Greetings to all,
Most building codes these days include a term of the form (1 + n * z/h) in their equations for equivalent static loading on mechanical components, where "h" is the average roof height, "z" is the height in the structure at the point of attachment of the component, and "n" is usually 2. The purpose of the term is to amplify the equivalent static seismic load according to the height of the component above grade.
I'm hoping someone can provide guidance in how to appropriately apply this term to piping systems. Specifically, if a piping system is supported from the building structure at an elevation near the roof of a building, then it makes sense to use z/h=1. But if the piping system is on top of a pipe rack (inside or outside the building) that is only 20' or 30' high, what z/h should be used? Taking this further, if the piping were on top of a structural frame that is only a few feet above grade, what then would be the appropriate z/h? In short, what did the structural guys have in mind?