Round HSS most typically are manufactured in the U.S. to the ASTM A500 Standard. Pipes covered under the AISC Specification are manufactured to the ASTM A53 Grade B Standard. The materials have different minimum specified yield strengths but similar dimensional characteristics in the cross-sections that match between these different products. Fy = 42 ksi for ASTM A500 Grade B Round HSS, whereas Fy = 35 ksi for ASTM A53 Grade B Pipe. For further information about differences and similarities, see “Are You Properly Specifying Materials?” in the January 2009 issue of MSC (available online at www.modernsteel.com).