A. For piping to operate at hoop stresses of less than 20 percent of specified minimum yield strength, if the nominal wall thicknesses of the adjoining ends do not vary more than 1/8-inch, no special treatment is necessary provided adequate penetration and bond is accomplished in welding. If the offset is greater than 1/8-inch the following paragraphs will apply.
FOR STRESS LEVELS ABOVE 20 PERCENT OF THE MINIMUM SPECIFIED YIELD STRENGTH.
B. If the nominal wall thicknesses of the adjoining ends do not vary more than 3/32 inch, no special treatment is necessary provided full penetration and bond is accomplished in welding. See sketch (a).
C. Where the nominal internal offset is more than 3/32 inch and there is no access to the inside of the pipe for welding, the transition must be made by a taper cut on the inside end of the thicker section. See sketch (b). The taper angle shall not be steeper than 30 deg. nor less than 14 deg.
D. Where the nominal internal offset is more than 3/32 inch, but does not exceed 1/2 the thinner section, and there is access to the inside of the pipe for welding, the transition may be made with a tapered weld as shown in sketch (c). The land on the thicker section must be equal to the offset plus the land on abutting section.
E. Where the nominal internal offset is more than 1/2 the thinner section, and there is access to the inside of the pipe for welding, the transition may be made with a taper cut on the inside end of the thicker section as shown in sketch (b), or by a combination taper weld to 1/2 the thinner section and a taper cut from that point as shown in sketch (d)