India, one of 60 signatories who approved changing the definition of the unit of mass — kilogramme — to an electromagnetic force from a specially-preserved artefact, at an international conference last week in France, will spend ₹60 crore to build a facility that will calibrate “weights” used in the country.

“The 26th meeting of General Conference of Weights and Measures (CGPM) held between November 13 and 16 in Versailles in France unanimously decided to redefine the kilogramme in terms of electromagnetic energy rather than the reference mass of a platinum iridium ingot kept in the International Bureau of Weights and Measures (BIPM) in Sevres, near Paris,” said Dinesh Kumar Aswal, Director of National Physical Laboratory, which doubles up as India’s national metrology institute.

“This is being done to make sure that measurement of weight becomes more accurate,” Aswal said.

Aswal, together with Consumer Affairs Secretary Avinash Kumar Srivastava, represented India at the CGPM meeting, which changed the definition of kilogramme, which was around for a record 130 years. India was one of 60-member states that unanimously voted for redefining the kilo.

The device that will be used to accurately measure the weight is called Kibble balance — a self-calibrating electromechanical balance — named after a British scientist, Bryan Kibble, who invented it. The new definition will come into force on May 20 next year, which happens to be World Metrology Day.

Crucial for hi-tech industries

Currently, there are only four Kibble balances in the world. Apart from the one in BIPM, there is one each in Canada, Germany and the US. “We plan to build a Kibble balance over the next three years, once the funds are approved by the Government,” Aswal said.

“The balance will be as tall as a three-storied building. We are in the process of getting funds approved for setting it up,” said Srivastava.

According to Aswal, NPL has already built a Kibble balance that accurately measures 1 gm weight.

Having a more accurate measurement of mass will be very important for hi-tech industries based on nanotechnology and biotechnology as well as the pharmaceutical industry where weighing drugs in minute quantities is crucial, Srivastava said.