 | Bob Crager of Lewis Street Glass is a 26 year veteran in the glass business. Lewis Street Glass is a leading Wichita Glass company, serving the entire Wichita/Sedgwick County area since 1919. They do anything and everything having to do with glass, both residential and commercial. They also do Auto glass. They are located at 743 South Market, facing Kellogg on the South, and you can reach them by phone at (316) 263-8259. You can email Bob Crager at bcrager@lewisstreetglass.com |
Glass
2006-03-01 13:04:00
Stopping sounds at the speed of glass
ANSWER: Sound is measured by a rating system, much like earthquakes are measured by a Richter Scale. STC is the acronym which stands for Sound Transmission Class. STC ratings are established as a way to get an average of how much sound is stopped by something. The ratings are used to measure windows, walls, drywall, doors, and a lot of other building materials. The rating range for windows is 18 to 50. These ratings are the industry accepted way of measuring the amount of noise that is stopped. There are a total of 18 different frequencies in which the average amount of noise measured is being stopped, and this is measured in decibels. Each number on this logarithmic scale is quite a bit higher than the one before. Single pane window panes generally have ratings between 20 and 27. Thickness of the glass, and the air tightness of the panes determine the difference. Double-paned windows usually vary from 28 to 35, assuming that the panes have good airtight seals. The variation is not only due to the thickness of the glass, but also the amount of air space between the panes of glass forming the double-paned glass.Actual Soundproof Windows range from 41 to 51 (with higher numbers possible), and the number varies depending upon the existing window and the air space. With a single-paned window in a standard wall, the STC rating is 41. With double-paned windows, the STC rating is 45 or more. With increases of air space, figures greater than 50 are easily achieved.An increase in the number from 28 to 38 means 90 percent of the noise is reduced. A change from 28 to 43 represents a noise reduction of over 95 percent. Small increases can mean a lot of extra noise reduction. The increase from 38 to 43 mentioned above does not sound like much (90 percent versus 95% plus in reductions) But going from 90 percent to over 95 percent means that 60 percent of the remaining noise was removed. Every number gained or lost represents a large amount of noise being added or subtracted from the interior of the room or building. More next month…
