ss v hss

huangyhg

tss v hss
are tss and hss sections the same? if not what are the differences?  
i meant to say ts, not tss
the reason i ask is becuase risa has the option of using  hss and tu sections
hss matches aisc
tu does not
ie, according to risa a hss 7x5x1/8 has a wall thickness of 0.116" but a tu7x5x1/8 has a wall thickness of 0.125"
i have never seen tu called out on a dwg, but i have seen ts
hss, or hollow structural section, has replaced ts, aka tubular section, in the aisc nomenclature.
i'm not familiar with the tu name...
if you "heard" it on the internet, it's guilty until proven innocent. - dcs
i have risa as well, and i have never understood why they have hss sections and tu sections.
daveatkins
swearingen is right. the "old" green steel book has ts sections and pipes. the new black book has hss sections, and round hollow sections (pipes) also noted as being hss sections. there are some minor differences in wall thickness between some ts and hss section, suggesting a tightening of tolerances or maybe even an attempt a "metrification". please note the round hss sections. it suggests that the pipes will be going away too.
old ca se
for an explanation of the hss vs. ts (or tu in risa terminology) go here:
thanks!
to my understanding, the hss shapes were devised because most mills were creating ts shapes at the low end of the tolerance for the wall thickness, thus creating shapes with smaller section property values than what was given by the nominal wall thickness.  the hss designation uses a reduced wall thickness to calculate the section properties.  if i re