On Thu, 09 May 2013 12:08:01 -0500, -MIKE-
wrote:

On 5/9/13 12:03 PM, wrote:
On Wed, 08 May 2013 23:43:02 -0500, -MIKE-
wrote:

On 5/7/13 7:56 PM, Lew Hodgett wrote:
Lew Hodgett wrote:

Don't want to rain on your parade, but how big do you think those
pressure
cookers in Boston were/are?

BTW, a pressure relief valve is a must.

Even your hot water tank has one.
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"-MIKE-" wrote:

I hope you're joking.
There was a lot more than air in those things.
--------------------------------------------------------------
Lew Hodgett wrote:

Absolutely not kidding, shrapnel is shrapnel regardless of the
source.
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"-MIKE-" wrote:

That's kind of the point. There is no shrapnel when an air tank
"explodes."
-----------------------------------------------------------------
Lew Hodgett wrote:

What do you call the parts of the vessel that are created when
a vessel bursts?

Chopped liver?


Shrapnel: Fragments of a bomb, shell, or other object thrown out by an
explosion.
When an air tank fails from over pressure there is not enough energy to
create shrapnel.
Could a part come flying off, perhaps. But that is certainly a very
loose interpretation of the accepted definition when talking about true
explosions.


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"-MIKE-" wrote:

Why do I keep putting explodes in quotation marks? Because of the
very
misconception you have and others are having. The energy from a
bursting
air tank is no where near enough to cause shrapnel.

The energy caused by gun powder is many multitudes higher than an
air
tank. The velocity of the explosion is also many magnitudes higher.

Oh, and last time I looked at air compressors, non of the tanks were
packed with ball bearings, either. sheesh.
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Lew Hodgett wrote:

You seem to have difficulty understanding what is written.

I made no mention of gun powder, ball bearings or any other items of
IBS
(Intellectual Bull ****) you attempt to introduce to confuse the
issue.


Quit bull****ting and digging the hole deeper. We're talking air tanks
failing from over pressurization and you're the one who brought up the
marathon bombers' pressure cooker bombs. YOU are the one attempting to
confuse the issue by introducing a BOMB into a conversation about air
compressors.


My comment simply stated that the size of the vessel is totally
independent of it's ability to raise the havoc created if it were to
burst in an area where people were assembled.

What causes a vessel to exceed design specifications and fail
by bursting is a totally different discussion.

What remains relevant is that if a vessel bursts in an occupied area,
chances are pretty good that somebody is going to get hurt.

Nothing more, nothing less.

Lew


I can pop a balloon ("vessel burst") in an occupied area? Who gets hurt?

There has to be enough energy to create the shrapnel. Even without
shrapnel, there would have to be a enough energy released to create a
pressure wave for anyone to be injured seriously. How do you not get that?

An air compressor "vessel" "bursting" has a tiny fraction of the energy
of a bomb. Aren't you the engineer, here? How do you not see that?
Perhaps, but IF it fails catastrophically - like a brittle fracture
( and they DO happen very occaisionally) they ARE very dangerous.

A hydrogen embrittled 20 gallon tank, 1/8" thick, at 200 psi could do
greivous harm to anyone within 20 feet.or more if struck, by say, a
falling hammer or other flying debris.


But where is the evidence of this happening. I'm not talking about
damage or injury. I'm talking shrapnel, because that's what was brought
up early in this discussion.

I remember the mythbusters episode where they pumped up an air talk way
beyond normal operating pressure, having disabled the relief valve. They
proceeded to ram all kinds of stuff into it, even shooting it with a gun
and could not get it to "explode."
Years ago, when I was service manager at the Toyota dealership,
there was an article in one of the trade magazines - Canadian Service
Station Management or something like that, which showed the results of
an air compressor tank explosion. The tank had lap joints and the
welding process caused an HAZ (Heat affected zone) along that end cap
joint that met with the HAZ from where the mounting foot was welded on
and vibration from running with the legs on concrete floor without
rubber isolation fatiqued the joint. somebody dropped a wheel or
something that hit the tank and set it off. Severe damage to the
adjoining wall and injuries to people in the shop from flying bits.

Also, a small compressor manufacturer in Minnesota? back in the
sixties or seventies had several tank explosions that caused personal
injury when they let go, including one user with serious head and
facial injuries when the exploding tank fractured the drive pully and
flung it at the poor guy's head. Several hundred of those tanks
apparently failed with varying injuries reported..

In both cases, "shrapnel" was involved.

It is not common - but it IS the uncommon that is the most dangerous
since it is totally unexpected.