# How strong does glass have to be to withstand a sonic boom? **URL:** \ **Category:** Factual Questions\ **Created:** [August 4, 2008, 8:40pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841 "2008-08-04T20:40:11Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [August 4, 2008, 8:40pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/1 "2008-08-04T20:40:11Z")
I’m wondering about the ‘ordinary’ glass used in home windows and the like. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [August 4, 2008, 8:56pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/2 "2008-08-04T20:56:30Z")
All sonic booms are not alike. What did you have in mind and at what distance? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [August 4, 2008, 9:06pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/3 "2008-08-04T21:06:33Z")
[QUOTE=Telemark] All sonic booms are not alike. [/QUOTE] Nor are all window frames. Are we talking glass nestled between two snakes of rubbery silicone, or straight up oak and nails with 70 year old hard caulk? ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [August 4, 2008, 9:10pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/4 "2008-08-04T21:10:06Z")
Wayyyy underspecified. The crack of a whip is a sonic boom. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 4, 2008, 9:18pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/5 "2008-08-04T21:18:33Z")
I’m looking for the chart I was using last week that described window size (area) versus overpressure necessary for 50% of the windows that size to break. As previous posters have stated, the answer is going to vary. A lot. Here’s a good start as to expected damage from different overpressures: ```auto Overpressure* (psig) Expected Damage 0.04 Loud noise (143 db); sonic boom glass failure. 0.15 Typical pressure for glass failure. 0.40 Limited minor structural damage. 0.50-1.0 Windows usually shattered; some window frame damage. 0.70 Minor damage to house structures. 1.0 Partial demolition of houses; made uninhabitable. 1.0-2.0 Corrugated metal panels fail and buckle. Housing wood panels blown in. 1.0-8.0 Range for slight to serious laceration injuries from flying glass and other missiles. 2.0 Partial collapse of walls and roofs of houses. 2.0-3.0 Non-reinforced concrete or cinder block walls shattered. 2.4-12.2 Range for 1-90% eardrum rupture among exposed populations. 2.5 50% destruction of home brickwork. 3.0 Steel frame buildings distorted and pulled away from foundation. 5.0 Wooden utility poles snapped. 5.0-7.0 Nearly complete destruction of houses. 7.0 Loaded train cars overturned. 9.0 Loaded train box cars demolished. 10.0 Probable total building destruction. 14.5-29.0 Range for 1-99% fatalities among exposed populations due to direct blast effects. ``` Remember that the pressure decreases as a cube of the distance, as well, so a big boom far away is functionally equivalent to a smaller, closer boom. ETA: Here’s another, they’re pretty similar. ```auto Overpressure, psi Expected Damage 0.04 Very loud noise (143 dB); sonic boom glass failures 0.1 Breakage of small windows under strain 0.15 Typical pressure of glass failure 0.30 10% of windows broken 0.5 Windows shattered, limited minor damage to house structures 0.7 Upper limit for reversible effects on humans 1.0 Partial demolition of houses; corrugated metal panels fail and buckle; skin lacerations from flying glass 2.0 Partial collapse of walls and roofs of houses 2.4 Eardrum rupture of exposed populations 2.5 Threshold for significant human lethality 3.0 Steel frame building distorted and pulled away from foundation 5.0 Wooden utility poles snapped 10 Probable total building collapse. Lungs hemorrhage 20 Total destruction. 99% fatality due to direct blast effects ``` ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [August 4, 2008, 9:56pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/6 "2008-08-04T21:56:59Z")
Say a normal (but supersonic) passenger plane going overhead at cruising altitude. ---
**Author:** ![Jman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jman/32/4416_2.png) [@Jman](https://boards.straightdope.com/u/Jman)\ **Post date:** [August 4, 2008, 9:58pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/7 "2008-08-04T21:58:44Z")
Well, a normal passenger plane at cruising altitude never breaks the sound barrier, so there is never a sonic boom associated with them. (I see you’ve edited). At cruising altitude, not much will happen. It’d sound like distant thunder,if you heard it at all, I would imagine. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 4, 2008, 10:20pm UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/8 "2008-08-04T22:20:48Z")
Okay, I found a similar one: > **[Forensic Investigation of Explosions](https://books.google.com/books?id=pZFrU_JFRZsC&pg=PA191&lpg=PA191&dq=break+glass+window+overpressure&source=web&ots=O0MB8MIXXN&sig=FEEYt1HT3k-vDK008vDCV8fyTJI&hl=en&sa=X&oi=book_result&ct=result)** > > This text has been shaped by the editor's experiences on task forces set up to investigate major explosives incidents and related civil and criminal proceedings. Chapters cover methods, applications, quality control, and significance of forensic... Page 192 and 193 should be of interest (they’re just graphs). This page looks to be of interest, too: > **[Sonic Boom 3 › Dr Karl's Great Moments In Science (ABC Science)](https://www.abc.net.au/science/articles/2002/04/18/528517.htm?site=science%2Fgreatmomentsinscience)** > [@](#): > > Sonic booms are usually less than this Threshold of Pain, because the supersonic > plane is a long way away from you. The aerospace engineers measure sonic booms in “pounds per square foot of overpressure” over and above the normal atmospheric pressure (which is around 2,116 pounds per square foot). > You hardly notice an overpressure of 0.3 of a pound per square foot. > > At around one pound per square foot of overpressure, you wouldn’t expect any damage to buildings. This is roughly the overpressure created by an SR-71 Blackbird flying at Mach 3 at 80,000ft. > > People begin to complain when the overpressure is between one-and-a-half and two pounds per square foot. This sounds like a cannon shot, or a nearby thunderclap and can sometimes damage windows. The Concorde generates around two pounds overpressure when it’s flying at Mach 2 at around 52,000ft. By the way, a pressure change of a few pounds per square foot is roughly the same pressure change you experience when you ride an elevator through three floors. But what makes the sonic boom audible is that you go through this pressure change very suddenly. > > At around 2-5 pounds of overpressure, you do get occasional minor damage to buildings. A structure in good condition will survive, without any damage, an overpressure of around 11 pounds. > > The loudest sonic boom every recorded was 144 pounds of overpressure - created by an F-4 fighter jet flying just over Mach 1 at an altitude of 100 feet. Thankfully, people survived this without any injury. Keep in mind the figures in that article are measured in pounds per foot instead of psi like most sources do, so there’s a factor of 144. Also, keep in mind that db = 20\*log(P/Pref) and Pref is 20 uPa if you want to convert from decibels to pressure. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [August 5, 2008, 3:07am UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/9 "2008-08-05T03:07:04Z")
That is good research and links, **Santo Rugger**. Thank you for making that effort. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [August 5, 2008, 3:23am UTC](https://boards.straightdope.com/t/how-strong-does-glass-have-to-be-to-withstand-a-sonic-boom/458841/10 "2008-08-05T03:23:31Z")
[QUOTE=Una Persson] That is good research and links, **Santo Rugger**. Thank you for making that effort. [/QUOTE] Thanks! It wasn’t too much effort, since I recently did a calc at work to determine if the public windows off site were going to need shielding if there was an inadvertent detonation during a project. There was a specific maximum amount of energetic material specified, a distance, and the size of the windows. My recommendation was to use [HESCOs](http://en.wikipedia.org/wiki/Hesco_bastion), but since it was so close to the threshold, they were able to simply do the work under a tent.