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ASME B31.1 (2008) 
ASME B31.3 (2008) 
ASME B31.8 (2007) 

Power piping: typically found in electric power generating stations, in heating and cooling systems 
Process piping: typically found in petroleum refineries, chemical, pharmaceutical, textile and paper plants 
Gas transportation and distribution systems: piping transporting products, predominantly gas 
Applicable: boiler external piping from first joint up to and including first block valve for boilers where:
Excluding: fatigue due to pressure cycling

Exclusions:
Including: fatigue due pressure cycling and thermal cycling

Exclusions:

Allowable stress:

Allowable stress:

Allowable stress:

Materials: material of unknown specification shall not be used for pressure containing components 
Materials: material of unknown specification shall not be used for pressure containing components 
Materials: material only as per 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 

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)):
P = internal design pressure D_{0} = outside diameter of pipe SE = maximum allowable stress, including quality factor t_{m} = minimum required thickness y = coefficient table 104.1.2A 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) 
Pipe under internal pressure (304.1.2):
P = internal design pressure D = outside diameter of pipe S = stress value for material E = quality factor t = pressure design thickness y = coefficient, also from table 304.1.1 W = Weld strength reduction factor 
Pipe under internal pressure (841.11):
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 
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

Bend under internal pressure (304.2.1): 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

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: where the t the wall thickness of the pipe is 
Elbows under internal pressure (102.4.5): Elbows manufactured according standards listed in Table 126.1 are suitable for use at the pressuretemperature ratings specified by such standards.
Elbows not according above standards or for which design formulas and not given in the code shall be based on calculations consistent with the design criteria of this code. These calculations shall be substantiated by one or more of the means stated in A B C or D of 104.7.2 (Does this mean or allow that an elbow can be calculated according a bend with uniform thickness? Refer B31.3) 
Elbows under internal pressure (304.2.1): Elbows manufactured according standards listed in Table 326.1 are suitable for use at the pressuretemperature ratings specified by such standards.
Elbows not according above standards or for which design formulas and not given in the code shall be based on calculations consistent with the design criteria of this code. These calculations shall be substantiated by one or more of the means stated in A B C or D of 304.7.2, or the elbow can be calculated according the Bend calculation, refer 304.2.2. 
Elbows under internal pressure (841.231?): No specific design rules are listed for fabricated elbows
(Does this mean or allow that an elbow can be calculated according a bend with uniform thickness? Refer B31.3) 
Miter bends under internal pressure (104.3.3): 1. Only straight pipe calculations required if: 2. Pressure shall be limited to 70 kPa if: or and thickness is not less than required for straight pipe 3. Pressure shall be limited to 700 kPa if: 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

Miter bends under internal pressure (304.2.3): 1. When theta =< 22.5 deg than max. allowable pressure shall be the lesser of (t = T  c): and 2. When theta > 22.5 deg than max. allowable pressure shall calculated as (t = T  c): For all miter bends the R1 shall not be less than: with A: (Tc) =< 13 mm → A = 25 13 < (Tc) =< 22 mm → A = 2(Tc) (Tc) > 22 mm → A = 2(Tc)/3 + 30 
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

Reducer under internal pressure (104.6): 1. Flanged reducer according Table 126.1 are considered suitable at the specified pressure temperature ratings. 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. 3. Components not covered by the standards listed in Table 126.1 shall be based on calculation consistent with this code. Calculations are to be substantiated by one of:  extensive, successful service experience  experimental analysis  proof test  detailed stress analysis, such as finite element analysis (Is ASME VIII div.1 UG32 acceptable?) 
Reducer under internal pressure (304.6.1(b)): 1. Reducers according Table 326.1 shall be considered suitable for use at established pressuretemperature ratings or corresponding straight pipe with 87.5% of nominal wall thickness. 2. Concentric reducers not listed in Table 326.1 may be designed according closures as per ASME VIII div.1 3. Eccentric reducers not listed in Table 326.1 are qualified as unlisted components and shall be designed and documented substantiated by one of:  extensive, successful service experience  experimental analysis  proof test  detailed stress analysis, such as finite element analysis (Is ASME VIII div.1 UG32 acceptable?) 
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). 
Stubon under internal pressure (104.3.1(D)): Required reinforcement area is = angle between branch and run with A is additional thickness for corrosion and tolerances, tmh from straight pipe calculation (104.1.2) header excess area, with
branch excess tr is reinforcement pad thickness weld area area reinforcement ring area saddle on right angle connections 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)) 
Stubon under internal pressure (304.3.3): Required reinforcement area is = angle between branch and run excess header, with
attached reinforcement, weld area and other area Assessment: 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))
If then assess 
Stubon under internal pressure (831.4 and app. F): Required reinforcement area is (Fig. F5): reinforcement by header reinforcement by branch with attached reinforcement, weld area and other area Assessment: Area A2 and A3 to be multiplied by the ratio of allowable working stress, maximum multiplication factor is 1.0 (para. 831.4(f)) 
Tee (extruded outlet) under internal pressure (104.3.1(G)): Required reinforcement area is K = 1.0 when K = when K = 0.7 when
reinforcement by header reinforcement by branch with excess branch area Assessment: 
Tee (extruded outlet) under internal pressure (304.3.4): Required reinforcement area is K = 1.0 when K = when K = 0.7 when
reinforcement by header reinforcement by branch with excess branch area Assessment: If then assess If then assess 
Tee (extruded outlet) under internal pressure (831.4 ref. App. F): Required reinforcement area is K = 1.0 when d/D > 0.60 K = 0.6+(2d)/(3D) when 0.15 < d/D <= 0.60 K = 0.7 when d/D <= 0.15 reinforcement by header reinforcement by branch with excess branch area Assessment:

Weldolet (branch) under internal pressure (104.3.1(D)): Required reinforcement area is reinforcement by header, with
reinforcement by branch with with = thickness pad or height of 60 deg angle fitting with in reinforcement material = area provided by deposited weld metal excess weldolet area in reinforcement zone 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)) 
Weldolet (branch) under internal pressure (304.3.3): Required reinforcement area is reinforcement by header, with
reinforcement by branch with with = thickness pad or a height of 0 = area provided by deposited weld metal and attached reinforcement Assessment: 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)) 
Weldolet (branch) under internal pressure (831.4 ref. App. F): Required reinforcement area is (Fig. F5): reinforcement by header reinforcement by branch with attached reinforcement, weld area and other area Assessment: Area A2 and A3 to be multiplied by the ratio of allowable working stress, maximum multiplication factor is 1.0 (para. 831.4(f)) 
Cap under internal pressure (104.4.1(B)): Can be calculated with ASME VIII div.1 UG32 app.14 L = radius dish r = radius knuckle
or 
Cap under internal pressure (304.4.1(b)): Can be calculated with ASME VIII div.1 UG32 app.14 L = radius dish r = radius knuckle
or 
Cap under internal pressure (831.372 and 831.373): Can be calculated with ASME VIII div.1 UG32 app.14 L = radius dish r = radius knuckle
or 
Flat closure under internal pressure (104.4.1(b)): Can be calculated with ASME VIII div.1 UG 34 …

Flat closure under internal pressure (304.4.1(b)): Can be calculated with ASME VIII div.1 UG 34 …

Flat closure under internal pressure (831.373): Can be calculated with ASME VIII div.1 UG 34 … 
Flange under internal pressure (104.5.1(B)): Can be calculated according ASME VIII div.1 app. 2 using B31.3 allowable stresses and temperature limits with: = design gauge pressure = bolt design stress at atmospheric temperature = bolt design stress at design temperature = product SE

Flange under internal pressure (304.5.1(b)): Can be calculated according ASME VIII div.1 app. 2 using B31.3 allowable stresses and temperature limits with: = design gauge pressure = bolt design stress at atmospheric temperature = bolt design stress at design temperature = product SEW

Flange under internal pressure (831.2): Allowed to use: ASME B16 series as listed in Appendix A such as B16.5. Also MSS SP44. For slipon welding flanges reference is made to ASME VIII div.1 design.
Can ASME VIII div.1 be used for calculation? 
Blind flange under internal pressure (104.5.2(B)): Can be calculated according ASME VIII div.1 UG34 with: = sum of allowances = internal design gauge pressure = product SE = pressure design thickness as per ASME VIII div. 1 UG34 
Blind flange under internal pressure (304.5.2(b)): Can be calculated according ASME VIII div.1 UG34 with: = sum of allowances = internal design gauge pressure = product SEW = pressure design thickness as per ASME VIII div. 1 UG34 
Blind flange under internal pressure:
Can ASME VIII div.1 be used? 
Blanks (spade) under internal pressure (304.5.3(B)): = sum of allowances = inside diameter of gasket 
Blanks (spade) under internal pressure (304.5.3(b)): = sum of allowances = inside diameter of gasket 
Blanks (spade) under internal pressure:
Can ASME VIII div.1 be used? 