Reference meters
5.—(1) Reference meters shall be tested either—
(a)by means of a local or working standard capacity measure which is of sufficient size to hold at least one minute’s delivery of the meter under test; or
(b)by means of a weighing machine which can weigh at least one minute’s delivery of the meter under test.
(2) The capacity measure or the weighing machine used to test a reference meter shall have a discrimination threshold of not less than 0.01 per cent. of the quantity delivered by the meter under test.
In a test under paragraph (1)(b) above, the density of the test liquid shall be determined to an accuracy of 0.01 per cent.