U.S. industries are increasing their SI usage at different rates. Manufacturers that rely on international supply chains are at the high end of the Metric Continuum. Multiple case studies have been published from various industries. Interestingly, most of these studies were conducted between 1970 to 1980 during early U.S. metrication discussions. Over the years, companies have continued to internally metricate without publishing the costs or the achieved benefits.
Caterpillar Tractor Company commenced its metrication efforts in 1971 after the Congress-commissioned study A Metric America: A Decision Whose Time Has Come was published. Caterpillar began its conversion because of its operations in metric countries. Caterpillar’s number of sheet steel sizes were reduced from 74 sizes to 34 metric sizes. Additionally, its metal bar sizes were reduced from more than 500 to fewer than 200. These adjustments yielded a 54 % decrease in metal costs. Utilizing one standardized measurement system benefited Caterpillar $900,000 to $1,000,000 annually because of inventory reductions and the decrease in the cost of parts internationally. Compared to the achieved benefits, Caterpillar’s cost of metrication was minimal.
General Motors began its metrication efforts in 1973. These metrication efforts significantly reduced the quantity of sized parts required. One provided example includes fan belts, which had its sizes reduced from more than 900 to fewer than 100. Additionally, switching to standardized wire gauges reduced the number of wire sizes used; this improvement in wire efficiency reduced costs by $1,600,000 each year. This single fiscal benefit surpassed General Motor’s annual metrication costs.
These case studies display potential cost savings, inventory reductions, and efficiency increases from switching to the metric system. In many case studies, any costs of metrication were quickly recovered, as portrayed in Caterpillar Tractor Company and General Motors. Furthermore, metrication is essential to efficient operation in international economies.
Small Businesses and Manufacturers
A survey of small businesses was administered by the U.S. Metric Board in 1980. The report noted that industry action and customer demand dominate as reasons for converting.
Between 1981 and 1982, the U.S. Metric Board commissioned a two-part investigation into the consequences of small businesses after metrication. The first phase identified small businesses that had made substantial investments in converting to metric. Research demonstrated that small businesses typically invest in metric production in response to a large corporation’s needs for metric parts and products. The second phase reported three case studies evaluating the effects of large businesses metrication on small business suppliers. The team studied how the conversion of a General Electric Company department, two Ford Motor Company product lines, and three divisions of Ingersoll-Rand affected their small business suppliers.
Wine and Distilled Spirits - U.S. Department of Treasury and US Industry
Metrication Study for Large Space Telescope
National Aeronautics and Space Administration (NASA), George C. Marshall Space Flight Center, Alabama, contracted a study to analyze approaches for implementing metric system operations for a Large Space Telescope. The evaluation considered three possible approaches: no metrication, soft, and hard processes. The report (1973) addresses data handling, unit conversion, dual measures, standard metric-sized materials, and aerospace metrication efforts. The use of machinery conversion groupings and “thinking metric” is emphasized. Investigators note a previous study, which stated that operations would not be negatively impacted by metrication. System cost during the transition were approximated.
Snow Sampling Metrication Study
From 1978 to 1983, the Western Snow Conference (WSC) conducted a Metrication Study. The Metrication of Manual Snow Sampling Equipment – Final Report (1983) describes the WSC metrication process activities, design recommendations, specifications, and drawings as well as a proposal for converting to metric snow sampling equipment. The University of Nevada maintains original research documentation in its collection, which is accessible by researchers onsite.
Effects of Metric Change on Safety in the Workplace for Selected Occupations
This 1982 study commissioned by the U.S. Metric Board assesses the potential safety issues of workplace metric conversion. Thirty-five occupations were sampled and analyzed to identify potential safety hazards by industrial hygienists, safety engineers and academia. Investigators reported that a well-planned metrication program reduces hazard potential.
Healthcare - Radiation Measurements
In 2017, an ad hoc National Academies of Sciences, Engineering, and Medicine committee conducted a workshop in Washington, DC to obtain perspectives from United States radiation protection and user communities on the potential communication improvements associated with adopting the SI for radiation measurement units. The Workshop Proceedings reported a summary of presentations and discussions that focused on improving national and international radiation emergency response, current national radiation unit practices (mixed use of both SI and non-SI units), benefits and challenges of exclusive SI radiation unit use, international SI radiation unit adoption lessons learned, and possible next steps towards exclusive U.S. use of SI radiation units. Some workshop participants noted that SI radiation unit adoption in the U.S. has been slow and that a lack of SI usage regulatory requirements for the nuclear power industry had subsequently inhibited SI adoption by local, state, and federal government agencies. Participants recognized that a coordinated interagency effort is needed to further examine costs and benefits, as well as plan for exclusive SI measurement unit implementation.
The American Society for Testing and Materials (ASTM) reported an analysis of SI use in documentary standards. The ASTM Standardization News editor, notes in Of SI and Standards that when work began in 2008, 66 % of documentary standards followed the rules found in Form and Style for ASTM Standards, which increased to 85 % by 2014. A great deal of progress has been made in ensuring that ASTM committees use SI units, non-SI units, or both, appropriately. “This effort has revealed that about 17 percent of standards, such as most terminology standards, do not use units. Of the standards that do use units, a majority, about 51 percent, use SI only; 33 percent use non-SI units; and 16 percent use both units combined.”
Disclaimer: Any mention of commercial products within NIST web pages is for information only; it does not imply recommendation or endorsement by NIST.