Another noise reduction question

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buddy
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#16 Post by buddy »

Thanks Bill!

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Windows on Washington
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#17 Post by Windows on Washington »

Oberon is wealth of information and I learned a ton from reading his posts in the past. Here is a little blurb on what I hijacked from the web.

Sound Control Principles
What is Sound?
Sound, which is defined as any thing the ear can hear, originates from something making vibrations. These vibrations spread out in all directions, much like the ripples created when a stone is dropped in still water.
When a sound is generated in air it causes air pressure changes. The human ear can hear such sounds in a range from 20 to about 20,000 air pressure changes per second.
The number of these air pressure changes emanating from the source of the vibration is measured by the number of cycles per second. In the field of acoustics, the international term for cycles per second is hertz (Hz). When a sound wave is said to measure 500 Hz, it means that there are 500 "ripples" of air pressure per second from the vibration. This 500 Hz is the sound frequency.
Sound Reduction
There are two fundamental considerations which come into play when measuring the reduction of sound through windows, walls, or other building components:
Sound Transmission Loss (STL) -- indicates the effectiveness of a window or wall in reducing exterior sounds and are measured in decibels. When measuring the ability of a window or wall to reduce outdoor sounds such as traffic noise, STL's are generally figured in the frequency range of 125-4000 Hz. STL's are frequency dependent.
Sound Transmission Class (STC) -- measured in decibels, is an average value associated with a material's effectiveness in reducing sound. An STC rating is a quick reference number for the entire frequency band, and is designed to measure interior noises at levels most common to human speech (500Hz-2,000Hz). The higher the value, the greater the reduction of sound.
Critical considerations when controlling sound
Sound transmission occurs whenever there is an air-space. It is important to note that sound reducing glazing systems are rendered less effective if air leaks exist around glass, doors, vents or other areas. In addition, it is important when increasing the effectiveness of one component or material in a structure, such as the windows, other building components such as the walls need to be brought to a similar efficiency level. Sound will always travel through the weakest component.
Factors relating to the effectiveness of controlling sound
There are three physical properties of glass that have a bearing on its effectiveness in sound reduction:
Mass - sound reduction will increase with increased glass thickness due to the greater mass involved.
Damping - the reduction of sound due to the ability of a material to absorb sound rather than allowing it to transfer through. Laminated glass, with its polyvinyl butryal interlayer, is an example of a material that is effective in absorbing sound.
Stiffness - refers to the ability of a glazing system to bend or wave with the sounds motion. 1/2" glass will bend or wave with sound where as 1/8 is likely to resonate or vibrate.
Sound Control Example
1/4" over 7/32" Laminated provides the following benefits:
1/4" provides the mass which reduces sound transmission.
The 1/8" lites which make up the 7/32" laminated glass have the ability to bend rather than vibrate. The polyvinyl butyral interlayer in the laminated lite provides the damping or absorbing of sound. This glazing option provides benefits of all 3 physical properties: Mass, Damping and Stiffness.
Sound Solution Ideas
Glass
Laminated Glass -- Best
1/4" over 1/4" -- Adequate for many situations
Lites of differing thickness
Insulated Glass -- a noticeable improvement from a single lite
Frame
Quiet Line Vinyl Windows -- multiple glass lites combine to reduce sound dramatically. Wider, multi-chamber frame further reduces sound effects.
Vinyl Windows -- hollows in vinyl frame help deaden sound.
WoodClad Windows -- hollows in pultrusion frame help deaden sound.
Air infiltration can affect the amount of sound that enters the home. Quick Guide for Applications for Adequate Sound Control (units only, does not include frame)
General neighborhood noises - 1/8" over 1/8" (STC 28)
Near a busy road or highway - 1/4" over 1/4" (STC 35)
Near Airport - Laminated over 1/4" (STC 39)
Near Train - Laminated over 1/4" (STC 39)
Near park or gathering place - 1/4" over 1/4" (STC 35)
Loud music from neighbor - Laminated over 1/4" (STC 39)
Other Considerations
Laminated glass also provides great protection from UV and adds safety and security.
Use caution specifying differing thickness of glass. The wavelengths where this combination is effective are very specific.

buddy
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#18 Post by buddy »

Very interesting.


So then to answer my original question TP "can" be quieter than a DP with laminated glass depending on the frequency of the sound one is trying to deaden. If that is safe to one might wonder what hz levels things like lawnmowers make.

I'm an audiophile. My truck is my soundstage. It's funny how this topic applies to my present situation. I went to great pains to deaden the sound with the use of various materials. I'm trying to identify the frequencys that are affecting my sound system adversly. Off topic but funny how things happen.

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Windows on Washington
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#19 Post by Windows on Washington »

buddy wrote:So then to answer my original question TP "can" be quieter than a DP with laminated glass depending on the frequency of the sound one is trying to deaden. If that is safe to one might wonder what hz levels things like road traffic and lawnmowers make.

I'm an audiophile. My truck is my soundstage. It's funny how this topic applies to my present situation. I went to great pains to deaden the sound with the use of various materials. I'm trying to identify the frequencys that are affecting my sound system adversly. Off topic but funny how things happen.
TP can be quieter but only with the utilization of Laminated glass. Think about each given thickness of glass canceling out a given frequency. 3 panes of glass of a given thickness will not cancel any more sound that two pane of the same thickness when the overall IGU is the same thickness. I don't really know of too many manufacturers putting laminated glass in triple pane units because of width and weight limitations.

That combined with the fact that TP units typically use thinner glass to offset window weight so there is less mass as well and less performance.

If you look at airport windows, they have offset glazing (differing thicknesses) and a very large airspace between panes.

buddy
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#20 Post by buddy »

Windows on Washington wrote:
buddy wrote:So then to answer my original question TP "can" be quieter than a DP with laminated glass depending on the frequency of the sound one is trying to deaden. If that is safe to one might wonder what hz levels things like road traffic and lawnmowers make.

I'm an audiophile. My truck is my soundstage. It's funny how this topic applies to my present situation. I went to great pains to deaden the sound with the use of various materials. I'm trying to identify the frequencys that are affecting my sound system adversly. Off topic but funny how things happen.
TP can be quieter but only with the utilization of Laminated glass. Think about each given thickness of glass canceling out a given frequency. 3 panes of glass of a given thickness will not cancel any more sound that two pane of the same thickness when the overall IGU is the same thickness. I don't really know of too many manufacturers putting laminated glass in triple pane units because of width and weight limitations.

That combined with the fact that TP units typically use thinner glass to offset window weight so there is less mass as well and less performance.

If you look at airport windows, they have offset glazing (differing thicknesses) and a very large airspace between panes.
So it seems. Interesting thanks.

rmleer
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#21 Post by rmleer »

I'm assuming my quote of about $600-$650ea looks reasonable if the installation is good?
I asked if he'd use low expanding foam if I provided the materials but he already has a gun.
He told me he's been kind of set in his ways (fiberglass) but would use the foam if I wanted.

For now, I'm probably going to replace the one in my loudest room to see how it compares to the old one. ($650)
If all goes well I'll go ahead and replace the other 3 sliders.
Just waiting to hear from them about the reinforced meeting rails being an option for me or not.
I can't see why it wouldn't be.
If anyone has some info they'd like to add but doesn't want to step on anyones toes, rmleer atYahoo.com

Thanks.
All the info and replies are appreciated.

bad_andy
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#22 Post by bad_andy »

I'm new to the board and have a quick question. What is the approximate STC rating of a window with 1/8" glass + 0.090 PVB laminate + 1/8" glass?

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Windows on Washington
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#23 Post by Windows on Washington »

bad_andy wrote:I'm new to the board and have a quick question. What is the approximate STC rating of a window with 1/8" glass + 0.090 PVB laminate + 1/8" glass?
It ultimately depends on the window and material choices. Is this a vinyl window?

In a vinyl window with a dual pane IGU and one pane consisting of a laminated glass, I would guess that you will be in the low to mid 30's STC range.

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#24 Post by bad_andy »

It is indeed vinyl.

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#25 Post by bad_andy »

Just out of curiousity, what is the typical STC rating of a car window/windshield?

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Windows on Washington
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#26 Post by Windows on Washington »

Figure two layers of tempered glass with a thick PVB interlayer and I would guess somewhere in the low to mid 20's

Oberon
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#27 Post by Oberon »

A single 1/4" laminated lite consisting of 1/8" glass / .030 pvb interlayer / 1/8" glass will get you an STC rating of 35.

Since we all know that an IG is better at blocking sound than is a single lite; we mount this 1/4" laminated lite into an IG consisting of an 1/8" outer lite and a 1/4" airspace and we end up with an overall STC rating of....35.

There's a head scratcher.

What happened is that the narrow (1/4") airspace actually negated the potential sound attenuation advantage of adding a second lite to the original lami lite. If we were to increase the airspace to 3/8", we get an STC of 36. Increase to 1/2" airspace and we increase the STC to 37.

None of which really answers any question, but it is interesting, I think anyway.

But to answer a question...

As mentioned, 1/8" / .030pvb / 1/8" lami has an overall STC of 35. If we increase the interlayer to .060, then we get an overall STC of...35.

Again we have a head scratcher.

So what happens if we jump the interlayer to .090? Well, we now have a product that may be suitable for use in a hurricane impact area, but we really haven't done much to increase the sound attenuation performance.

Stopping unwanted sound thru any material is determined by three things – mass, stiffness, and damping. Laminated glass improves the damping performance of the unit by squeezing that softer interlayer material between the two outer solid and much more dense glass lites. The primary advantage of laminated glass is the change in density as sound penetrates the material rather than the thickness of the interlayer material.

And as an aside, there are PVB interlayer formulations that have improved sound-blocking performance versus "ordinary" PVB.

Trosifol (a European manufacturer of PVB) claims that their PVB has better sound-blocking performance than other products and they market their interlayer material as such.

Solutia, probably the largest manufacturer of PVB in the world, markets a "sound control" PVB as well as "regular" PVB. Typically the sound performance products have some advantage in certain frequency ranges and possibly a point or two advantage in overall performance.

Curiously, sound perfomance PVB products seem to be more commonly used in Europe - but then Europeans tend to use a good bit more laminated glass in their buildings than we do in North America in any case.

My daughter and I are in the process of building a home for her. The windows that I spec'd and that we installed in her home are tilt/turn, triple pane with 4mm outer lites with a 3mm center lite and 7/16" airspace between the lites - dual LowE (surfaces 2 and 5) and argon filled. T

These windows have U-factor of .16 on the fixed units and .21 on the operators; but the point here is that these windows are really quiet because of the construction - a by product really - but a nice added value.

I don't know that this make-up has ever been specifically STC rated by the window manufacturer, but I would suspect an STC value of about 38 or so...maybe a little better...

And btw, these things were freaking heavy!!!!!

One very common misconception is that car windshields are laminated tempered glass. Actually, windshields are laminated annealed glass that use a lower adhesion (versus architectural or residential grade) interlayer in their construction.

In a collision between a forehead and a windshield something is going to break. By design, we would much prefer it to be the widnshield and not the forehead (or neck, etc). Windshield's are manufactured using a lower adhesion interlayer to produce what is called a "controlled delamination" in the event of a collision.

Basically, the weaker bond between the glass and the interlayer allows the glass to "slip" as the windshield is broken by the impact and the interlayer will then stretch like a balloon absorbing the impact of the victim's forehead - hopefully saving the person's life.

A tempered windshield would be much less likely to break in a collision with a forehead and as a result the victim would be more likely to have serious or fatal injuries as a result.

rmleer
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#28 Post by rmleer »

Well I guess I didn't need to ask the Window co. how thick the interlayer was after all. heh

I did sign a contract to replace one slider with the 9800, 1" IGU, SS, laminated inside pane @ .125x.060x.125 and .125 regular outer pane.
Along with low-e,argon this time...
Low expanding foam was added to the contract.

After knowing no insulation was used on my current windows and remembering how I could get eye level with the window sill and see outside through a crack, I think a good install and this type of window is going to do the trick.

But in case it doesn't, I only wasted $650 instead of $3000 lol
It actually won't be a waste bc they'll be a heck of alot more efficient than my "new" loud drafty ones are.
Another option I'm thinking about is the possibility of using my old window as an interior one if there's any space left.

rmleer
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#29 Post by rmleer »

I'll be getting my new window put in today. :D
edit: It had to start raining...oh well, I'll post my review and a comparison pic when it's done.

Thought I'd throw an ugly pic up I took the other day.
Check out Window World's top notch quality! :roll:
Image

rmleer
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#30 Post by rmleer »

All of my windows were installed by WW sticking out a bit like in the previous pic.
The noise reduction of the new window installed by (can I mention their name here?) worked for most things except the barking dogs who look thirsty for antifreeze. JK!

Here's a couple pics of the new installed Simonton.
It looked like rain today so I wasn't able to paint yet.

Image

Image

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