2 General Information on Fall Protection
2.1 Introduction
Heavy industry and construction work has many hazards. Whether
the hazard is moving equipment, thermal, explosive, or contaminated
atmosphere, they are all dangerous.
Workers are trained to recognize most hazards in their work places
and take appropriate measure to ensure their safety. This is normally
accomplished by wearing Personal Protective Equipment (PPE) and
through training in the proper way to deal with the hazard. Unfortunately
individuals largely overlook one of the most common hazards, in
any workplace or home, because it seems too trivial, or it takes
longer to be safe than the job takes.
What is the hazard? FALLS!
How prevalent is this fall hazard?
Falls from elevation are, according to the National Safety Council,
one of the highest causes of death in the workplace. A study by
the United Roofers Union conducted between 1985 and 1989 reported
297 fatalities from heights six feet or less. In Maine between 1997-98
31% of all industrial fatalities were fall related. The cost? The
pay out made by employers and insurance companies averaged out to
1 million dollars per episode.
Fall related accidents are complex events involving multiple factors.
A number of issues both human and equipment related should be addressed
to educate employees on fall hazards both in general and specific
to their work environment. These issues include:
· Where and when protection is required
· Establishment and implementation of a fall protection plan,
including provision for rescue
· Proper selection of fall protection systems
· Correct construction and installation of these systems
· Proper training in selection, use and maintenance of the
selected equipment
The key to preventing falls is through education and skill proficiency.
A thorough knowledge of the hazards, available equipment, application
and limitations of the appliances along with a program to implement
learned skills will further the goal of reducing and minimizing
workplace injuries and fatalities due to falls.
What are the chances of surviving a fall?
From an eleven-foot fall the chances of surviving are 15%. That
means there is an 85% chance of becoming a fatality. This course
is designed to keep you from becoming one of the 85% by giving you
a better understanding of what is required to protect workers at
elevation and the tools to work safely at heights.
2.2 Hazards of Elevated Work
For some individuals working at heights is a thrill, while for
others it can be a nightmare due to fear of falling. It can be enjoyable
on a nice day, but miserable on a cold windy day. Hazards working
at heights are normally much the same as working on the ground with
the exception of falling and either being injured or requiring some
form of rescue. There are four general categories of hazards while
working at heights.
· Atmospheric
· Psychological / Medical
· Attitude
2.2.1 Atmospheric
2.2.1.1 Heat
The body's normal core temperature is 98.6 F. When this temperature
increases, the body tries to maintain the proper core temperature
through perspiration. As the core temperature continues to rise,
heat cramps, heat exhaustion or heat stroke can occur.
Heat Cramps
Heat cramps are painful spasms of muscles usually in the calf or
abdomen. A fluid and salt loss resulting from heavy exercise or
work outdoors in warm or even moderate temperatures cause these.
Signs and Symptoms
· Severe muscle contractions, usually in the legs and the
abdomen
· Usually normal body temperature
· Moist skin
Heat Exhaustion
This is the most common heat illness leading to fluid depletion,
and is caused by exercise or work in a hot environment. The cause
is fluid loss from excess sweating, which is not adequately replaced.
This loss leads to low blood volume. Blood flow is reduced to vital
organs as the body tries to give off heat by increasing blood flow
to the skin.
Signs and Symptoms
· Normal or slightly elevated body temperature
· Cool, moist, pale, or red skin
· Headache
· Nausea
· Dizziness and weakness
· Exhaustion
Heat Stroke
The least common yet the most serious heat illness. Heat stroke
develops when the body cannot cool itself and gradually stops working.
Sweating stops because the body tissues have a lower fluid content.
The body then cannot cool itself, and body temperature rapidly rises.
It soon reaches a level at which the brain and other vital organs,
such as the heart and kidneys, cannot function properly.
Signs and Symptoms
· High body temperature, often as high as 106F
· Red, hot, dry skin especially in the elderly
· Irritable, bizarre, or combative behavior
· Progressive loss of consciousness
· Rapid, weak pulse becoming irregular
· Rapid breathing
2.2.1.2 Cold
Some people find working outdoors in the cold invigorating and
some don't. A couple things occur in the winter, one being the worker
must dress in heavy cloths, which make movement awkward, and the
other is the lowering of the body's core temperature causing hypothermia.
Hypothermia
This condition is caused by exposure to the cold to a point that
the body cannot keep itself warm. Air temperature, the humidity,
whether the skin is wet or dry, and wind all affect how the body
maintains its temperature and how much exposure is needed before
hypothermia begins. The air temperature does not have to be below
freezing to cause hypothermia.
Signs and Symptoms
· Shivering (may be absent in later stages)
· Numbness
· Lack of coordination
· Confused or unusual behavior
· Body temperature below 95F
2.2.1.3 Wind
Wind is an indirect hazard as it can cause wind chill factors leading
to hypothermia and frostbite. Stronger winds can move the staging
or structure causing unsteady work surfaces. The wind can also blow
loose material around which could hit workers or cause them to avoid
flying objects.
2.2.2 Medical Problems
2.2.2.1 Vertigo
Fear of heights is the first thing most people think about when
discussing medical problems that relate to work involving heights.
This isn't that large of a problem, as people with this fear either
have overcome it enough to work at heights or they don't go up.
Vertigo is a disorder that can happen to anyone, anytime.
Vertigo is a disorder of balance that gives a person the sensation
of spinning around in space when at rest. Alternatively, objects
may appear to be spinning around the person.
Vertigo is caused by a disorder of the ear the affects balance.
Infections of the inner and middle ear or blockages of the Eustachian
Tube can cause vertigo. A build up of wax in the outer ear can also
cause the disruption of balance. Drugs, alcohol, or food poisoning
as well as sudden disturbances of the eye will have a great affect
on vertigo. Thus, if a person shows up to work with an ear infection
or hung over, there is a possibility of vertigo.
Signs and Symptoms
· Nausea and vomiting is common
· Difficulty walking with a tendency to fall side ways
· Eyes may flicker
· Buzz in ears
· Hearing loss
The above are symptoms that may occur, but not always.
2.2.3 Attitude
2.2.3.1 Complacency
Complacency is one of the leading causes of falls due to the worker
becoming careless. Due to experience, lack of training, or other
factors, many workers become unconcerned with the hazards and fail
to take appropriate action to protect them from a fall.
2.2.3.2 Horseplay
Fooling around at heights can be very dangerous and must not be
tolerated. It can take many forms from pushing and shoving to playing
with others safety gear. Horseplay can result in serious injury
for which participants may be held responsible.
2.2.3.3 Housekeeping
Although overlooked on many occasions, housekeeping is very important.
The more equipment, tools and left over material left lying about,
the more hazards that are available for slips, trips and falls.
To avoid injury from falls, or falling objects, practice good housekeeping.
Dispose of scrap and waste materials promptly, in approved containers.
Return tools and equipment to storage as soon as you are finished
with them. Obtain and use a good tool belt to avoid dropped tools.
2.3 Fall Protection Systems
Basic fall protection systems can be as simple as a guardrail,
a ladder cage or a handrail. All provide basic protection but, as
in the case of a ladder cage, imperfect protection. Fall protection
systems can be divided into three types:
· Fall Restraint
· Work Positioning
· Fall Arrest
2.3.1 Fall Restraint
A fall restraint system is designed to eliminate the possibility
of falling to the next level whether it is a floor or suspended
obstructions such as pipes or conduit. The simplest form would be
a guardrail. Properly constructed and secured the rail will give
more than adequate protection for a worker performing his task or
transiting the area. Guardrails that are poorly made and designed
lend a false sense of security and may be more hazardous then having
no rail at all.
Hand or stair rails are there to be used to assist a worker to
ascend or descend stairs. They may not prevent a scraped knee or
banged shinbone but they can stop a person from tumbling down a
stair or falling into the risers if the rail is used in a safe and
contentious manner.
Ladder cages are the least effective of all. In fact, OSHA is studying
the elimination of cages as a protective device. Loosing your grip
on a ladder and falling within the interior of a cage can cause
serious injury and if it does arrest a fall it does so by entangling
the workers body within it's framework. If it does not, then the
worker merely tumbles within the cage till they strike the ground.
Many times there are no guardrails and in many more cases the task
to be completed may be a one-time exercise or due to other variables
it is not possible to erect a rail or properly secure it. This is
where a constructed restraint system is necessary.
Designed properly, a restraint system allows a worker to perform
their task without the possibility of loosing contact with the walking
/ working surface. This means the anchor point will not be subjected
to an impact load. Because of this the anchor strength requirements
are limited to four times the intended load. For example, a 200-lb.
worker would need an anchor point capable of sustaining an 800-LB
load. Equipment for restraint systems should be compatible and in
good working order. Although a waist belt can still be used for
restraint it is highly recommended that a full body harness be worn.
2.3.2 Work Positioning
Work positioning allows a worker to perform their task in the vertical
plane while being exposed to a minimal free fall, two feet or less.
Two examples of this would be a construction worker assembling or
performing a task on a metal form structure or a window washer.
Anchor points for a work-positioning device are rated at 3,000
lbs because of the possibility of a 2-foot free fall. Many of these
devices are simple chain devices with a specialized hook or carabiner.
The connection points to a worker will be on each hip. The workers
feet are in contact with the structure they are working on. In the
case of a window washer, this would be the powered swing stage.
A device such as a DBI RPD 1 would be used as a back up or as a
primary device utilizing a vertical lifeline with a rope grab as
a redundant system.
A worker using a work-positioning device should employ a backup
system in case the primary system should fail. This is especially
true for a window washer or any worker employing the use of a swing
stage or powered platform. Make sure that the device is inspected
and is compatible with the task. Jury rig systems using old lanyards,
pieces of chain and a collection of snap hooks are an invitation
to trouble.
2.3.3 Fall Arrest Systems
Fall protection is addressed within OSHA 1910 General Industry
Standards but only draw attention to guardrail, handrails and related
matters. Fall protection for floor and wall openings in this standard
are governed by the four-foot rule. Simply stated, if the floor
or wall opening is four feet above the next level then that opening
shall be guarded by use of rails or other appropriate measures.
This standard is weak and OSHA is in the process of rewriting the
rules to make them conform to the 1926 Standards.
OSHA addresses fall protection within the 1926 Construction Standards.
Anchor points, connectors, shock absorbers, in fact all the components
that establish the parameters of restraint, positioning and fall
arrest systems are contained in this standard. The Construction
Standard follows the six-foot rule. Any worker exposed to a six-foot
free fall is required to have fall protection whether it is restraint,
positioning, or a combination of components that would comprise
a fall protection system.
When a fall arrest system is in place there is a high probability
of a worker sustaining a fall. This system is not designed to prevent
a fall but to arrest the fall with minimal injury to the worker.
The components of a fall arrest system are as follows:
· Anchor Point
· Connecting Means
· Energy Absorbers
· Body Holding Devices
As part of any fall arrest or work positioning system there must
be a provision for rescue and / or retrieval. This component is
part of a required plan as stipulated by this standard. Planning
for the worst may also facilitate identification of hazards and
could help in removing the need for fall protection by using other
means of production or assembly.
2.4 Anchors
Anchors fall into two categories, certified and improvised. But
exactly what constitutes an anchor? By simple definition it is any
secure structure that can withstand and absorb the impact and /
or static forces exerted by fall protection equipment. They can
be a beam, girder, floor or column. Certified anchors are rated
at a minimum of 3,600 lbs., improvised at a minimum of 5,000 lbs.
Some points that should be considered in selecting or designing
an anchorage would be: work area access, potential fall distance,
utilization of shock absorbing equipment and ease of rescue.
2.4.1 Certified Anchors
These are specifically designed and tested products or points prominently
marked and labeled for use with fall protection products or systems.
Although most certified anchors are built and designed for site-specific
applications such products as tripods, davit arms, eye bolts and
beam clamps fall into the same category. All engineered anchor points
and related products should be rated at a minimum of 3,600 lbs.
and distinguished by paint or markings to insure they are not used
as material handling load points. Routine inspections of these points
should be carried out to insure they have not been damaged or compromised
by virtue of accident or misuse.
2.4.2 Improvised Anchors
Often there are no engineered anchor points within the work area.
It is now up to the employee to select the correct engineered product
and determine whether the area has a hard point capable of withstanding
a 5,000-lb. impact. Before making the selection the employee should
remember these points:
· The hard point should be unquestionably strong
· It does not show excessive wear or deterioration
· Has no sharp edges
· Is not electrical in nature (electrical conduit or trays)
(if it is imperative that a hard point such as a crane rail be utilized
lock out / tag out becomes an absolute necessity)
· Is not mobile or capable of movement
· Is not subject to high temperature, contact with solvents
or corrosives
· (Steam or air lines, fire suppression systems, intake or
drain lines)
If the anchorage does not appear to be secure, multiple anchorage
points meeting the above criteria must be utilized. While it may
be difficult to mark improvised anchorage's, if one is identified
and used on a regular basis certification and / or testing would
be prudent to eliminate uncertainty.
2.4.3 Anchorage Connectors
Once it has been determined that an improvised anchorage is to
be used the next step is the identification and proper use of an
appropriate anchorage connector. All of the products on the market
today have practical applications and range from a simple eyebolt
or sling to self-locking hooks and sophisticated quadruped assemblies.
Some of the more common types are belt type connectors, tripods,
slings both synthetic and cable and beam clamps of various types.
The synthetic belt type connectors are either a simple basket type
or a pass through. In either case the belt should have an integrated
softener pad so that any blunt edge or undiscovered burr does not
compromise the load-bearing portion of the strap. There are many
belt types available that do not have a pad and routinely advise
users to provide one if there is concern with abrasion. Manufacturers
instruction on the use, care and maintenance of these appliances
should be followed. Slings should not be configured in a girth or
choke style hitch unless the product is so designed by the manufacturer.
Improper configuration could cause the sling to fail in the event
of a fall.
When faced with high temperature, such as welding or areas that
may have contact with chemicals or solvents an effective alternative
to synthetic slings would be 1/4-inch aircraft cable with Flemish
eye splices. These slings are rated at roughly 7,600 lbs. and it
is recommended that two be used in tandem and hung in a basket configuration.
Proper training in the use and configuration of these type slings
should be done by certified personnel, as there are certain considerations
to be addressed with these appliances. Never girth or choke hitch
steel cable. This type of configuration allows for undue stress
on the slings and in the case of a fall the impact forces may cause
the slings to part.
2.4.4 Inspection, Care, and Maintenance
All the above-mentioned appliances should be inspected on a daily
basis by the end user and periodically by competent personnel. Cuts,
tears, abrasions, discoloration, kinks, burrs, deformations should
be noted. Serious wear or damage would preclude the use of the appliance
as would a fall. One hazard often overlooked in relation to synthetic
slings is UV exposure. Slings left out in direct sunlight for long
periods of time will degrade and loose their tensile strength. Discoloration
and brittleness are two immediate symptoms of UV damage. Synthetics
can be cleaned. Refer to manufacturers recommendations in the area.
2.5 Connectors
Connecting means for fall protection systems are divided into four
main sections. Snap hooks, carabiners, lanyards and shock absorbing
lanyards. In this section we are going to examine each of these
connector types so that the employee will have a better working
knowledge of the equipment available and it's use.
2.5.1 Snap Hooks
In the past non-locking snap hooks have been the rule however,
as of January 1st, 1998 OSHA requires self - locking snap hooks
to be used. The use of self - locking snap hooks reduces the probability
of accidental roll out (disengagement of connectors) however, there
is still the possibility of a forced roll out disengagement especially
if the connectors are improperly used, mated or poorly maintained.
ANSI requires that the hooks be either drop forged, stamped or
machined from high tensile steel, proof tested to 3,600 lbs and
are capable of withstanding a 5,000lb-impact force. A quality hook
should have its rating, country of origin and either in writing
or by symbol a drop forged manufacture notation. While the hook
itself is rated for 5,000 lbs it should be important to note that
the weakest point of the hook is the gate. Side gate loading of
the device is dangerous when you consider that only 350 to 400 pounds
of impact force is needed to " blow" the gate.
Snap hooks come in various designs and it is crucial that the hook
be user friendly in all types of environments and weather conditions.
Hooks that are easy to use in mild conditions may be found to be
difficult to open with a gloved hand while others may tend to jam
up if not cleaned on a regular basis.
Other types of hooks available are ladder or scaffold hooks. While
these types offer larger mouth openings and are very easy to open,
there is always the possibility of accidental unlocking of the hook
if the device becomes wedged between the employee and a work surface.
Some snap hook variants incorporate integral swivels which allows
for an attached lanyard to align itself eliminating the possibility
of twisting the lanyard or cross gate loading if the hook is connected
to an eye bolt.
Inspection, Care, and Maintenance
Hooks should be inspected by the end user on a per use basis. Deformations,
cracks, burrs, discoloration and improper alignment of the gate
should be notated and the hook retired. Broken springs or excessive
slop in the gate would also mandate retirement of the device. Hooks
exposed to harsh environments such as acids and metal particulate
contamination and are subject to heavy use where they are dropped
or banged against machinery are prime candidates for early replacement.
Note: On some occasions workers have compromised hooks by grinding
out the locking mechanism or merely taping the lock open. Not only
is this dangerous but borders on the criminal if the hook is being
used by someone unaware that the hook has been "altered".
Further, many times a hook sewn into a shock-absorbing lanyard has
been involved in a fall, taken out of service then cut from the
lanyard and used for other purposes. This is poor practice. There
is no practical avenue to determine whether that particular hook's
capabilities have been compromised. Once a hook is involved in a
fall, identify and destroy.
Keeping a hook clean is a simple affair. Gates should be cleaned
with WD-40 or similar type solvent, then cleaned with a soft, dry
clothe. Greases or oils may lubricate but if not completely removed
have a tendency to attract dirt. Lubrication can be accomplished
with a dry lubricant such as graphite. Again, consult the manufacturers
recommendations if unsure as to the correct process for the appliance.
2.5.2 Carabiners
Carabiners by definition are connector components comprised of
an oval, elliptical or trapezoidal shaped body with a normally closed
gate that may be opened to permit the body to receive an object.
In the case of OSHA approved devices the gate must be self-locking.
ANSI does not recognize non-locking types. In the recent past manual
or screw gate carabiners were accepted however, there were legitimate
concerns on the advisability of using these devices in the workplace.
Fire and rescue personnel are still allowed the use of screw gate
carabiners for rescue purposes since OSHA does not specifically
address rescue services or equipment.
Carabiners have their origin in mountain climbing and the earliest
versions were in steel, then aluminum. All were non- locking to
allow for quick access and egress of the climbing rope however care
and attention was needed to ensure that roll out did not occur as
it did many times because of negligence or oversight.
Screw Gate or Manual Lock Carabiners
The need to have a secured carabiner led to the screw gate carabiner,
a device that requires the user to manually screw or lock the carabiner.
The carabiners were available in either aluminum or steel. The major
concerns over using these types centered on proper loading of the
device and the whether an employee could be counted on to lock the
device each and every time. Other problems arose when the device
was exposed to continuous vibration and would occasionally "unlock"
itself. In other cases, under load the carabiner would stretch and
the screw gate slip down. When the load was released in would be
almost impossible to unlock the device by hand.
Auto - Locking Carabiners
In response to the concerns with the screw gate types auto - locking
carabiners were introduced. These devices could be opened with one
hand and when the sleeve was released, would lock without any further
assistance. Since the gate did not have to be screwed shut these
carabiners would not jam closed after a load was not released nor
would they open because of excessive vibration. Loading or proper
positioning of the carabiner ceased to be a concern since the device
would load itself along its spine. There is one cautionary the user
should be aware of, if the sleeve of the carabiner is allowed to
come into close contact with clothing, harnesses and equipment the
sleeve may be forced open effectively unlocking the carbine.
Aluminum Vs Steel
There has been a continual debate over the use of these two materials.
OSHA allows for the use of aluminum by stating that the connector
can be made of " materials of equivalent strength." The
controversy over aluminum stems from the question of durability
and whether aluminum carabiners could sustain an impact from height
without compromising their tensile or impact strength ratings. On
the question of durability steel wins out. Steel carabiners are
capable of absorbing a tremendous amount of wear and tear and continue
to function. Dropping them or having them tossed into tool bins
is not recommended but the reality is this is the type of treatment
most of the devices are subject to. Admittedly, aluminum is not
as durable as steel but on the question on their ability to absorb
impact it appears that the concern is not over the body of the carabiner
but rather the sleeve.
If the carabiner is dropped any deformation of, or difficulty opening
and closing of the gate would be the criteria for removal of the
device from use. From the industrial standpoint steel, auto - locking
carabiners are still the best choice.
Cross Gate Loading
Although this condition has been mitigated by the self-loading
design of modern industrial carabiners employees should be aware
of the possibility and it's consequences. This condition is exemplified
by the carabiner being loaded across it's gate rather than along
it's axis or spine. A carabiner that is rated at 5,000lbs along
its spine is rated at less than half the rating when cross gate
loaded. This condition can be caused by having too many slings in
the carabiner or having the load rotate and catch the sleeve of
the carabiner.
Types of Carabiners
The basic designs for industrial use can be reduced to three basic
types.
· The standard D
· The Offset D
· Scaffold.
The major point of the D type carabiners is the great strength
that this device is capable of. They are also prone to load properly
which relates to less probability of cross gate loading.
The scaffold type carabiners are much larger and have large mouth
openings some as wide as 2 inches. This allows workers to secure
them to larger structural members that their smaller cousins cannot
do. These scaffold carabiners are available in three shapes, pear,
triangle, and offset triangle. Another type would be a captive eye
with a swivel designed to allow full movement of the worker without
twisting the lanyard. These carabiners rarely exceed the 5,000lb
rating because of the pin that has been drilled into the spine to
allow the 360-degree movement however, if used properly these devices
are extremely versatile especially if used with self-retracting
lifelines.
The minimum rating for carabiners is 5,000lbs. Most will exceed
these ratings however, one should be careful and read the rating
that is stamped on the device. There are carabiners that are rated
at 3,600lb and these do not fulfill the OSHA requirements.
Inspection, Care and Maintenance
Inspection of carabiners should be done on a daily basis. Carabiners
that have significant dents, gouges discoloration, improper alignment
of the gate or gates that are stiff and difficult to open or close
should be taken out of service. Carabiners involved in falls should
also be removed and destroyed with the view that if allowed to be
used for other purposes there is always the possibility of catastrophic
failure of the device. Like snap hooks, carabiners should be serviced
with a dry lubricant and cleaned with a soft, dry cloth.
2.5.3 Lanyards
The ANSI definition of a lanyard is as follows: A component consisting
of a flexible line of rope, wire rope or strap which generally has
a connector at each end for connecting the body support to a fall
arrestor, energy absorber, anchorage connector or anchorage. (ANSI
Z359.1)
Lanyards are typically three to six feet in length however; some
lanyards are adjustable in length and in some specialized applications
may be as much as 12 feet in length. OSHA only allows a maximum
free fall of six feet for the vast majority of industries. The major
exception would be those people involved in the erection of steel.
Other types of lanyards that are available would the dual lanyard
that is actually two lanyards attached to a specially designed shock
absorber. This type would be used as a 100% tie off for those workers
moving in a horizontal direction while involved in their work tasks.
Basic Types
There are three basic types of lanyards, based on the materials
used for their construction.
Laid Rope: This type was the most common until the introduction
of the synthetic, web style lanyard. It consisted of three strands
of nylon with a minimum total diameter of 1/2 inch. The nylon construction
gave this type high strength and elasticity. The downside of a nylon
lanyard was its propensity to absorb water and thus loose up to
30% of its strength while wet. With the laid rope construction,
foreign material such as grit, sand, and any type of particulate
matter could find it's way in between the strands and so degrade
the lanyard from the inside out. Nylon also did not fare well in
the areas of hot work or where there was exposure to corrosives
or acids.
Flat Synthetics: These types of synthetics are very strong and
compare very favorably with nylon and unlike nylon are not affected
by rain or water. They have high resistance to abrasion but are,
like nylon, suspect around areas of high temperature, hot work and
corrosive exposure. Another factor to consider with synthetics is
UV degradation. Leaving them exposed for long periods to strong
sunlight has a detrimental effect on their strength and durability.
Synthetics also have very little in the way of elasticity.
Stainless Steel and Galvanized Cable: This type of lanyard is usually
found in very unique work areas. High strength, excellent abrasion
resistance, and affected by only the most extreme temperatures.
They are used in welding, hot work and any type of environment that
would be hostile to the other types. One caution would be in the
area of electrical work for obvious reasons. One point to keep in
mind, these types have no elasticity.
Along with these three there is a fourth type commonly referred
to as a manyard. This type incorporates an internal shock absorber
within the nylon core of its construction. While very popular because
of it's relatively lightweight and absence of a pouch - type shock
absorber there are concerns with this style. There are variants
on the market that show impact on the lanyard but do so in reverse.
The Miller Manyard and the DBI product exemplify this problem, which
operate exactly the same with the exception of their impact indicators.
Mixing these lanyards is apt to cause confusion even if personnel
are highly trained in their use.
Impact Concerns
All the lanyard types previously described with the exception of
the manyard should be used in conjunction with a shock absorber,
preferably one that is integrally attached to the lanyard. Cable
lanyards, if used in a fall protection system should always be used
in conjunction with a shock absorber!
The reason is the amount of impact force that can be generated
on a human body during a fall. Medical studies show that the human
body cannot sustain impacts of 2,500lbs and above. Tests have shown
that dropping a 220lb test weight six feet can generate as much
as 6,000 lb. of impact if a steel cable is used and 2,800 lb. with
a flat web synthetic. Nylon lanyards generated between 1,700 and
1,900lbs of impact force due to nylon's elastic capabilities. Even
so, OSHA mandates that the maximum impact force that a worker can
be exposed to is 1,800lbs while wearing a full body harness. The
inconsistency of a nylon lanyard mandates the use of a shock absorber
if the lanyard is part of a fall protection system.
One of the most common abuses of lanyards is girth hitching, which
is tying the lanyard back onto itself by utilizing the snap hook.
Many times workers will use this method to tie themselves off. This
is an extremely dangerous practice because of the pressure being
exerted against the gate of the snap hook. While discussing snap
hooks we noted that the gate of the hook could only sustain 350
- 400 lb. worth of force. Further, the amount of pressure being
exerted against the lanyard material itself could cause the material
to break even if it's steel cable. There are now devices with an
integrated shock absorber that will allow for tie offs but these
use steel D-ring sewn directly to the lanyard itself. We will examine
this type and other variants in the next section.
Inspection, Care, and Maintenance
Lanyards should be routinely inspected for cuts, tears, abrasions
and discoloration. Brown or black spots in flat synthetic webbing
may be indicative of splatter burns from grinding or welding work.
Discoloration may stem from UV degradation or exposure to chemicals.
Laid rope lanyards should be inspected inside and out. Opening the
weave to see if the lanyard has grit, stones or other foreign matter
that may degrade the interior portion of the lanyard. In cable lanyards
fraying of the cable, or signs of excessive wear at the point of
connection with the hook or the shock absorber would dictate removal
of the lanyard from service. Synthetics that may be unusually stiff
or soft may indicate exposure to petroleum products such as gasoline,
diesel fuel, turpentine or kerosene. Lastly, any lanyard that has
seen service for any other reason other than fall protection should
be taken out of service for that purpose and so labeled or if it
has seen an impacted fall it should be removed and destroyed.
2.5.4 Shock Absorbers
Shock absorbers or as referred to by ANSI, energy absorbers, is
a component whose primary function is to dissipate energy and limit
deceleration forces imposed on the body during fall arrest. A personal
energy absorber is one that is attached to the harness.
There are three basic types of energy absorbers defined by their
construction. One is made of flat webbing folded over on itself
and stitched in a pattern that upon activation will break the stitching
in a controlled manner thereby dissipating the energy.
The second form is a woven pattern with a designed fault that upon
activation will tear the material up the middle at set rate of speed.
The third is a loomed effect; this type has often been referred
to as the "Velcro effect" in that when the materials that
have been loomed together tear apart during a fall, the remaining
material appears to have a Velcro type appearance.
The fourth type of absorber was discussed in the previous section.
This is the Manyard style, which has a woven interior that will
tear out at a pre-determined rate. An additional problem with manyard
style absorbers is they look like simple lanyards and may be used
as such by those who are not trained in their use.
Energy absorbers should meet or exceed ANSI standards. Section
5.3 of the ANSI standard should be read and reviewed by those whose
task it is to purchase and maintain fall protection equipment. NOTE:
When purchasing energy absorbers read the manufacturers label closely.
Energy absorbers manufactured for the Canadian market will allow
maximum elongation of forty-eight (48) inches; those manufactured
for the U.S. market will have a maximum tear out of forty-two (42)
inches. Energy absorbers for both markets will appear to be identical
from external appearances; you cannot use Canadian style energy
absorbers in the U.S. All energy absorbers must have the ability
to support 5,000 pounds after they have been activated. Which means
even after they have been fully deployed to their full extent they
must be able to support the above quoted weight. If they do not
they will not meet the standard and should not be used. NOTE: Energy
absorbers are required to limit the amount of impact force to the
worker to 900 pounds. Most, if not all, will keep well below that
number.
Energy absorbers can be purchased in a variety of ways. The most
common is an energy absorber integrated into a six-foot lanyard.
Others are sewn to three and four foot lengths to accommodate worker
requirements. There are versions that have twelve-foot lengths however,
these have been specifically designed for the steel industry and
should only be used by those properly trained in their use. Others
are integrated directly into the harness, which has merit because
this ensures that workers will have the availability of the absorber
immediately. It also reduces the possibility of girth hitching the
lanyard. There are products on the market that allows girth hitching
but these use steel rings sewn directly into the lanyard that allow
the hook to secure to the ring and have reinforced areas of the
lanyard to allow it to wrap around the selected anchor point.
Another type is the 100% tie off which is two equal length lanyards
integrated into an energy absorber that has been so designed and
engineered that upon activation, even if both lanyards are secured
at different lengths, the tear out will be equalized so the worker
will not be subjected to unequal or excessive impact.
Inspection, Care, and Maintenance
The decision to retire and energy absorber from service rests on
a number of issues.
· Length of service. If the absorber has been well taken
care of and has seen little in the way of abuse then between five
and seven years will be the rule of thumb. Again, check with the
manufacturer. The products produced today are much better than products
produced five years ago.
· Check for tears, cuts abrasions and discoloration of the
synthetic material of the lanyard.
· Deformation and damage to the energy absorber pouch. Damage
in this area may impede the workings of the absorber and may even
indicate a partial activation of the device. Remember: The amount
of force to begin activation of the energy absorber is rated at
450 pounds. A partial fall may tear out a very insignificant portion
of the device however, at this point the absorber MUST be removed
from service and DESTROYED!
· Examine the hardware for burrs, deformities and proper
operation. These include the hooks and ring if so equipped.
2.6 Body Holding Devices
Body holding devices are designed to support the human body during
and after fall arrest. For full information on harnesses refer to
ANSI Z359.1. This section will provide the reader with the technical
aspects and requirements of this specific type of PPE.
Body holding devices have been in service for quite awhile however,
the types, styles and materials used to manufacture these harnesses
has changed dramatically over the last decade. For the sake of brevity
we will discuss only two styles and address the types by application.
As to the material used for their construction it is safe to assume
synthetic material in the form of a polyester blend is the predominant
choice of manufacturers today.
2.6.1 Waist Belts
This type of belt has been used in virtually every type of industry.
As of January 1, 1998 the use of a waist belt as part of a fall
arrest system is illegal. Originally OSHA allowed the use of a belt
if the maximum arresting force exhibited on an employee was 900
lbs. As we will learn, this is totally unacceptable and after serious
examination, OSHA concurred. Are waist belts still allowed? Yes,
but only in work positioning and fall restraint situations. This
brings up the argument of whether belts should be incorporated into
a complete fall prevention / arrest program. The general consensus
is no. Full body harnesses can be equipped with all the necessary
attachments making the belt redundant. All too often an employee
may opt to leave a belt on rather than change out to a harness simply
because they "don't have the time."
Impact Forces
Medical studies have shown that the human is capable of sustaining
impact loads up to 2,400 lbs. The reality is the human body cannot
sustain these forces without injury. A more practical threshold
is 1,800 lbs. The arguments surrounding the waist belt were muted
when military studies showed the types and severity of the injuries
sustained by those using belts in free fall incidents. Ruptured
spleens, internal injuries, broken ribs and backs just to highlight
a few. Subjecting a person to a concentrated 900lb impact in the
abdominal area followed by a period of suspension guaranteed critical
injury and a high probability of a fatality.
OSHA will allow a worker to be subjected to 1,800lbs of impact
if they are wearing a full body harness. This primarily because
of the harnesses ability to absorb the impact forces due to its
elasticity and design which concentrates the vast majority of the
forces where the body can best tolerate such impacts i.e. the buttocks.
After the fall the harness will allow a worker to be suspended
for a much greater time than a belt and without the threat of further
serious injury. How long? Twenty to twenty-five minutes with minimal
discomfort. Beyond that period it is safe to say that a worker will
suffer increasing discomfort however, the alternative is far less
attractive.
2.6.2 Full Body Harness
The modern basic harness is constructed with synthetic materials
such as Nylon, polyester or a blend of both. The material of choice
is polyester because of its abrasion resistance, strength, ability
to shed water and its flexibility.
While many models are monochromatic, a better choice would be those
that come in contrasting colors. This allows for easy identification
of the upper and lower harness sections. Straps are to be at least
1 5/8 inches wide and rated at 5,000 lbs. All attachment hardware
i.e. the rings, whether they are steel or equivalent material, are
to have a rating of 5,000 lbs. NOTE: There are harnesses available
on the market that utilizes synthetic loops or rings instead of
steel rings. These are usually found in areas were there is a concern
for electrical conductivity and are often seen with the shock absorbing
lanyard integrated into the ring assembly. Connecting hardware on
the harnesses such as friction buckles, parachute buckles, and tongue
and grommet assemblies are rated at 3,600 lbs. All harnesses are
rated for 310lbs. A worker cannot weigh more than 310 lbs., this
weight includes clothes and tools. If they exceed the rated weight,
harness manufacturers can deny product liability. If you or any
of your employees see this as a problem approach a supervisor or
your supplier and / or manufacturer direct. Harnesses can be manufactured
and rated for weights in excess of 310.
The biggest concern for the harness wearer other than correct application
identification is FIT! An improperly adjusted harness can cause
injury. It is important for the wearer to select the correct size.
A harness designated as a universal fit does not automatically guarantee
the harness will fit every worker in the plant. Harnesses that after
being donned have excessive slop or play, are extremely hard to
adjust or after adjustment have excessive material are usually the
wrong size for the individual. Trying to make an improper harness
fit is an extremely frustrating and time consuming exercise that
will only increase an employee's resistance to the wearing of the
harness on a regular basis.
Another concern has developed with the increasing number of female
workers in industries that have been traditionally male dominated.
Vest style harnesses for the most part present no problem to the
average male worker but the proper adjustment of this style requires
that the chest strap line up across the nipple line. This adjustment
may be difficult for a woman and in some cases, not possible. Chest
straps worn above the bust line may increase the probability that
the strap would rise up and impact the throat area if the strap
were worn too high, if worn below the bust line there is a danger
the strap may ride up under impact injuring the breast tissue. If
it all possible a woman should be given the option of choosing a
cross strap version. This style allows the straps to cross at the
sternum area thereby eliminating the possibility of impacting this
soft tissue area. Again, allow workers to try on various harness
sizes. A harness that fits and adjusts easily will be worn. If it
doesn't, it won't.
Fitting the harness is a matter of putting it on and making the
proper adjustments. A properly adjusted harness should be snug,
not tight. Sloppy fitting harnesses may be comfortable but they
pose a number of dangers, even to the point of allowing the wearer
to slip through or being flipped out. The Dorsal D ring or the fall
arrest ring at the rear of the harness should be centered between
the shoulders and high enough up the back so that the wearer can
reach back over his shoulder and grab the ring so that it can be
secured and centered to fit the hook or carabiner into it. A ring
that is too low will be impossible to reach and in the case of a
fall will cause the victim to be impacted improperly and during
the period of suspension will cause the body to lean at a severe
angle causing undue stress in the lower leg area. A ring that is
too high will allow the hook or connector to strike the head or
helmet causing annoyance and in the case of a fall, a real headache!
Chest straps on vest style harnesses should be nipple height and
snug. Loose straps could allow a worker to pitch forward and literally
fall out of the harness. Too tight and the harness will be bunched
and uncomfortable. If the strap is too high, under impact it could
slide up, too low and we could have a repeat of the scenario described
with loose straps.
The most important area of adjustment is in the leg straps and
sub pelvic strap. Keep in mind this is where the major impact to
the body is to be centered allowing for the major muscle areas to
absorb the forces being generated in a fall. The sub pelvic strap
should be centered under the cheeks of the buttocks. If the strap
is too high there will be little if any support mechanism to support
the lower section of the body and the impact will center on the
inner thighs. Leg straps should be snug and not overly tight. Loose
straps will hang down and under impact will slide up rapidly causing,
at minimum, severe pain to the wearer. Make sure that the straps
form a "V" in the genital area. Man or woman, improperly
adjusted straps here could cause severe damage to these soft tissue
organs. Make sure the straps are not crossed or twisted in either
case this can cause injury. It is important these straps are properly
position to allow them to work properly and still allow the worker
freedom of movement with a minimum of discomfort.
Rule Of thumb: Either wear the harness or take it off. A common
practice is to undo the leg straps while at lunch or break. This
may lead to failure to reattach the straps. The same thing can be
said for chest straps. While it may seem impossible there have been
instances where workers have failed to properly reconnect the harnesses
with serious results.
After donning the harness and making preliminary adjustments have
a friend do a buddy check and see if the harness is properly fastened
and adjusted. Take the time and go through your range of work motions.
You will find that over time the harness will stretch and conform
to your body. Stretching and moving will help make fine tuning the
harness easier. If you are working through the range of seasonal
weather make sure that if you wear the harness over heavy outer
clothing allow more time for adjustment. When warmer weather returns,
adjust again. Many workers will keep the harness under heavy coveralls
or work jackets and have slits tailored in the backs to allow the
dorsal D ring to slide through eliminating the adjustment cycle.
2.6.3 Harness Styles
OSHA and ANSI do not address harnesses by application or by class.
The Canadian Standards Association (CSA) does and their classification
methods are what will be used to help identify the styles available
on the market today.
The CSA breaks harnesses into five classes: Class A, D, E, L and
P. All Canadian harnesses have an "A" with an arrow pointing
to the dorsal D ring. This arrow along with the "A" indicates
the point of attachment for the restraint lanyard or the energy
absorbing lanyard component. This ring, and only this ring, is to
be used for fall arrest. Using any other ring will cause the wearer
to suffer severe injury should a fall occur.
· Class A - A basic harness with one sliding dorsal D ring
used in situations where a single fall arrest anchor or restraint
lanyard is used. This harness can come in two styles, simple vest
or a cross strap variant.
· Class D - This is classified as a descent harness. This
harness features a D ring in the middle of the chest in addition
to the dorsal ring. This harness is utilized in raising and lowering
systems often found in confined space applications. It is also used
for ladder climbing devices. Another application would be for rescue
situations using the center ring for a rappelling device. While
this use is not common, pick off rescues can be done with this class
of harness. NOTE: The center ring should never be used as attachment
point for fall arrest!
· Class E - Entry / Exit harness. This harness features two
rings mounted on the shoulders and are used in conjunction with
spreader bars or collapsible A frames. The rings may either be fixed
or sliding. The use of these rings insures that a worker can raised
or lowered in a near vertical position for confined space areas.
· Class L - Essentially this harness is the same as a descent
control harness. The only difference is the position of the front
ring, which is often placed in the midriff area. This harness is
rarely seen here in the U.S. , it's function incorporated into the
Class D
· Class P - This harness features the steel rings attached
to the hip area of the harness to facilitate use of work positioning
devices.
In many cases you will see harnesses with multiple rings incorporating
all the above classes. At this point it is imperative that employees
be trained in the identification and use of the rings and the dangers
in the misuse of them. Supervisors should determine the best class
of harness for the workers by virtue of the task assigned. Complicated
harnesses make the possibility of misuse far greater than if the
employee were given the right harness for the job in the first instance.
2.6.4 Inspection, Care, and Maintenance
Manufacturers have detailed inspection and maintenance programs,
which must be followed. It is very important to keep written logs
of all inspections to ensure compliance with regulations.
A daily inspection is required prior to use. Annually a competent
person, other than the wearer, must conduct an inspection.
Fall protection products are designed for today's rugged work environments.
To maintain proper service life and high performance, all products
should be inspected frequently. Visual inspection before each use
is just common sense. Regular inspection by a competent person for
wear, damage or corrosion should be a part of your safety program.
Inspect equipment daily and replace it if any defective conditions
are found.
Harnesses can be cleaned. Washing it in cold water with a cleaner
such as Simple Green in the correct proportions allows it to keep
it's flexibility by removing accumulated body oils and salts, reduces
excess particulate matter and makes inspection processes easier.
After washing the harnesses should be rinsed thoroughly and hung
up to dry in a well-ventilated area out of direct sunlight. Check
with the manufacturer for recommended cleaning solutions and cleaning
procedures.
Harness / Body Belt Inspection
· Webbing - Grasping the webbing with your hands 6 to 8
inches apart. Bend the webbing in an inverted "U". The
surface tension resulting makes damaged fibers or cuts easier to
see. Follow this procedure the entire length of the webbing, inspecting
both sides of each strap. Watch for frayed edges, broken fibers,
pulled stitches, cuts, burns, and chemical damage.
· D-Rings / Back Pads - Check D-rings for distortion, cracks,
breaks, and rough or sharp edges. The D-ring should pivot freely.
D-ring pads should also be inspected for damage.
· Attachment of Buckles - Attachments of buckles and D-rings
should be given special attention. Note any unusual wear, frayed
or cut fibers, or distortion of the buckles or D-rings.
· Tongue / Grommets - The tongue receives heavy wear from
repeated buckling and unbuckling. Inspect for loose, distorted or
broken grommets. Webbing should not have additional punched holes.
· Tongue Buckle - Buckle tongues should be free of distortion
in shape and motion. They should overlap the buckle frame and move
freely back and forth in their socket. Roller should turn freely
on frame. Check for distortion or sharp edges.
· Friction and Mating Buckles - Inspect the buckle for distortion.
The outer bars and center bars must be straight. Pay special attention
to corners and attachment points of the center bar.
2.7 Lifelines
Lifelines fall into three categories: vertical, horizontal and
self-retracting. All three types require an understanding of the
mechanics, installation and use of these lines. In this section
we will be examining and explain the criteria.
2.7.1 Horizontal Lifelines
Horizontal lifeline (HLL) systems are usually permanent systems
that have been engineered for a specific environment, application
and location. Over the years portable and temporary systems have
been developed but these too, have specific areas of use and in
all cases are limited in size and number of workers that can be
attached. Permanent horizontal lines can only be designed and erected
under the supervision of a qualified person i.e. a structural or
mechanical engineer with an extensive background in fall protection.
The amount of stress exhibited on the anchors is extreme hence the
need for design and testing by qualified people. Homemade systems
are immediately suspect in spite of their robust appearance.
Portable systems utilize cable or synthetic lines. Most are limited
to a maximum of sixty feet in length, allow no more than two workers
on it at any one time and require a minimum of thirty feet clearance.
While newer versions allow a greater operational span and reduced
clearances, potential users should examine the individual manufacturers
products and study whether the product satisfies their needs and
expectations.
2.7.2 Vertical Lifelines
Vertical lifelines (VLL) while appearing to be straightforward
in their use and design are far more complex due to the components
that are used to assemble them. The most overlooked and least appreciated
component is also the most important, the lifeline or rope.
2.7.3 Lifeline Construction
Lifelines are synthetic in construction. The use of natural fiber
ropes is not allowed and for good reason. Ropes such as manila and
hemp are subject to rot, damage due to vermin, have poor abrasion
properties and do not approach the strengths that synthetic ropes
can offer. Rope sizes are 5/8 and 3/4 inches in diameter and incorporate
an eye integrated into the terminus of the lines. The ropes are
usually constructed with polyester or polyester / polypropylene
blend utilizing a three-strand, laid rope design. Their rated strength
is a minimum of 5,600 lbs. Polyester ropes have good abrasion resistance,
are impervious to moisture and have limited stretch. The polyester
blends are a little less abrasion resistant and have a lower rated
strength but on the whole meet all the requirements. The difference
in the two is price.
Another type of line would be a kernmantle rope. This is actually
a two piece rope. The outside of the rope consists of a polyester
sheath that protects the internal parts of the rope. The abrasion
and moisture resistance of polyester is necessary since the internal
structure of the rope consists of lineal strands of nylon. Although
nylon is the strongest of synthetic fibers it has the propensity
to absorb moisture that reduces it's strength and has moderate abrasion
properties. This rope is extremely strong with rated strengths as
high a 16,000 lbs. however, it is elastic and will stretch under
load. It requires closer inspection procedures and in comparison
to the other types is expensive.
A third type is polypropylene. While almost waterproof, lightweight
and inexpensive it is often difficult to work with, especially at
lower temperatures, has poor abrasion resistance, mediocre strength
ratings and is subject to UV damage. These ropes are constructed
with the three-strand, laid rope design and considering their inherent
problems constant inspection is not a luxury but a necessity.
If tasked with purchasing ropes it is important to remember the
two basic rope types based on elasticity. They are either static
or dynamic. Static ropes have limited stretch and are used for rescue
or other tasks where the possibility of impact stresses are minimal.
Static ropes are also used as vertical lifelines because they have
limited stretch thereby limiting fall distance. Since these ropes
have so little stretch, a rope grab should have an energy absorber
attached to it or have an extremely short lanyard to limit impact
load to the rope.
Dynamic ropes, such as the kernmantle as described above, have
elastic properties. These ropes are used in rock and mountain climbing.
Climbers do not afford themselves the luxury of rope grabs and depend
on the rope to absorb the energy of their fall to ensure that attachment
points in the rock are not torn free. When used as a vertical lifeline
in industrial settings rope grabs used with these ropes do not necessarily
need energy absorbers because the rope stretches under impact and
many times the 450 lbs. of impact force necessary to engage the
absorber is not reached. Keep in mind that using a rope of this
type would also increase the fall distance a worker.
2.7.4 Rope Grabs
The other component in a vertical lifeline is the rope grab. Robe
grabs should be mated to the rope. Some rope grabs do not work well
with a specific line because of incompatibilities due to the line
material or the construction design of the grab. Rope grabs fall
into two basic designs, manual and automatic. In the following paragraphs
we will examine these grabs in detail.
2.7.4.1 Manual Rope Grabs
Manual rope grabs must be moved and adjusted by the worker as they
proceed up and down the vertical lifeline. Manual grabs utilize
a one or two cam system that is spring loaded so when the ring or
bar is released the cams will automatically lock onto the line.
Most manual rope grabs do not have lanyards or shock absorbers integrated
into their construction. This requires that the worker make the
proper determination on what component to use. If the unit does
have a lanyard or shock absorber sewn into it, the question of clearance
comes into question.
There are a number of points to remember when working with this
type of grab.
· The grab should be positioned above or in front of the
worker. This does two things, it allows the worker to keep an eye
on the grab, and it keeps their fall distance to a minimum. This
is true whether they are in a vertical or inclined position and
reduces the possibility of them seizing the grab and opening it
should they slip or fall.
· Once the grab is set, it should be released and allowed
to lock. Holding it in the hand is an invitation to disaster.
· Make sure the correct diameter rope is used. Too small
and the cams will not hold the rope, too thick and the rope will
not feed properly.
· The "UP" and arrows placed on the grab indicate
the anchor. The worker needs to understand that these markers must
always point to the point where the vertical line is anchored
· There are a number of styles of manual rope grabs and although
this manual does not specifically endorse a manufacturer, the Miller
offering has shown itself to be the best. Large enough to be manipulated
with gloves, able to accept both 3/4 and 5/8-inch lines and equipped
with an oversize ring for placement of lanyards makes this grab
an excellent performer in comparison to the other grabs available
today.
2.7.4.2 Automatic Rope Grabs
The automatic style grab allows a worker the move up and down a
vertical line without touching the grab. This design works well
with workers on powered swing stages and other powered devices and
when a worker is constantly moving between levels. The ability move
and lock automatically is based on the design and construction of
these grabs. One style features an inertial cam wheel that does
not rely on cam movement but rather the speed that the rope exhibits
on the wheel. This completely eliminates the "death grip"
problem because the grab cannot be accidentally held open. The other
design operates on the typical levered cam design so that the worker
must actually fall past the device to fully lock the teeth onto
the rope. Both these designs work equally well, both however anticipate
the worker having a clean fall. If the fall speed is slowed or impeded
or the worker fails to pass the grab the cam lever may not engage
or the wheel may fail to lock the rope in place. Again, if the worker
is staying at a specific location for a period of time it is suggested
that the worker "park" the grab above them to insure minimal
fall distance. One major consideration when using an automatic grab,
these types should not be used on inclined surfaces by virtue of
their operation. Remember, these grabs are actuated by speed or
worker movement past the grab. If this does not happen, a slow slide
on a roof or other area will not activate the devices.
2.7.5 Self-Retracting Lifelines (SRL's)
There are numerous types and styles of retracting devices on the
market. They fall into two basic types, self-retracting lanyards
and self-retracting lifelines.
2.7.5.1 Self-Retracting Lanyards
For the lack of a better description these devices are no more
than upgraded seat belt retractors. The good points of these devices
are that they are relatively inexpensive, light weight, lock up
very quickly thus allowing very little free fall potential and come
in a variety of equipment variations.
The deficiencies are more extensive. Because of their quick lock
up speed they restrict movement and can be annoying to the point
of frustration. If subjected to a fall of any height they must be
disposed of immediately. Their internal workings and lanyard are
routinely exposed to the environment that may adversely affect their
workings and durability. Work areas such as paint shops or any environment
that suffers from high particulate contaminate are suspect for the
use of the devices. As they get older and become worn they acquire
a symptom commonly referred to as the "dog tongue effect"
whereby the device looses it's ability to fully retract allowing
the lanyard to hang as much as two feet below the main body of the
device. This is a sure sign that the retractor spring has lost its
strength. If not equipped with a swivel either at the main body
or the point of connection there is the possibility of the line
becoming twisted so as to restrict the line's ability to retract
fully. This could cause slack in the system raising the potential
of free fall potential.
While there are many worthwhile applications for this unit, special
attention to inspection care and maintenance become necessary and
if constant replacement becomes an issue it may be time to investigate
the acquisition of a sell retracting lifeline.
2.7.5.2 Self-Retracting Lifelines
Self-retracting lifelines have been in use for more than two decades
and have seen marked improvement in their reliability, design and
construction. Originally designed to allow an 1,800-lb. impact on
a worker, they are now capable of reducing that impact to 900 lbs.
or less. All the major manufacturers as well as some specialty manufacturers
of safety equipment offer these devices. In the following paragraphs
we will take a close look at the workings and uses of these units.
The basic internal design includes a drum containing excess line
or cable, a locking mechanism comprised of spring-loaded pawls and
a toothed wheel. This in turn is mated to a clutch type assembly,
which acts as an internal energy absorber. Externally, there is
an anchor point comprised of a handle or eye. The connecting means
are usually snap hooks or carabiners.
The housing of these units are usually made of cast aluminum, steel
or composite synthetics. Some units are partially sealed which reduces
the possibility of foreign particles causing damage or impeding
the operation of the unit. The line lengths of SLR units range from
11 feet to 150 feet in length. Lengths from 11 to 20 feet are synthetic
lines of flat webbing, lengths from 20 feet and longer are 3/16
inch galvanized or stainless steel cable.
The cable or line is also equipped with a reserve section that
can deploy if a catastrophic fall is experienced.
The locking mechanism is engaged by centrifugal force. The locking
pawls engage when a speed of 4.5 feet per second is exhibited on
the unit. Once the unit has locked a disc brake type assembly or
clutch engages slowing the worker's fall and reduces the impact
forces to the worker to 900 lbs. or less. The smaller units will
have two pawls, the larger ones, three. This redundancy ensures
that should one pawl miss the gear the second or third will engage
effectively arresting the fall.
Points to consider:
· The SRL should always be suspended directly above the
worker or as close as physically possible. SRL's that are positioned
at an angle or if the worker moves too far horizontally away from
the anchor point may result in a swing fall that will not allow
the SRL to gain the 4.5 fps needed to lock the device. This will
result in the worker being allowed to fall much farther than anticipated
and will add undue stress on the SRL. Most manufacturers recommend
an angle of 45 degrees or less is maintained when moving away from
the anchor point of the SRL.
· Do not lay the SRL on its back or allow the cable or web
line to travel across edges even with a pad. Lines that are stressed
in this fashion could part under shock load if used in this manner.
· Do not tie knots in the web or block off lengths of the
cable with a vise grip to provide slack in the line. In the event
of a fall the speed and impact forces generated on the SRL may be
enough to cause the unit to fail.
· Do not add shock absorbers or lanyard extensions to the
connecting means. These units are self-contained and adding equipment
in this manner will only defeat the design of the unit.
· Do not use these units on sloped surfaces or above fluids
and semi solids such as slurries, grains, sand or viscous fluids.
Remember, the unit needs 4.5 fps to engage and these areas described
will not allow that speed to be reached.
· Do not extend the line and secure it. Allow the line to
fully retract after use. Retrieval can be accomplished by use of
a tag line attached to the connector. This will allow the worker
access to the hook without exposing the line to contaminates or
causing the retractor spring to become weak and suffer retraction
memory loss. Web lines are especially vulnerable to UV damage or
particulate contamination if not allowed to retract fully inside
the housing.
· SRL's should be connected to the dorsal D ring only. This
is a fall protection device. Use of any other ring will result in
injury.
· If the worker is using an older device not equipped with
a swivel at the anchor point or the hook is static, it is advisable
to obtain and use a swivel type carabiner at the anchor point. This
will allow the cable or web free movement with the worker. Static
devices in the past have contributed to lines being twisted and
stretched as the worker moved about.
· This device is not to be used as a work-positioning device.
Although these units lock up in less than two feet they are not
be construed as anything but fall protection devices. This means
that suitable 5,000 anchor points must be used, fall distance calculations
must be done and the worker must never lock the device and lean
into the line. Any movement backward, however slight, will unlock
the device.
2.7.6 Inspection, Care, and Maintenance
Inspection of these devices should occur at two levels. On a "per
use" basis by the worker and on a regular schedule by a competent
person. Simple steps such as pulling on the device at least twice
will enable the worker to check on the unit's function and an inspection
of the hook to ensure proper operation and determine if an impact
has taken place on the unit by examining the impact indicator.
* Impact indicators on older units were usually found on the housing
assembly in the form of a red dot or a red flag in a semi-transparent
window. Units today have the impact indicator at the point of connection
in the form of red bands or torn out red stitching. In some cases
where the hook rotates, the hook will be seized and a red band exposed.
The line should be inspected routinely by the user especially the
area closest the hook. Discoloration, abrasion marks, loose cable
fibers, cuts are signals to remove the device from service or require
inspection from a designated competent person. The entire line length
should be inspected on a routine basis. The frequency of inspection
should be predicated on the use and environment the SRL is subjected
to.
The formal inspections should be done according to the manufacturers
recommendation and these usually include a yearly factory inspection
and re-certification. Never attempt to open these devices to repair
or inspect unless qualified. Spring tension in these units is such
that attempts to service them without proper training could lead
to serious injury.
There are variants in the SRL family. A popular version is the
winch / fall protection unit. These are often found in confined
space situations and other venues that would require a worker to
be lowered and raised. The salient feature of these devices is if
a worker does slip or fall, the device will arrest their fall. If
an incapacitating injury occurs then the attending worker can engage
the winch and retrieve the worker. If the worker is required to
enter into confined spaces on a regular basis it might be wise to
have a secondary line on a dedicated man-rated winch and allow the
fall protection to be addressed by a separate unit.
2.8 Ladders and Climbing Systems
Ladders are either fixed or portable. OSHA regulations for ladders
can be found in 1910.27 and 1926 Subpart X. OSHA in the 1910 section
addresses ladder cages, platforms and lengths of climb. Safety devices
for fixed ladders in this section may be substituted for cages and
platforms were the length of climb exceeds 20 feet, especially for
towers and chimneys.
1926 is a bit broader in its scope. Ladders 24 feet or greater
and with a length of climb greater than 24 feet are required to
have cages, wells, ladder climbing safety devices or SLR's in addition
to rest platforms. It would be prudent to read both the 1910 and
1926 sections carefully to determine what your work area requires.
It is interesting to note that OSHA is seriously considering the
elimination of ladder cages as a protective device for climbers.
Cages were not designed for safety but rather to allow a worker
to rest during the climb. Anyone who has fallen in a ladder cage
will attest to the fact the cage will not arrest the fall but will
merely keep you bouncing inside the structure till you either hit
the ground or become entangled in the cage structure. In either
case the injuries sustained are substantial. OSHA has finally recognized
this fact and a final rule is expected in the near future.
2.8.1 Portable Ladders
Using portable ladders creates other fall hazards. Proper climbing
and work habits can eliminate a lot of falls.
· Inspect the ladder prior to use and do not use it if it
is in bad shape.
· Make sure the ladder is fully open and locked.
· The worker should never go above the third step from the
top. NEVER work on the top level of a ladder.
· Do not over extend creating an off balance situation.
· Tie off above your head to a secure anchor if possible.
When a straight or extension ladder is used
· Inspect before use, if in doubt, throw it out
· Get help raising the ladder, and NEVER raise the ladder
if the fly is extended.
· Ensure the proper angle is created before climbing (rule
of thumb - every 24' up, go 6' out)
· Ensure the ladder extends 3' beyond the level of the roof.
· Ensure the proper overlaps at the fly sections are maintained.
It is recommended that:
§ 32' ladder uses 3' overlap
§ 32'-36' ladder uses 4' overlap
§ 36-38' ladder uses 5' overlap
§ over 48' ladder uses 6' overlap
· Ensure the feet are secure and are on even solid ground
· First person up secures the ladder against movement
· Maintain 3 points of contact at all time
· Never over extend (rule of thumb - keep belt buckle between
rails at all times)
· Do not carry tools up; bring them up the ladder with a
rope and bucket
2.8.2 Ladder Climbing Systems
Ladder climbing systems are found on fixed ladders and fall into
two basic types, cable or rail systems. Rail systems can be either
a flat or notched rail.
Ladder climbing devices require the user to use a full body harness
with a front D ring. Attachment distance from the user to the device
can be no more than 9 inches. This is effectively done with a carabiner.
Frontal attachment is acceptable because the lock up distance for
these devices is 6 inches or less and free fall is insignificant.
Both the cable or rail systems work equally as well, the major differences
are in price and application.
Cable systems tend to be less expensive. A galvanized or stainless
3/8-inch solid core cable. The cable can be cut to any length and
attachment points placed along the length of the ladder either in
the center or the side of the ladder. Narrow ladders would benefit
from side placement of these devices so as not to interfere with
the climbers' ability to safely access the rungs. This will be true
in the rail systems as well. The cable device is a mechanical sleeve
with a cam device that seizes the cable is sudden downward movement
is made. While ascending or descending the device will follow the
climber. One often overlooked benefit of these devices is it restricts
the rate of descent by a climber forcing them to descend in a safe
controlled manner rather than attempting to "slide" the
ladder. Another feature of the cable systems is their ability to
detach from the cable at any point along its length. This is especially
valuable when there are multiple levels and thus multiple users
of the system at any one time. The user can detach the device from
the cable and keep it on their person insuring that they will have
it to descend the ladder. It also eliminates the problem of having
a device blocking the ladder.
There have been concerns over outdoor use of cable systems especially
in cold weather. Ice or snow buildup on the cable is addressed by
striking the cable with a wooden handle or rubber mallet, the subsequent
vibrations will shake the snow and ice from the cable.
Retorquing the cable to specifications eliminates questions on whether
stretch in the cable could compromise its effectiveness. A periodic
check on tension will ensure proper tautness in the line.
Rail systems can be aluminum, galvanized or stainless steel. These
systems are expensive but durable and are, for the most part unaffected
by weather or industrial environment. They utilize a 2-inch flat
rail or a notched rail system that varies in diameter. A flat rail
system will lock up as quickly as a cable, a notched rail will lock
up almost as fast with the exception being the device must engage
a notch before arresting which means that the worker must fall to
the notch. While completely safe, it can surprise someone unfamiliar
with the workings of the device.
All these systems can go up and around curves such as found on
water towers or arched roof as in an aircraft hangar roof. They
are reliable, safe and provide a sense of security for climbers
especially for those that do not climb ladders on a regular basis.
One major drawback for rail systems is their inability to detach
from the system. This causes problems if the ladder is used to access
multiple levels and if more than one person is on the ladder at
different times and at different levels. Once a person leaves the
ladder, the device is left on the rail leaving the ladder blocked.
This problem illustrates the need to effectively assess the type
of system that works best before a purchase is made.
2.9 Calculation of Fall Distances
We have discussed anchor points, lanyards, shock absorbers, SRL's
and a whole list of components that make up systems either as restraint,
positioning or fall arrest. What we need to find out and determine
is how far we these systems allow us to fall and what clearances
we need to keep from striking the surface of the ground or object
after the system engages.
With restraint the answer is simple. No fall therefore no clearance
calculation.
Work positioning systems are allowed a maximum two-foot free fall.
When setting up these systems we already know a device will allow
us to fall two feet. Add in our own height and placement of the
anchor and we can determine where our feet will touch if we fall.
Fall arrest systems are more complicated because of the number
of components and the variables accompanied by their use. Here are
the factors that you will need to determine fall distances:
· Location of anchor point. (Shoulder height or above)
· Length of lanyard (3,5 or 6 foot)
· Maximum tear out of an energy absorber (3.5 Feet)
· Height of worker
· Stretch of Harness / Connector lengths (Hooks / Carabiners)
If the average worker is 6 foot and they use a 6-foot lanyard with
the anchor point just above their heads the distance needed underneath
a worker would be an average of seventeen feet. Remember too, that
planning fall distances must take into account obstructions such
as pipes, conduits, beams, trusses, machinery and even other workers.
Hitting the ground may not be your biggest concern. The pipe you
hit ten feet below you can kill you as easily as the ground thirty
feet beyond the pipe.
Swing or pendulum falls are another concern. This was discussed
in the SLR section. This type of fall occurs when anchor points
are set at extreme angles to the position of the worker. Falls generated
from the side can impact a worker against beams, walls, standpipes,
rebar or steel assemblies with nearly the same force as a vertical
fall. Try to keep the anchor point as close to your body position
as possible. Use the 45-degree or less rule for SRL's as a standard
for all fall protection systems.
2.10 Rescue
Any fall protection plan needs a rescue component. It wouldn't
do the worker any good if their fall was arrested and there was
no established method available to get them down. Planning for problems
will also help eliminate them. If hazards are identified it may
be possible to eliminate them removing the need for fall protection
and in turn, rescue concerns.
Rescue does not have to be a complicated affair. A conscious worker
can easily access a ladder, cherry picker, or scissors lift and
effect a self rescue.
Calling 911 is not always the answer. Many municipal services do
not have high angle capabilities and in some instances qualified
personnel may be engaged in other tasks. It would be wise to contact
the local rescue or fire company and have them review with you their
capabilities and your needs.
2.10.1 Self Rescue
If 911 cannot service you and ladders or other equipment are inadequate
then self-rescue by employees becomes an option. Devices such as
Rope Riders, Rope Genies, and descenders allow trained staff to
lower themselves from heights and leave the affected area. These
are all friction devices of one sort or another using rope, usually
1/2-inch nylon line. While all of them can be reset and used again
they are, in reality, one-person escape units. These units are fairly
inexpensive, portable and can be used for almost any height. All
that is needed is the correct length and the proper training.
Automatic rescue units such as the RescueMatic are designed to
allow an infinite number of people to use the same device repeatedly
to exit a specified area. These devices run at a rate of 3.5 feet
per second and require no more training than putting the rescue
straps on in the specified manner. Once the worker steps off the
platform or surface the machine will engage and lower the worker
at a controlled of speed. Once the worker touches down, they will
remove the rescue straps and allows the next worker to descend.
Again, training is required for the proper use and operation of
this unit.
The last option is a rescue team. This is an expensive and time
consuming alternative but if workers are in remote areas removed
from municipal services this may become a viable alternative. Equipment
and training will need to go hand in hand. Seek advice in this area
before committing to either equipment purchase or training.
2.11 Inspection Log
Description: ______________________________________________
Serial Number: ____________________________________________
Manufacturer: _____________________________________________
Date of Manufacture: _______________________________________
Date Comments Print Name Signature
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