper fit by the user, a poorly designed harness by the manufacturer, or a combination of both.
In order to be properly “fit” the D Ring needs to end at the top of the back of the user’s head following the fall. The starting position of the D Ring needs to be somewhere between the shoulder blades.
There are a couple of factors that can affect the final location of the harness D Ring. These include:
Harnesses constructed out of “stretchy” materials, such as the Miller Duraflex are designed to “follow” the worker’s position throughout the day. This makes the harness more comfortable to wear since it doesn’t restrict the movement of the user.
If the end user hasn’t been properly trained to fit this type of harness, the D Ring can actually end up a foot or more above their head. Remember, it needs to finish off behind the top of the head of the user.This in turn can cause 2 problems:
First, because the D Ring ended up so high, it actually adds distance to the fall. Consequently, the fall clearance has been increased; and
Secondly, when the D Ring moves up this high, it causes the chest strap to move accordingly. As a result, it can impact the user’s throat at forces in excess of 900lbs….. OUCH!
These “stretchy” harnesses can be adjusted to eliminate these issues. I’ve witnessed many demonstrations by competitors of this product demonstrating what happens when this harness isn’t adjusted properly. Ironically, they don’t take the time to demonstrate that the harness can be fit properly. Don’t discount the use of this type of harness; once you’ve been shown how to fit them, they make a great addition to your fall protection equipment inventory.
Harnesses that come equipped with thick shoulder straps (apparently for comfort) or large back pads (again, apparently for comfort) can actually prohibit the vertical movement of the D Ring. This lack of vertical movement causes the user to be “pushed” forward ending up at an angle of 45 degrees or more off perpendicular. I’ve witnessed end users actually parallel to the ground when improperly fitted in these types of harnesses.
This forward angle can generates tremendous amounts of pressure on the user’s femoral arteries, which in turn significantly reduces the amount of time the associate can safely suspend in their harness. Rescuers better be prepared for a quick response time.
Chest Strap Location:
The proper position for the chest strap is nipple height and nipple width apart (for males) and below the breasts for females.
In our classes, we observe participants with chest straps positioned directly under the throat (too high) or down just above the navel (too low).
With the chest strap being positioned too high, the chest strap can impact the user’s throat at significant forces. Keep in mind that choking isn’t the issue here, it’s blunt trauma to the trachea and other areas of the throat.
With the chest strap positioned too low, the user could actually fall out of their harness should they be involved in a head first fall.
Sub-Pelvic Strap Location:
This is by far one of the most common mistakes made by untrained users. The sub-pelvic strap needs to end up (post fall) under the user’s rear end. The purpose of this strap is to allow the worker to draw their knees up to their chest (like performing a cannonball in a pool) so that they end up actually sitting into this strap.
This seated position eliminates the leg strap loading on the femoral arteries. As long as the user can pump their legs periodically in order to ensure the blood is circulating, they can remain suspended in their harnesses for longer periods of time.
In our experience, most classroom participants have their sub-pelvic straps positioned too high initially. A good “rule of thumb” is that once the harness has been donned, if you can look between your legs and see the sub-pelvic strap it’s in the correct location. It may appear to be loose and hanging down, but keep in mind when the fall occurs, the users goes “south” and the harness will travel “north”. If the strap is initially positioned too high, the sub-pelvic strap will be located half way up the user’s back side and as a result, rendered useless.
Leg Strap Location:
Once again, in our classes, we observe most leg straps positioned in either a “French cut” position, or loosely hanging down the legs (almost to the legs….. we refer to this as the “gun slinger” leg strap).
In either of these cases, the outcome is the same. Following the fall, the metal buckles on the leg straps can impact an area of the body that most of us wouldn’t want to be impacted!
To be properly fit, the leg straps should be positioned (as much as possible) parallel to the ground, with the metal buckles as far away from the inside of the groin (the danger zone!) as possible.
Proper leg strap fit involves 2 fingers positioned flat between the strap and the user’s leg. If you can barely fit one finger into that space, or if you can’t fit your entire fist in that area, the strap has not been adjusted properly.
PROPER HARNESS FIT:
So how does one determine if the harness has been properly fit? The only true way is to simulate a load on the harness. This way one can observe how the harness would actually react should a fall occur.
Obviously, we don’t want to expose the user to actual fall forces, so we introduce a static force to the system.
This load is applied by slowly lifting the user 4-6 inches off of the ground. In our classes we select an appropriate anchor point (remember, we’re conducting a static lift which is totally different than the dynamic forces generated during a fall) and connect our 4:1 rope hoist, which in turn is used to raise the user.
Once lifted, constructive comments can be made on the D Ring, sub-pelvic strap, chest strap and leg strap locations.
Remember to mindful of the participants existing medical limitations. Obviously, you wouldn’t expose an end user to this process if they are suffering from a bad back, have just undergone surgery, if they’re pregnant, etc.
Once the user has been lifted and an evaluation of fit has been made, lower the user, have them make the appropriate adjustments and lift again to ensure that those adjustments have solved the problems encountered with the initial lift.
Fit testing is a mandatory component of all our fall protection training sessions. I think you’ll be surprised how well this element of your training program will be received by those participating.
In conclusion, improper fit of harnesses is a huge problem in the “working at heights” industry. Proper fit will involve reviewing the D Ring location, chest strap, sub-pelvic strap and leg strap positions. Conducting a static lift guarantees that the end user has donned the harness properly.