General Question - for ranking severity, the only difference between a 9 and a 10 is, a 9 is with warning and a 10 is without warning. Does warning include operator notification that the process he/she is performing may be "hazardous" or, does the process have to signal some type of warning that a failure is about to occurr, say a flashing light or horn sounding. Also, does process failure warning include a part that fails in steps? For example, an operator pressurizes a pipe, and the pipe starts to hiss (which warns the operator) before it explodes, versus, the pipe is pressurized and then explodes without any warning (no hissing)? Any clarification on this issue is greatly appreciated.