In a recent CCRL lab inspection the inspector commented that the effective gauge length for ASTM C1293 was not in compliance. ASTM C1293 refers to ASTM C490/490M for apparatus. Since C1293 is a SI unit standard the inspector referred to the SI limits for the gauge length in ASTM C490/490M.
Section 5.2.2 of ASTM C490/490M requires the gauge length to be 250±2.5 mm (SI Units) or 10±0.1 in. (Inch-Pound units) and the gage studs to extend into the specimen 17.5±0.5 mm (SI Units) or 0.625±0.025 in. (Inch-Pound units).
Most laboratories in the country use the same molds as ASTM C157 for casting the ASTM C1293 specimens. ASTM C157 is a dual-unit standard. So, their molds meet the ASTM C490/490M gauge length requirements for Inch-Pound units. But the same molds do not meet the ASTM C490/490M gauge length requirements for SI units.
If ASTM C1293 is changed to a dual-unit standard like ASTM C157 this problem would not arise and the same molds could be used for both ASTM C157 and ASTM C1293. This ballot item seeks to convert ASTM C1293 into a dual unit standard.