[SoCal-SERCA] Re: Ever shipped Airbags?

[Boonrat Lohwongwatana]

On Fri, 16 May 2003, Raymond A. Kawski wrote:

> Electricity is required as a catalyst for the chemical in
> there to burn causing a gas to be created.

Ray is right. Electrical impulse is what igniting the reaction. What's
inside the airbag before deployment is just powder. When ignited, nitrogen
gas is released in the reaction. It is not dangerous since
it is abundant in the air and you are breathing it in even more than
oxygen. When blowing up, the nitrogen gas can be pre-calculated to
fill the exact volume of the bag.

If one could avoid the ignition (a small pulse will trigger it), you are
safe to transport the airbag. But I do not know the mechanics underlying
it, so I cannot tell where to disable the electric ignition.

Sorry if I bore you with this technical stuff, it is just a bit related to
my life these days.

Boonie

On a technical notes on those who are interested:

There are three chemicals in the bag to begin with. NaN3, KNO3 and
SiO2. Sodium azide (NaN3) is the main source of nitrogen (three N's in the
formula!). It is ignited and you get pure sodium (Na) and Nitrogen gas
(N2) as a product in the reaction: 5 NaN3 ---> 10 Na + 15 N2

But sodium (Na) is not quite stable. By adding KNO3, Na will reduce it
down to K2O and Na itself will form Na2O and a bit more of nitrogen gas.
10 Na + 2 KNO3 ---> K20 + 5 Na2O + N2

Third chemical is SiO2, and it is just silicate glass. It is used to
stabilize Na2O and K2O compounds. Silicate glass is the wet slimey stuff
that you see in a punctured airbag. When it is dried, this is the same
thing as the coating inside beer cans these days. The thin silicate
coating will prevent the reaction between beer and aluminum can, giving
you the legendary "from-bottle" taste.