# Thread: A few lift bag questions.

1. ## A few lift bag questions.

Hey guys, I have a few questions about lift bags, I'm hoping someone can help me out.

1) When stacking 2 lift bags, is it acceptable to put a barrier between the object being lifted and the top airbag? We have a 3/4 inch thick piece of rubber for this purpose, some people say it's acceptable, others say it's just as bad as stacking 3 air bags.

2) Lets say you had a vehicle that had one of it's tires on top of a pt. when lifting this vehicle is there anything you can do to keep the suspension compressed so the tire doesn't stay on the ground as you lift?

3) Do you have any tricks you use for estimating (or figuring out) the weight of object to be lifted?

Thanks!

2. 1) Yes, actually recommended by Vetter when used against sharp or hot objects.

2) I would not recommend this, using a ratchet strap or something, because if the strap fails during the lift the pt. will receive another dose of massive blunt trauma. I don't really see this as a probability though, how many times is the person under the tire?

3) Normal reinforced concrete weights 150lbs/cu ft so; (W*L*H)*150 = weight in pounds
Heavy reinforced concrete weights 160 to 180lbs/cu ft

Lift frame wood construction 10 to 20lbs/sq foot (for walls)
6 inch thick concrete floors 100-150lbs/sq foot
Structural steel 490lbs sq foot or 3.4 lbs per square inch per foot of length
Use ((L*W)*factor)*square footage = weight in pounds

REMEMBER, LIFT AN INCH CRIB AN INCH.

3. Few more calculations;

Round object (Columns); length * 0.8 * diameter * diameter * weight per cu ft

Pipe; length * 3 * diameter * thickness * weight per cu ft

Steel I Beam; (width of top plate * width of bottom plate * height between plates) * length in feet * 12 * 3.4lbs
(double this for 2 inch thickness and so on)

4. Hi

1, We use a similar rubber barrier or even the bag to protect the bags from sharps or hot objects, the rubber will compress and pose no risk to the lift.

2, We train to use a ratchet strap to secure the wheel to the chassis or suitable point, so that when you lift, the wheel moves with the load.
It will also depend on the load limits of the ratchet strap, we also use them on trucks, unless we have a chain set available to use instead, remember the only load on the ratchet / chain will be the weight of the wheel and some suspension resistance, which will be minimal

Look at this video, a lift using a combi tool to lift straight from the wheel nut.

3, sorry i dont really know to much on that one sorry

5. Well,I don't think NORMAL suspension chained/strapped is all that reactive. Using the person under wheel scenerio.Remember you are holding 25% weight which any DECENT ratchet strap can do easily.I've NEVER(in 40 years)ever taken a VIABLE victim out from under a wheel unless it involved a SLOW speed run over(like no chocks/broken E brake).If clearance was an issue and I had a strap,I'd be inclined to use it. Crib as you lift. T.C.

6. 1)Yes...we do it all the time. Not even close to being the same as stacking three bags.

2) In most cases I would just lift the vehicle without strapping the wheel. If it is a car it will (in most cases) take a while to properly strap the wheel (not much space under that vehicle to do strapping). I would propperly crib the car and using stacked bags (2) start lifting. You should be able to lift a wheel way off the ground. Crib the opposite side of the car so that it does not drop/lower as you raise the side that the pt is trapped under. You could also lift the front and/or the rear of the vehicle...again cribbing the opposite side.

3) Research, research and more research...starting writing down the known weights of objects in a little note book and keep it with you in your bag of tricks. The other thing that is good to know is the Center of Gravity of the objects that you are lifting.

Hope that helps.

7. Here is what happens when you stack 3 bags together. http://www.supportingheroes.org/inde...ge=hero&hid=69

2 days before Christmas and he left a 2yr old (I think)daughter behind. I couldnt attend the funeral but when I saw a pic of her standing beside him at the funeral home I was glad I wasn't there.

8. I agree with most - the chances of a GOOD quality(inspected and stored correctly ) rachet strap failing are minimal - you can what if to death - we have some 1/2" rubber conveyor belting cut into pads.

9. If you carry Hi-Lift jacks on your rescues (which you should), this attachment would also be an option: http://www.4wheelparts.com/ProdDetai...No=H%2fLLM-100

10. A couple of other ideas to add to the good ones I'm seeing:

A simple and fast way to retain the wheel and suspension is to attach a ratchet strap to the wheel (use webbing, chain or a hook cluster to attach if the strap hook won't work). Run the strap over the hood or trunk and attach the other end to the opposing wheel or to a frame member. The T-hook slot works really well for this. If it's an SUV or wagon use the hook cluster to hook the other end of the strap to a window frame or roof frame. You shouldn't be carrying any ratchet straps rated less than 10,000 lbs anyway, so the strap will have no problem holding or even compressing the suspension.

The best place to learn loads is the FEMA Structural Collapse Technician Student Manual. It is on-line at:

http://www.fema.gov/emergency/usr/sctc.shtm

Module 2a (page 2) has weights for many common building materials. The rest of the manual is an excellent training resource for you to use. While in Module 2a print page 12 and put it in your cribbing compartment as a ready reference on the rules for making box cribs, which most Firefighters don't know or have been taught incorrectly.

Estimating weights on vehicles is mostly common sense - learn basic weights of cars and figure how much of it is on your victim. Trucks, trailers and cement trucks, etc. depend on contents.

-Tim

11. Some good answers on here. As for lifting with the high lift jack (farm jack) I tend to shy away from that and here are the two reasons why. First if you are lifting the vehicle from a patient the jack will come back down slightly to allow the climbing pin to catch the next hole. Even if we crib the appropriate I still dont like the fact that as we use the jack it has to drop down ever so slightly to climb up to the next hole. My second reason is the fact that they are inherently unstable. Between using them in the rescue service and for offroading, I still feel that there are better options out there. But it is still part of the "toolbox". I prefer the use of the air lifting bags or even hydraulic lifting jacks in either scenario.

As for the suspension, if you can strap it or chain it safely and quickly do it.

The top protection for the airbag is a good idea, I don't like to use cribbing but a nice heavy piece of rubber such as a mud flap for a tractor trailer comes in handy.

12. That's why you use a crib wedge as you lift,replacing it with a square block when you can. We use Hi lifts A LOT but you need to have a healthy respect for them and their limitations. But the DO serve a purpose and are a very versatile tool. T.c.

13. It is important to protect the bag when need be. but if it doesn't need protection, then don't. most modern air bags/cushions are made with a grip surface. this surface is designed to ...grip. putting a barrier in between the two should only be done when necessary. and if you don't need to cover the entire surface...then don't.

this becomes even more crucial with the use of low and medium pressure. I have seen people put sheets of plywood in between the bag surface and a side of a trailer (semi dry van). It doesn't take a rocket scientist to figure out that u have 1) now taken the bags ability to "grip" to the surface. 2) when the sheet of plywood comes flying out you have created a environment of getting someone hurt.

Of course this does not apply to putting "lifting plates/boards" on the bags.

14. Always been a mystery to me why one would attempt to put a piece of marine grade plywood(smooth and shiny)against a FRP and think they were going to maintain CONTROL during the lift. If it's that "soft" one of two things needs to happen: add a bag or two or DON'T try to lift it. Most of the trailers around here are so stove up by the time they stop sliding you're NOT going to lift 'em without unloading anyway. Even for RESCUE, I wouldn't use plywood. T.C.

15. How thick are the plywood pads you guys use to protect your airbags.

16. The ONLY place I would use a Plywood pad is as a ground pad UNDER the bag and ONLY in very soft ground conditions. NEVER on the item to be lifted.3x3' or 4x4' 3/4 or 1" MARINE grade plywood for ground pads. T.C.

17. Originally Posted by Rescue101
The ONLY place I would use a Plywood pad is as a ground pad UNDER the bag and ONLY in very soft ground conditions. NEVER on the item to be lifted.3x3' or 4x4' 3/4 or 1" MARINE grade plywood for ground pads. T.C.
What is your reasoning T.C.? I don't think plywood (I wouldn't use marine grade) between the high pressure lift bag and the load is appropriate every time, but I do think I think there are instances when using plywood between the load would be appropriate. In the Paratech manual (http://www.lacountyfirefighters.org/...RCE_MANUAL.pdf) it says to use a plywood pad to distribute the lift across a thin surface, lift something with a temp over 150 degrees, or to distribute the lift when lifting something with a small surface area. A plywood pad is also used regularly in Fire Engineerings training minutes when they cover lift bags. See this video on Fire Engineering's web site http://bcove.me/yhuk2wrz @ 1:47

18. See post 13. Scooby and I lift heavy stuff,with bags,a LOT. Likely MORE than most FD's. We've all seen the horror shows that come when end users think they know more than the folks who built the bags. Bag on bag, you're grated rubber surface to grated rubber surface. NOW put a piece of plywood in there. WHAT is your surface NOW? NOT a good idea! If you are going to put ANYTHING between bags or the item being lifted, make it a RUBBER pad.Once you see a piece of plywood fly out of the stack,you will know two things: ONE,it's unlikely you'll do it again(assuming you survived) and TWO: you'll KNOW why we tell you it's a bad idea. Or you can ignore the advice and hope for the best. I'm NOT going to use plywood,EXCEPT as I outlined.Under certain RARE events, I might,if I can, pad both sides of the plywood with rubber sheets/pads. T.C.

19. Another big concern I have is the number of high pressure lifting bags that have out lived their life expectancy that are still in front line service on rescue units. Ron had addressed this previously however when conducting training programs at fire stations I continue to come across departments that have these bags in front line service. It is quite obvious that many of these departments do not have an understanding of the need for hydrostatic load testing of these bags. At a recent training program I advised the fire department we could not utilize their bags for training due to the age (20 years +) and they had never been tested. They immediately removed the bags from service on the recue unit and scheduled them for testing. Each and every bag in there cache of equipment failed the hydrostatic testing and they are now in the process of purchasing new bags. A lot of departments similar to this one had purchased bags in the early to mid 80's when they gained popularity in the rescue service and unfortunately many still remain in service unbeknownst that they are one inflation away from catastrophic failure.

http://www.firehouse.com/mz/images/2..._life_span.pdf

20. It's thus astonishing I can't believe it. Wow! Thanks for your posted clause it's a large service for me and for all. . This info. actually, truly aid me a lot. . Thanks brother preserve the good work!

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