Dynamometer in Life Safety operation

[stickboy42]

What do you all think about the use of a dynamometer in a life safety application (ie inline with anchors, highlines, etc...)

The dynamometers I'm looking at have a 5:1 SSF with a 2000 to 5000 lb rating (proof tested to 1.5x rating, Dillon AP series). This would put failure in the 10k - 25k range above most other components of the system. However, since many dynos aren't specifically rated for life safety is this a big no-no or is this a non issue. Since many of these dynos are being used specifically in crane applications that do end up having a man basket attached that becomes life safety... I know the dynos at work for aerial testing are calibrated every year, is this all that's needed?

Are there special shackles that are rated for human loads?

I'll stop rambling now, let me know your thoughts.

-m

[Always_learning]

Hello, we use an Ed Junior Dyno all the time in our rigging during training, always good to see if what we worked out on the whiteboard plays true on the Dyno.

We also ways back up the Dyno by either wrapping it or by pass it with a soft interface so it no longer creates that 25000 lb point of concern.

As the lead on the training I take responsibility on the use of the Dyno in our systems, I base this off good engineering of my rope system so that the Dyno is not a concern.

If you think about it, the Dyno is probably the best loooked after piece of kit you have, its sealed up in a plastic case that is foam lined and only see's the light of day during training where it is constantly watched while in operation to see what the figures are reading, it never reaches any great number, the most I have seen on ours is 1100 lbs during a Cross Haul with two dummies and a litter where we were showing the increase in force on the anchors as the angle increased.

I'm more concerned with the knots my guys tie or the anchors they choose then whether my 25000lb Dyno is up to the task.

But thats my opinion and I realize it goes against the 'Life Safety' rating but so does the fact I use 7/16th non-G rated rope for 2 person loads.......

Great topic by the way, should get people thinking for sure!

[jdcalamia]

As long as you utilize soft interfaces to attach it to the system I think all is fine. We've used them in training with highlines, to insure proper tensioning of the system. The chances of failure of the actual device itself (especially if it's primarily designed for use in crane operations, far greater force potential with a crane) is far less than the probability of failure of the soft interfaces. If the system is properly designed the mainline or belay tandem prusiks/device will catch at the anchor and the failure can be dealt with then.

[jmatthe2]

Always Learning summed it up. I will add one caveat; I wouldn't use one for a rescue unless the situation was extreme. One of the purposes with training with a dyno is you can see how your setups behave under certain load conditions. There are many field friendly estimates for high-line applications that are tried and true. I just can't see lugging a dyno into the woods.

One more comment - Always Learning I bet you would be surprised how many departments and rescue teams, would love to switch to 7/16 rope. I can't tell you the complaints I get about how heavy 600' of 1/2" rope is. Many are still caught up in the G and L ratings, one/two person loads...yada yada... Even thought teh G and L ratings still exist, NFPA allows US to decide what an acceptable SSF is and then what equipment we need to do the job. With new technology breaking strengths are up to around 7,400 lbs!

The bottom line is SSF. If you can maintain an acceptable SSF use what works best for your team. At an 8:1 SSF there should be no issue with a 2-person load....depending on their mass!!

Personnally, I think it's awesome you have the respect of your organization and your organization has the knowledge to available to committ to this!

[cpfdmiller]

can ask what would OSHA say if something were to happen with the system knowing that a 2person load needs a g rated devise used? or so i have been told..

[ProgressiveRescue]

I'm curious why you would you would want to use it in a live rescue? If you'r rigging is done properly you shouldn't be worrying that much about how much load force is on your system and it's components. Granted there are times when we're forced to rig systems outside of the parameters we'd like to stay in.... but in those instances we'll take the necessary steps to ensure that we build the safest system possible.
I think using a dynamometer in training however is great because it helps you understand how forces will travel through your system and what can be done to lower those forces. (changing you'r rigging configurations)
Unless the dynamometer has a "G" rating assigned to it I wouldn't feel comfortable using it, only because should the system fail for some reason someone is going to look back and find that a non "G" rated piece of equipment was used during a life application and whether that was the cause of the failure or not ,you've now stepped outside the NFPA standard and I would think be held liable for any injuries as a result of the failure. I may be over thinking this but I'd keep the dynamometer for training and not live rescue. I love the thought behind it ,however I think there's just to much liability.
Just My Thoughts,
MIke Donahue

[DCFDRescue2]

NFPA 1983 is a MANUFACTURER standard not a user standard. So unless you are manufacturing a piece of rope rescue equipment with a dyno integrated in it you should be OK.

How many times do you hook your NFPA 1983 rated equipment to something like a tree or a fire truck? Neither of these are rated in accordance with NFPA 1983. For that matter, what could you anchor a rope system to that is 1983 compliant? Aside from a tripod there isn't much else. I'd be curious to see any instance of a failed dyno in a real rope rescue incident, or even unexpectedly during pull testing.

If you're comfortable using a dyno in a training environment with people on rope, how is that any different than using it on a real incident? It's still live bodies on rope.

Sorry for the small rant, but 1983 does not apply to users. There's a whole new document in the works for that.

[ProgressiveRescue]

NFPA 1983 is a MANUFACTURER standard not a user standard. So unless you are manufacturing a piece of rope rescue equipment with a dyno integrated in it you should be OK.

How many times do you hook your NFPA 1983 rated equipment to something like a tree or a fire truck? Neither of these are rated in accordance with NFPA 1983. For that matter, what could you anchor a rope system to that is 1983 compliant? Aside from a tripod there isn't much else. I'd be curious to see any instance of a failed dyno in a real rope rescue incident, or even unexpectedly during pull testing.

If you're comfortable using a dyno in a training environment with people on rope, how is that any different from using it on a real incident? It's still live bodies on rope.

Sorry for the small rant, but 1983 does not apply to users. There's a whole new document in the works for that.

DCFDRescue2,
That makes sense....good point of view. I'm still not sure if I would personally use it during a live rescue. Honestly are you going to stop the rescue with people on rope because you don't like what the dyno is reading? If the dyno is giving you a reading that concerns you was this something that could have been avoided during your initial rigging operation? I just don't see how this will benefit you during a live rescue...training sure.
My point of view may just stem from being anal regarding the equipment used for rigging operations. Clearly a dyno isn't going to fail during a rescue it has the same chance of failure as any other piece of hardware. Would you use a Light Use rated beaner for a two person load? I wouldn't...would it hold the load?...sure but we have G rated hardware designed for such applications. I can think outside the box like anyone else however I just can't see the "outside the box" benefits on this one during a live rescue. I like the idea of being able to monitor the forces on the system but again are we going to stop a rescue....bring the victim/rescuer to a point there we can off load the rope and make the necessary changes to the system? seems like a waist of what could be precious time. Maybe I'm just looking at this from the wrong angle.
Mike Donahue
Great topic stickboy42
Mike Donahue

[DCFDRescue2]

I'm not advocating putting a dyno in for live rescues, but I'm not really opposed to it either.

I do think that using an L rated biner is no problem though. If you take a G rated rope and put a knot in it that will decrease the strength by 25%, you have already reduced the strength to a point lower than an L rated biner.

If you're worried about breaking an L rated biner during an incident there are two options that come to mind quickly:

Put a dyno in your system or avoid a critical load on that biner during your initial rigging operations. Like you, I'd choose the latter. Having used L rated biners for 2 person loads on highlines, I'm pretty confident in their ability to hold and my ability to rig.

[ProgressiveRescue]

DCFDRescue2
I hear what you're saying the chances of an "L"rated beaner failing are a million to one. Most "G" rated beaners these days are rated over 9000 lbs so I don't really agree with the statement "I do think that using an L rated beaner is no problem though. If you take a G rated rope and put a knot in it that will decrease the strength by 25%, you have already reduced the strength to a point lower than an L rated beaner." I personally just believe in a life safety operation you should always anticipate for a two person load therefore I like to use "G" rated equipment.
I think his just comes down to personal prefrence and how you were trained.
Mike Donahue

[stickboy42]

great conversation...turning more into a g vs l vs no rating discussion which is good...

i saw a comment earlier about assuming i wanted to use the dyno in a real rescue. i actually only referred to using it in a life safety application which could be either training or real rescue. in my case the training environment, however i wouldn't be opposed to using it in a rescue either. i was surprised by how little of a difference in the angle of a trackline made in the tension of the trackline at a recent RTR class i went to. a very little change in sag made the tension go between 2kN and 4.5kN which no rule of thumb tensioning system could have shown you. i guess my point being that i do see a place for a dyno in these situations albeit not a requirement just an easy thing to add.

mike, on the g rating issue, i hear you saying that you want a 2 person rated biner therefore it should be g rated? i to like to use equipment in anticipation of a 2 person load but i disagree that using g rated equipment is the solution. it is a solution but so might a L rated biner or a 36kN rated pulley that hasn't been independently tested (ie the Aztek, Rock Exotica Omni Blocks, etc). i think a critical force analysis and maintaining a desired SSF is the critical component here.

just my .02...

-mike

[ProgressiveRescue]

mike, on the g rating issue, i hear you saying that you want a 2 person rated biner therefore it should be g rated? i to like to use equipment in anticipation of a 2 person load but i disagree that using g rated equipment is the solution. it is a solution but so might a L rated biner or a 36kN rated pulley that hasn't been independently tested (ie the Aztek, Rock Exotica Omni Blocks, etc). i think a critical force analysis and maintaining a desired SSF is the critical component here.

Mike,
You make a great point and allowed me to see things from a different perspective. Let me rephrase my thought on the "G"rated issue. If I'm going to be operating at a life safety incident I would prefer to have hardware rated at the 40 KN mark. With all the strength that's lost when tying knots or a careless rigger mistake such as loading the beaner from the minor axis as opposed to the major axis I think the 40 KN rating is important to me. I'm a big what if guy....sometimes to a fault.
Again...Freat Topic.
Mike Donahue