by Henry Zumbrun
Morehouse has been performing both ASTM E74 and ISO 376 calibrations for more than fifteen years. We have been calibrating in accordance with the ASTM E74 standard since its introduction in 1974, and performing ISO 376 calibrations since sometime in early 2000. Until recently, we assumed that the rest of the world and force community knew that the standards were completely different and that either standard could not be substituted for another. However, we have learned that not only are some laboratories providing field calibrations by intermixing and using an ASTM E74 calibration to certify a tensile machine to ISO 7500, but that several organizations throughout the world are not aware that the standards are vastly different in the criteria requirements. Basically, if ISO 7500 is the requirement, then calibration needs to be performed in accordance with ISO 376 on the force-proving instruments used to certify the tensile machine. If ASTM E4 is the requirement, then the elastic force-measuring instrument needs to be calibrated in accordance with the ASTM E74 standard. The differences have already begun to emerge with the subtle use of terminology. Read the full article (PDF)
