Tempered vs. Annealed?

[Welmoed Sisson]

Did a pre-drywall inspection today and over the master tub were three stationary windows: a big palladian and two smaller sidelights. They were labeled "annealed", rather than "tempered". Is this an AHJ thing? My client looked up the difference between the two and decided he's going to ask the builder to replace the annealed windows with tempered. Is an annealed window acceptable in such an application? He's just curious whether he'll have to pay for an "upgrade" if it is.

[Garry Sorrells]

So have you put a call into the Permit office?

I think you need to check with Howard Co Permits Office or county building located in.. Some inspectors (depending on county and the inspector) will sign off on either others will not.

Howard Co requires safety glazing and that is where the fuzzy area occurs. Some inspectors require the exact wording of "tempered" to be on glass others go with either as considered safety glass.

Then if the plans with specifications were signed off on with annealed glass the water is muddied a bit.

Try this number 410-313-1810

[Gunnar Alquist]

Did a pre-drywall inspection today and over the master tub were three stationary windows: a big palladian and two smaller sidelights. They were labeled "annealed", rather than "tempered". Is this an AHJ thing? My client looked up the difference between the two and decided he's going to ask the builder to replace the annealed windows with tempered. Is an annealed window acceptable in such an application? He's just curious whether he'll have to pay for an "upgrade" if it is.

Welmoed,

I believe that standard window glass is annealed and this is not the same as tempered or safety glass. Annealing is a process of slowly cooling the glass to reduce internal stresses. Tempering, on the other hand, increases internal stresses so the glass will shatter rather than break into shards.

In short, annealed glass should not be used at those locations where tempered is required, no matter what is in the plans.

[Garry Sorrells]

So have you put a call into the Permit office?

I think you need to check with Howard Co Permits Office or county building located in.. Some inspectors (depending on county and the inspector) will sign off on either others will not.

Howard Co requires safety glazing and that is where the fuzzy area occurs. Some inspectors require the exact wording of "tempered" to be on glass others go with either as considered safety glass.

Then if the plans with specifications were signed off on with annealed glass the water is muddied a bit.

Try this number 410-313-1810

Correction:::: Sorry for wrong information on annealed glass. Do not know where my mind was, but annealed glass is not a substitute for tempered glass. Again sorry. Was thinking of something else.

Annealed will produce large shards as opposed to small bits when broken.

[Steven Turetsky]

Annealed glass is used to make laminated [annealed] safety glass. In some locations laminated tempered glass is called for.

[bob smit]

As a machinist, I can assure you there is great difference in the meaning, application, and methods in obtaining such and that the processes vary greatly depending on the alloys and required degree of annealing or tempering.
Having said a mouthful, you have me thinking about methods, processes, and outcome of amorphous solids...hmmmm Now I'm going to waste the rest of my evening researching that which I will never have need of, thanks.

[Kristi Silber]

As a machinist, I can assure you there is great difference in the meaning, application, and methods in obtaining such and that the processes vary greatly depending on the alloys and required degree of annealing or tempering.
Having said a mouthful, you have me thinking about methods, processes, and outcome of amorphous solids...hmmmm Now I'm going to waste the rest of my evening researching that which I will never have need of, thanks.

I'm something of a glass fanatic, and I work with metals myself. Annealing in both cases eliminates stresses within the material. Annealing a metal realigns the crystals, right? Makes the internal structure regular? And the metal ends up softer and less brittle. Annealing glass is similar, but without crystals.

Gunnar is right - annealing glass is simply cooling it slowly and preventing internal stresses. Otherwise it cracks or breaks if cooled too quickly. Annealed window glass is normal plate glass. Tempered glass, I believe, is formed, annealed, reheated to above the annealing point, then rapidly cooled. It's harder, just as tempered metal is harder, and the process creates imbalanced stresses, which make it break into little chunks when it does break. There is also a chemical process for tempering glass.

Not sure about laminated safety glass. Layers of glass can be formed when the glass is molten, or fused after being formed and annealed

[Brandon Adams]

Welmoed,

I believe that standard window glass is annealed and this is not the same as tempered or safety glass. Annealing is a process of slowly cooling the glass to reduce internal stresses. Tempering, on the other hand, increases internal stresses so the glass will shatter rather than break into shards.

In short, annealed glass should not be used at those locations where tempered is required, no matter what is in the plans.

I agree with Gunnar

[Jerry Peck]

Did a pre-drywall inspection today and over the master tub were three stationary windows: a big palladian and two smaller sidelights. They were labeled "annealed", rather than "tempered". Is this an AHJ thing? My client looked up the difference between the two and decided he's going to ask the builder to replace the annealed windows with tempered. Is an annealed window acceptable in such an application? He's just curious whether he'll have to pay for an "upgrade" if it is.

This is an older thread, but, hey, it was resurrected so here goes: Depends on how you define "over the master tub were three stationary windows".

"over" the master tub means what? Because you also said "a big palladian and two smaller sidelights" I will presume the windows are in an exterior wall adjacent to the master tub, so the question needing defining is 'how high' above the master tub are the windows? Down to the edge of the tub or almost that low, or up higher than 5 feet above the drain of the tub, and how close horizontally to/from the tub? Each matters for the correct answer to whether annealed is okay of if tempered is required.

[Welmoed Sisson]

Jerry,
I went back and looked at my pictures from that inspection to make sure. The window sill was about 6" above the lip of the tub, and there was maybe 6-8" between the tub and the window. The central window was about half the width of the tub, and the side windows were each a little less than 1/4 the width; so the entire window assembly was almost the full width of the tub.
I've attached a picture of the installation. In my opinion, it is entirely possible that an occupant could slip in the tub and land against the window.
annealed-not-tempered.jpg

[Jerry Peck]

Jerry,
I went back and looked at my pictures from that inspection to make sure. The window sill was about 6" above the lip of the tub, and there was maybe 6-8" between the tub and the window. The central window was about half the width of the tub, and the side windows were each a little less than 1/4 the width; so the entire window assembly was almost the full width of the tub.
I've attached a picture of the installation. In my opinion, it is entirely possible that an occupant could slip in the tub and land against the window.
annealed-not-tempered.jpg

Welmoed,

The two critical dimensions for bathtubs, showers, pools, hot tubs, spas, whirlpools, saunas, steam rooms, swimming pools (basically wet areas) are:
- glazing is
- - less than 60 inches vertically above the standing or walking surface and
- - 60 inches or less horizontally from the edge of the water

And the above applies to a single pane glazing and to *all* panes in multiple pane glazing (i.e., one does not just measure to the glazing panes which are within those dimensions, if any pane of a multiple pane glazing is within those dimensions it applies to all of the panes).

[Mark Reinmiller]

Did a pre-drywall inspection today and over the master tub were three stationary windows: a big palladian and two smaller sidelights. They were labeled "annealed", rather than "tempered". Is this an AHJ thing? My client looked up the difference between the two and decided he's going to ask the builder to replace the annealed windows with tempered. Is an annealed window acceptable in such an application? He's just curious whether he'll have to pay for an "upgrade" if it is.

Welmoed, I'm not being critical, but just for reference, I believe that the combination of the three windows you are referring to is a Palladian window, not just a single window with a half round top. Realtors seem to be fond of calling windows with a half round top Palladium windows.

[Robert Gaspy]

What if the bathtub would be locate perpendicular to the window ( instead of align to the window as in this case )

________________________________window
-b
-a
-t
-h
-t
-a
-b
in such case- does the window needs to be tempered?
-
-

[Jerry Peck]

What if the bathtub would be locate perpendicular to the window ( instead of align to the window as in this case )

________________________________window
-b
-a
-t
-h
-t
-a
-b
in such case- does the window needs to be tempered?
-
-

Yes.

Unless the glazing is more than 5 feet from the tub, which would also apply to a tub parallel with the window.

[Robert Gaspy]

This window (4 feet ) is in the middle of bathroom ( 8 feet wide ) and the bathtub is located along the wall and is 3 feet wide. So the bathtub is not exactly against the window , but it is aside, furthermore it is located perpendicular to the window. It is not as if it will be exactly under the window. I could not understand if code required it to be tempered. Could you help me to understand what is right,please.

Yes.

Unless the glazing is more than 5 feet from the tub, which would also apply to a tub parallel with the window.

[Jerry Peck]

This window (4 feet ) is in the middle of bathroom ( 8 feet wide ) and the bathtub is located along the wall and is 3 feet wide. So the bathtub is not exactly against the window , but it is aside, furthermore it is located perpendicular to the window. It is not as if it will be exactly under the window.

From the 2012 IRC: (underlining is mine)
- R308.4 Hazardous locations. - - The locations specified in Sections R308.4.1 through R308.4.7 shall be considered specific hazardous locations for the purposes of glazing.
- - R308.4.5 Glazing and wet surfaces.
- - - Glazing in walls, enclosures or fences containing or facing hot tubs, spas, whirlpools, saunas, steam rooms, bathtubs, showers and indoor or outdoor swimming pools where the bottom exposed edge of the glazing is less than 60 inches (1524 mm) measured vertically above any standing or walking surface shall be considered a hazardous location. This shall apply to single glazing and all panes in multiple glazing.
- - - - Exception: Glazing that is more than 60 inches (1524 mm), measured horizontally and in a straight line, from the water’s edge of a bathtub, hot tub, spa, whirlpool, or swimming pool.

If the glazing is "more than 60 inches" from the water's edge of the tub - safety glazing is not required.

If the glazing is 60 inches or less from the water's edge ... and ... the "bottom exposed edge of the glazing is less than 60 inches" above the floor/walking surface - safety glazing is required.

Your description is that the window is 60 inches or less (4 feet) from the tub, that means you now need to check the height of the bottom of the window - if the bottom of the window is less than 60 inches above the floor, then safety glazing is required ... if the bottom of the window is 60 inches or more above the floor, safety glazing is not required.

[Jerry Peck]

Tempered ...

I thought I should also add that tempered glazing is not required in that location ...

Safety glazing is required in that location.

Tempered is a type of safety glazing, but not all safety glazing is tempered.

It is a hard habit to break - I sometimes still say tempered - and then have to correct myself and say safety glazing.

Similar to saying that something can't be done ... yet we are standing there looking at it - what we mean is that it is 'not allowed' to be done, whether it 'can' is a completely different issue.

[Robert Gaspy]

Thank you , Jerry. It was very clear explanation!

Tempered ...

I thought I should also add that tempered glazing is not required in that location ...

Safety glazing is required in that location.

Tempered is a type of safety glazing, but not all safety glazing is tempered.

It is a hard habit to break - I sometimes still say tempered - and then have to correct myself and say safety glazing.

Similar to saying that something can't be done ... yet we are standing there looking at it - what we mean is that it is 'not allowed' to be done, whether it 'can' is a completely different issue.