# Is overpressure really an appropriate criteria for blast damage?

So, I went on Nukemap, and they gave me the following values for blast effects.

1 psi (7 kPa): windows break 5 psi (34 kPa): most residential buildings collapse

These numbers are way too high. 1 psi corresponds to 237mph (381 km/h, 66 m/s) at sea level. This is enough to destroy every single building.

What this tells me is that there is some other factor at play. Specifically, the blast wave is of such a short duration that no building has sufficient time to react. In effect, the blast wave is an impact force, not a wind or pressure force. Therefore, it would seem more appropriate to quantify destructive potential in impulse, rather than pressure. L The implications of this error are serious, since for a given overpressure, a larger blast produces greater impulse. Hence Nukemap and all other calculations that use the overpressure to determine destruction are wildly wrong.

• After some distance, being hit by blast debris or 'wind' is almost impossible, and there are just 2 things that can reach you; pressure waves and radio waves. So pressure is actually quite important parameter. Jan 20 at 10:10
• @Abdullah You are right some air movement is required, but I would not call that wind. A good example of pressure wave is sound. When you hear a sound, do you also sense wind? Jan 20 at 11:45
• @DanielHatton I simply used the dynamic pressure equation Jan 21 at 15:14
• @DanielHatton Will you prefer Rayleigh or Buckingham? :) Jan 24 at 11:40
• @SolarMike The Rayleigh method is just a special case of the Buckingham pi theorem anyway. But then, you knew that. Jan 24 at 11:44