Horizontal Lifelines Implications of Rescue

7/30/2019 Horizontal Lifelines Implications of Rescue

1/19

rescue implicationsrescue implications

A presentation by

David Riches

Lyon Technical Symposium 2006Lyon Technical Symposium 2006

consultants in fall protection and safety atconsultants in fall protection and safety at heightheight

TemporarilyTemporarily--installedinstalledhorizontal lifelineshorizontal lifelines


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What is a temporarilyWhat is a temporarily --installed horizontal l ifeline (HLL) ?installed horizontal li feline (HLL) ?

End anchor

HLL

Anchor connection

Energy-absorbinglanyard

Travelling device

Tensioning device (with excess ropepulled through)


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What is a temporarilyWhat is a temporarily --installed horizontal lifeline? (2)installed horizontal li feline? (2)

In-line energy absorber

Intermediate anchor


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(i) at the onset to the fall

(ii) worker falls and lanyardbecomes taut

(iii) lifeline begins to stretch anddeflect;travelling device slides downlifeline


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(v) energy absorbed; lifeline tends

to oscillate up and down about anequilibrium position until residualmotion is fully damped; workeradopts post-fall suspensionposition awaiting rescue

(iv) lifeline at maximum deflection,providing sufficient reaction forcefor energy absorbing lanyard toextend; applied arrest forcetransmitted to and magnified atend-anchors


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Main performance parametersMain performance parameters

Length of the HLL span

Length of the interconnecting fall-arrest equipment

Elastic properties

Energy absorbing characteristics

Initial tension in the HLL

Sub-spans between intermediate anchors (if installed)

Amount of free fall (where the fall starts in relation to the level of the HLL)

Position of fall (in relation from end-anchor)

Weight of the worker(s)

Compatibility and interaction between interconnecting fall-arrest equipment

Number of workers who fall, and whether they fall simultaneously or not


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1.25 m


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Arrest shock loading

Badly-fitting harness

Collision with structure

Collision with fall-arrest system

Collision with other workers

Incapable of self-recovery

Unconscious/motionless

Legal WAHR 2005

Injury mechanisms & reasons for rescueInjury mechanisms & reasons for rescue


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What will be the vertical and horizontal distance betweenRescuer(s) and Rescuee(s) from nearest safe rescue

position How many people will need rescuing? What equipment will be used in the rescue? Where can equipment be installed to HLL or to

separate anchors? Will it be better to lower or raise the Rescuee(s)? Will the rescue method create new risks for Rescuer and

Rescuee? Will Rescuee(s) require medical treatment prior to

lowering/raising operation? Will there be sufficient time to carry out the rescue?

r e s c u e i m p l i c a t i o n sr e s c u e i m p l i c a t i o n s


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,

m

3 10 30 50

3 10 30 50

m

m

initial

tension

initial

tension

initial

tension

Note: HLL based on 1/2 inch diametersteel rope 6 x 25 IWRC construction,

clipped eyes on each end.

Interconnection equipment consisted ofa 5/8 inch nylon lanyard of 1.0 m overalllength. Free fall distance 1.285 m, dropmass of 100 kg.

PerformancePerformance


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Research on 33 m span HLL

No of masses V deflection

1 x 100 kg 2080 mm

2 x 100 kg 3545 mm

4 x 100 kg 3900 mm

V deflectionV deflection versus rescue accessversus rescue access


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rescue anchorsrescue anchors

for attachment offor attachment ofrescue equipmentrescue equipment

??

?


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TestNo

Cable type /span (m)

No. of testmasses released

Free fall(m)

No. of in-lineenergyabsorbers

Maximum endanchor load(kN)

01 Galv / 33 1 1.0 - 17.7

02 Galv / 33 1 2.0 - 19.8

03 Galv / 33 1 2.0 - 20.3

04 Galv / 33 2 2.0 1 16.0

05 Galv / 33 4 2.0 2 27.2

06 Galv / 33 6 1.3 3 26.8

07 SS / 33 4 1.3 2 19.3

08 Galv / 17 2 1.3 1 17.4

09 Kern / 17 2 1.3 - 8.4

10 Galv / 33 2 1.3 - 25.2

11 SS / 17 2 1.0 - 33.3

Summary of test results of multiple nearSummary of test results of multiple near--simultaneoussimultaneous

fall simulations on long singlefall simulations on long single--span HLLspan HLL


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Potential anchor points that may have been weakenedPotential anchor points that may have been weakened

as a result of fall impactas a result of fall impact


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HLL mayHLL mayweakenweaken

as a result ofas a result of

being draggedbeing draggedover an edgeover an edge

in a fallin a fall


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Answers:

No rescue methods are available

This is a difficult area Gaps in structure over which HLL spans limits the number of safe rescue

anchor positions Users are not asking for rescue equipment at the moment

We are recommending that users find their own rescue equipment We are analysing the problem and are designing rescue methods and

equipment to suit

HSE Research Report 266HSE Research Report 266A review of criteria concerning design, selection, installation,A review of criteria concerning design, selection, installation, use, maintenance anduse, maintenance and

training aspects of temporarilytraining aspects of temporarily--installed horizontal lifelinesinstalled horizontal lifelines

HLL manufacturers survey 2004

Question what rescue advice can be given and what equipment do you supply?

2


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RescueRescue

ApproachesApproaches

1. drag Rescuee back toa safe area usingequipment mounted to

an end-anchor

2. install twin parallelHLLs in close

proximity one for fall-arrest purposes andone of rescuepurposes

3. reassessing anchorsto allow attachment ofrescue equipment,and stresses of fall-

arrest loadings

1

2

3


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HLL installation should facilitate rescue plan

Rescue plan should encompass envisaged fall scenarios Rescue plan should consider:

How many people will need rescuing What equipment will be used in the rescue

Method of installation Method of rescue Rescue risks Likely injuries sustained by rescuee(s)

Time needed to execute rescue Rescue plan should be validated by training and rehearsals

-- SummarySummary --

The Rule of the 6 PThe Rule of the 6 Ps:s:PPriorrior PPreparationreparation andand PPlanninglanning PPreventsrevents PPossibleossible PProblemsroblems

When you bui ld a new house, make a parapet around your roof so tWhen you build a new house, make a parapet around your roof so that you may not bring the guilt of bloodshed on yourhat you may not bring the guilt of bloodshed on your

house if someone falls from the roofhouse if someone falls from the roof

Moses, circa 1400 BC (Deuteronomy 22:8)


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Useful informationUseful information

HSE Research Report 266HSE Research Report 266A review of criteria concerning design, selection, installation, use, maintenance and

training aspects of temporarily-installed horizontal lifelines

available at http://www.hse.gov.uk/research/rrhtm/rr266.htm

BS 8437: (2005)BS 8437: (2005)Code of practice for selection, use and maintenance of personal fall protection systems

and equipment for use in the workplace

BS 8454: (2006)BS 8454: (2006)Code of practice for the delivery of training and education for work at height and rescue

available from BSI

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Horizontal Lifelines Implications of Rescue

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