reg 2 MPEs
The MPE, positive or negative in mm, between two non-consecutive scale marks is (a + bL), where: — L is the value of the length rounded up to the next whole metre; and — a and b are given in Table 1 below. When a terminal interval is bounded by a surface, the MPE for any distance beginning at this point is increased by the value c given in Table 1. The MPE for the length between consecutive scale marks, and the maximum permissible difference between two consecutive intervals, are given in Table 2 below. Where a rule is of the folding type, the jointing shall be such as not to cause any errors, supplementary to those above, exceeding: 0.3 mm for Class II, and 0.5 mm for Class III.