2021-06-24_REVISION - M2012032 - Laserfiche WebLink

Home Browse Search

ASME B31.3-2016 Table K302.3.3D Acceptable Severity Levels for Steel Castings Acceptable Acceptable Thickness Applicable Severity Discontinuity Examined, mm (in.) Standards Level Categories T<_ 51 (2) ASTM E446 1 A, B, C 51 <T_S 114 (4.5) ASTM E186 1 A, B, C 114<T<_305 (12) ASTM E280 1 A, B, C (d) Allowable Displacement Stress Range, SA, The com- for use at pressure—temperature ratings in accordance puted displacement stress range,SE,in a piping system with para. K302.2. (see para. 319.4.4) shall not exceed the allowable dis- placement stress range, SA (see para. 319.2.3), calcu- lated by K304 PRESSURE DESIGN OF HIGH PRESSURE COMPONENTS SA = 1.25Sc+0.25Sh (32) K304.1 Straight Pipe where K304.1.1 General Sc = allowable stress from Table K-1 at minimum (a) The required wall thickness of straight sections of metal temperature expected during the dis- pipe shall be determined in accordance with eq. (33). placement cycle under analysis Sh = allowable stress from Table K-1 at maximum tm = t +c (33) metal temperature expected during the dis- placement cycle under analysis The minimum wall thickness,T,for the pipe selected, K302.3.6 Limits of Calculated Stresses Due to considering manufacturer's minus tolerance,shall be not Occasional Loads less than tm. (a) Operation. The sum of the longitudinal stresses, (b) The following nomenclature is used in the equa- SE,due to sustained loads,such as pressure and weight, tion for pressure design of straight pipe: and of the stresses produced by occasional loads, such c = ci + co 2 as wind or earthquake,may be as much as 1.2 times the = the sum of mechanical allowances (thread or allowable stress given in Table K-1.Where the allowable groove depth) plus corrosion and erosion stress value in Table K-1 exceeds two-thirds of Syt, SE allowances (where ci = the sum of internal shall not exceed 90% of Syt listed in the BPV Code, allowances and co = the sum of external allow- Section II,Part D,Table Y-1.Wind and earthquake forces ances). For threaded components, the nominal need not be considered as acting concurrently. thread depth(dimension h of ASME 131.20.1 or (b) Test. Stresses due to test conditions are not subject equivalent) shall apply,except that for straight to the limitations in para. K302.3. It is not necessary threaded connections, the external thread to consider other occasional loads, such as wind and groove depth need not be considered provided earthquake, as occurring concurrently with test loads. (a) it does not exceed 20% of the wall thickness; K302.4 Allowances (b) the ratio of outside to inside diameter, In determining the minimum required thickness of D/d,is greater than 1.1; a piping component, allowances shall be included for (c) the internally threaded attachment pro- corrosion,erosion,and thread or groove depth. See the vides adequate reinforcement; and definition of c in para. K304.1.1(b). (d) the thread plus the undercut area,if any, does not extend beyond the reinforcement for (16) K302.5 Mechanical Strength a distance more than the nominal wall thickness Paragraph 302.5 applies. of the pipe. t = pressure design wall thickness, as calculated in para. K304.1.2 for internal pressure, or in PART 2 accordance with the procedure listed in PRESSURE DESIGN OF PIPING COMPONENTS para. K304.1.3 for external pressure K303 GENERAL z For machined surfaces or grooves where the tolerance is not Components manufactured in accordance with stan- specified, the tolerance shall be assumed to be 0.5 mm (0.02 in.) dards listed in Table K326.1 shall be considered suitable in addition to the specified depth of the cut.