Comparison Between ASME B31.1 & 31.3 & 31.8

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RB-EG-UE301 Comparison ASME B31.1, B31.3 and B31.8

RB-EG-UE301 Comparison ASME B31.1, B31.3 and B31.8 (/engineeringguides/254-rb-eg-ue301-comparison-asme-b31-1-b31-3-and-b31-8.html) This is a LIVE STUDY document and will be changed without notice. The content may contain errors and omissions. ASME B31.1 (2008) Power piping: typically found in electric power generating stations, in heating and cooling systems

ASME B31.3 (2008) Process piping: typically found in petroleum refineries, chemical, pharmaceutical, textile and paper plants

ASME B31.8 (2007) Gas transportation and distribution systems: piping transporting products, predominantly gas

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7/16/2014

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ASME B31.1 (2008) Applicable: boiler external piping from first joint up to and including first block valve for boilers where:

ASME B31.3 (2008) Exclusions:

ASME B31.8 (2007) Exclusions: • pressure vessels, heat exchangers, pumps

• steam or vapor is generated over 100 kPa

• piping systems pressure above 0 and less 105 kPa nonflammable, nontoxic and not damaging to human tissues

• high temperature water over 1103 kPa and/or temperatures of 120 Celsius

• power boilers covered in BPV code and external piping covered in B31.1

• metal temperatures below -28.88 Celsius (-20 F) or over 232.22 Celsius (450 F)

• tubes, tube headers, crossovers and manifolds of fired heaters

• piping beyond customer's meter set assembly

• pressure vessels, heat exchangers, pumps

• piping in refineries, natural gasoline extraction, gas treating plants

Excluding: fatigue due to pressure cycling

Including: fatigue due pressure cycling and thermal cycling

• vent piping to substantially atmospheric pressures

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• wellhead assemblies • proprietary items such as equipment • liquid petroleum transportation systems, slurry transportation, carbon dioxide and liquefied natural gas piping systems Allowable stress:

Allowable stress:

• as per tables in Appendix A

• as per Table A-1 and A-2

• shear to remain below 80%, bearing to remain below 160% of allowable stress

• shear to remain below 80%, bearing to remain below 160% of allowable stress

• basis are same as ASME section II Part D Appendix 1 except for cast iron and ductile iron

• basis for bolting, cast iron, other material

Allowable stress: • as per table Appendix D times temperature derating factor in table 841.116A

• flanges due to leakage below 75% • allowable stress of unlisted material (not conforming 323.1.2) can not be used

Materials: material of unknown specification shall Materials: material of unknown specification shall Materials: material only as per not be used for pressure containing components not be used for pressure containing components Appendix A Quality factor E: depending type of weld, radiography and material

Quality factor E: depending type of weld, radiography and material

Quality factor E: depending type of weld, radiography and material

Factor y: factor depending Ferritic, Austenitic, Nickel and design temperature Factor W: weld strength reduction factor

Factor W: weld strength reduction factor Factor f: stress range factor Factor F: design factor

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ASME B31.1 (2008)

ASME B31.3 (2008)

ASME B31.8 (2007) Factor T: temperature derating factor, compensate material allowable stress values for temperature, Table 841.166A

Pipe under internal pressure (104.1.2 and 104.1.4 (in creep)):

Pipe under internal pressure (304.1.2):

Pipe under internal pressure (841.11):

P = internal design pressure P = internal design pressure

D = outside diameter of pipe

D0 = outside diameter of pipe

S = stress value for material

SE = maximum allowable stress, including quality E = quality factor factor t = pressure design thickness tm = minimum required thickness y = coefficient, also from table 304.1.1 y = coefficient table 104.1.2A W = Weld strength reduction factor A = additional thickness to compensate threading, provide additional strength, corrosion allowance W = Weld strength reduction factor when in creep range, is 1 outside creep range (table 102.4.7)

P = internal design pressure D = nominal outside diameter of pipe S = specified minimum yield strength E = longitudinal joint factor, table 841.115A t = wall thickness F = design factor from table 841.114A T = Temperature derating factor from table 841.116A

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ASME B31.1 (2008) Bend under internal pressure (102.4.5):

pipe under internal pressure where I for intrados is:

and I for the extrados is:

and at sidewall I = 1.0, R = radius of pipe bend

ASME B31.3 (2008) Bend under internal pressure (304.2.1):

pipe under internal pressure where I for intrados is:

and I for the extrados is:

ASME B31.8 (2007) Bend under internal pressure (841.231): For cold bends the deflection of longitudinal axis and the radius is limited according table in paragraph 841.231

Hot bends are to be designed and manufactured according ASME B16.49, the internal pressure rating shall not be less than that which is calculated for straight seamless pipe and the intrados wall thickness should be:

and at sidewall I = 1.0, R = radius of pipe bend

Elbows under internal pressure (102.4.5):

Elbows under internal pressure (304.2.1):

Elbows manufactured according standards listed in Table 126.1 are suitable for use at the pressure-temperature ratings specified by such standards.

Elbows manufactured according standards listed in Table 326.1 are suitable for use at the pressure-temperature ratings specified by such standards.

where the t the wall thickness of the pipe is

Elbows under internal pressure (841.231?): No specific design rules are listed for fabricated elbows

(Does this mean or allow that an Elbows not according above standards or for Elbows not according above standards or for elbow can be calculated according a which design formulas and not given in the code which design formulas and not given in the code bend with uniform thickness? Refer shall be based on calculations consistent with the shall be based on calculations consistent with the B31.3) design criteria of this code. These calculations design criteria of this code. These calculations shall be substantiated by one or more of the shall be substantiated by one or more of the means stated in A B C or D of 104.7.2 (Does this means stated in A B C or D of 304.7.2, or the mean or allow that an elbow can be calculated elbow can be calculated according the Bend according a bend with uniform thickness? Refer calculation, refer 304.2.2. B31.3)

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ASME B31.1 (2008)

ASME B31.3 (2008)

Miter bends under internal pressure (104.3.3):

Miter bends under internal pressure (304.2.3):

1. Only straight pipe calculations required if:

1. When theta =< 22.5 deg than max. allowable pressure shall be the lesser of (t = T - c):

2. Pressure shall be limited to 70 kPa if: or

and

and thickness is not less than required for straight pipe 3. Pressure shall be limited to 700 kPa if:

2. When theta > 22.5 deg than max. allowable pressure shall calculated as (t = T - c):

and and thickness is not less than required for straight pipe 4. For pressure over 700 kPa: proof test, FEA, etc required with a defined minimum for closely spaced and widely spaced miter bend

For all miter bends the R1 shall not be less than:

ASME B31.8 (2007) Miter bends under internal pressure (841.232): 1. If system hoop stress > 40% of specified minimum yield strength miter bends are not permitted. Deflections caused by misalignment up to 3 deg are not considered as miters. 2. If 10% < hoop stress < 40% SMYS the deflection of each miter shall not exceed 12.5 deg. 3. If hoop stress < 10% SMYS the total deflection angle shall not exceed 90 deg. 4. If hoop stress > 10% SMYS the distance measured at the crotch shall not be less than one pipe diameter

with A: (T-c) =< 13 mm → A = 25 13 < (T-c) =< 22 mm → A = 2(T-c) (T-c) > 22 mm → A = 2(T-c)/3 + 30

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ASME B31.1 (2008)

ASME B31.3 (2008)

Reducer under internal pressure (104.6):

Reducer under internal pressure (304.6.1(b)):

1. Flanged reducer according Table 126.1 are considered suitable at the specified pressure temperature ratings.

1. Reducers according Table 326.1 shall be considered suitable for use at established pressure-temperature ratings or corresponding straight pipe with 87.5% of nominal wall thickness.

2. Where butt welding reducers are made to a nominal pipe thickness, the reducers shall be considered suitable for use with pipe of the same nominal thickness.

2. Concentric reducers not listed in Table 326.1 may be designed according closures as per ASME VIII div.1

3. Components not covered by the standards listed in Table 126.1 shall be based on calculation 3. Eccentric reducers not listed in Table 326.1 are qualified as unlisted components and shall be consistent with this code. Calculations are to be designed and documented substantiated by one substantiated by one of: of: - extensive, successful service experience - extensive, successful service experience - experimental analysis - experimental analysis - proof test - proof test - detailed stress analysis, such as finite element - detailed stress analysis, such as finite element analysis analysis (Is ASME VIII div.1 UG32 acceptable?) (Is ASME VIII div.1 UG32 acceptable?)

ASME B31.8 (2007) Reducer under internal pressure (831.373): 1. Steel butt welded fittings shall comply with ASME B16.9 or MSS Standard Practice and shall have pressure and temperature ratings based on stresses for pipe of the same of equivalent material (831.31b) 2. Other pressure containing components shall be designed the according design philosophy of this code substantiated by one of: - extensive, successful service experience - experimental analysis - proof test - engineering calculations 3. Closure heads such as flat, ellipsoidal, spherical or conical heads are allowed for use under this code. Such items may be designed in accordance with ASME VIII div.1 (UG32).

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ASME B31.1 (2008)

ASME B31.3 (2008)

Stubon under internal pressure (104.3.1(D)):

Stubon under internal pressure (304.3.3):

Required reinforcement area is

Required reinforcement area is

ASME B31.8 (2007) Stubon under internal pressure (831.4 and app. F): Required reinforcement area is (Fig. F-5):

= angle between branch and run with

= angle between branch and run

A is additional

thickness for corrosion and tolerances, tmh from straight pipe calculation (104.1.2)

excess header, with

reinforcement by header reinforcement

header excess

by branch with

area, with

attached reinforcement, weld area and other area Assessment:

branch excess

attached reinforcement, weld area and other area Assessment:

tr is reinforcement pad thickness weld area area reinforcement ring

Area A2 and A3 to be multiplied by the ratio of allowable working stress, maximum multiplication factor is 1.0 (para. 831.4(f))

Area A2, A3 and A4 to be multiplied by the ratio of allowable working stress, maximum multiplication factor is 1.0 (para. 304.3.3(f3))

area saddle on right angle connections

If

Assessment: Area A2,A3, A4 and A5 to be multiplied by the ratio of allowable working stress, maximum multiplication factor is 1.0 (para. 104.3.1(D.2.3)) then assess If

then assess

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ASME B31.1 (2008)

ASME B31.3 (2008)

Tee (extruded outlet) under internal pressure (104.3.1(G)):

Tee (extruded outlet) under internal pressure (304.3.4):

Required reinforcement area is

Required reinforcement area is

ASME B31.8 (2007) Tee (extruded outlet) under internal pressure (831.4 ref. App. F): Required reinforcement area is

K = 1.0 when

K = 1.0 when

K = 1.0 when d/D > 0.60 K=

when

K=

when

K = 0.6+(2d)/(3D) when 0.15 < d/D