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mikecarr  
#1 Posted : 10 October 2019 09:11:20(UTC)
Rank: Forum user
mikecarr

Hi  Team

One for the WAH gurus

Would a shock absorbing lanyard generally be used  on a work restraint system?

I thought that would onle be for fall arrest?

Any thoughts welcome!

Dazzling Puddock  
#2 Posted : 10 October 2019 09:48:26(UTC)
Rank: Forum user
Dazzling Puddock

Shock absorbing lanyards are not suitable for a fall restraint system.

Xavier123  
#3 Posted : 10 October 2019 14:58:11(UTC)
Rank: Super forum user
Xavier123

I respectfully disagree - with some caveats around likely forces being imposed during the work. If just straightforward restraint then there is no reason why a shock absorbing lanyard can't be used as work restraint lanyard. Critical aspect is the distance between anchor and 'edge'.

BS8437 and The Work at Height Safety Association agree.

http://www.wahsa.org.uk/wp-content/uploads/2014/12/WAHSA-TGN04-Guidance-on-the-use-of-single-and-twin-energy-absorbing-lanyards.pdf

Dazzling Puddock  
#4 Posted : 10 October 2019 15:25:31(UTC)
Rank: Forum user
Dazzling Puddock

The problem I have with that is the caveats around the likely forces imposed during the work, The WAHSA guidance says the same, you have to ensure that the forces involved cannot make the shock absorbing bit deploy.

If you use the correct harness then you do not have to worry about that aspect.

I have investigated an accident where the absorber deployed sending a worker through an atrium roof so it does happen.

Xavier123  
#5 Posted : 11 October 2019 08:23:54(UTC)
Rank: Super forum user
Xavier123

Or did going through the roof deploy the shock absorber? ;)

Genuinely not sure how much lateral force is required to start tearing the webbing etc. on those things. Surely one would have to be giving it some sustained effort or taking a running leap?! They don't deploy casually or it would happen whilst in use as arrest system too.

fairlieg  
#6 Posted : 11 October 2019 10:30:22(UTC)
Rank: Forum user
fairlieg

You would need to check with the lanyard manufacturer.

It might vary however, the ones [shock absorbing lanyard] I have use in the past will not deploy at forces below 200kg and have a weight limit up to 140kg.

To give you an idea of the forces required (I am aware that restraint does not allow a person to fall this is just an example as shock absorbing lanyards are mentioned to help understand what they are desinged to do) they are designed to keep the force limited to 6kN

a 140kg mass falling 1m will exert 1372N into the system which is 139.91kg

a 140kg mass falling 2m will exert 2744N into the system which is 279.81kg 

It will also depend on how the restraint system is set up.

have you looked retracable lanyards?

TommyH  
#7 Posted : 11 October 2019 12:22:28(UTC)
Rank: Forum user
TommyH

Can I please ask the forum if it is acceptable to use a restraint harness with an inertia reel in the horizontal plain.  i'm currently in a debate with someone else.  I'm saying it can't?

Thanks

Tom

Martin Gray  
#8 Posted : 11 October 2019 14:51:45(UTC)
Rank: Forum user
Martin Gray

TommyH the answer is no as the inertia will not work.  The manufacturers paperwork that came with the certificate of conformity states it should not be used vertically.

Brian Hagyard  
#9 Posted : 14 October 2019 06:59:36(UTC)
Rank: Super forum user
Brian Hagyard

Should not be used vertically? Is that a typo Martin? I thought most inertia real's were designed to work vertically not horizontaly? Although i note some now say the will work in both plains.

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