Winter is now upon us and our training will have slowed down because of the holidays and the colder weather. We should be getting ready to crank back up as spring makes its arrival.
Last issue we looked at frontal airbags as well as side impact bags. One thing I forgot to mention when we were looking at frontal bags last issue, is the smart system. This system was originally found in the BMW and basically allows for the passenger bag to not deploy if no one is in the seat. This system is designed with a sensor in the seats to determine the weight for activation.
During a frontal impact only the drivers airbag will deploy if there is no passenger in the vehicle. So, remember that if the driver’s airbag has deployed, the passenger air bag theoretically is still hot, and if you put your weight on the seat, the sensor may detect this. Since we are talking about BMW’s, I need to also mention that you will find the battery in the trunk, not under the hood. Another feature it has is that when the frontal airbag deploys, a small explosive charge will disconnect the main battery cable from the vehicle. There is a smaller cable that will remain that works the accessories. There is also a disconnect on the battery so it can be rendered safe if needed.
Looking at curtain bags, knee bags, and seat belt tensioners. — all may play a part in our extrication practices. We discussed that side impact bags are designed to deploy when a vehicle is struck from the side and helping to reduce the force applied to the occupants upon impact. Curtain bags are designed to protect the occupants during a rollover, helping to cushion the window from a head impact. These bags come down from the edge of the headliner, and operate under less pressure. However, as with the side bags, there are cylinders inside the frame work that are used to inflate these bags. As you did with checking for the side bags and looking for the “SRS” markings, you will also see these markings on the plastic molding that runs above the doors. It only takes a moment to look for this labeling and only another moment to rip the plastic back and expose the bag system and cylinders. A few extra seconds can save a lot of heartache.
The other air bag that you may run across, although nowhere near as common, is the knee bag. Again, you will find these in the higher end vehicles, like the BMW’s and Lexus. This airbag is under the steering column and helps to protect the lower legs and knees on a frontal impact. These bags are tied to the frontal bags, so they can be deactivated along with the frontal bags. There will be a “SRS” marking under the steering wheel, in the lower dash. I am sure as technology continues to advance, there will be more airbags to contend with.
The other device I want to touch on is the seatbelt tensioner. These are going to be found in the “B” post and “C” post, or under the seat or center console. The seat belt tensioner is designed to retract when a frontal collision occurs. As the frontal airbag deploys and comes toward the driver, the force is pushing the driver toward the bag as well. To help minimize the forces of impact here, the seat belt tensioner will retract the belt several inches to prevent the occupants from thrusting forward as far. The tensioner is usually aligned with the frontal bags so both engage together.
They may also use a pyrotechnic activator that causes the recoil to occur. We have to be careful where we make our cuts, as you DO NOT want to cut one of these tensioners, if it has not activated. Take the extra time to analyze the vehicle before you make cuts. This extra few seconds is invaluable to you and the patients.
Another seat belt safety feature you may see is a special stitching design that works like a rope fall protection screamer. The threads are designed to pull out and help release the belts force on the occupant.
Next issue we will look at some alternate vehicle designs such as LP fuels, hybrids and electric. Again, we will keep things simplistic and easy to understand, and only look at the main concerns we would have as rescuers.
From the Reds Team, my family, and me, hoping you and your family had a very Merry Christmas and a wonderful New Year. Looking forward to some great training this year, so stay safe and train hard.