Hello,

Here is what my friend Ron had to say on the subject:

I do have a comment on sway braces, both with springs and without (which makes them struts). Either can can act as a seismic support -- the strut, obviously, and the spring type sway brace also, as it changes the piping frequency, i.e., stiffens the piping system. Normally it would be adjusted to provide no load in the hot position and as soon as the pipe tries to move (in either direction) it will provide a spring force of some initial magnitude increasing in load to it's design limit (e.g., 3000 lb, increasing at 1000 lb/in to a maximum of 7000 lb for a sway brace I recently encountered). I don't see any reason it wouldn't limit seismic movements.

Ron Haupt

[ November 27, 2001: Message edited by: John Breen ]