Allowable stresses, table

Special note for the sixth edition At diis time, metric equivalents have not been provided for the allowable-stress tables of the piping code B31.3. Tliey may be computed by the following rela-tionsliips ( F - 32) x 9 = C Ibf/iir (stress) x 6.S9.5 x 10 = MPa. 

TABLE 10 49 Allowable Stresses in Tension for Materials (4/ 13/ 28) Continued)... 

For use in code piping at the stated allowable stresses, the tensile and yield strengths listed in these tables must be verified by tensile tests at the mill such tests shall be specified in the purchase order. 

For welded construction with work-hardened grades, use the stresses for annealed material for welded construction with precipitation-hardened grades, use the special allowable stresses for welded constrnction given in die tables. 

SE values shown in tliis table for welded pipe include the joint quality factor E, for the longitudinal weld as required by Fig. 10-164 and, when applicable, the structural-grade quality factor Es of 0.92. For some code computations, particularly with regard to expansion, dexibility, structural attachments, supports, and restraints, the longihidinal-joint quality factor E, need not be considered. To determine the allowable stress S for use in code computations not ntdizing the joint quality factor E, divide the value SF shown in tliis table by the longitudinal-joint quality factor E, tabulated in Fig. 10-164. 

The SE values in Table 10-49 are equal to the basic allowable stresses in tension S multiplied by a quality factor E (see subsection Pressure Design of Metallic Components Wall Tliick-ness"). The design stress values for bolting materials are equal to die basic allowable stresses S. The stress values in shear shall be 0.80 times the allowable stresses in tension derived from tabulated values in Table 10-49 adjusted when applicable in accordance widi Note 13. 8tress values in bearing shall be twice those in shear. 

The allowable stress range for displacement stresses and permissible additive stresses shall be as specified in Eqs. (10-93) and (10-94) for systems primarily stressed in bending and/or torsion. For pipe or piping components containing longitudinal welds the basic allowable stress S may be used to determine S. (See Table 10-49, Note 13.)... 

Subsection C This subsection contains requirements pertaining to classes of materials. Carbon and low-alloy steels are governed by Part UCS, nonferrous materials by Part UNF, high-alloy steels by Part UHA, and steels with tensile properties enhanced by heat treatment by Part UHT. Each of these parts includes tables of maximum allowable stress values for all code materials for a range of metal temperatures. These stress values include appropriate safety fac tors. Rules governing the apphcation, fabrication, and heat treatment of the vessels are included in each part. 

The maximum allowable stress values at normal temperature range for the steel plates most commonly used in the fabrication of pressure vessels are given in Table 12-3. For stress values at higher temperatures and for other materials, the latest edition of the ASME Code should be referenced. 

Key material is usually AlSl 1018 or AlSl 1045. Table 59.4 provides the allowable stresses for these materials. 

As with materials of construction correction factors, the pressure correction factors in Table 2.5 are average and only approximate and will vary, amongst other things, according to the type of equipment. Finally, its operating temperature also influences equipment capital cost. This is caused by, amongst other factors, a decrease in the allowable stress for materials of construction as the temperature increases. Table 2.6 presents typical factors to account for the operating temperature. 

The allowable stress or component rating at any temperature below the minimum shown in the tables of Mandatory Appendix IX or Fig. GR-2.1.2(b)A shall not exceed the stress value or rating at the minimum... 

When an unlisted material is to be used, or when a listed material is to be used above the highest temperature for which stress values appear in the tables of Appendix IX, the designer is responsible for demonstrating the validity of the allowable stresses and other limits used in design and of the approach taken in using the material, including the derivation of stress data and the establishment of temperature limits. 

A material performance factor, My, shall be applied to the allowable stress, S, in all minimum wall thickness or pressure calculations (see Mandatory Appendix IX, Tables IX-5B and IX-5C, for My). 

Some of the standards for components in Table IP-8.1 (e.g., ASME B16.9 and ASME B16.ll) state that pressure-temperature ratings are based on straight seamless pipe. Except as limited in the standard or elsewhere in this Code, such a component, made of a material having the same allowable stress as the pipe, shall be rated using not more than 87.5% of the nominal thickness of seamless pipe corresponding to the schedule, weight, or pressure class of the fitting, less all allowances applied to the pipe (e.g., thread depth and/or corrosion allowance). 

The allowable stress for occasional loads of short duration, such as surge, extreme wind, or earthquake, may be taken as the strength reduction factor times 90% of the yield strength at temperature times Mj for materials with ductile behavior. This yield strength shall be as listed in ASME BPV Code Section II, Part D, Table Y-l (ensure materials are suitable for hydrogen service see API 941), or determined in accordance with para. 

Sc Allowable stress from Table IX-1A for the material at design temperature MPa ksi... 

This table is split into two tables by usage Table IX-l A, Basic Allowable Stresses in Tension for Metal Piping Materials and Table IX-1B, Specified Minimum Yield Strength for Steel Pipe Commonly Used in Pipeline Systems. 

Table IX-1A Basic Allowable Stresses in Tension for Metal Piping Materials...

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