All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj

Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj
Hi,
No fan to draw the hot air into the room? All my FPs are direct vent gas
ones with thermostat controlled fans. No glass front ever cracked or
shattered in their use for more than 10 years.

Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj

Instead of temperature, it could have taken a sharp hit from an
exploding ember. It's not unusual to find nails in wood. Also it
could have been in a strain from a slightly warped frame.

"Chris Jarshant" wrote in message
. ..
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj

Not sure if you're fire got too hot or not but I would think the glass would
trap a lot of the heat with little escaping to the outside. If you have a
choice, you might consider replacing them with a screen.....it'll allow more
heat to pass as well. I can get my fire going pretty hot (never measured
it but I would think it's above 550 degrees easily). On the install, it's
hard to say what you've got. Fireplace clearances and dimensions are
pretty specific but for the pre-built units, I'm not sure what they are. I
do know that for a built fireplace, you need 8-8.5" behind the firebox of
nothing but masonry or air (I see different opinions on whether it's 8 or
8.5" and whether or not to leave an air space), the mantle should be 12" in.
minimum above the opening, and wood members shouldn't come within I think 2"
of the fireplace masonry but you really should check that. I'm building a
fireplace now outdoors and have no combustibles near it at all so I really
haven't paid much attention to the clearances required. If you do decide
to build your own, I believe a footing of 12" thick that extends 6" beyond
the footprint of the fireplace is necessary. It may not make sense for you
if you're in a slab floored house as you may have to cut out an opening in
your floor to pour a footing that thick.
Cheers,
cc

Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

I wouldn't worry about it.

Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

Call any glass shop and they will tell you this.

BTW, I'm sure there is a scientific reason for it but a glassman isn't
a scientist : )

Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj

This doesn't answer your question, but about three years ago I bought a
glass and screen doored one for out firplace from Home Cheepo. While
installing it I was suprised to see the instruction sheet warned against
closing the glass doors while a fire was burning inside.

I thought this was strange, since the box it had just come out of had a
nice color picture on it showing a fire merrily burning behind the
closed glass doors.

I went to the manufacturer's web site and found similar photos, so I
hooked an email to them asking why the instructions said not to do that.

I got a wishy washy answer from them saying that it was ok to close the
doors on a fire "most of the time", but that an extra hot fire could
possibly cause the glass to shatter.

WTF? We've gone ahead and closed the doors on plenty of fires in that
fireplace since then and the glass is still OK.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

No I haven't. I haven't even heard of window glass blowing up in a car for
no reason at all.

I think you are mistaken.

On Sun, 05 Feb 2006 01:59:04 GMT, Chris Jarshant
wrote:

All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj


I'd contact the company and complain. If it made for heat, it should
not explode. Besides someome could get hurt and they would have a
legal case. Even if they dont do anything they at least know, but
likely they will give you a free door. Who knows, there may even be a
recall. All it takes is a phone call, email or letter.

The old wood stoves used mica, that never broke.

I should note that you could have had the wood too close to the doors,
The fire should be to the rear.

I agree with the guy that said you are losing heat with glass in
front, a screen is better. No sense wasting the heat with fuel prices
what they are.

Of course there is one other possibility.....
Did you notice a guy wearing a turbin near your house?
Could be terrorists lol

On 4 Feb 2006 20:10:49 -0800, "Ron" wrote:


Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

I wouldn't worry about it.

Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

I'm sure there is a reason, you just don't know what it is. [g]

I had the pane of a sliding glass door spontaneously self-destruct
"for no reason." We were sitting right there when it started. My
wife first though the PITA neighbor kid shot it with a bb gun but it
was the inside pane of a double-pane glass. It actually took a minute
or so for the crazing to propagate over the whole surface.

On Sun, 05 Feb 2006 01:59:04 GMT, Chris Jarshant
wrote:

All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

I've had this happen. I did some searching and there is a ceramic
product available. DAGS but be careful, there is some material that
is designed to limit infrared transmission (like for viewing windows
in furnaces, etc) but you want it to pass IR.

I can't use the stuff in my fireplace because it's too thick for my
doors but it sounds like yours might.

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

No I haven't. I haven't even heard of window glass blowing up in a car for
no reason at all.

Had that happen to me once, scary as anything. Just buckling my son in
his carseat in the back after church one Sunday, my wife is standing
next to the car talking to some people, and BOOM, the entire back
window shatters into a million tiny pieces. We puzzled over this for
hours. No cars were going by (to throw a stone), not under any trees
(something to drop), very few people around on sunday morning (to throw
or shoot something), no one was touching the window at the time or for
at least an hour prior, not a very cold or hot day (for temp stress),
not windy at all (?). It was a pretty old window -- probably 22 years
or so.

The glass repair company wasn't surprised at all. "Happens all the
time" they said, explaining that it is just a terrible coincidence of
stresses and wear and whatever, combined with old glass, possibly a
tiny defect from the manufacturing, a hairline crack spreading slowly
over time, or whatever. But the effect is that it seems fine one minute
(we even scrapered ice off it that morning), and next thing you know it
is just bits and pieces.

clipped
I'm sure there is a reason, you just don't know what it is. [g]

I had the pane of a sliding glass door spontaneously self-destruct
"for no reason." We were sitting right there when it started. My
wife first though the PITA neighbor kid shot it with a bb gun but it
was the inside pane of a double-pane glass. It actually took a minute
or so for the crazing to propagate over the whole surface.


The windshield on my car broke a while back. For a few days there was a
small "y" shaped crack, then it went all the way up. I suspect it
happened because heat was uneven. Car has been sitting in Florida sun
for 8 years. Even morning sun is surprisingly hot, and I think the
sunny side got hot before the shady side did. Slider could have had
just a scratch, and enough stress from heat to expand it. After all,
glass cutting is just extending a scratch.

Had the glass on a gas grill explode once, but that was because it was
hot and it began to rain.

clipped

WTF? We've gone ahead and closed the doors on plenty of fires in that
fireplace since then and the glass is still OK.

Jeff

Probably not the heat but uneven heating. Glass doesn't conduct, and if
the middle is hotter than the perimeter of the glass, it would logically
be stressed. Any tiny scratch is the beginning of a crack, just like
when you use a glass cutter.

"Ron" wrote in message
ups.com...

Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

I wouldn't worry about it.

Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

Call any glass shop and they will tell you this.

BTW, I'm sure there is a scientific reason for it but a glassman isn't
a scientist : )

The best answer the OP has received to date.
This happened to my fireplace years ago, replaced the glass with a new piece
and it has been good for over ten years now.
Any defect in the glass will be exposed under the extremes presented in a
fireplace installation. Tempered glass is only designed not to shatter into
dangerous, sharp shards. Many people think it is the same as bulletproof
glass. No.
The only thing you want to be sure of is that the glass is loose in the
frame. You need to account for thermal expansion. If the glass is tight to
the frame when it is cold it will be stressed when it gets hot. And you have
to clean the crud out of the frames regularly too.

"Toller" wrote in message
...
Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

No I haven't. I haven't even heard of window glass blowing up in a car
for no reason at all.

I think you are mistaken.

This was all over the news a few years back. How could you have missed it?

Wood won't even start to burn until it's about 300 deg. F. A typical fire is
well over 1000 deg. F, and can easily go above 1500 deg. F. You got the fire
too hot, plain and simple. Don't remove the doors and put up a screen as
some suggest and don't bother complaining to the company. The reason that
glass is tempered, is because you're not the first person this has happened
to. Once is an accident, twice is stupidity.

"Chris Jarshant" wrote in message
. ..
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj

Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie,
Did my fire get that hot?
2. I'd like to not worry about the glass doors anymore

Well tempered or heat treated glass is by it's nature under tension.
See:
http://rabi.phys.virginia.edu/HTW//w...and_glass.html
The internal stress is what causes it to shatter into small cubes
instead of long shards. Still sharp and potentially dangerous but not a
10" shard stuck in your chest. You can this stress in the side and
especially rear windows of your car. It's very obvious when viewed
under polarized light, normally occurring or through sunglasses. See:
www.pilkington.com/resources/ ats157swquenchmarksinft10400.pdf
So any imperfections, contamination in manufacture, external stress,
framing errors that cause undue stress or frame to glass contact ( as
noted above), damage, scratches, thermal cycling, large thermal
gradients can cause the glass to fail and fail rather dramatically as
you experienced. So I wouldn't worry about it any more than you would
that your auto glass would suddenly fail. Which (as above) it does do.
Richard

On 5-Feb-2006, wrote:

I agree with the guy that said you are losing heat with glass in
front, a screen is better. No sense wasting the heat with fuel prices
what they are.

How does the glass reduce the heat?

Replace the glass with a screen and the air flow will increase the rate of
combustion and carry the heat up the flue. Using glass doors, properly
sealed, increases the efficiency of a fireplace by a lot. They reduce the
air flow and allow you to choke down the fire. That's why glass doors
have been used on fireplaces for the last few decades.

Since glass doors are quite common and they are there to increase
efficiency,, it is not reasonable to assume that they shouldn't be used.
I think the most reasonable explanations are either that the glass had a
scratch or crack in it and differential heating caused the crack to propagate
or that some liquid (was the wood really dry?) hit the glass and caused a
significant temperature gradient locally.

Mike

Toller wrote:
Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

No I haven't. I haven't even heard of window glass blowing up in a car for
no reason at all.

I think you are mistaken.

Well, I've been in the glass business for going on 26 yrs, so I believe
YOU are the one who is mistaken.

Wes Stewart wrote:
On 4 Feb 2006 20:10:49 -0800, "Ron" wrote:


Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

I wouldn't worry about it.

Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

I'm sure there is a reason, you just don't know what it is. [g]

I had the pane of a sliding glass door spontaneously self-destruct
"for no reason." We were sitting right there when it started. My
wife first though the PITA neighbor kid shot it with a bb gun but it
was the inside pane of a double-pane glass. It actually took a minute
or so for the crazing to propagate over the whole surface.

Why snip my post when I wrote the following?

"BTW, I'm sure there is a scientific reason for it but a glassman isn't
a scientist : )"

Tempered glass explodes all the time. If there is a reason, I've never
heard of what it is in the 26 yrs that I've been in the glass business.

kevin wrote:
Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

No I haven't. I haven't even heard of window glass blowing up in a car for
no reason at all.

Had that happen to me once, scary as anything. Just buckling my son in
his carseat in the back after church one Sunday, my wife is standing
next to the car talking to some people, and BOOM, the entire back
window shatters into a million tiny pieces. We puzzled over this for
hours. No cars were going by (to throw a stone), not under any trees
(something to drop), very few people around on sunday morning (to throw
or shoot something), no one was touching the window at the time or for
at least an hour prior, not a very cold or hot day (for temp stress),
not windy at all (?). It was a pretty old window -- probably 22 years
or so.

The glass repair company wasn't surprised at all. "Happens all the
time" they said, explaining that it is just a terrible coincidence of
stresses and wear and whatever, combined with old glass, possibly a
tiny defect from the manufacturing, a hairline crack spreading slowly
over time, or whatever. But the effect is that it seems fine one minute
(we even scrapered ice off it that morning), and next thing you know it
is just bits and pieces.

For all you doubters just read this post.

"Michael Daly" wrote in message
...

On 5-Feb-2006, wrote:

I agree with the guy that said you are losing heat with glass in
front, a screen is better. No sense wasting the heat with fuel prices
what they are.

How does the glass reduce the heat?

Replace the glass with a screen and the air flow will increase the rate of
combustion and carry the heat up the flue. Using glass doors, properly
sealed, increases the efficiency of a fireplace by a lot. They reduce the
air flow and allow you to choke down the fire. That's why glass doors
have been used on fireplaces for the last few decades.

Since glass doors are quite common and they are there to increase
efficiency,, it is not reasonable to assume that they shouldn't be used.
I think the most reasonable explanations are either that the glass had a
scratch or crack in it and differential heating caused the crack to propagate
or that some liquid (was the wood really dry?) hit the glass and caused a
significant temperature gradient locally.

Mike

It has always amazed me how few people know that glass doors are supposed to be
closed when you are burning a fire. I always try to appeal to the pure logic of
it. If they are not supposed to be closed while the fire is burning then what
is their purpose? The fireplace already has a flu to close when you are not
burning a fire so logically there is no purpose served by glass doors at all
unless they are closed while the fire is burning.

I mean do these people think they are there to keep the cat out?

I just had some FP doors shatter recently, after getting my money back,
I plan to replce the shattered glass with something called "NeoCeram".
Some kind of transparent ceramic stuff that good for 3x the heat( saw a
video on the net one time where they poor ice water on a sheet while a
propane torch is firing up at the bottom) A bit pricey at $39 sq ft.

http://www.onedayglass.com/neoceram.php

On Sun, 05 Feb 2006 20:08:56 GMT, "Rick Brandt"
wrote:


It has always amazed me how few people know that glass doors are supposed to be
closed when you are burning a fire. I always try to appeal to the pure logic of
it. If they are not supposed to be closed while the fire is burning then what
is their purpose? The fireplace already has a flu to close when you are not
burning a fire so logically there is no purpose served by glass doors at all
unless they are closed while the fire is burning.

I mean do these people think they are there to keep the cat out?

No one wants a toasted cat.

Well, no one who still likes cats wants a toasted cat.


Remove NOPSAM to email me. Please let
me know if you have posted also.

On Sat, 04 Feb 2006 23:30:31 -0700, Wes Stewart
wrote:

DAGS but be careful, there is some material that

What is DAGS?

is designed to limit infrared transmission (like for viewing windows
in furnaces, etc) but you want it to pass IR.


Remove NOPSAM to email me. Please let
me know if you have posted also.

On Mon, 06 Feb 2006 02:18:56 -0500, mm
wrote:

On Sat, 04 Feb 2006 23:30:31 -0700, Wes Stewart
wrote:

DAGS but be careful, there is some material that

What is DAGS?

Do a Google search.

Screened opening makes sense if you're trying to heat the county, at
the expense of cooling your house, or if you want ventilation in spring
or fall; else you gotta be nuts. A fire at 550F is a smoker; over 1000F
you're cooking.

Forget the screen. Go for a properly-designed woodstove or insert and
hook it in, and get some useful heat out of it without having to wear a
flack-jacket and full-visor.

J

Rick Brandt wrote:

Since glass doors are quite common and they are there to increase
efficiency,, it is not reasonable to assume that they shouldn't be used.
I think the most reasonable explanations are either that the glass had a
scratch or crack in it and differential heating caused the crack to propagate
or that some liquid (was the wood really dry?) hit the glass and caused a
significant temperature gradient locally.

Mike

It has always amazed me how few people know that glass doors are supposed to be
closed when you are burning a fire. I always try to appeal to the pure logic of
it. If they are not supposed to be closed while the fire is burning then what
is their purpose? The fireplace already has a flu to close when you are not
burning a fire so logically there is no purpose served by glass doors at all
unless they are closed while the fire is burning.

Yes, this is what I understood when I first got the house - open the
door, start the fire, wait for it to get going a little, then shut them.
Else it sucks in air from inside the house, causing the house to suck in
ouside air, cooling off every single room except maybe the one the fire
is in. My fireplace is specifically designed to work this way. It has
a closeable vent to the outside so that it can draw outside air into
the fireplace instead of heated, indoor air.

In any case, I guess it's just my bad luck that the thing broke. I do
believe fires burn hotter when the doors are closed and the overall
efficiency is better.

One more question. If I could heat up tempered glass slowly to a
ridiculous temperature, what would eventually happen? Would the
glass liquify, or shatter first?

cj

Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).


It was probably damaged to begin with. Just not visible to the naked eye.

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?


My mother had glas doors on hers and we loaded that sucker with tons of
wood and it heated the whole living room and kitchen.

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?


Shouldnt be anything around the fireplace that is flammable with high
heat. Oddly enough people tend to load their furnace rooms with all
sorts of cardboard boxes though...



Thanks for any insight!

cj


--
Thank you,



"Then said I, Wisdom [is] better than strength: nevertheless the poor
man's wisdom [is] despised, and his words are not heard." Ecclesiastes 9:16

On Sun, 05 Feb 2006 01:59:04 GMT, Chris Jarshant
wrote:

All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

cj
Let me know what you find out. Mine did the same thing!
Regards in fullest Anthony




.................................................. ...............
Posted via TITANnews - Uncensored Newsgroups Access
at http://www.TitanNews.com
-=Every Newsgroup - Anonymous, UNCENSORED, BROADBAND Downloads=-

On 6-Feb-2006, Chris Jarshant wrote:

One more question. If I could heat up tempered glass slowly to a
ridiculous temperature, what would eventually happen? Would the
glass liquify, or shatter first?

It would anneal. Well, actually, it would reduce the stresses in the
tempered glass and would end up annealed if you then cooled it slowly.
If you just kept heating it, it would melt.

It will only shatter if it has a good reason. There has to be a reason for a
crack to form and/or propagate. If it already has a crack (or scratch) as a
stress riser _and_ the heating causes sufficient differential expansion that
the stress riser goes into tension, the crack will grow rapidly and the glass
will shatter. If the tempering process has created sufficiently high internal
stresses that heating one side causes the expansion (or even annealing) on
that side to result in serious tension stresses, it might crack as a result of
the high stresses without a precursor stress riser.

Personally, I take claims of tempered glass shattering "with no reason" with
the same enthusiasm as claims of people spontaneously combusting.

Mike

Michael Daly wrote:
On 6-Feb-2006, Chris Jarshant wrote:

One more question. If I could heat up tempered glass slowly to a
ridiculous temperature, what would eventually happen? Would the
glass liquify, or shatter first?

It would anneal. Well, actually, it would reduce the stresses in the
tempered glass and would end up annealed if you then cooled it slowly.
If you just kept heating it, it would melt.

It will only shatter if it has a good reason. There has to be a reason for a
crack to form and/or propagate. If it already has a crack (or scratch) as a
stress riser _and_ the heating causes sufficient differential expansion that
the stress riser goes into tension, the crack will grow rapidly and the glass
will shatter. If the tempering process has created sufficiently high internal
stresses that heating one side causes the expansion (or even annealing) on
that side to result in serious tension stresses, it might crack as a result of
the high stresses without a precursor stress riser.

Ok, I do remember a few weeks ago, I had piled 5 or 6 pieces of wood
inside the fire place, and as the fire burned, the log stack became
unstable and the top-most one fell forward and smacked into the inside
surface of the glass. I guess that must have started something that
two weeks later resulted in the shattering. The glass is attached to
the frames rather loosely (to allow for expansion I guess) and one
theory may be that the glass was forcefully scraped across the metal
pressure tabs holding it in place when the log hit, starting a tiny
scratch.

One other thing, the glass door is actually 4 separate pieces of glass
with 1/4" or so of space between each piece. Maybe when the fire gets
real hot, the differential heating caused by the sucking in of room air
through that crack causes local low temperatures near the spaces and
thermally stresses the glass too much?

cj

"Michael Daly" wrote in message
news

On 6-Feb-2006, Chris Jarshant wrote:

One more question. If I could heat up tempered glass slowly to a
ridiculous temperature, what would eventually happen? Would the
glass liquify, or shatter first?

It would anneal. Well, actually, it would reduce the stresses in the
tempered glass and would end up annealed if you then cooled it slowly.
If you just kept heating it, it would melt.

It will only shatter if it has a good reason. There has to be a reason
for a
crack to form and/or propagate. If it already has a crack (or scratch) as
a
stress riser _and_ the heating causes sufficient differential expansion
that
the stress riser goes into tension, the crack will grow rapidly and the
glass
will shatter. If the tempering process has created sufficiently high
internal
stresses that heating one side causes the expansion (or even annealing) on
that side to result in serious tension stresses, it might crack as a
result of
the high stresses without a precursor stress riser.

Personally, I take claims of tempered glass shattering "with no reason"
with
the same enthusiasm as claims of people spontaneously combusting.

Mike

sorry, it wouldn't anneal.

it would become untempered once you get it over bending temperature, which
for ordinary and normally found clear float glass, is around 1030F. on
cooling, it would no longer be tempered but regular window glass.

annealing is the process of reducing temperatures slowly enough so that
stress is evened out across the entire sheet of glass. if the temperature on
one part of the glass is different enough than another, when cooled, it
would set up uneven stresses, leading to eventual cracking and shattering.

in order to temper glass, it is heated up in special tempering ovens to
around 1200F (which takes about 5 minutes), then cooled to around 700F in
another 5 minutes. the tempering oven i'm familiar with has a 60 hp blower
to remove that amount of heat quickly enough. the equipment to do so starts
around $2million. it's not possible to temper glass without use of this type
of equipment.

there are other glasses, like pyrex or borosilicate, which can be tempered
the same way, but just at different temperatures. pyrex usually isn't
tempered at all.

regards,
charlie
http://glassartists.org/chaniarts

Michael Daly wrote:
On 6-Feb-2006, Chris Jarshant wrote:

One more question. If I could heat up tempered glass slowly to a
ridiculous temperature, what would eventually happen? Would the
glass liquify, or shatter first?

It would anneal. Well, actually, it would reduce the stresses in the
tempered glass and would end up annealed if you then cooled it slowly.
If you just kept heating it, it would melt.

It will only shatter if it has a good reason. There has to be a reason for a
crack to form and/or propagate. If it already has a crack (or scratch) as a
stress riser _and_ the heating causes sufficient differential expansion that
the stress riser goes into tension, the crack will grow rapidly and the glass
will shatter. If the tempering process has created sufficiently high internal
stresses that heating one side causes the expansion (or even annealing) on
that side to result in serious tension stresses, it might crack as a result of
the high stresses without a precursor stress riser.

Personally, I take claims of tempered glass shattering "with no reason" with
the same enthusiasm as claims of people spontaneously combusting.

Mike

Didn't I write that I'm sure there is a "scientific reason" for it.

Hardly worth getting into in the grand scheme of things.

On 7-Feb-2006, "Charles Spitzer" wrote:

"Michael Daly" wrote in message
news

It would anneal. Well, actually, it would reduce the stresses in the
tempered glass and would end up annealed if you then cooled it slowly.

annealing is the process of reducing temperatures slowly enough so that
stress is evened out across the entire sheet of glass.

Ok.

clipped
One other thing, the glass door is actually 4 separate pieces of glass
with 1/4" or so of space between each piece. Maybe when the fire gets
real hot, the differential heating caused by the sucking in of room air
through that crack causes local low temperatures near the spaces and
thermally stresses the glass too much?

cj
I would have to re-take physics to answer that one, and I didn't do that
well the first time )

Ron wrote:
Chris Jarshant wrote:
All,

A few nights ago I had a good fire going with the
tempered glass doors closed on my pre-fabricated
fireplace. Well, I guess it got too hot, after an
hour or two, because one of the glass pieces shattered
into small cubes. No biggie, I had a replacement, but now I have
questions.

Questions:

1. The fireplace has tempered glass (it is a "Majestic BR42")
whose glass doors are able to withstand a documented gradual
rise to 550F.
Did my fire get that hot? I admit I loaded it with 4 or
5 small logs but it was not roaring by any means (I had
good embers at the bottom tho that were burning quite hot).

2. I'd like to not worry about the glass doors anymore.
My choices are a) get rid of them, b) never close them,
c) rebuild a *real* fireplace or woodstove, or d) get
better doors. I'd like to do d) for now. If I were to
replace the glass, should I simply get thicker tempered
glass? Or is there some other product that is the same
thickness (3/16" or 1/4" I don't know for sure) that has
extra heat protection?

3) Assuming a correct installation (the home builder installed
it so you never know, but assume for the moment). Using
standard wood for fuel, could I cause the fire to get so
hot that it catches something on fire inside the wall, like
some studs or drywall or insulation? Is it really that easy
for a residential fireplace to get so hot with traditional
fuel that it is a hazard to surrounding material used that
is "to code" in all respects?

Thanks for any insight!

I wouldn't worry about it.

Tempered glass can blow up for absolutely NO reason at all. You will
probably never have this problem again if you simply do nothing.

This may sound like a half-ass answer but it's the truth. I've been
holding a piece of tempered glass in my hand and had it blow up for NO
reason.

Ever heard of a doorglass blowing up in a car before for no reason?
Same thing.

I've seen back window glass blow up, under mild heat from sunlight or
even less reason. often there is an initiating flaw, like a nick, and
any mild stress from not being exactly conforming in curvature to the
opening, or not having enough expansion room will do it. Tempered glass
is less "liquid" than regular glass; it will handle a lot of stress
evenly distributed, any thermal stresses, but a tiny local stress riser
like a scratch or nick will quickly propagate into a big bang.

On the other hand, the windshield of my volvo has a serious curvature
error (you can feel it by hand) which I assume stresses it as it's
constrained into the correct shape, and I've been watching a crack
slowly propagate from the top to the bottom for the past 15 years. Just
about there.

Call any glass shop and they will tell you this.

BTW, I'm sure there is a scientific reason for it but a glassman isn't
a scientist : )

"Norminn" wrote in message
link.net...
clipped
One other thing, the glass door is actually 4 separate pieces of glass
with 1/4" or so of space between each piece. Maybe when the fire gets
real hot, the differential heating caused by the sucking in of room air
through that crack causes local low temperatures near the spaces and
thermally stresses the glass too much?

cj
I would have to re-take physics to answer that one, and I didn't do that
well the first time )

well, yes, but tempered glass takes stress of heat differentials much better
than untempered. there is a limit to this stress though, and any small chip
or scratch makes that limit a WHOLE lot less.

regards,
charlie
http://glassartists.org/chaniarts

On the other hand, the windshield of my volvo has a serious curvature
error (you can feel it by hand) which I assume stresses it as it's
constrained into the correct shape, and I've been watching a crack
slowly propagate from the top to the bottom for the past 15 years. Just
about there.
I have seen this happen a lot. I got a small rock crack in my Toyota
windshield 10 years ago. I immediately flowed cyanoacralayte into it
using a vacuum. The crack hasn't moved at all in that time. I've heard
it explained that water molecules stress the crack, expanding it. If it
went through a freeze thaw cycle that would do it.
Richard

On 7-Feb-2006, "spudnuty" wrote:

I've heard
it explained that water molecules stress the crack, expanding it. If it
went through a freeze thaw cycle that would do it.

I've had a crack in the front window of my Honda Civic for years. Every winter,
on the very coldest days that I drive (I rarely drive in the winter), the crack can
be seen growing a few millimeters to a centimeter or so when I turn on the front
window defroster. It has about 10cm to go to to the edge of the glass - given
how warm this winter has been here, that will probably not happen til next year.

Mike