Regulation 93
Spring balances shall be tested by means of both increasing and decreasing loads, and the spring shall be allowed to vibrate before a reading is taken.
In the case of a spring balance the pan of which is above the spring—
if the pan is not in the form of a scoop, the instrument shall indicate the same weight within half the prescribed limits of error if the centre of a load equal to half the capacity of the instrument is placed on the pan anywhere within a distance from the centre equal to one-third of the greatest length of the pan, or, if the pan has a vertical side, against the middle of that side;
if the pan is in the form of a scoop, the instrument shall fall within the prescribed limits of error when a load equal to half the capacity of the instrument is placed against the middle of the back of the scoop and again when a like load is placed in any position on the scoop.
In the case of a spring balance the pan of which is below the spring, the instrument shall fall within the prescribed limits of error when a load equal to the capacity of the instrument is placed in any position on the pan.