[pianotech] concert pitch

[Renee Ingeberg]

I was wondering what the standard concert pitch is these days. In  
certain parts of the world, there are different meanings on the  
subject. What is the concert pitch for orchestras in the U.S.?
The question comes up every once in a while...and is always followed  
by some discussion.
Also, does anyone know how much one raises the tension ( in kilograms)  
in a grand when raising the pitch from 440 to 442?

Renee