StoneCold,
SIF stands for stress intesification factor jost like factor of safety, it is always used when branch connection is involved, this takes into consideration compansation for the areas of stress concentration.
pipe span depends on line size as well as fluid carried, this combine load and other parameters like space, operating condition, availability of structure and cost will dictate type of support to be used. I hove not heared of blanket treatment.
Thanks