http://www.woodshopnews.com/news/fea...s-of-wood-dust

Nice article.

How OSHA currently judges with a paper clip.

"So is the sawdust in my facility a hazard? It depends, Scott says.
The really dangerous stuff is so-called “wood flour” — fine particles
500 microns or smaller."

It appears to be a very small chance.

However as far as I am concerned the breathing of the "wood flour" is
my concern, so I will be paying attention, to this for my sake.

Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.

On 2/23/2016 9:43 PM, OFWW wrote:
http://www.woodshopnews.com/news/fea...s-of-wood-dust

Nice article.

How OSHA currently judges with a paper clip.

"So is the sawdust in my facility a hazard? It depends, Scott says.
The really dangerous stuff is so-called €œwood flour€� €” fine particles
500 microns or smaller."

It appears to be a very small chance.

However as far as I am concerned the breathing of the "wood flour" is
my concern, so I will be paying attention, to this for my sake.

Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system. They
must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.

OFWW writes:
Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.

Setting steel wool on fire is an old boy scout trick for starting camp
fires, since two D cells are sufficient, and flashlights often had D
cells in them.

Mythbusters did a test with coffee creamer and a flare. The creamer
wouldn't catch fire until it was blown (as in with wind) into the air.
When it got to the right mix it nearly exploded. Wood flour (and even
wheat flour) is the same thing; as a pile on the ground it's safe but as
a cloud in the air it's highly flammable.

DJ Delorie wrote in :


OFWW writes:
Steel wool catches fire easily, just so as you are aware of it. I
like to bet that I can set steel on fire. Haven't lost yet.

Setting steel wool on fire is an old boy scout trick for starting camp
fires, since two D cells are sufficient, and flashlights often had D
cells in them.

Mythbusters did a test with coffee creamer and a flare. The creamer
wouldn't catch fire until it was blown (as in with wind) into the air.
When it got to the right mix it nearly exploded. Wood flour (and even
wheat flour) is the same thing; as a pile on the ground it's safe but
as a cloud in the air it's highly flammable.


It makes an awesome looking fireball, too. We've been tempted to try it
at home. Way better than sitting in some overcrowded park watching
people set off fireworks.

I've got the air tank, know my way around the hardware store to find the
misc plumbing bits, and the only thing temporarily missing is the flame
source. Propane would probably be a bad idea...

For all you safety Nazis out there, I'm not going to try this at home.
I'm going to go over to the neighbor's house and do it there!

Puckdropper

On 2/23/16 9:30 PM, DJ Delorie wrote:

OFWW writes:
Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.

Setting steel wool on fire is an old boy scout trick for starting camp
fires, since two D cells are sufficient, and flashlights often had D
cells in them.

Mythbusters did a test with coffee creamer and a flare. The creamer
wouldn't catch fire until it was blown (as in with wind) into the air.
When it got to the right mix it nearly exploded. Wood flour (and even
wheat flour) is the same thing; as a pile on the ground it's safe but as
a cloud in the air it's highly flammable.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his shop.
Lord know, I wouldn't want to see any of his work if he's that reckless.

I can't even imagine a normal woodworking scenario in which that high a
concentration of wood dust could occur.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 2/23/16 9:24 PM, Keith Nuttle wrote:
On 2/23/2016 9:43 PM, OFWW wrote:
http://www.woodshopnews.com/news/fea...s-of-wood-dust



Nice article.

How OSHA currently judges with a paper clip.

"So is the sawdust in my facility a hazard? It depends, Scott
says. The really dangerous stuff is so-called €œwood flour€� €” fine
particles 500 microns or smaller."

It appears to be a very small chance.

However as far as I am concerned the breathing of the "wood flour"
is my concern, so I will be paying attention, to this for my sake.

Steel wool catches fire easily, just so as you are aware of it. I
like to bet that I can set steel on fire. Haven't lost yet.


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system.
They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.

And again, I have yet to see or hear of a credible documented case of a
dust collector pipe explosion from static charge. I'm still waiting.
It's the Loc Ness Monster of woodworking folklore. :-)


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

-MIKE- writes:
I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

The linked report had a suspect cause: wood flour collected in hidden
spaces, something else went FOOM (like a small contained bit of wood
flour) and that blew all the other wood flour up into the air in a
contained space, starting a chain reaction.

Granted, this is rare in a home shop, but the focus of the report was a
commercial building that actually exploded, so it's not *impossible*.

Keith Nuttle wrote in
:


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system.
They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it. It's not
for safety per se, but just to keep you from getting an annoying shock.
One of the normal human reactions when you get a shock is to move rapidly
away from it, which could cause you to hit something.

I had to ground the discharge chute (a piece of downspout extender) on my
planer because of the annoying shocks. That's the only reason I bothered.

Puckdropper

On 2/24/16 12:03 AM, DJ Delorie wrote:

-MIKE- writes:
I can't even imagine a normal woodworking scenario in which that
high a concentration of wood dust could occur.

The linked report had a suspect cause: wood flour collected in
hidden spaces, something else went FOOM (like a small contained bit
of wood flour) and that blew all the other wood flour up into the air
in a contained space, starting a chain reaction.

Granted, this is rare in a home shop, but the focus of the report was
a commercial building that actually exploded, so it's not
*impossible*.


Right. But there's a boatload of things that aren't *impossible* about
over I'm not about to lose any sleep. The perfect storm can always
occur when the odds are stretched far enough. The fact that something
happened once, or even twice does not justify rampant paranoia about it.

Of course, I forget I'm living in the age of the tinfoil hat society
where a good portion of society thinks we're hiding aliens at area 51
and the moon landing was filmed on a Hollywood sound stage.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 2/24/16 12:07 AM, Puckdropper wrote:
Keith Nuttle wrote in
:


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system.
They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it. It's not
for safety per se, but just to keep you from getting an annoying shock.
One of the normal human reactions when you get a shock is to move rapidly
away from it, which could cause you to hit something.

I had to ground the discharge chute (a piece of downspout extender) on my
planer because of the annoying shocks. That's the only reason I bothered.

Puckdropper


Thank you, voice of common sense.
I believe that's the *actual* reason for grounding a dust collector
system. Unfortunately it seemingly got hijacked by the oak rust society
and now the common but false believe is that's it's done to prevent
"explosions."

Another reason to use metal ducting.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Wed, 24 Feb 2016 00:15:55 -0600, -MIKE-
wrote:

On 2/24/16 12:07 AM, Puckdropper wrote:
Keith Nuttle wrote in
:


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system.
They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it. It's not
for safety per se, but just to keep you from getting an annoying shock.
One of the normal human reactions when you get a shock is to move rapidly
away from it, which could cause you to hit something.

I had to ground the discharge chute (a piece of downspout extender) on my
planer because of the annoying shocks. That's the only reason I bothered.

Puckdropper


Thank you, voice of common sense.
I believe that's the *actual* reason for grounding a dust collector
system. Unfortunately it seemingly got hijacked by the oak rust society
and now the common but false believe is that's it's done to prevent
"explosions."

Another reason to use metal ducting.

BOY HOWDY!

On 24 Feb 2016 05:45:27 GMT, Puckdropper
puckdropper(at)yahoo(dot)com wrote:

DJ Delorie wrote in :


OFWW writes:
Steel wool catches fire easily, just so as you are aware of it. I
like to bet that I can set steel on fire. Haven't lost yet.

Setting steel wool on fire is an old boy scout trick for starting camp
fires, since two D cells are sufficient, and flashlights often had D
cells in them.

Mythbusters did a test with coffee creamer and a flare. The creamer
wouldn't catch fire until it was blown (as in with wind) into the air.
When it got to the right mix it nearly exploded. Wood flour (and even
wheat flour) is the same thing; as a pile on the ground it's safe but
as a cloud in the air it's highly flammable.


It makes an awesome looking fireball, too. We've been tempted to try it
at home. Way better than sitting in some overcrowded park watching
people set off fireworks.

I've got the air tank, know my way around the hardware store to find the
misc plumbing bits, and the only thing temporarily missing is the flame
source. Propane would probably be a bad idea...

For all you safety Nazis out there, I'm not going to try this at home.
I'm going to go over to the neighbor's house and do it there!

Puckdropper

ROTFLOL!

On Tue, 23 Feb 2016 23:49:12 -0600, -MIKE-
wrote:

On 2/23/16 9:30 PM, DJ Delorie wrote:

OFWW writes:
Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.

Setting steel wool on fire is an old boy scout trick for starting camp
fires, since two D cells are sufficient, and flashlights often had D
cells in them.

Mythbusters did a test with coffee creamer and a flare. The creamer
wouldn't catch fire until it was blown (as in with wind) into the air.
When it got to the right mix it nearly exploded. Wood flour (and even
wheat flour) is the same thing; as a pile on the ground it's safe but as
a cloud in the air it's highly flammable.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his shop.
Lord know, I wouldn't want to see any of his work if he's that reckless.

I can't even imagine a normal woodworking scenario in which that high a
concentration of wood dust could occur.

Well Mike, when you used the magic word imagine, I did.

In a vacuum strange things happen, given a spark, and a whoosh of dust
already suspended in the pipe (your cloud) and I can see things happen
that wouldn't happen in a positive pressurized pipe.

Yet the bottom line is all the home and small shops around and no real
stories other than health hazards. If there were fires then the
insurance industry would be all over it in a minute, raising prices as
if you had a bad dawg in the back yard.

On Wed, 24 Feb 2016 00:12:34 -0600, -MIKE-
wrote:

On 2/24/16 12:03 AM, DJ Delorie wrote:

-MIKE- writes:
I can't even imagine a normal woodworking scenario in which that
high a concentration of wood dust could occur.

The linked report had a suspect cause: wood flour collected in
hidden spaces, something else went FOOM (like a small contained bit
of wood flour) and that blew all the other wood flour up into the air
in a contained space, starting a chain reaction.

Granted, this is rare in a home shop, but the focus of the report was
a commercial building that actually exploded, so it's not
*impossible*.


Right. But there's a boatload of things that aren't *impossible* about
over I'm not about to lose any sleep. The perfect storm can always
occur when the odds are stretched far enough. The fact that something
happened once, or even twice does not justify rampant paranoia about it.

Of course, I forget I'm living in the age of the tinfoil hat society
where a good portion of society thinks we're hiding aliens at area 51
and the moon landing was filmed on a Hollywood sound stage.

You've got it wrong, the aliens are holding us hostage at area 51.
That is why our taxes are so high.

On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

..


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.

On 2/23/2016 11:45 PM, Puckdropper wrote:
DJ Delorie wrote in :


OFWW writes:
Steel wool catches fire easily, just so as you are aware of it. I
like to bet that I can set steel on fire. Haven't lost yet.

Setting steel wool on fire is an old boy scout trick for starting camp
fires, since two D cells are sufficient, and flashlights often had D
cells in them.

Mythbusters did a test with coffee creamer and a flare. The creamer
wouldn't catch fire until it was blown (as in with wind) into the air.
When it got to the right mix it nearly exploded. Wood flour (and even
wheat flour) is the same thing; as a pile on the ground it's safe but
as a cloud in the air it's highly flammable.


It makes an awesome looking fireball, too. We've been tempted to try it
at home. Way better than sitting in some overcrowded park watching
people set off fireworks.

You think? ;~)

On 02/24/2016 12:03 AM, DJ Delorie wrote:
....

The linked report had a suspect cause: wood flour collected in hidden
spaces, something else went FOOM ...

But what caused the FOOM (that is, what was the ignition source)???

--

On 02/24/2016 1:38 AM, OFWW wrote:
....

In a vacuum strange things happen, given a spark, and a whoosh of dust
already suspended in the pipe (your cloud) and I can see things happen
that wouldn't happen in a positive pressurized pipe.

If it were a vacuum, there'd be no oxygen, hence no combustion.

Even in the highest CFM DC systems the air pressure is only a minimal
amount below atmospheric pressure; yes it's a big "vacuum" cleaner, but
there's really not a lot of vacuum, it's just slightly lower pressure
air moving at a pretty high velocity. Hence, there's not going to be
any strange things happening owing to anything other than that there is
a concentration of dust created and given a large enough ignition
source, one could potentially cause a boom. But, static electricity
from PVC for at least home-shop-sized duct work simply doesn't have
sufficient energy to do so. Metal hitting an iron impeller, _maybe_,
but still unlikely. More likely would be an overheated bearing or
another open ignition source like a steaming tube or the like that gets
away but getting it into the necessary location is the trick there...

--

On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 2/24/2016 11:52 AM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)




You are more likely to cut yourself on a TS if you don't own a SS. ;~)

On 2/24/2016 12:52 PM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


There is a difference between worrying about the probabilities of
accident, and taking steps to avoid a potential for an accident. You
do not spend a lot of money installing things to prevent an 1 in a
million probability of accident. However you don't ignore the
possibility that it can happen. Sort of like walk under a ladder, the
probability of something falling off of the ladder is remote, it is just
good practice not to get in the habit of doing it.

There are other places where this applies. You buy home owners insurance
even though there is a small probability that your house will be damaged
or broken into. You make sure there are not children in the area where
you are mowing even thought the probability you will hit something that
will fly our and hit a child. Most people modify there behavior or
make purchases based on low probability events.

On 2/24/2016 12:34 PM, Keith Nuttle wrote:
On 2/24/2016 12:52 PM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


There is a difference between worrying about the probabilities of
accident, and taking steps to avoid a potential for an accident. You
do not spend a lot of money installing things to prevent an 1 in a
million probability of accident. However you don't ignore the
possibility that it can happen. Sort of like walk under a ladder, the
probability of something falling off of the ladder is remote, it is just
good practice not to get in the habit of doing it.

There are other places where this applies. You buy home owners insurance
even though there is a small probability that your house will be damaged
or broken into. You make sure there are not children in the area where
you are mowing even thought the probability you will hit something that
will fly our and hit a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.

On 2/24/16 12:34 PM, Keith Nuttle wrote:
On 2/24/2016 12:52 PM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


There is a difference between worrying about the probabilities of
accident, and taking steps to avoid a potential for an accident. You
do not spend a lot of money installing things to prevent an 1 in a
million probability of accident. However you don't ignore the
possibility that it can happen. Sort of like walk under a ladder, the
probability of something falling off of the ladder is remote, it is just
good practice not to get in the habit of doing it.

There are other places where this applies. You buy home owners insurance
even though there is a small probability that your house will be damaged
or broken into. You make sure there are not children in the area where
you are mowing even thought the probability you will hit something that
will fly our and hit a child. Most people modify there behavior or
make purchases based on low probability events.

Everything you mentioned is covered by insurance because the probability
or likelihood of them happening is actually fairly high, in the context
of this conversation.

When's the last time you saw insurance companies offering personal
lightning/meteor strike policies. Heck, I should do that. It would
the most lucrative profitable business ever.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 2/24/16 1:06 PM, Leon wrote:
On 2/24/2016 12:34 PM, Keith Nuttle wrote:
On 2/24/2016 12:52 PM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every
day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


There is a difference between worrying about the probabilities of
accident, and taking steps to avoid a potential for an accident. You
do not spend a lot of money installing things to prevent an 1 in a
million probability of accident. However you don't ignore the
possibility that it can happen. Sort of like walk under a ladder, the
probability of something falling off of the ladder is remote, it is just
good practice not to get in the habit of doing it.

There are other places where this applies. You buy home owners insurance
even though there is a small probability that your house will be damaged
or broken into. You make sure there are not children in the area where
you are mowing even thought the probability you will hit something that
will fly our and hit a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.


I ground my dust collector duct-work to fend off the mind control rays
from outer-space.
It also helps disperse those pesky chemtrails the gummint is using to
make me more subservient.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 2/24/2016 1:28 PM, -MIKE- wrote:
On 2/24/16 1:06 PM, Leon wrote:
On 2/24/2016 12:34 PM, Keith Nuttle wrote:
On 2/24/2016 12:52 PM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every
day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


There is a difference between worrying about the probabilities of
accident, and taking steps to avoid a potential for an accident. You
do not spend a lot of money installing things to prevent an 1 in a
million probability of accident. However you don't ignore the
possibility that it can happen. Sort of like walk under a ladder, the
probability of something falling off of the ladder is remote, it is just
good practice not to get in the habit of doing it.

There are other places where this applies. You buy home owners insurance
even though there is a small probability that your house will be damaged
or broken into. You make sure there are not children in the area where
you are mowing even thought the probability you will hit something that
will fly our and hit a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.


I ground my dust collector duct-work to fend off the mind control rays
from outer-space.
It also helps disperse those pesky chemtrails the gummint is using to
make me more subservient.


I simply don't worry about it. There are numerous other things in the
shop that make sparks and on a continuous basis. Like "any" electric
tool or machine that has a universal motor. Yes damn near any hand held
power tool. ;~)

On 2/24/2016 3:02 PM, Leon wrote:
On 2/24/2016 1:28 PM, -MIKE- wrote:
On 2/24/16 1:06 PM, Leon wrote:
a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.


I ground my dust collector duct-work to fend off the mind control rays
from outer-space.
It also helps disperse those pesky chemtrails the gummint is using to
make me more subservient.


I simply don't worry about it. There are numerous other things in the
shop that make sparks and on a continuous basis. Like "any" electric
tool or machine that has a universal motor. Yes damn near any hand held
power tool. ;~)
You have worried about the excessive collection of dust in your shop,
and ALL of the problems that it may cause. You have installed a dust
collector so the dust is controlled and diverted to safe areas.

On 24 Feb 2016 06:07:39 GMT, Puckdropper
puckdropper(at)yahoo(dot)com wrote:

Keith Nuttle wrote in
:


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system.
They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it. It's not
for safety per se, but just to keep you from getting an annoying shock.
One of the normal human reactions when you get a shock is to move rapidly
away from it, which could cause you to hit something.

OK, ground the equipment (it should be anyway) but the plastic pipe
between them? Really?! The only thing I see the ground wire
accomplishing is to plug the thing up.

I had to ground the discharge chute (a piece of downspout extender) on my
planer because of the annoying shocks. That's the only reason I bothered.

On 2/24/16 3:53 PM, krw wrote:
On 24 Feb 2016 06:07:39 GMT, Puckdropper
puckdropper(at)yahoo(dot)com wrote:

Keith Nuttle wrote in
:


I hope every one also noted the comments about the static electricity
that can build up in plastic pipes in your dust collection system.
They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other organic
material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it. It's not
for safety per se, but just to keep you from getting an annoying shock.
One of the normal human reactions when you get a shock is to move rapidly
away from it, which could cause you to hit something.

OK, ground the equipment (it should be anyway) but the plastic pipe
between them? Really?! The only thing I see the ground wire
accomplishing is to plug the thing up.


The one's I've seen grounded (to prevent uncomfortable static shocks,
not "explosions") were grounded by a wire on the outside of the plastic
pipe, not inside.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On Wed, 24 Feb 2016 13:06:45 -0600, Leon lcb11211@swbelldotnet
wrote:

On 2/24/2016 12:34 PM, Keith Nuttle wrote:
On 2/24/2016 12:52 PM, -MIKE- wrote:
On 2/24/16 7:45 AM, Keith Nuttle wrote:
On 2/24/2016 12:49 AM, -MIKE- wrote:
On 2/23/16 9:30 PM, DJ Delorie wrote:

.


Broken record: the concentration would have to be so high that you
couldn't see across the room, let alone breathe.

I think Darwinism would do us all a favor and explode the shop of any
woodworker who would let that kind of "cloud" be produced is his
shop. Lord know, I wouldn't want to see any of his work if he's that
reckless.

I can't even imagine a normal woodworking scenario in which that high
a concentration of wood dust could occur.

Broken record or not. There is a very low probability of people being
stuck by lightning, but they are. There is a very low probability of
people being struck by a meteorite but there is a recent story in the
news about that happening.

There is a very low probability of a person being killed by a falling
tree, but there are people who are cutting down their trees every day so
they do not fall on them and kill them.

Low probability means exactly that, it can happen but infrequently.

Remember Murphy's law. Why tempt Murphy.


The point is, there's a low probability in everything. If you want to
worry about everything that is technically "possible" happening to you,
go for it. Enjoy that life.

That's the kind of severely flawed logic that inhabits the brains of
people who will never fly on an airplane but have no problem driving on
the interstate, even though the chances of injury or death are almost
unbelievably, exponentially higher when driving a car.

If people want to live in fear of everything that "might" or "could"
happen to them, well... let's just say they make lots of pills for that
condition. :-)


There is a difference between worrying about the probabilities of
accident, and taking steps to avoid a potential for an accident. You
do not spend a lot of money installing things to prevent an 1 in a
million probability of accident. However you don't ignore the
possibility that it can happen. Sort of like walk under a ladder, the
probability of something falling off of the ladder is remote, it is just
good practice not to get in the habit of doing it.

There are other places where this applies. You buy home owners insurance
even though there is a small probability that your house will be damaged
or broken into. You make sure there are not children in the area where
you are mowing even thought the probability you will hit something that
will fly our and hit a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.


Remember an accident is a chain of unlikely events aligning. Now if
and when someone has a dust explosion from saw dust, the cause will
not be static. The water heater, furnace or other open flame in the
room yep that would do it. But what did "you" do to suspend that much
dust in the air? Sugar on the other hand burns great and fast,
powdered is best (do not try in a confined space).

Mark

-MIKE- wrote in :

On 2/24/16 3:53 PM, krw wrote:
On 24 Feb 2016 06:07:39 GMT, Puckdropper
puckdropper(at)yahoo(dot)com wrote:

Keith Nuttle wrote in
:


I hope every one also noted the comments about the static
electricity that can build up in plastic pipes in your dust
collection system. They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other
organic material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it.
It's not for safety per se, but just to keep you from getting an
annoying shock. One of the normal human reactions when you get a
shock is to move rapidly away from it, which could cause you to hit
something.

OK, ground the equipment (it should be anyway) but the plastic pipe
between them? Really?! The only thing I see the ground wire
accomplishing is to plug the thing up.


The one's I've seen grounded (to prevent uncomfortable static shocks,
not "explosions") were grounded by a wire on the outside of the
plastic pipe, not inside.


Right, that's how I did mine. I just wrapped a wire around the outside
of the pipe and that pretty much solved the problem.

Puckdropper

On 2/24/16 4:34 PM, Puckdropper wrote:
-MIKE- wrote in :

On 2/24/16 3:53 PM, krw wrote:
On 24 Feb 2016 06:07:39 GMT, Puckdropper
puckdropper(at)yahoo(dot)com wrote:

Keith Nuttle wrote in
:


I hope every one also noted the comments about the static
electricity that can build up in plastic pipes in your dust
collection system. They must be grounded to dissipate this charge.

Also while the article is about wood dust, the dust of other
organic material can be equally explosive.

Bottom line keep things clean and avoid excessive dust.


If you notice static from your DC system, by all means ground it.
It's not for safety per se, but just to keep you from getting an
annoying shock. One of the normal human reactions when you get a
shock is to move rapidly away from it, which could cause you to hit
something.

OK, ground the equipment (it should be anyway) but the plastic pipe
between them? Really?! The only thing I see the ground wire
accomplishing is to plug the thing up.


The one's I've seen grounded (to prevent uncomfortable static shocks,
not "explosions") were grounded by a wire on the outside of the
plastic pipe, not inside.


Right, that's how I did mine. I just wrapped a wire around the outside
of the pipe and that pretty much solved the problem.

Puckdropper


AND it blocks the mind control rays.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 2/23/2016 11:45 PM, Puckdropper wrote:

It makes an awesome looking fireball, too. We've been tempted to try it
at home. Way better than sitting in some overcrowded park watching
people set off fireworks.

Good there was no Tannerite around when I was a kid. All that would be
left of that small part of Louisiana would be a sink hole.

Did enough damage with Black Cat fire crackers and cherry bombs. In the
Corps at A&M as a Fish (Aggie freshman in the Corps), been known to
have"Bab-O Bombed" an upper class-man's dorm room, whilst he slept in
the wee hours of the AM, right before a very important white glove
inspection. EG

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://www.google.com/+eWoodShop
https://plus.google.com/+KarlCaillouet/posts
http://www.custommade.com/by/ewoodshop/
KarlCaillouet@ (the obvious)

-MIKE- wrote in :


AND it blocks the mind control rays.


Are they the ones that cause you not to end a sentence with a punctuation
mark?

Puckdropper

"OFWW" wrote in message
...
http://www.woodshopnews.com/news/fea...s-of-wood-dust

Nice article.

How OSHA currently judges with a paper clip.

"So is the sawdust in my facility a hazard? It depends, Scott says.
The really dangerous stuff is so-called "wood flour" - fine particles
500 microns or smaller."

It appears to be a very small chance.

However as far as I am concerned the breathing of the "wood flour" is
my concern, so I will be paying attention, to this for my sake.

Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.

When I was an 8th grader, a buddy of mine and I were hired by the local
CO-OP to broom out the corn dust in the head houses of the grain elevators
in my home town. They wanted it done because they feared a buildup of the
dust might cause an explosion given the right conditions. We liked the job
because no one came to look in on us because it was such a dirty job: after
about five minutes of pushing brooms the headhouses would have so much
powder in the air you couldn't see across the room. We also liked it
because we could stand outside the headhouse and smoke cigarettes without
fear of being caught.
An additional elevator was built when I was a sophomore. It was about 60
feet taller than the old one so the design was to build a 24" diameter auger
up to the head house on the new structure from the old one. One Saturday
after the new elevator had been slipped and had been cured enough to drill
concrete anchors into it, the engineers came up to the top of the old
elevator where we had started cleaning. Of course we were smoking. It was
cold outside so we were inside. They got off the man lift just as my buddy
took a deep drag on his cig. They saw the glowing coals through the corn
dust cloud and nearly trampled each other getting the hell back on the man
lift to escape what they were sure to be a huge explosion.
They apparently didn't squeal on us. But a few minutes later the elevator
operator came up and said to stay up there until the dust cleared then come
down.

When I was a Junior I told the story to my science teacher. Without
profanity he called my buddy and I a couple of dumb asses and then explained
spontaneous combustion. For the class he made an example. He took a 2
pound coffee can. He drilled a hole on the side near the bottom where he
attached a length of tubing. He put a votive candle inside near the center
of the bottom. Then he poured a ring of cornstarch around the candle. He lit
the candle and put a lid on the can. He blew a short puff of air in the
tube. The ball of fire was big enough to scorch the ceiling tiles!

Stupid is as stupid does.

Steve

On 02/24/2016 6:30 PM, SnA Higgins wrote:
....

When I was a Junior I told the story to my science teacher. Without
profanity he called my buddy and I a couple of dumb asses and then explained
spontaneous combustion. For the class he made an example. He took a 2
pound coffee can. He drilled a hole on the side near the bottom where he
attached a length of tubing. He put a votive candle inside near the center
of the bottom. Then he poured a ring of cornstarch around the candle. He lit
the candle and put a lid on the can. He blew a short puff of air in the
tube. The ball of fire was big enough to scorch the ceiling tiles!
....

But not spontaneous combustion...that is like the haystack that catches
itself on fire from internal heat buildup from decomposition owing to
having been too damp when put up.

Explosive combustion such as you're describing requires an external
ignition source; here the candle; possibly your cigarette butt in the
story.

Is fortunate you didn't have a "boom!" moment, indeed. Perhaps were
lucky in there being sufficient "dirt dirt" in the mixture besides the
grain dust so that had a high aerial concentration but much of it wasn't
that combustible, who knows...or maybe it "just wasn't your time" yet.

--

On 2/24/2016 2:26 PM, Keith Nuttle wrote:
On 2/24/2016 3:02 PM, Leon wrote:
On 2/24/2016 1:28 PM, -MIKE- wrote:
On 2/24/16 1:06 PM, Leon wrote:
a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.


I ground my dust collector duct-work to fend off the mind control rays
from outer-space.
It also helps disperse those pesky chemtrails the gummint is using to
make me more subservient.


I simply don't worry about it. There are numerous other things in the
shop that make sparks and on a continuous basis. Like "any" electric
tool or machine that has a universal motor. Yes damn near any hand held
power tool. ;~)
You have worried about the excessive collection of dust in your shop,
and ALL of the problems that it may cause. You have installed a dust
collector so the dust is controlled and diverted to safe areas.


No I have not worried about excessive dust in the shop. I once buried
my choc Lab under a pile on the out feed side of the planer. She was
not worried either. ;~)

I got a dust collector because I got sick and tired of cleaning up and
tracking dust into the house. I absolutely did not worry about any
dangers other than breathing in that stuff. And again FWIW I was
commenting about a spark creating an explosion not excessive dust or any
other problems that it caused other than a mess.

On 2/24/2016 6:30 PM, SnA Higgins wrote:
"OFWW" wrote in message
...
http://www.woodshopnews.com/news/fea...s-of-wood-dust

Nice article.

How OSHA currently judges with a paper clip.

"So is the sawdust in my facility a hazard? It depends, Scott says.
The really dangerous stuff is so-called "wood flour" - fine particles
500 microns or smaller."

It appears to be a very small chance.

However as far as I am concerned the breathing of the "wood flour" is
my concern, so I will be paying attention, to this for my sake.

Steel wool catches fire easily, just so as you are aware of it. I like
to bet that I can set steel on fire. Haven't lost yet.

When I was an 8th grader, a buddy of mine and I were hired by the local
CO-OP to broom out the corn dust in the head houses of the grain elevators
in my home town. They wanted it done because they feared a buildup of the
dust might cause an explosion given the right conditions. We liked the job
because no one came to look in on us because it was such a dirty job: after
about five minutes of pushing brooms the headhouses would have so much
powder in the air you couldn't see across the room. We also liked it
because we could stand outside the headhouse and smoke cigarettes without
fear of being caught.
An additional elevator was built when I was a sophomore. It was about 60
feet taller than the old one so the design was to build a 24" diameter auger
up to the head house on the new structure from the old one. One Saturday
after the new elevator had been slipped and had been cured enough to drill
concrete anchors into it, the engineers came up to the top of the old
elevator where we had started cleaning. Of course we were smoking. It was
cold outside so we were inside. They got off the man lift just as my buddy
took a deep drag on his cig. They saw the glowing coals through the corn
dust cloud and nearly trampled each other getting the hell back on the man
lift to escape what they were sure to be a huge explosion.
They apparently didn't squeal on us. But a few minutes later the elevator
operator came up and said to stay up there until the dust cleared then come
down.

When I was a Junior I told the story to my science teacher. Without
profanity he called my buddy and I a couple of dumb asses and then explained
spontaneous combustion. For the class he made an example. He took a 2
pound coffee can. He drilled a hole on the side near the bottom where he
attached a length of tubing. He put a votive candle inside near the center
of the bottom. Then he poured a ring of cornstarch around the candle. He lit
the candle and put a lid on the can. He blew a short puff of air in the
tube. The ball of fire was big enough to scorch the ceiling tiles!

Stupid is as stupid does.

Steve


Are you a ghost? ;~)

On Wed, 24 Feb 2016 00:12:34 -0600, -MIKE-
wrote:

On 2/24/16 12:03 AM, DJ Delorie wrote:

-MIKE- writes:
I can't even imagine a normal woodworking scenario in which that
high a concentration of wood dust could occur.

The linked report had a suspect cause: wood flour collected in
hidden spaces, something else went FOOM (like a small contained bit
of wood flour) and that blew all the other wood flour up into the air
in a contained space, starting a chain reaction.

Granted, this is rare in a home shop, but the focus of the report was
a commercial building that actually exploded, so it's not
*impossible*.


Right. But there's a boatload of things that aren't *impossible* about
over I'm not about to lose any sleep. The perfect storm can always
occur when the odds are stretched far enough. The fact that something
happened once, or even twice does not justify rampant paranoia about it.

Of course, I forget I'm living in the age of the tinfoil hat society
where a good portion of society thinks we're hiding aliens at area 51
and the moon landing was filmed on a Hollywood sound stage.

Come on! No one really believes it was shot on a sound stage.
Regardless of films like "Star Wars", everyone knows there's no sound
in space.

On Wed, 24 Feb 2016 15:26:31 -0500, Keith Nuttle
wrote:

On 2/24/2016 3:02 PM, Leon wrote:
On 2/24/2016 1:28 PM, -MIKE- wrote:
On 2/24/16 1:06 PM, Leon wrote:
a child. Most people modify there behavior or
make purchases based on low probability events.

And yet there are really no reasonable steps to take to keep saw dust
from exploding because of static electricity in your DC, which is what
this thread is about.


I ground my dust collector duct-work to fend off the mind control rays
from outer-space.
It also helps disperse those pesky chemtrails the gummint is using to
make me more subservient.


I simply don't worry about it. There are numerous other things in the
shop that make sparks and on a continuous basis. Like "any" electric
tool or machine that has a universal motor. Yes damn near any hand held
power tool. ;~)
You have worried about the excessive collection of dust in your shop,
and ALL of the problems that it may cause. You have installed a dust
collector so the dust is controlled and diverted to safe areas.

Right. A safe area is anywhere that's not in my lungs. Other than
that, a DC is a convenience.

On Wed, 24 Feb 2016 10:04:59 -0600, dpb wrote:

On 02/24/2016 1:38 AM, OFWW wrote:
...

In a vacuum strange things happen, given a spark, and a whoosh of dust
already suspended in the pipe (your cloud) and I can see things happen
that wouldn't happen in a positive pressurized pipe.

If it were a vacuum, there'd be no oxygen, hence no combustion.


At sea level the air pressure is 15PSI. Every 2" of vacuum is
equivalent to a 1 PSI drop in pressure. So at what point do you
consider a vacuum a vacuum? And how does a gasoline engine operate
when its intake manifold is in a vacuum if there was no oxygen?
IOW's how many inches of vacuum required before all oxygen is boiled
off, and that includes the oxygen from moisture.

Even in the highest CFM DC systems the air pressure is only a minimal
amount below atmospheric pressure; yes it's a big "vacuum" cleaner, but
there's really not a lot of vacuum, it's just slightly lower pressure
air moving at a pretty high velocity. Hence, there's not going to be
any strange things happening owing to anything other than that there is
a concentration of dust created and given a large enough ignition
source, one could potentially cause a boom. But, static electricity
from PVC for at least home-shop-sized duct work simply doesn't have
sufficient energy to do so. Metal hitting an iron impeller, _maybe_,
but still unlikely. More likely would be an overheated bearing or
another open ignition source like a steaming tube or the like that gets
away but getting it into the necessary location is the trick there...

An overheated bearing would have to be above 425 degF as I recall to
burn wood. A spark is a different animal. A spark hitting a muffler
packed with steel wool sets it on fire which sets the sawdust on fire
and minor implosion in a vacuum system, and hey! It was my imagination
so don't be a party pooper, K?