Specification

ASME A112.18.1-2018/CSA B125.1-18 Plumbing supply fittings
July 2018 © 2018 Canadian Standards Association
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Annex A (informative)
Unit conversion and rounding criteria
Note: This Annex is an informative (non-mandatory) part of this Standard.
A.1 Conversion
The following conversion rules are used in this Standard:
a) Zeros to the left of the first non-zero digit are not significant.
b) If the number is greater than 1, all zeros to the right of the decimal point are significant.
c) In multiplication and division, the original number with the smallest number of significant digits
determines the number of significant digits in the product or quotient.
d) If an exact constant is used (e.g., 3 ft = 1 yd), it does not affect the number of significant digits in
the calculated value.
e) If inexact constants are used (e.g., π = 3.1416), the constant with at least one more significant digit
than the smallest number of significant digits in the original data is used.
A.2 Rounding
The following rounding rules are used in this Standard:
a) The digits that follow the last significant digit are dropped if the first digit is less than 5.
b) If the first digit dropped is greater than 5, the preceding digit is increased by 1.
c) If the first digit dropped is 5 and there are non-zero digits following the 5, the preceding digit is
increased by 1.
d) If the first digit dropped is 5 and there are only zeros following the 5, the digit is rounded to the
even number (e.g., for three significant digits, 1.655000 becomes 1.66, 1.625000 becomes 1.62).
e) For maximums and minimums, rounding is performed within the range of the maximum and
minimum values in a way that does not violate the original limits.