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  1. #1
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    Default LRH Load Releasing Hitches(Rope or Web)

    What are the opinions on what to make your LRH's out of. I will only use 3/8" or 5/16" rope to tie my LRH's because in an advance rope I class I took I saw webbing LRH's fuse and melt with a two person factor one fall drop test. If I remember correctly 50% of the time the webbing fused and made it unuseable. The webbing never failed and dropped a load but you couldn't use it. But I met a few people in a current class that won't use rope or cord, they just like webbing saying its easier to use with webbing. What are some opinions as wellas fact based responses to this. Thanks again.


  2. #2
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    Rigging for Rescue in Invermere BC published a report on various load release hitches in use in the rescue community. The remarks you have made regarding the webbing fusing are factual. This has been found in a number of tests while the Radium load release hitch has held up through the tests. You can buy the report from the website:
    http://www.riggingforrescue.com
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  3. #3
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    We don't use rope or webbing, we use a load release strap. http://www.cmcrescue.com/product.php?dept_id=1254
    it is far stronger then any of the others at 8,039 lbs.
    Also to protect the system and the victim / rescuer we use shock absorbers on the load.

  4. #4
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    The "load release strap" is webbing and is subject to fusing under dynamic conditions due to its low elasticity. The use of shock absorbers can be hazardous aswell. Why expose the rescuer and patient to a potential 4 foot deceleration when the rescue system without the shock absorber has impact forces that are acceptable. Also if the rescuer and patient are each attached to a seperate shock absorber then they will be suspended at different heights after deployment due to different mass. Patient care is then compromised. A strictly rope based system can better maintain the pre and post arrest positioning of both the patient and rescuer. It can also be very difficult to perform self rescue when all you have to attach a prussik to is the torn out shock absorber. It's interesting how many people are using shock absorbers because of their use in the fall arrest world when they are not mandatory for fall arrest. OSHA allows for a maximum arrest force of 8kn and the rescue system, when exposed to a 1 meter fall on 3 meters of rope, will impart a force of about 5kn on each person. So for 1 kn difference in force you are willing to introduce all the hazards that come with shock absorbers. As far as the strength goes, do you know the strength of the radium load release hitch? Not the strength of a single strand of the cord but the total component strength. A lot of people get fooled by instructors who throw out the individual material strength instead of the component strength. I would bet the load release strap is stonger staticly than the radium release but by how much? There is more involved than simply strength. Due to the dynamic nature of belay systems you must consider the dynamic performance of the LRH. The radium LRH also reduces the peak force by 10-25% by allowing slippage.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  5. #5
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    Jast as a point of academia: If your LRH made of webbing was shock loaded, wouldn't you want to place it out of service regardless of whether it was fused or not?

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    Yes you would but in the mean time you will need to either re-establish a mainline or turn your belay line into a lowering line. To make this transfer it is nice to have a LRH that still functions. Most people have never trained for the scenario that occurs after mainline failure and have a hell of a time when they try it. Also, if you can have enough heat to fuse the material, you can possibly have enough for total failure.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  7. #7
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    Yes, having a still functioning LRH is a good thing. What is your take on the 540 belay. It can be used as a capstan type friction device if the lever is held in the reset position. While this is certainly not ideal, it is still somewhat functional.

  8. #8
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    We use the 540. It works well. It's performance is very rope dependant. Different brands will behave differently in the device. Some will continually lock up in the device while others will have more slippage when activated. Also if the rope becomes wet or muddy, the device will lock up quite a bit. When this happens we switch over to a tandem prussik belay.

    As far as using the device for a capstain, I would do it for a short distance but if I had a considerable distance to lower, I would transfer to a descent control device. This can be quickly accomplished by attaching a prussik to the rope after the 540. This prussik is anchor to a LRH. Let the prussik grab the load, remove the 540, insert DCD, and transfer the load to the DCD with the LRH. The reason I am saying this is because it is difficult to maintain a consistent speed of descent when using the release lever of the 540.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

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    I have not yet seen the problems with the shock absorber that you mention. For us the majority of the time the rescuer is on a safety line. This is where the shock absorber is located. So if something bad happens it is his safety that will be his last protection.
    As for the LRH I have a question:
    You have a haul system with a LRH on it to turn it into a lowering system. How are your guys falling so that the LRH has the oportunity to fuse?
    The test drops of 1 seem a bit extreme. I'm wondering if the instructor doesn't have an agenda?
    We had a department conduct tests with some old equipment to see how well the tandum prusik held up vs the gibs etc. They subjected the system to fall factors that would mame or kill the guy on line, then claimed that the prusik was junk because how it preformed.
    Look carefully at the tests people conduct. In the rope rescue arena their are many ways of doing things. None are necessarilly wrong or right.
    Just off of the top of my head, some departments use a rescue 8 still, others have banned its use, some use prusik others will not. etc.

    Get a good understanding and keep many things in the computer under your hat.

  10. #10
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    The standard rescue drop test is a 1 meter fall on 3 meters of rope. This represents the situation where the rescue load is being raised back to the top with the mainline being passed through a high directional. The load is at the edge transition when the mainline fails. It is assumed that the anchor staion is 3 meters from the edge. At this point the load will drop about 1 meter until the belay line catches. This could be even higher if the belay ran through the high directional and the high point failed but it is common practice to run the belay independant from the high directional. This is our sample worst case as the rope is the shortest and the fall distance is the greatest. The test is not extreme and there is certainly no agenda involved. We are simply testing systems to the worst case scenario. I would ask if someone is not testing to the worst case scenario wheter there is an agenda involved. This test was created by the British Columbia Council for Technical Rescue and has been adopted as the standard rescue belay test across the industry with the exeption of companies using questionable techniques. I agree that aside from the edge transition, there is little or no fall involved in a mainline failure. Infact drop tests I have performed simply show a gentle settling in to the belay system. This is obviously not accounting for pure stupidity and incompetence.

    As far as the shock absorber goes, when you perform the belay competence drop, there is additional deceleration distance from the shock absorber deploying on the belay line. If you do a risk benefit analysis, it just doesn't make sense to expose the resue load to any additional deceleration for a difference of 1kn of impact when the impact without the shock absorber is more than acceptable. It is also quite a challenge to try to tie a prussik onto a deployed shock absorber to perform self rescue. This becomes even more of a problem if you are attached to the dosal d-ring on your harness. Even with 50 feet of rope in service and only a one foot drop, there is enough energy in the resulting change in suspension position to do serious damage to the rescuers face as it is driven into the wall.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  11. #11
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    It is always useful to test "worst case scenarios" given your standard system configurations. Don't use high directionals? Use parallel systems vs. main/belay? Great - test against what you do use. It's always fun and a good chance for rescuers to get an in-your-face lesson in the dynamics of system failures.

    Resqtek - you mentioned little or no fall in a mainline failure. I have seen many instances where the belay has sufficient slack that a mainline failure would result in a fall of, potentially, several feet onto the belay. And this is beyond the edge transition. Just a note of caution that proper system operation is critical in protecting against drops onto slack static lines.

    Re: webbing vs. rope. We use rope (3/8).

  12. #12
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    We always have one edge attendant maintaining tension in the belay system by watching the load and regulating the slack with the rope running through his hand. This way the belay operator only needs to concentrate on the slack between the belay station and the edge attendant. If it will be a long lower and rope weight will become an issue we will place a brake rack in the belay system to manage the slack. The rack would be placed in front of the 540 and behind tandem prussiks to ensure adequate room for LRH activation. I believe that if there is several feet of slack in the belay, there is a competence issue, not a system issue. Even still, if there is 30 feet of rope in service, it would take a 10 foot fall to duplicate the 1m on 3m drop. There is also a larger concern of striking objects during large falls.
    Sometimes, in order to make an operation idiot proof, you must remove the idiot!

  13. #13
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    Default response to the gibbs

    We had a department conduct tests with some old equipment to see how well the tandum prusik held up vs the gibs etc. They subjected the system to fall factors that would mame or kill the guy on line, then claimed that the prusik was junk because how it preformed.
    To:ADSNWFLD

    I have heard this gibbs arguement many times. I have seen the drop test, and everytime in the test I witnessed it had less than desirable results. I worked for several years as a Rescue Technician for the Yosemite Search and Rescue office before making a move to the Fire Service, with 14 years of rockclimbing experience I offer this food for thought.
    What was the Gibbs designed to do? What does it say on the side of the box? It was designed for a single person ascending device. I can assure you that Gibbs will not stand behind their product when used for things other than it was designed for. It wasn't designed for rescue work.
    It has the making for a good lawsuit for someones wife if anyone ever dies while using one. I don't mean to step on any toes or offend just offering something to think about.

    In Yosemite we used the BCCTR load releasing hitch tied form 33ft of 8mm low stretch accessory cord, to hard for some to tie though, I prefer it over the 1" tubular mariner knot being taught by the California State Fire Marshalls cirriculim.

    kary

  14. #14
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    We use the Rock-n-Rescue pre made load release strap.

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    We either utilize a BCCTR load releasing hitch in the system or the Radium 3 to 1 LRH.

    The LRH is utilized on both the Raise and Lower systems.
    TecRsq
    North Georgia

    - Let No Mans Ghost Come Back To Say My Fire Training Let Me Down -

  16. #16
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    We use webbing for the simple fact that if our main line fails, our safety line prevents or minimalizes any shock. Any shock that does occur is on our line and not on our LRH webbing because it is still "packaged" until we are ready to introduce a new line into the system. We operate under and practice under the assumption that something will go wrong, so we have all safeties in place and back up rope and rigging ready to go.

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    swcfpd340, unsure of what you are trying to say. Could you try it again?

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    .............

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    ..............

  20. #20
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    Quote Originally Posted by kwmedic
    What was the Gibbs designed to do? What does it say on the side of the box? It was designed for a single person ascending device. I can assure you that Gibbs will not stand behind their product when used for things other than it was designed for. It wasn't designed for rescue work.
    Look again. The Gibbs #3 and #4 (SS) are specifically designed for litter rescue, and the Petzl Rescucender, CMI Ropewalker, and PMI Progressor are all designed for rescue applications.

    Like any tool, they are appropriate for certain applications and not for others. As a progress capture device or haul cam, they may be suitable. They are certainy NOT appropriate as belay devices. But testing has demonstrated that any of them will strip the sheath at 1200+ lbs force. And, like any mechanical device, they can fail if dirt gets inside them.

    As for LRH material, I agree with others that webbing or commercial straps make no sense for this purpose since they are too static and because of their propensity to fuse.

    There is a tendency, in rope rescue as in all areas of consumer culture, to pay high prices for manufactured goods when simple, inexpensive, hand-made alternatives often work better.

    This is true of prusiks compared to mechanical rope grabs, 8mm cordage LRHs compared to LR straps, wrap-3-pull-2 anchors made of 1" tubular webbing compared to commercial D-ring anchor straps, adjustable rope litter spiders compared to commercial strap systems, etc.

    Americans used to be known for their ingenuity and creativity. Now we're known for our consumer appetites. And we think we're making out like bandits when we spend all that FEMA grant money, forgetting that it's our tax money we're spending.

    - Robert
    aVERT - a Vertical Emergency Response Training
    To Avert Disaster in the Vertical Environment

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