national measurement act 1960
determination by the national standards commission
Recognized-Value Standard of Measurement
of Viscosity
In pursuance of paragraph 8A(1)(a) of the National Measurement Act 1960, the National Standards Commission hereby determines that the magnitude of the dynamic viscosity of water prepared as in the Schedule and at a temperature of 20°C shall be a recognised-value standard of measurement having the exact value of 0.001 002 Pa.s.
The water shall have been prepared by being distilled at least twice, the final distillation having been performed after addition to the water of potassium permanganate to a concentration of not less than one part in ten thousand by mass. In the final distillation the distillate shall have been collected in silica or borosilicate glass at a temperature of not less than 10°C and not more than 30°C in air at a pressure in the range 80 000 to 120 000 Pa, and shall have been maintained subsequently in contact with air within that temperature range and pressure range. The water shall be free from bubbles and its electrical resistivity at 20°C shall be not less than 3 000 Ω.m.
Dated this 21st day of March 1985
The common seal of the national T.J. PETRY
standards commission was hereto
affixed by authority of the Commission
in the presence of