An unexpected location for falling danger, anchorage was the failure point here.

Previously, on Battlestar Galactica: …Ah, sorry, perhaps a little too much television lately.  In our last article we were discussing the harness and anchorage system within fall arrest.  Today we discuss the connectors and decelerators in fall arrest, cover fall restraint, and dabble into conclusions on fall protection in general.

The connector is the item which links the harness to the anchor.  This element is usually a rope which can be either lifeline rope or static rope.  Lifeline rope is designed to stretch when in tension, so that some of the energy of the fall is absorbed by the stretching.  Static rope does not stretch, and is designed to reduce falling distance.  Depending on the requirements of the site, either may be used, as long as the fall is stopped without damaging the person.

Typical lifeline rope [1]

Typical static rope [2]

Example of under-designed connector and improper use of full body harness

Finally, the decelerator is the system which safely slows the falling person to a stop, avoiding abrupt jerks which could cause damage.  Decelerators exist as lifeline ropes (as discussed above), shock absorbing lanyards, retractable lanyards, and rope grabs.

Shock absorbing lanyards reduce falling speeds by “ripping” as they are extended.  These lanyards have their lines sewn back on themselves and when the lanyard is stressed the stitching breaks, absorbing energy and slightly increasing the length of the line at the same time, thus reducing the abruptness of the fall.  It is important to inspect lanyards prior to use because lanyards work due to their stitching (ripped stitching results in a lanyard which cannot absorb fall damage) and have a design life.

Shock Absorbing lanyards [3]

Example of shock absorbing lanyard with rope ladder attachment

Retractable lanyards work akin to seat belts.  This type of lanyard will allow a worker to travel at typical speeds around the work zone, but if they fall the lanyard will engage and lock in, preventing movement.

Retractable lanyard (background) [4]

Similar to retractable lanyards, rope grabs are typical for ladder systems where a worker goes up and down on a line.  The line acts as the anchor while the rope grab acts as both the connector and the decelerator.  The concept of the grab is that at slow speeds the grab glides along the rope, but if it is jerked, the grab locks onto the line, preventing a fall.

Rope grab [3]

Fall Restraint

“It’s not the fall that kills you; it’s the sudden stop at the end.” – Douglas Adams

Perhaps a good time to use fall restraint

Fall restraint can also come in a variety of forms, as long as it stops someone from falling.  Commonly, fall restraint involves a simple fence, guard rail, or walling systems to impede movement into dangerous areas.  An additional method involves horizontal lifelines tied to workers, which work similar to dog leashes, such that it is impossible for workers to travel towards fall dangers (or fire hydrants).

Horizontal lifeline anchorage system

Horizontal lifeline anchorage connection

Horizontal lifeline in operation [5]

It should be noted that horizontal lifelines can act as both a fall restraint and arrest.  The anchorage system involves a set of anchors connected by cable, through which workers are tied via lanyards.  If the lanyards are short enough, they will restrict the possibility of the worker to fall in the first place, but if not they may act as a fall arrest, where the lanyard lifeline acts as described above.

Conclusion

“Out of this nettle, danger, we pluck this flower, safety.” – William Shakespeare

Reducing falling hazards is the duty of both the employer and the employee.  It is the employer’s duty to provide the employee with sufficient protection as to adequately prevent the likelihood of a worker to injure themselves from falling.  Similarly, it is the employee’s duty to prevent their own injury by using a reasonable degree of care with the given equipment and surrounding environment.  Perhaps it is just this writer’s own leap of faith, but with the technology mentioned above, the probability of falling injuries can be greatly reduced if both the employer and employee jump on the bandwagon.  My apologies for that last line, I could not restrain myself.

Citations

[1] AC Tool Supply (2008).  Safewaze PPE Fall Protection.  Retrieved Friday, October 9, 2009, from http://www.aikencolon.com/Safewaze-PPE-Fall-Protection–Fall-Arrest-100ft-58-Lifeline-0221-100-2_p_998.html

[2] Heightec Products (2009).  Anchor lines, Rope.  Retrieved Friday, October 9, 2009, http://www.heightec.com/equipment/general.html

[3] Construction Safety Organization of Ontario (2008).  Fall Arrest.  Retrieved Friday, October 9, 2009, http://www.csao.org/UploadFiles/Magazine/Vol9No3/93fall.htm

[4] Meridian Safety (2007).  T-Line Safety System.  Retrieved Friday, October 9, 2009, http://www.meridiansafety.com/products/t-line-safety-system.aspx

[5] Liferail (2008).  The Horizontal Life Line.  Retrieved Friday, October 9, 2009, http://www.liferail.ca/product.php

[6] ACE Industrial Equipment (NA).  Beam Trolley for Industrial Use.  Retrieved Friday, October 9, 2009, http://www.aceshelf.com/beam-trolley.htm

The dangers of falling can be found in the most unlikely of places.

“Better safe than sorry.” – American Proverb

To the masses of Joe Publics walking down your city streets every day, fall protection may only include mittens and a scarf, but it is important for those working at heights to know the important difference between the protective measures required for a chilly breeze as opposed to a large vertical plummet; if you have ever worked in high places then you too have had the ever-creeping fear of slipping and going splat grow in the back of your mind.

However, as luck may have it the people who work for our government were afraid of heights and they added law stating that anyone working from over about three meters high is required to be protected from the dangers of falling.  This legislation does not cover people installing fall protection though, or the legalities would become absurd.

Fall protection comes in two general forms: you can either stop a fall from causing harm, or you can stop the fall from happening in the first place.  These two prevention methods are called fall arrest and fall restraint, respectively.

Falling: Don’t do it.

Fall Arrest

“If you ever fall off the Sears Tower, just go real limp, because maybe you’ll look like a dummy and people will try to catch you because, hey, free dummy.” – Jack Handy

Billy Slippyfeet found himself unwittingly working with a newly developed fall arrest system: snow.

Fall arrest has multiple forms, which all involve the reduction of injury during a fall.  This method typically involves netting or a lifeline.  A net system will catch a falling person and slow them down as they tumble into the center of the sagging net.  For a lifeline, four elements are used together for stopping a fall: an anchor, a harness, a connector, and a decelerator.

The Golden Gate Bridge introduces a ground breaking safety net and lifeline system

An anchor is the point to which the arresting system is tied; the anchorage will be designed to never fail under the highest falling loads.  Common forms of anchorage include hooks which are bolted (adhesive, through-bolt, and mechanical) or welded to a rigid structure, beam clamps, and beam trolleys (For anchorage moving with one degree of freedom.).  Furthermore, for ladder systems, a line running the length of the ladder may be used as an anchor with a rope grab system, described below.

Typical anchorage

Beam clamp

Beam trolley [6]

Anchorage being tested for strength

The harness is what is attached to the person, to allow for a connection between the person and the anchor.  Harnesses have existed for the belt and the full body, however now the full body harness is the common selection as belts have a tendency to cause too much stress to the waist in a fall or in the worst case even allow a worker to drift out of the belt.   Full body harnesses must be adequately designed to have strong enough connections for the load of falling and to support the body without causing physical damage.

Example of equipping and using a full body harness

Well I am afraid that is all for today! For the exciting conclusion to this article you will have to wait for a few days, but eventually the link will be provided below.  Stay tuned for connectors, decelerators, and fall restraint!  Same bat time, same bat channel.