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ASME B31.3-2016
<br /> tm = minimum required wall thickness,including P = internal design gage pressure
<br /> mechanical, corrosion, and erosion allowances S = allowable stress from Table K-1
<br /> T = pipe wall thickness (measured or minimum in
<br /> Adequate reinforcement by the attachment is defined accordance with the purchase specification)
<br /> as that necessary to ensure that the static burst pressure
<br /> of the connection will equal or exceed that of the (b) At design temperatures where allowable stress,S,
<br /> unthreaded portion of the pipe. The adequacy of the values in Table K-1 are in boldface(solution heat treated
<br /> reinforcement shall be substantiated as required by austenitic stainless steels and certain nickel alloys with
<br /> para. K304.7.2. similar stress-strain behavior only),the internal pressure
<br /> K304.1.2 Straight Pipe Under Internal Pressure design wall thickness,t,shall be not less than that calcu-
<br /> lated in accordance with eq. (34c)for pipe with a speci-
<br /> (a) Except as provided in (b) below for solution heat fied outside diameter and minimum wall thickness, or
<br /> treated austenitic stainless steels and certain nickel eq. (34d) for pipe with a specified inside diameter and
<br /> alloys with similar stress-strain behavior, the internal minimum wall thickness.
<br /> pressure design wall thickness,t, shall be not less than
<br /> that calculated in accordance with eq. (34a) for pipe °D -2c 45
<br /> with a specified outside diameter and minimum wall t = 2 �1 -exp�-1.155P�j S (34c)
<br /> thickness, or eq. (34b) for pipe with a specified inside
<br /> diameter and minimum wall thickness. or
<br /> N
<br /> d+2c, 1.155P 45
<br /> t D -2c= ° -exp S (34a)3 4 s t = exp 1 (34d)
<br /> or LLLLLL Alternatively,the internal design gage pressure,P,may
<br /> be calculated by eq. (35c) or (35d).
<br /> d+2c p
<br /> t = exp - 1� (34b)3 4 s
<br /> 2 S
<br /> S D -2co
<br /> LLLLLL P =
<br /> 1.155 In�D -2(T-ci) (35c)4,5
<br /> 35c)4 s
<br /> Alternatively,the internal design gage pressure,P,may
<br /> be calculated by eq. (35a) or (35b). or
<br /> D -2co _ S [d+2(T-co)] 4,5
<br /> ID -2(T-c�)
<br /> P = S x In (35a)4,5 P 1.155 d+2c, (35d)
<br /> K304.1.3 Straight Pipe Under External Pressure.
<br /> or The pressure design thickness for straight pipe under
<br /> Id +2(T-co) external pressure shall be determined in accordance with
<br /> P = S x In d+2ci (35b)4,5 para. K304.1.2 for pipe where D/t <3.33,if at least one
<br /> end of the pipe is exposed to full external pressure,
<br /> where producing a compressive axial stress.For D/t>-3.33,and
<br /> D = outside diameter of pipe. For design calcula- for D/t<3.33 where external pressure is not applied to
<br /> tions in accordance with this Chapter, the out- at least one end of the pipe, the pressure design wall
<br /> side diameter of the pipe is the maximum value thickness shall be determined in accordance with
<br /> allowable under the specifications. para. 304.1.3 except that the stress values shall be taken
<br /> d = inside diameter of pipe.For design calculations from Table K-1.
<br /> in accordance with this Chapter, the inside K304.2 Curved and Mitered Segments of Pipe
<br /> diameter of the pipe is the maximum value
<br /> allowable under the specifications. K304.2.1 Pipe Bends. The minimum required wall
<br /> thickness t,,,of a bend,after bending,may be determined
<br /> 3 An exponential [e.g.,the term exp (-PIS)]represents the base as for straight pipe in accordance with para. K304.1,
<br /> of natural logarithms e raised to the stated power(i.e., -PIS). provided that the bend radius of the pipe centerline is
<br /> 4 The intent of this equation is to provide a factor of not less than equal to or greater than ten times the nominal pipe
<br /> 1.732(or f)on the pressure required,according to the von Mises outside diameter and the tolerances and strain limits
<br /> theory, to initiate yielding on the outside surface of a cylinder of para. K332 are met. Otherwise the design shall be
<br /> made from an elastic-perfectly plastic material.For solution heat
<br /> treated austenitic stainless steels and certain nickel alloys with qualified as required by para. K304.7.2.
<br /> similar stress-strain behavior,this factor is as low as approximately K304.2.2 Elbows. Manufactured elbows not in
<br /> 1.5 at elevated temperatures. accordance with para.K303 and pipe bends not in accor-
<br /> Any mechanical,corrosion,or erosion allowance,c,not specified
<br /> as internal,ci,or external,co,shall be assumed to be internal,i.e., dance with para.K304.2.1 shall be qualified as required
<br /> c = ci and co = 0. by para. K304.7.2.
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