Thread: Webcast Question: Stabilization
10-22-2010, 03:55 PM #1
Webcast Question: Stabilization
A question from a webcast viewer is;
Mr. Moore: There are two sides to every issue, and my concern is whether or not to let the air out of tires of vehicles for stablization. I have always taught to lift the vehicle slightly, place cribbing of some kind under the four corners of the vehicle, and then let the vehicle down to rest on the cribs. I understand that you think it is better to place cribs under the four corners, and let the air out of the tires so that the vehicle will lower itself onto the cribs. Dosen't this make moving the vehicles a little more difficult at the conclusion of the incident?
My Reply Is;
I understand what you are saying. The bottom line is that you may have to “prove” later that whatever you did to stabilize the vehicle resulted in a truly stable vehicle.
If you lift a little like a lot of departments do and the way you teach, then that’s fine if the end result is the structure of the vehicle is resting on the cribbing suspension and is completely relaxed. I see a lot of crews lift a little, shove the stepchock in snug and then deflate the tires anyway. No problem with that as long as 'stable' is the end result.
If you do what I recommend and at some step in the stabilization process, blow the tires by deflation, you have done a ‘best practice’ and are done with initial vehicle stabilization. No matter what car components are removed and regardless of how many victims you take out of that vehicle, no matter how much lighter it might get during the extrication, you have connected it from “structure to cribbing” once and for all.
I agree that a car with air in the tires would be easier to tow away from a crash scene. What I see however is that across the US, the huge majority of tow/recovery operators run rollbacks. With this vehicle, all they do is winch the crash-damaged car onto their flatbed and haul it away.
10-23-2010, 03:36 PM #2
- Join Date
- Feb 2005
I have always been a fan of tire deflation. Use 4x4 tire deflators. You can buy them out of a 4-wheel-drive catalogue. Tires will deflate slowly & gently, and when you are done you can re-inflate them.
10-23-2010, 09:25 PM #3
On the other side of this,if you ADOPT flattening tires as A SOP, you CAN create two issues.
One there are FEW "rollbacks"for vehicles over say a F450-550 size. I'm aware of the Landoll style TT units but they are not numerous and not particularly viable particularly in multi vehicle crashes.
Secondly many states are implementing "rapid clearance" on major highways.Not much of a problem with cars/pickups but a bit more problematic on larger stuff . Flattening tires CAN be dangerous on larger vehicles even if you do it correctly,internal pressures of 100 psi or more are common.
We DON'T flatten tires,not that what we do affects how the world turns. Just another perspective. T.C.
Last edited by rmoore; 10-23-2010 at 11:31 PM.
10-23-2010, 11:30 PM #4
OK, Rescue 101. Not fair. You changed the subject from passenger cars that were addressed in the webcast and what the question was focusing on to tires on large vehicles, typically with 120psi and split rims. I call foul on that.
As long as you brought up F-450 and F-550's, then in a scenario where they are sitting on their wheels on a level surface, their real stabilization issue is their high ground clearance. A typical stepchock that will function well on the passenger vehicles we were originally talking about won't do the job with these big boys.
With any 'large' vehicle, in lieu of deflating the tires, crews who need to settle the structure of the vehicle onto the cribbing that they have in place beneath the frame should then become proficient at 'softening' tires. Bleed a little air out of the tires if you really need to settle these guys down.
10-24-2010, 03:14 PM #5
i didnt think they used split rims on anything newer than 1995ish year model. I know they were even getting away from them on large trucks or so i was told.??
10-24-2010, 05:47 PM #6
Actually Ron I didn't catch the webcast and for that I apologize. No FOUL implied or intended, at least in my eyes. As you know,I work the towing side as well as the Fire side. My Boss is well noted for POLICY and therein lies my concern:IF you develop a POLICY that calls for flattening tires for stabilization,they will get FLATTENED no matter what they are on. OR at least that is what would happen HERE. Now you and I are on geographical opposite ends of the earth as far as transportation goes. We have a wide ranging collection of interesting stuff traveling on the goatpaths we call roads. Density of vehicles is VASTLY different and trucks outnumber cars HERE. We often use the spreader to set chocks,it's out,fast and smooth. Sometimes can't do that and that's OK too. I like to keep my options open,and our people are taught that. We do stuff that would likely not be allowed in Texas but that have had positive life saving results here. Examples: Using a pulp loader with rated chains to lift(with proper cribbing)a broken cab and logs off a crushed logging truck. NONE of these are common happenings,they are always thought thru with all staff(Fire/medics) on site and CAREFULLY executed. In this case the entrapped recovered fully and went back to work. I just wanted to present another perspective on the tire practice on larger vehicles. Oh, MOST large trucks are now on tubeless tires.HOWEVER the split rim can still be found and ALWAYS can present a hazard depending on damage. T.C.
Last edited by Rescue101; 10-30-2010 at 12:30 PM.
10-25-2010, 07:40 PM #7
I am in complete agreement that tires should generally be deflated after insertion of step chocks. The laws of physics don’t lie. I do have issues with the techniques many of my students are taught on how to deflate the tires. I have seen guys taking numerous swings with a halligan trying to punch a sidewall and shaking the hell out of the car and victim while doing it. I have seen students badly slice their fingers when their “lock blade” knife wasn’t locked or lose their grip on the handle mid-stab and have their hand slide down the blade. I have seen stems fly through the air when a student tried to pull it out with pliers and didn’t have a grip on it. All of these techniques are dangerous as well as make it impossible to re-inflate the tires, thereby forcing all of us to spend much more time out in traffic while the RO-RO or dolly get hooked up to the car. Unfortunately we keep getting injured and killed at accident scenes by drunk or distracted drivers. Getting the scene cleared as fast as possible is crucial.
We teach students to use a stem tool to partially unscrew the stem to deflate the tires. It is very fast, GENTLY lets the air out of the tires, and allows the tires to easily re-inflate so we can clear the road much faster, thereby reducing the exposure of Fire, Medical, Police and Tow crews to road hazard. All of our rigs have an air quick-connect plumbed into the pneumatic brake systems and there is a spiral hose and air chuck under each seat to fill tires. What’s not to like about all that, you ask? You’d be amazed that some of the students get really mad when we insist they do it that way. “You’re wasting time. The victim is gonna DIE!” “Let the cops worry about that”. “Screw the tow company. It’s their job”.
We have two jobs at a crash: Protect ourselves (yes, that includes cops and tow truck operators. Even medics...), and patient care. Popping tires may be fun, but it isn’t smart and ends exposing us rescuers to danger longer. If you have some old dinosaurs who insist that it’s their God Given right to destroy tires in order to deflate them try to gently educate them that better tools exist.
10-26-2010, 11:18 PM #8
So here is a generic scenario for me to gather your opinions on...
4-door passenger car, head-on crash damage (moderate), airbags deployed, seated and belted injured driver as only occupant, complaint of neck pain, all doors open normally, car on level blacktop surface, all tires inflated...
To what degree would your organization "stabilize" this vehicle prior to bringing the patient out?
10-26-2010, 11:38 PM #9
Since I stirred the pot. Immediately chock the wheels to prevent rolling. We would then use the spreader (or Rapid jack) to gently lift and chock both sides of the car and then remove any pieces necessary(if required) to remove the patient. AFTER C-spine immobilization was in place( Hospital based Ems). T.C.
Last edited by Rescue101; 10-26-2010 at 11:42 PM.
10-26-2010, 11:44 PM #10
- Join Date
- May 2008
In this scenario we would chock all 4 wheels, steps chocks at base of A & C Pillars (inverted for better fit if needed), assure vehicle is in park and key shut off, disconnect battery, disconnect or cut seat belt and assist EMS crew with patient extrication via driver's door.
10-29-2010, 01:39 PM #11
- Join Date
- Feb 2005
I'm not a big fan of upside-down step chocks, although I see it being taught a lot these days. I feel that you get a lot more stability using them the proper way. you get a larger footprint on the bottom, and your car is resting on a flat surface, as opposed to a sloped one. Just my opinion.
Last edited by MEAN15; 10-29-2010 at 04:57 PM. Reason: spelling
10-29-2010, 03:50 PM #12
10-29-2010, 03:59 PM #13
The problem I've seen with using them "right-side up" (step-size up) is that it is harder to get a good fit between the ground and vehicle. Inevitably the height will end up in between one of the steps and you'll need a wedge.
Used "upside down" (step-side down" and the ground will bridge the steps while the side facing the vehicle has a more granular slope (not stepped). This allows you to wedge the chock to the exact height.
Last edited by rmoore; 10-30-2010 at 12:42 AM.So you call this your free country
Tell me why it costs so much to live
10-29-2010, 04:55 PM #14
- Join Date
- Feb 2005
that's why you deflate the tires and lower the car onto the chock.
(or back in the olden days when we lifted the car a few inches & shoved the chock in)
10-30-2010, 12:45 AM #15
Remember, the stepchock was created in 1984 by a Florida team participating in extrication competitions sponsored by T.E.R.C. Their original design, which is now the most common, has a wider board or base and thinner 'steps'. That original design means that the stepchock is more stable when used right side up. Yes, stability is greatest when the car settles into one of the steps of the stepchock.
The problem comes when the crashed car just doesn't quite settle onto one of the steps of the stepchock. That's where the upside down stepchock idea came from. Upside down, the stepchock becomes a giant wedge. Regardless of how the car settles, it will be able to make physical contact with the stepchock because the bottom side is continuous.
I like using stepchocks upside down when necessary and use stepchocks upside when they don't readily contact the underside of the car in their normal right-side-up position. I am always concerned however when the stepchock is used in this manner. It is not as stable. A too steep slope of an upside down stepchock, especially a plastic chock, can cause the car to slide along the bottom surface of the stepchock and not really stay stable. The stepchock can actually work its way loose and become unstable.
I think teams should know when the bottom side should be down and when the bottom side of the stepchock should be up. Both positions have good and bad aspects.
10-30-2010, 03:45 PM #16
- Join Date
- Jan 2007
This debate has been around for many years, the step chock is designed to be used the correct way up, as this increases the maximum surface area in contact with the ground, which is what stability is about. If the block does not quite reach the sill we can simply correct this with the use of wedges.
Naturally as already stated it can be used upside down for the right situation in the same way it can be used on its end or interlocked with another step block. Lets use it the right way for the right job and not just for simplicity.
Flat tyre blocking is about creating a solid work platform, we should not be letting the air out so that the vehicle lowers onto the blocks, we should stabilise the vehicle as normal and then deflate the tyres so that the vehicle stays still, this just prevent the vehicle raising up on it suspension as it gets lighter.
We used to lift the vehicle slightly to fit the step block under the sill etc but this practice has long been stopped, we are stabilising the vehicle to prevent further movement so by lifting it slightly we are creating movement that we are trying to prevent.
A good topic
10-30-2010, 04:30 PM #17I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.
"The last thing I want to do is hurt you. But it's still on the list."
"When tempted to fight fire with fire, remember that the Fire Department usually uses water."
10-30-2010, 11:45 PM #18
Ron, are you referring to plastic or wood cribbing??
The wood cribbing can be made however you want. I remember years ago the wide base (wider wood) was used for the bottom (long) section and the remainder where not as wide.
Personally I haven't used that design in over 20 years. I also don't see it to often in the field anymore either. We do allot of training classes a year including outside the US.
All my WOOD steps (not talking about plastic), are the same size. I use 6" and also larger wood. It also serves as a great platform/base for lifting bags.
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