minimum wall thickness at any point
e min
minminimum value for the wallthickness at any point around the circumference of a component, as specified
maximum wall thickness at any point
emax
maximum value for the wall thickness at any point around the circumference of a component, as specified
mean wall thickness
em
arithmetical mean of a number of measurements of the wall thickness, regularly spaced around the circumference and in the same cross-section of a component, including the measured minimum and the measured maximum values of the wall thickness in that cross-section
tolerance
permitted variation of the specified value of a quantity, expressed as the difference between the permitted maximum and the permitted minimum value
wall thickness tolerance
Ty
permitted difference between the wall thickness at any point, e, and the nominal wall thickness, en
standard dimension ratio
SDR
numerical designation of a pipe series, which is a convenient round number, approximately equal to the dimension ratio of the nominal outside diameter, dn, and the nominal wall thickness, en
en=dn/sdr