Comparison of Explosive Potential of Gasoline vs. Dynamite

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Greylock

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Jun 17, 2003, 11:52:00 AM6/17/03
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I'm looking for a realistic comparison of the explosive potential of
gasoline in a finely atomized or vaporized state to a standard TNT
formulation. (Whatever formulation is typically used for the comparison of
explosive strengths.)

A web search has yielded a great variety of figures ("a gallon of gasoline
is equal to 4, 8, 10, 22, or 115 sticks of dynamite" - take your pick) but
no calculational basis that I can examine.

I suspect, but cannot verify since none of the calculations are shown, that
one of the causes of the variability is tied up with the assumed time
duration of the gasoline energy release (energy/unit time).

Assuming the gasoline atomization/vaporization is near theoretical
perfection would seem to be a reasonable basis to eliminate at least that
particular source of variability.


Boomer

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Jun 17, 2003, 2:39:35 PM6/17/03
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FAE are about 4 times more powerful than TNT. You will not find much info on the net other
than this

http://www.fas.org/man/dod-101/sys/dumb/fae.htm

http://www.gexcon.com/index.php?src=handbook/GEXHBcontents.htm


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"Greylock" <vin...@hal-pc.org> wrote in message
news:AOGHa.26279$1w1.2...@twister.austin.rr.com...
: I'm looking for a realistic comparison of the explosive potential of

:
:


JaM

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Jun 17, 2003, 3:40:47 PM6/17/03
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On Tue, 17 Jun 2003 13:39:35 -0500, "Boomer" <wcw...@chartermi.net>
wrote:

>FAE are about 4 times more powerful than TNT. You will not find much info on the net other
>than this
>
>http://www.fas.org/man/dod-101/sys/dumb/fae.htm
>
>http://www.gexcon.com/index.php?src=handbook/GEXHBcontents.htm
>

A detailed account:

http://www.gichd.ch/pdf/TN_09_30__04__2001_FAE%20_Version%201.pdf

Although it's info regarding de-mining, it has some thought on FAE
power.
Regards, JaM

---------
Sometimes wishfull thinking cloud ones mind
AA #2105

Boomer

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Jun 17, 2003, 4:19:32 PM6/17/03
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Nice PDF, hadn't seen that one before :-)

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"JaM" <oute...@hotmail.com> wrote in message news:3eef6e6b...@dtext.news.tele.dk...
: On Tue, 17 Jun 2003 13:39:35 -0500, "Boomer" <wcw...@chartermi.net>

Scott Kuli

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Jun 18, 2003, 3:30:16 AM6/18/03
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You may want to check more into the "moment of force" aspect
of detonations. The Russian explosives makers have discovered a neat
way to package "FAEs" (fuel and air explosives) that allow them to be
highly effective. They have attached these warheads to RPGs, and the
results are impressive. They've been using them since Afghanistan, but
only recently has any Western news source learned about them (Soldier
of Fortune magazine, as usual). The blast effect of the 80 some
millimeter shell on the RPG is equivalent in force to the 122mm
Katyusha rocket warhead. The duration of force, when made longer,
makes an explosive considerably more powerful. When a howitzer shell
explodes, it produces a short lived, albeit powerful blast, but when
one of these goes off, it produces a very extended moment of force -
enough so that quite a number of Mujahideen fighters were blasted
right out of their bunkers by these.

On Tue, 17 Jun 2003 15:52:00 GMT, "Greylock" <vin...@hal-pc.org>
wrote:

Dirk Bruere at Neopax

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Jun 18, 2003, 8:55:52 AM6/18/03
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"Scott Kuli" <yode...@mnsi.net> wrote in message
news:cc40fvk0c4t14bdb0...@4ax.com...

> You may want to check more into the "moment of force" aspect
> of detonations. The Russian explosives makers have discovered a neat
> way to package "FAEs" (fuel and air explosives) that allow them to be
> highly effective. They have attached these warheads to RPGs, and the
> results are impressive. They've been using them since Afghanistan, but
> only recently has any Western news source learned about them (Soldier
> of Fortune magazine, as usual). The blast effect of the 80 some
> millimeter shell on the RPG is equivalent in force to the 122mm
> Katyusha rocket warhead. The duration of force, when made longer,
> makes an explosive considerably more powerful. When a howitzer shell
> explodes, it produces a short lived, albeit powerful blast, but when
> one of these goes off, it produces a very extended moment of force -
> enough so that quite a number of Mujahideen fighters were blasted
> right out of their bunkers by these.

So Chuck Norris was ahead of his time in the special effects dept?

Dirk


George William Herbert

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Jun 20, 2003, 2:03:11 PM6/20/03
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Greylock <vin...@hal-pc.org> wrote:
>I'm looking for a realistic comparison of the explosive potential of
>gasoline in a finely atomized or vaporized state to a standard TNT
>formulation.

Ok.

>(Whatever formulation is typically used for the comparison of
>explosive strengths.)

This is a problem. We use a lot of different factors,
from velocity of detonation, to detonation pressure (also
known as Chapman-Jouget pressure or Pcj), to energy content,
brissance (a combination of Vet and Pcj), 'ballistic mortar'
test results, gas volume produced, heaving power, etc.
Some of these are fundamentally derived from others,
but are more useful than the lower level values for
a particular application.

In summary:
There is no single formulation typically used for comparison
of explosive strengths.

In rough terms... the energy released by combusting gasoline
is somewhat less per unit weight than methane or propane.
Methane and propane mixed with oxygen or air release in
rough order 10 times as much energy as TNT. But in a very
diffuse reaction even if it efficiently detonates in the air;
the density of air, or an air-propane mixture, is about 1.25
kilograms per cubic meter, and the detonation pressure of
that air-propane mix will be a couple of hundred PSI or so
compared to millions of PSI for TNT.

Still extremely dangerous, but very hard to compare because
the conditions of reaction are so different...

Very bad for shearing steel or blasting rock, for example,
even if you use a lot more energy equivalent compared to
a quantity of TNT.


-george william herbert
gher...@retro.com

Greylock

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Jun 20, 2003, 7:47:52 PM6/20/03
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Please note my comments below.

"George William Herbert" <gher...@gw.retro.com> wrote in message
news:bcvi8v$p5i$1...@gw.retro.com...


> Greylock <vin...@hal-pc.org> wrote:
> >I'm looking for a realistic comparison of the explosive potential of
> >gasoline in a finely atomized or vaporized state to a standard TNT
> >formulation.
>
> Ok.
>
> >(Whatever formulation is typically used for the comparison of
> >explosive strengths.)
>
> This is a problem. We use a lot of different factors,
> from velocity of detonation, to detonation pressure (also
> known as Chapman-Jouget pressure or Pcj), to energy content,
> brissance (a combination of Vet and Pcj), 'ballistic mortar'
> test results, gas volume produced, heaving power, etc.
> Some of these are fundamentally derived from others,
> but are more useful than the lower level values for
> a particular application.
>
> In summary:
> There is no single formulation typically used for comparison
> of explosive strengths.

{{ Understandable. The best I can see in terms of trying to get a somewhat
{{ (although flawed) comparison would be a look at the release of BTU per
{{ unit time. Essentially integrating the area under the pressure curve.

> In rough terms... the energy released by combusting gasoline
> is somewhat less per unit weight than methane or propane.
> Methane and propane mixed with oxygen or air release in
> rough order 10 times as much energy as TNT.

{{ Is this on a per pound basis?}}

>But in a very
> diffuse reaction even if it efficiently detonates in the air;
> the density of air, or an air-propane mixture, is about 1.25
> kilograms per cubic meter, and the detonation pressure of
> that air-propane mix will be a couple of hundred PSI or so
> compared to millions of PSI for TNT.

{{ Point taken, but it is my understanding that the peak pressure is much
longer {{ and is no longer a "point source" (no more "dead zones" caused by
{{ "shadows").
{{
{{ The explosive action is certainly different in character. But I gather it
is {{ particularly damaging to structures and unprotected humans.

> Still extremely dangerous, but very hard to compare because
> the conditions of reaction are so different...

{{ Agreed

George William Herbert

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Jun 20, 2003, 9:15:49 PM6/20/03
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Greylock <vin...@hal-pc.org> wrote:
>> In summary:
>> There is no single formulation typically used for comparison
>> of explosive strengths.
>
>{{ Understandable. The best I can see in terms of trying to get a somewhat
>{{ (although flawed) comparison would be a look at the release of BTU per
>{{ unit time. Essentially integrating the area under the pressure curve.

That particular way of looking at it .. hmm. I think that
equates to something like heave, but not sure.

>> In rough terms... the energy released by combusting gasoline
>> is somewhat less per unit weight than methane or propane.
>> Methane and propane mixed with oxygen or air release in
>> rough order 10 times as much energy as TNT.
>
>{{ Is this on a per pound basis?}}

Yes. 1 lb of TNT releases about 4.2 million joules of
energy if detonated. 1 lb of propane mixed with 'enough'
air (enough to combust completely) releases 43 million
joules of energy. But, to be completely balanced,
you have to factor in the quantity of oxygen required
to burn that propane, which reduces it by a factor of
3-4 in overall mass efficiency.

But if you're looking at solid HE versus just the fuel
gas content in a fuel air explosion system, not the
overall mass including atmospheric oxygen, then it's
very close to 10:1 energy ratio by mass.

>>But in a very
>> diffuse reaction even if it efficiently detonates in the air;
>> the density of air, or an air-propane mixture, is about 1.25
>> kilograms per cubic meter, and the detonation pressure of
>> that air-propane mix will be a couple of hundred PSI or so
>> compared to millions of PSI for TNT.
>
>{{ Point taken, but it is my understanding that the peak pressure is much
>longer {{ and is no longer a "point source" (no more "dead zones" caused by
>{{ "shadows").

Yes, the peak pressure lasts longer with a air-fuel explosion.
How much longer... takes a lot of math explanation.

>{{ The explosive action is certainly different in character. But I gather it
>is {{ particularly damaging to structures and unprotected humans.

It's particularly bad to structures. Not useful against people
much at all.

Humans can withstand over 25, often up to 35 PSI of overpressure
before they are typically fatally injured by blast per se.

Really well built concrete buildings usually fall down at 10 PSI,
and typical houses disintegrate at 2-5 PSI.

Military explosives kill mostly by fragmentation, not blast.
A modern military hand grenade will throw out say a thousand
fragments (steel balls, notched wire fragments). These will
typically fly for 15 meters or so at high energy. At 1 meter
from the grenade, the spherical area is 4 pi m^2 (12.56 m^2 or so).
So that's about 80 fragments per square meter. If we assume
a human target has a 1 square meter cross section, they will
be hit by typically 80 fragments at a 1 meter distance.
At 5 meters, the number of fragments will be 1/5^2 or 1/25
as many per square meter, about 3 per square meter.
At a distance of 15 meters, that's 1/15^2 or about 0.35
fragments per square meter; about 1/2 to 1/3 of the people
at a distance of 15 meters would be expected to be hit and
wounded by a fragment.

Grossly simplifying overpressure as 1/R^2 in the below
analysis... which is not really true, but a reasonably
close curve match over the pressure range in question...

A fuel air explosion with an equivalent fuel mass to the
grenade's explosive mass ... say, 150 grams... is going to
occupy a gas cloud volume of oh, say 5% of the gas in the
volume is propane, so that's about 2.5 cubic meters, or a
sphere about 85 cm in diameter. At that radius the pressure
is about 200 PSI. At 1.7 meters away it's 100 PSI. At 3.4
meters away it's 25 PSI. At 6.8 meters away it's about 6 PSI.

So it's going to kill people within about 3-4 meters if it
detonates efficiently, but then will not wound them effectively
past 7 meters.


-george william herbert
gher...@retro.com

Boomer

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Jun 20, 2003, 9:42:41 PM6/20/03
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Some info here George from one of my old posts

Most of the mass destruction from an FAE comes from the excess pressure in
the shock wave front, which can get as high or higher than 30 kg / cm 2 in
the center of the cloud ( under detonation ). The temp in that zone can
reach as 3000C and develops in -100 micro sec.

The peak pressure from a standard FAE is quite low compared to HE, but its
time is longer. Its main advantage is it can go off in enclosed volumes
fortifications ), it follows terrain and has a very high impulse. The shock
can have an overpressure of over 1 kg / cm2 at distances greater than 100
meters. Its P/T curve is quite distinct, when compared to HE.


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"George William Herbert" <gher...@gw.retro.com> wrote in message

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:


Greylock

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Jun 22, 2003, 4:36:48 PM6/22/03
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Thanks for the contributions.

"JaM" <oute...@hotmail.com> wrote in message
news:3eef6e6b...@dtext.news.tele.dk...

michaelka...@gmail.com

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Feb 8, 2018, 6:07:33 AM2/8/18
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Try a bleve, that's what happened to me with only a few gallons of unleaded gas.

ezti...@gmail.com

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Jul 30, 2018, 5:08:31 PM7/30/18
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Thank you good info this is JAMES GORDON FREIBERG SO YOU KNOW WHO IS REAL. I SEE THat I am a bit off when I say gas exploder is about 7sticks of TNT thank you

program...@gmail.com

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May 4, 2020, 5:48:58 PM5/4/20
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On Tuesday, June 17, 2003 at 8:52:00 AM UTC-7, Greylock wrote:
> years ago i read that a V8 (1piston firing) I equal to 80 sticks ???
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