Re: Holdbacks As Workforce Safety Devices?
Do NOT do this job, unless you are fully convinced of the safety.
Just asking this question makes me worry.
Have you asked and/or informed the technician sitting on the return?
Ending with:
TAKE CARE
Teus ■
Teus
Re: Holdbacks As Workforce Safety Devices?
If the holdback / interface was to fail, could the worker be injured?
If so (I suspect yes) then it is apparently a "safety device".
Regards,
Lyle ■
A Nip In The Air.
Teus is absolutely correct. His comment about worrying because the question is even asked proves the high level of disturbance.
Assuming you might release the tension,a normal prerequisite for this type of work then there will be inadequate support for the technician anyway.
You will have to clamp to maintain support. Releasing the tension also relaxes the torque which might be locked somewhere in the drive.
Bibby used to, might still, make a gradual release holdback so that the infamous lethal tail pulley traps were avoidable. Obviously you don't have them fitted.
If you read some recent threads concerning dramatic holdback failure you will appreciate that they are not safety devices. They are merely anti-run back units...and often enough they aren't even that.
Reading further it says that some ceramic lagging came adrift. What happened to the belt? Is there any chance of the technician getting caught in any holes punched in the belt?
I wouldn't run this one past your safety man just yet. ■
Re: Holdbacks As Workforce Safety Devices?
Thankyou for your replies. The belt will be clamped!
I'm not an old salt at this game and haven't experienced an anti-run back failure. Further research on failures of them has me worried.
The pulley has about 1000 x 300mm of lagging missing in one section. The pulley showing signs of corrosion where the ceramics have come off. The belt is not damaged. ■
Um, You're Kidding, Right?
How it could possibly be contemplated that a hold-back was a safety device when the job is to repair the head pulley (through which the holdback acts) is a total mystery to me? And how is clamping the return belt going to be safe? It seems a pretty dubious proposition. If I was doing it there would be a sufficient area planked out under so the person has a proper working platform, to suggest he can work off a clamped belt is pretty silly in my opinion! I would also point out if the fellow is liable to slip and have an uncontrolled fall over a distance he should also have a lanyard & harness!
In Australia AS1755:2000 states in part 2.2.3.2 Anti-runaway device: "....Where a hazard to people exists from the failure of an anti-runaway device then two automatically operated devices shall be provided to prevent run away. Each device shall be capable of holding the load independently. These devices should be monitored for wear and effective operation."
And that is a fundamental test (risk of injury), I am surprised nobody's mentioned it. Usually I find the opposite - ie people want to put that second braking system on when there is not a reasonable risk of injury. Of course the whole thing is somewhat irrelevant as the worst thing that can happen is a belt break and nothing prevents against a conveyor load of material turning up at the tail end better than a physical barrier. When doing the risk assessment on the job that should be the key criteria - is it actually a safe way to work or not? I don't think you've got there yet..... ■
Re: Holdbacks As Workforce Safety Devices?
BELT SAFETY 101!
Always always always remove or eliminate any energy from the system prior to performing any maintenance. Any means Lock out electrics on all starters, hydraulic pressures for take-ups, raise and lock suspended gravity counterweights, etc, etc, etc. You need to achieve ZERO ENERGY in the system before any maintenance can be done. Lockout procedures need to be developed and followed to the letter. I have heard of and even witness the aftermath of far too many serious accidents including death in my long career to not think anything otherwise.
Here is a true story that happened in the mine where I worked at and something everyone needs to be aware of. Large chunks of muck had lodged itself into the tail pulley of a conveyor, unknowing (or not realizing) to the crew, the jammed pulley had allowed the entire belt all the way to the head pulley drive to be fully tensioned. The man climbed onto the return side of the belt on his belly, after doing the normal lock out procedures, and proceded to clear the muck that had jammed the pulley. As soon as he got it free the tension released and pulled him into the pulley killing him instantly. Had the crew thought to take the time to lift and secure the gravity counter weight he would still be alive today and I would not be telling this story.
In respect to the query above when in doubt do it anyway for the workers sake please. ■
Gary Blenkhorn
President - Bulk Handlng Technology Inc.
Email: garyblenkhorn@gmail.com
Linkedin Profile: http://www.linkedin.com/in/gary-blenkhorn-6286954b
Offering Conveyor Design Services, Conveyor Transfer Design Services and SolidWorks Design Services for equipment layouts.
Re: Holdbacks As Workforce Safety Devices?
Gary’s statement about releasing ALL ENERGY from the system is the core of safe behavior.
Whether it is a belt conveyor, an electrical system, a pressurized system, a high temperature system, this principle always applies.
And a safe and protected workplace for the technician(s) with the proper tools and also a plan of actions.
This thread made the alarmed forum members to express their high concern about the obvious underestimation of safety in the maintenance business.
Maybe, a potential dangerous situation is prevented with this thread.
(Or did we just supported Scott in his struggle with the pushing management)
So much for the importance of this forum.
Again: take care (always)
Teus ■
Teus
In Addition
Dear Scott,
If i might add: release all energy and make sure no one can re-energize without proper checkout. Locking down (in the sense of a steel lock) of controls, Locking (in the sense of a material lock) the number of persons in the area and NO switch on if not everyone is accounted for.
If still someone tries to play the the-holdback-is-enough card: Holdbacks are devices to hold the belt back under operational conditions, meaning there's no person "on board". Bringing a person into the vicinity or onto the conveyor changes the legal situation, now you have a human interface and a holdback can now by no means be considered an adequate safety device against an energy-storing force transmitter, which the belt is.
Regards
R. ■
Safely Completed
To be honest I was just researching for a collegue who was organising the job. Counterweight was raised, belt was clamped, positive isolation of the drive, scaff, work at heights permit, all following a risk assessment which was completed by all involved.
Thankyou everybody for your replies and your concern. I do agree that safety is paramount and if in doubt questions must be asked.
Scott. ■
Pull The Other Strand.
Originally Posted by Sideshow
Personally I think it would be fine but would like to be well informed when I speak to the safety departrment before we start this job.
Any help greatly appreciated.
Scott.
So: between 10:28 on 10th until 17:15 on 11th your safety departement had agreed to the work package; your colleague had re-assessed the safe working requirements;prepared and submitted the method statement etc. Then the repair was undertaken including the curing time for the lagging attachment. Fast work. I'd seriously think of promoting your workmate. ■
General Arrangement Drawing
Originally Posted by SideshowWe have some ceremic lagging that has fallen off the head drum of one of our conveyors. We will be completing an insitu repair of this. This conveyor had dual drive, with each reducer having an internal holdback device.
There will be a technician sitting on the return of the belt to complete the repairs. Could the holdback be considered the safety device or should there be some form of clamping arrangement holding the belt to the frame of the conveyor? Personally I think it would be fine but would like to be well informed when I speak to the safety departrment before we start this job.
Any help greatly appreciated.
Scott.
Dear Mr.Scott,
Could you please post the general arrangement drawing of this conveyor ?
Regards, ■
Holdbacks as Workforce Safety Devices?
Hi,
We have some ceremic lagging that has fallen off the head drum of one of our conveyors. We will be completing an insitu repair of this. This conveyor had dual drive, with each reducer having an internal holdback device.
There will be a technician sitting on the return of the belt to complete the repairs. Could the holdback be considered the safety device or should there be some form of clamping arrangement holding the belt to the frame of the conveyor? Personally I think it would be fine but would like to be well informed when I speak to the safety departrment before we start this job.
Any help greatly appreciated.
Scott. ■