The impact of reinforcing-steel industry's plan to fully convert to soft metric rebar production is quite obviously going to affect a designers grasp of steel rebar sizes, but that’s about it. Since soft metric bars are physically the same size as corresponding inch-pound bars, the use of soft metric rebar will not require design changes or changes in fabrication and construction practices. The need for designers and contractors to become familiar with the specifications of the new metric steel rebar sizes are obvious, but steps have been taken by mills and rebar fabrications in order to lessen confusion and make the transition as easy as possible.
Gerald Ford said, “We are making miles and miles of progress toward the metric system.” And while it’s fun to joke, the President was right. Overseas, US architects, engineers and contractors do over $100 billion of metric work every year, and that includes metric steel rebar sizes, and generally everyone easily adapts and then prefers the system. Metrication is largely a paper process, and with that complete (i.e. codes and standards) the new generation will have no problems with the new system.
So, there is clear benefit to the metric switch of steel rebar sizes. Metrification can increase the industry’s efficiency and quality, making the US cost-effective at home, and a tough-competitor abroad.
Again, the metrification of steel rebar sizes should be an easy transition in the grand scheme, undergoing simply a name change (per ASTM A615M-96a
and ASTM A706-96a) as follows: as follows: No. 3 to No. 10; No. 4 to No. 13; No. 5 to No. 16; No. 6 to No. 19; No. 8 to No. 22.
No so bad, is it? So steel rebar sizes are in metric, baseball and football stays imperial (some things are sacred), and slowly but surely 6 million US works join the world standard of measurement, benefiting the entire country.