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ASME B31.3-2016 <br /> (16) Fig. 323.2.213 Reduction in Lowest Exemption Temperature for Steels Without Impact Testing <br /> (See Table 323.2.213 for Tabular Values) <br /> Temperature Reduction,'F <br /> 20 40 60 80 100 120 140 160 180 200 217 <br /> 1 <br /> 0.9 <br /> 0.8 <br /> 0.7 <br /> 0.6 <br /> 2 <br /> 0.5 <br /> 0.4 <br /> 0.3 <br /> 0.2 <br /> 0.1 <br /> 0 <br /> 0 10 20 30 40 50 60 70 80 90 100 110 120 <br /> Temperature Reduction,'C <br /> GENERAL NOTES: <br /> (a) The stress ratio is defined as the maximum of the following: <br /> (1) circumferential pressure stress for the condition under consideration (based on minimum pipe wall thickness less allowances) <br /> divided by the basic allowable stress at the condition under consideration. <br /> (2) for piping components with pressure ratings,the pressure for the condition under consideration divided by the pressure rating at <br /> the condition under consideration. <br /> (3) combined stress due to pressure, dead loads, live loads, and displacement strain for the condition under consideration divided <br /> by the basic allowable stress at the condition under consideration. In calculating this combined stress,the forces and moments <br /> in the piping system for these combined sustained loads and displacement strains shall be calculated using nominal dimensions, <br /> and the stresses shall be calculated using eqs. (23a) through (23d)with all of the stress indices taken as 1.0 (IQ = l; = to = <br /> It = 1.0) and using section properties based on the nominal dimensions less corrosion, erosion, and mechanical allowances. <br /> Also see Appendix F, para. F323.2.2. <br /> (b) Impact testing is not required if the design minimum temperature is greater than or equal to —104°C (-155°0 and the stress ratio <br /> does not exceed 0.3. <br /> (c) For stress ratios greater than 0.3, the lowest design minimum temperature permitted is—48°C (-55°F). <br />