Brain Teaser - Air Bag De-Energizing and Storage Capacitors - UPDATED 10/15

So here is a brain teaser for you FFN members.

So how long have you been told to wait to assure the energy stored in a capacitor is no longer a hazard to you and your crew when preforming extrication around air bags?

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Permalink Reply by JASON RUNDHAUGEN on October 6, 2009 at 1:03pm

ANY WHERE FROM THE THE TIME YOU CUT THE BATTERY CABLE UP TO THIRTY DAYS,MY DEPT. WAS TOLD THAT BY AN EXTRICATION TECH WHO SOLD US OUR NEW JAWS

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Permalink Reply by Joe Stoltz on October 6, 2009 at 9:21pm

Good question. We carry a Holmatro reference guide in our rescue pumper and, although I can't remember any specific cars it seemed like one to three minutes was a common number.

If one knew where the storage capacitors were located the charge could be bled off by shorting across the terminals. Assuming there was no fuel spilled, of course.

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Permalink Reply by FETC on October 7, 2009 at 8:01am

OK Seeing this is getting little attention. Just want to point out that air bag fired in a car in which had NO BATTERY for over 6 months. Now that I got three peoples attention...Here is the firefighter safety alert I created because many are mis-informed about de-energizing the vehicle's electrical system.

The Volvo Car Manufacturer in the early 90's designed their side impact air bag system to be armed and ready to activate without ANY power source. This SIPS system is not even shown on the electrical schematics for the cars wiring system. Recent training by a local department had an example of having a car without any battery in it, still remain with ACTIVE airbags.

After following up with a Volvo Master Service Technician, he stated that PRE-1998 Volvo's equipped with SIPS - Side Impact Protection Systems do indeed have a firefighter or service technician hazard even if the battery was disconnected. The SIPS is designed separate from the SRS system that fire the steering and dashboard airbags. POST 1998 Volvo’s were re-designed with a new system that works similar to the energized SRS.

SIPS does NOT require energy to fire the air bags located in the seats. Therefore, the system is awaiting an
impact. A sensor located below the plastic trim molding just inside the rocker panel to be impacted. The dash and B-post have warning decals identifying the hazard. The plastic molding has SIPS labeling as well. These warning decals identify: DO NOT USE EXCESSIVE FORCE IN THE AREA OF THE SIDE SEAT.

To disarm the SIPS sensor, there are two wires coming from the impact sensor and running underneath the
seat to the torso airbag. On our training Volvo, the wire was noticeable from the open door where the bottom
seat cushion meets the upper back seat at the hinges (see photo) There appears to be enough room to cut this wire with a pair of trauma sheers or a knife without intruding on the patient's buttocks.

Reminder that the de-energizing the 12V battery in the engine compartment, will disarm the SRS system
but if the vehicle is equipped with SIPS, the impact sensors will need specific attention.

TCSS
FETC

www.fetcservices.com
"Average Training Breeds an Average Fire Department - Let FETC Help You Achieve Excellence"

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Permalink Reply by FETC on October 7, 2009 at 7:37pm

Always amazing that someone can start a thread about pimped out POV's and lights and we can get 60-70 replies in a day. Now here is firefighter safety information and it just slides on by without any attention.

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Permalink Reply by Ben Waller on October 7, 2009 at 7:43pm

Well, you did say that you didn't want the "experienced extrication gurus" to reply, and that's got to be at least 25,000 FFN members you excluded there...right? :-)

In all seriousness, I've always taught - and used - the theory that all SRS and SIPS components are live no matter what you do to the battery or electrical system. If you use the "pry and peek" technique, it will expose most SRS and SIPS components. If you look before you cut or pry and make sure that you're cutting or prying only structural metal, you'll generally be OK.

Good information, and thanks.

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Permalink Reply by Jack/dt on October 7, 2009 at 7:43pm

FETC sorry, was totally engaged with some of the absolutely worst written "blogs" imaginable.

To your point, I DID NOT KNOW. I learned something today, do I get a cert? Can I? Pretty please? Also which do you think are better, RED trauma sheers or Blue trauma sheers?

So post 1998 the system has been changed. Is this setup prevalent on any other makes/models of cars besides volvo?

Also, a suggestion for you 'motto',
"Average Training Breeds an Average Fire Department - Let FETC Breed You Excellently"

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Permalink Reply by Rusty Mancini on October 8, 2009 at 3:10am

I don't put any trust in the air bags even after cutting the battery cables, they scare me period ! I really learned something here, and these are the kind of post that are needed. Thanks FETC ,keep it coming !

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Permalink Reply by Joe Stoltz on October 9, 2009 at 6:18pm

Thanks for sharing this tidbit FETC. I'm sure many no-reply viewers have learned something here, as I did.

Now, to clarify: was 1998 the last model year with the no-battery hazard, or the first year with the newer system?

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Permalink Reply by FETC on October 15, 2009 at 4:27pm

Joe,

1990-1997 Volvos offered a closed loop SIPS system that had its own impact sensor and power source. Any Volvo 1998 and newer with SIPS are designed like SRS system in the dash and steering wheel.

Email me direct at training@fetcservices.com and I will forward you the PowerPoint for this incident.

TCSS
FETC

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Permalink Reply by Derek R. on October 15, 2009 at 4:34pm

Same as Jack/dt......Did not know. Thougt it was 3 days or something. Just goes to show. We were taught the pry before you cut theory. Take a peek behind the moul;dings to see what's there for all the time it would take to do that. Still doesn't de-energise the system though. Thanks for the tread. Learned something.

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Permalink Reply by Ron Ayotte on October 15, 2009 at 4:48pm

We get the Holamatro guide to vehicle safety systems with the updates. Before we cut into any vehicle, we look up airbag locations, battery location and capacitor drain times. It only takes a minute and can save us and our patients from potential injury or death.