Govt to develop prototype of 1kg after 60 nations including India okays change in def of kg

With the new definition of kilogramme coming into effect from May 20 next year globally, the government said Monday it would develop a prototype of 1 kg in next three years at a cost of Rs 60 crore.

The new scientific standard of kg will help in accurate measurement benefitting immensely sectors like pharma, a top official said.

Last week, the world's standard definitions of kilogramme, the ampere, the kelvin and the mole have been changed, after representatives from 60 countries voted to redefine the International System of Units (SI) for weight, current, temperature and amount of chemical substance. The definition has been changed after 130 years.

"From one kg artefact was kept in France, now one kilogramme will be measured in scientific physical constant," Consumer Affairs Secretary A K Srivastava told reporters here.

He said the new standard of kilogramme will lead to accurate measurement, helping pharma sector in defining the doses of medication. "Right doses of medicine is very important to treat a disease. An overdose and underdose of medicine will not give desired result and could be harmful".

At present, the International Prototype of the Kilogramme (IPK) is made of 90 per cent platinum and 10 per cent iridium, and is a cylinder of 39 mm each of diameter and height. It is kept at the International Bureau of Weights and Measures (BIPM) in France.

Now, this will be replaced by the Planck constant (h), the fundamental constant of quantum physics. While the stability of the IPK could only be confirmed by comparisons with identical copies, a difficult and potentially inaccurate process, the Planck constant is ready for use everywhere and always.

"In the recent General Conference on Weights and Measures (CGPM), we have demonstrated prototype of 1 gram," National Physical Laboratory (NPL) Director D K Aswal said.

He said the NPL, in association with the Consumer Affairs Ministry, would develop 1kg prototype in India. The US, the UK, Canada and Germany have successfully developed Kibble balance for 1 kg.

Kibble balance is a self-calibrating electromechanical balance and provides the measurement of mass, traceable in terms of electrical parameters and linking of macroscopic mass to the Planck constant.

Srivastava said the SI unit system would finally be a truly universal system, free of any human artifacts. He said the proposal to develop prototype of one kg in India is at budget formulation stage and it would take 3-4 years to develop