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Author Topic: laminated vs. non-laminated glass for traffic noise  (Read 12526 times)

viki

  • Guest
laminated vs. non-laminated glass for traffic noise
« on: December 28, 2006, 08:08:14 PM »

We are getting bids for replacement windows. Since we live on a street with a lot of traffic noise, we want to remedy that. One contractor said that two panes of unequal width would only stop voices, not road noise, and that we had to go with laminated glass. Is this true?

johnbergstromslc

  • Guest
Re: laminated vs. non-laminated glass for traffic noise
« Reply #1 on: December 28, 2006, 08:58:12 PM »

Well, he's wrong, but he's right.....
 
As is true in a wall, so it is with windows:  The more mass and bigger the airspace, the better.  The unequal thicknesses of glass help dampen resonance.  A pane of 1/8" + 3/16" probably won't do much, but 1/4" + 3/8" will really kill some sound.  3/8" + 1/2" would be better still.  Problem is, no window manufacturer makes window sashes or the counterweight hardware to accomodate glass thickness over 1/4".  It would be a custom order and very expensive. 

So go with laminated, double-glazed, with glass as thick as you can get (at a reasonable price).     

professorkev

  • Guest
Re: laminated vs. non-laminated glass for traffic noise
« Reply #2 on: January 10, 2007, 11:58:44 PM »

I thought Triple Pane windows help alot in blcoking noise?  I am looking seriously at Loewen windows Heatsmart 3 plus windows, triple pane.  have an STC rating of 33, their next line, tranquilty is 40.  I am trying to block the humm of a highway about 1/3 of a mile away.  Just a constant hum thta I can't stand.  noticeable from windows that face that direction.  Figured the 3 pane will help to block that noise and provide help with heat loss too.

The rep told me he felt Tranquility os overkill and that I should be happy with triple pane AND he went to a place that installed their windows for a guy in Brooklyn, NY city and was amazed at how quiet they were.

johnbergstromslc

  • Guest
Re: laminated vs. non-laminated glass for traffic noise
« Reply #3 on: January 12, 2007, 01:44:35 AM »

STC 33 for a triple-paned window is pretty good, although a double-paned STC 40 would be a lot better, especially in the lower frequencies.  Maybe before you spend any money on windows, it would be a good idea to consult somebody to do an 'energy audit' for your house.  Tell them your 2 options, the insulation values and sizes of the windows you're considering and they can estimate how much money you're gonna save by going with triple glazed. 

You'll have to decide if better thermal performance is worth lessened acoustical performance, but I'm betting the energy savings will be minimal, one or two dollars per year per window and you'll opt for the quieter windows.

A triple paned window is also known as a 'triple-leaf partition'.  Check out this link to understand why STC value is lower than double-paned.
(The page only deals with walls, but the same principles apply to windows.)

http://www.greengluecompany.com/understandingTripleLeaf.php

professorkev

  • Guest
Re: laminated vs. non-laminated glass for traffic noise
« Reply #4 on: January 13, 2007, 08:09:03 AM »

well the windows I have now are 15 year old Anderson slimline.  you can FEEL a coldness coming through the glass, not a draft just the coldness, thus why I thought triple pane would be better.  I think the double  stc 40 pane window was $500 more.

johnbergstromslc

  • Guest
Re: laminated vs. non-laminated glass for traffic noise
« Reply #5 on: January 15, 2007, 01:17:12 AM »

Sounds like you've got a lot of trade-offs to consider.  Since you're trying to block highway noise, you'll want the windows that have the best transmission loss in the lower frequencies.  It's a longshot, but see if the window manufacturers will send you a copy of the acoustical tests on the windows, or at least a table of the TL frequencies, not just the STC value.  Relying on the STC alone can be misleading.

bjnash

  • Guest
Re: laminated vs. non-laminated glass for traffic noise
« Reply #6 on: February 08, 2007, 05:31:19 AM »

Something missing in these posts is that just being a double or triple pane window does not make it a "Acoustical" window.  A true "Acoustical" window has characteristics that differ from a hardware store double or triple paned window in that it is tested and meets certain requirments as to it's performance.

There are no acoustical ratings for such a ordinary window, although many have been rated as around a STC of 20.  (Can hear conversation thru them).

We have found that increasing the thickness of glass has a diminishing return- that is that after 3/16" there is little or no measurable performance increase by increasing the thickness.

A STC of around 40 or above desired in these windows.  And even a high STC in this range can be misleading as the low frequency reduction can be very low and because the high frequency reduction high, one would falsely assume such a window to be superior.

Clearly, this is not a place to budget as there is no benefit in the long term.

BJ Nash