Frequently Asked Questions

Hollow Structural Sections

What is the difference between the 1987 and the 1992 editions of CSA Standards G40.20, with respect to wall thickness tolerances for hollow structural sections?
9/5/1995

Table 31 of CSA Standard G40.20-92 "General Requirements for Rolled or Welded Structural Quality Steel" states that "the actual weight of an individual length of hollow structural section shall not deviate from the published weight by more than -3.5% or +10%". The metric version of the standard says the same thing, substituting the word "mass" for the word "weight". Table 31 in the 1987 edition of the CSA G40.20 Standard has exactly the same requirement. This requirement has existed in the relevant standard since it was first published in 1969 as clause 6.1 in CSA Standard G40.15 "General Requirements for Delivery of Welded or Seamless Hollow Structural sections", which was one of a group of steel material standards published by CSA prior to the initial publication of CSA Standards G40.20 and G40.21 in 1973.

The only difference between the 1987 and the 1992 editions of CSA Standard G40.20, as far as hollow structural sections are concerned, is a change in table 32. In the 1992 edition, this table states that "wall thickness shall not deviate by more than -5% or +10% from the nominal wall thickness specified, ....". In the 1987 edition, the maximum deviations permitted were -10% or +10%.

In spite of this change, certification of hollow structural sections in accordance with the requirements of CSA Standard G40.20 with regard to dimensional and weight (or mass) requirements requires that the sections conform to the specified maximum tolerance for weight per foot (or mass) of table 31, which is the same in both the 1987 and the 1992 editions of the standards.