energy absorbing lanyards

WHAT YOU NEED TO KNOW ABOUT
ENERGY ABSORBING LANYARDS
New standard implements major design changes:
double-legged lanyards, greater fall distances, environmental testing
Next to the full-body harness, the double-legged energy absorbing lanyard is the most commonly purchased piece of fall
arrest equipment. But until now, there hasn’t been an ANSI
standard that addresses double-legged energy absorbing lanyards.
ANSI/ASSE Z359.13-2009, titled
“Energy Absorbers and Energy Absorbing Lanyards,” was approved by
the American National Standards
Institute (ANSI) and the American
Society of Safety Engineers (ASSE)
on June 23, 2009, and became effective November 16, 2009.
absorbers) and those designed for applications where a 6’
free fall distance has been proven infeasible, allowing up to a
12’ free fall (“12 ft FF” personal energy absorbers). Until now,
standards for lanyards that were manufactured for a free fall
greater than 6’ did not exist.
Systems typically adhere to a maximum free fall distance of 6’ (1.8 m),
as specified by regulatory agencies.
With any rule, however, there are
exceptions. The Occupational Safety
& Health Administration (OSHA) has
recognized these exceptions for
years. In a letter of interpretation dating back to 1996, OSHA says it permits employers to exceed the 6’ free
fall distance when an anchorage point
that would limit a free fall to 6’ is not
available. OSHA refers to these scenarios as a “infeasibility situations.”
In these cases, the maximum arrest
force (MAF) must not exceed 1,800
lbs. (8 kN) and sufficient clearance is
required.
Every energy absorber and energy
absorbing lanyard on the market
will change as fall protection equipment manufacturers implement
major design changes and tougher requirements outlined in ANSI
Z359.13-2009. The standard details
specific guidelines for the perforCommon energy absorbing lanyards.
mance, design, marking, qualification, instructions, inspection,
maintenance and removal from service of energy absorbing
Personal energy absorbers that accommodate 12’ free falls
lanyards and personal energy absorbers. It also seeks to adhave been fabricated and sold by equipment manufacturers
dress all applications in which workers at height use these
for years in an effort to provide fall protection for workers
integral components of a personal fall arrest system.
who must tie off at their feet. This is a scenario common to
aerospace mechanics, railroad workers and wind energy techOne of the notable distinctions of the new ANSI/ASSE Z359.13
nicians, to name a few. The aim of the new standard is to
standard is the designation of two classes of personal energy
address the unique hazards encountered in these systems
absorbers: those designed for applications with free falls up
where a 6’ (1.8 m) free fall is infeasible and to better regulate
to 6’ (1.8 m) (referred throughout as “6 ft FF” personal energy
the performance of these systems.
ANSI/ASSE Z359.13-2009 Y-lanyard label
(black lettering on white background for
6 ft. FF category and white lettering on
black background for 12 ft. FF category).
Concerns with product endurance in extreme climates and
prolonged field use have resulted in the establishment of
more stringent qualification and performance testing. Under
the new standard’s testing requirements, guidelines for static
strength, ambient dry dynamic performance, and other conditioning tests, including abrasive testing of wrap-around energy
absorbing lanyards, are provided.
Now let’s get technical. Historically, a single peak force or MAF
measurement was used to record impact force during dynamic performance testing. To yield more meaningful performance
data, the new standard requires that an average arrest force
be used in addition to the MAF for product qualification and
performance testing. It specifies that 6 ft FF personal energy
absorbers have an average arrest force no greater than 900 lbs.
(4 kN) without exceeding an MAF of 1,800 lbs. (8 kN) and 12
ft FF personal energy absorbers have an average arrest force
no greater than 1,350 lbs. (6 kN) without exceeding 1,800 lbs.
(8 kN) MAF.
The new standard increases the allowable maximum deployment distance of the energy absorber from 42” (106.7 cm)
to 48” (121.9 cm) for 6 ft FF personal energy absorbers and
specifies a maximum deployment distance of 60” (152.4 cm)
for 12 ft FF personal energy absorbers. The addition of labeling
specifications offers additional safeguards to users. Contrasting labels are specified for the 6 ft FF and 12 ft FF energy
absorbers and must include the capacity, maximum free fall
distance and average deployment force.
As more employers recognize Y-lanyards as a cost-effective
means for the protected mobility of workers at height, there
is heightened potential for misuse. To ensure an MAF of 1,800
lbs. (8 kN) is not exceeded with any Y-lanyard configuration,
the new standard takes into account potential misuse and
offers safeguards through improved qualification testing. The
ANSI Z359 Accredited Standards Committee recognized that
Y-lanyard users will often attach the unused lanyard leg to the
side D-ring of their full body harness. This may lead to a hazard
called hip-loading. During a fall, the unused lanyard leg can become taught, loading the side D-ring with high impact forces.
Another common misuse of Y-lanyards is what is referred to as
a dual connection. Many Y-lanyards have two energy absorbers, one on each lanyard leg. If both legs of the Y-lanyard are
connected to the same anchor point, the energy absorbers
may load simultaneously, generating higher forces on the user.
The new standard has added test requirements for hip-loading
and dual connections along with additional labeling and warning requirements.
To date, a 220 lb. test weight was used for dynamic load testing of energy absorbers and lanyards. A ratio of 1.4:1 was used
to relate the rigid test weight to the human body, which was
assumed to absorb some of the acquired energy. Testing conducted by Gravitec Systems, Inc., has shown that a 1.1 conversation factor is more accurate for fall arrest systems utilizing a
full body harness. The new standard prescribes a test weight
of 282 lbs. (127.9 kg) to be used to represent the 310 lb. (140.6
Y-lanyards are commonplace in many industries.
Workers often employ Y-lanyards to move vertically as
well as horizontally.
Hip loading most commonly occurs when the unused
end of a pouch style energy absorbing lanyard is connected to a hip D-ring on a full body harness.
kg) fully tooled and clothed human body. Using a more accurate conversion factor and therefore a greater weight will
model energy absorbers during testing that will more closely
represent applications by the worker in the field.
Every ANSI-compliant energy absorber will change with the
release of the ANSI/ASSE Z359.13 standard. Improved test
weight specifications and arrest force calculation methods
will create a more aggressive energy absorber that is able to
meet the demands of higher free-fall distances. Additionally,
the new standard will be expanded to encompass much of
the equipment that, until this time, was excluded by ANSI (i.e.
wrap-around lanyards, 12 ft FF energy absorbers, Y-lanyards).
Equipment will be easier to identify and greater clarification
will be provided to authorized, competent and qualified persons to increase compliance and help ensure safety.
What does this mean for consumers? The transition to the new
and improved energy absorbers will not happen overnight.
Companies can elect to retire equipment designed under the
old standard and immediately benefit from added safeguards,
but it is expected that most will consume as needed.
The ANSI/ASSE Z359.13 standard is only one of eight existing
fall protection standards that make up the Z359 Fall Protection
Code and is best used in conjunction with the full Code. To
purchase the standard, visit ASSE’s web site at: http://www.
asse.org. For additional information about testing conducted
by Gravitec Systems, Inc., visit our Resources page on our
web site at www.gravitec.com.
ABOUT THE AUTHOR:
Randall Wingfield, chairman of the ANSI Z359 Accredited
Standards Committee, is extensively involved in the continuing
development of national standards for fall protection equipment and training. Mr. Wingfield is the president and owner of
Gravitec Systems, Inc., a leading provider of fall protection and
rescue services, specializing in engineering and training. He is
also the president of the International Society for Fall Protection (ISFP) and a member of the American Society of Safety
Engineers (ASSE).