Rappel Rack or Fig 8
I am currently seeking advise for Tech Rope Rescue Equipment, we have no Large Buildings however we do have Rock Pits and Deep River Banks to contend with for Extrication, for Basket Ops, Low Grade, and Vertical which tool would work best, I have used both and Prefer the Rack but I will not necessarily make the decision on Scene any Comments would be Helpfull.. Thanks
Here today for a Safer Tomorrow
Depends on what you are doing. We like to use a lowering system as opposed to rapelling down to victim. In this case a ladder rack works best. The rescuer then has two hands to go around obstructions. Communication is very important in this system. It is then pretty easy to convert to a haul system to bring up victim (in basket if necessary) and rescuer.
Remember, the life you save may be your own.
Some random thoughts on figure 8 plates and brake bar racks. First of all..try to make it a point to refer to the figure 8 as a Figure 8 Plate..as not to confuse it with a figure 8 knot.
Figure 8 plates are very simple to operate. This is a main advantage of them. They are easy to control, lock off and teach. Their application is limited to short hauls though..as they begin to heat up rather rapidly on longer descents. They are easy to rig as well. The figure 8 plate can be wrapped double to hold larger loads..but this tends to add to the twisting of the rope and sometimes causes the rope to roll over itself within the 8 plate, causing unwanted rope on rope friction. On long descents, the added weight of the rope hanging can actually act as a bottom belay..which can make travelling difficult. The 8 plate can be bottom belayed..which is good because it can allow the rescuer on rope to go hands free if need be in odd circumstances. The figure 8 plate is generally a good tool for the 1 or 2 person load as would be found in pick offs and rapelling...when it comes to basket stretcher work and hauling/lowering systems..the rack is a better option.
Brake bar racks are very tricky devices. If they are rigged wrong, they can catastrophically fail and send the rescuer on a deadly ride. If rigged properly and used properly, they have distinct advantages over figure 8 plates.
The brake bar rack allows you to control loads variably by adding and subtracting bars..while loaded. This is a distinct advantage over the figure 8 plate..which you cannot adjust once loaded. The brake bar rack is well suited for lowering systems, basket stretcher work and long distance lowers/rappels. Aluminum racks generally provide a bit more friction, but wear out faster..thats if you use it ALOT. Open ended racks are designed for single person rappels and such. for lowering systems, it is more advantageous to use the closed end rack..so if it loads up and lateral force is applied..there is less chance for the rack to bend...where an open ended rack would bend (this usually only looks worse than it really is). The closed end rack used in conjunction with a load releasing hitch as an anchor works well..because it allows the transition of a static line to a lowering line should the poo poo hit the fan.
The brake bar rack is not easy to teach, the concepts are almost opposite of a figure 8 plate. Force must be applied in an upward direction to create braking resistance..where force must be applied downward on an 8 plate. Teaching hand placement is harder also. Practice and frequency of use are key elements to this tool. The ability to be able to variably control the braking resistance by adding/subtracting bars is truly crucial in some cases. Lets say in the case of a pick off..if you were lowered from the top, that may only need 2 or 3 bars..once you loaded your victim into your harness, ore bars can be added to assist in smooth slow lowering. Again...it is crirical to load the rack right...or all the bars can fallout and cause sudden decelleration trauma!
Each is well suited to specific applications...I suggest consulting a training company and possibly having some classes to practice with each one..see what the advantages and disadvantages are for each.
http://www.specrescue.com is a great training group, they would be happy to set up a class for you! (no I am not associated with them..I have taken many classes and feel that what I have gained is very valuable information and recommend this fine group to everyone.
The above link is a setup with a brake bar rack from a class we held.
[This message has been edited by e33 (edited October 07, 1999).]
one more consideration you might keep in mind about figure 8 PLATES " http://www.firehouse.com/interactive/boards/smile.gif" and rappel racks is the whether they are aluminum or steel. Aluminum provides more friction than steel and many prefer it for that reason. Aluminum is is also lighter and weight may be a factor. However, aluminum oxide (the gray stuff on your rope after you've had your Indiana Jones drills) can combine with moisture and degrade the strength of your rope- good inspection and ,maintenance practices can help mitigate this problem but it is something to be aware of. Anodized aluminum can form razor sharp edges when the anodized outer layer becomes worn- it doesn't take much cutting to sever or desheath a kernmantle rope under tension (especially when your loading a rope with a patient and rescuer, or running a telpher). Finally, Aluminum doesn't have the tensile strength that steel does.
oh yeah...that too!
I see the common terminology emerging already! Im tickled http://www.firehouse.com/interactive/boards/smile.gif