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TODO ASME B31.4 Pipe (ext.)

Details
Last Updated: 10 September 2026

Calculation is according ASME VIII Div 1 UG 28.

 

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

 

Specific variables

These variables are component specific

 

Calculated Values

 

Scope errors

 

Errors

 

Remarks

 

Calculation errors

 

Warnings

 

ASME B31.4 Bend

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

Location – Location 
The physical location of the component 
Test medium – Test medium 
The medium used to test the component 
Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific.

Outside Diameter – D 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. 
Nominal Thickness neutral line – tn 
The neutral line is along the neutral axis of the bend. Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Nominal Thickness Intrados – tin 
Intrados is the inner radius of the bend. Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Nominal Thickness Extrados – ten 
Extrados is the outer radius of the bend. Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion/erosion/threading – A 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Allowed tolerance in thickness 
Joint Effeciency – E 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 
Mean Bend Radius – R 
Radius of the bend from the origin to the neutral axis of the bend. The origin lies in the intersection of the lines perpendicular to neutral axis, through the points where the bend ends turn straight. 

Calculated Values

Minimum yield strength at 20 °C – Symin 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Design factor – F 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Test design factor – Ft 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Allowable Operating Stress – S 
Stress in the component at which it is still allowed (without failure) to use the component. 
Allowable stress at 20 °C – St 
Stress in the component at which it is still allowed (without failure) to use the component at testing condition. 
Minimum radius cold field bend – Rmin 
The minimum radius of bending 
Neutral line factor – Ic (equals 1) 
Bend correction factor, considered unity at the neutral axis. 
Intrados factor – Ii 
Bend correction factor at the inner radius of the bend (bend radius − half the outside diameter). 
Extrados factor – Ie (equals 1) 
Bend correction factor at the outer radius of the bend (bend radius + half the outside diameter). 
Nominal Required Thickness neutral line, intrados, extrados – trn, tirn, tern 
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness. 
Maximum Allowable Working Pressure – MAWP 
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure. 
Design margin – P/MAWP 
Ratio of the design pressure to MAWP 
Test pressure factor – FPt 
Factor for maximum test pressure 
Maximum Allowable Test Pressure – MATP 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient wall thickness neutral line. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness at the neutral line. 
Insufficient wall thickness intrados. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness at the intrados. The intrados should generally be thicker than the minimum required thickness at the neutral line. 
Insufficient wall thickness extrados. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness at the extrados. The extrados should generally be thinner than the minimum required thickness at the neutral line.

ASME B31.4 Cap Elliptical

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific.

Outside Diameter – D 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. 
Nominal Thickness – tn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – A 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production. 
Joint Efficiency – E 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 

Calculated Values

Minimum yield strength at 20 °C – Symin 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Allowable Operating Stress – S 
Stress in the component at which it is still allowed (without failure) to use the component. 
Allowable stress test – St 
Stress in the component at which it is still allowed (without failure) to use the component at testing condition. 
Inside Diameter – Di 
Outside Diameter − 2 × Thickness 
Inside dish height – hi 
Inside Diameter / 4 
Spherical radius factor – K 
1/6 (2 + (Di / (2 hi))2) 
Nominal Required thickness – trn 
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness. 
Maximum Allowable Working Pressure – MAWP 
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure. 
Design margin – P/MAWP 
Ratio of the design pressure to MAWP 
Maximum Allowable Test Pressure – MATP 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 
Head thickness is out of scope: required is t ≥ 0.002 L 
This code determines for heads a minimum thickness. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient head thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness.

ASME B31.4 Cap Hemispherical

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific.

Outside Diameter – D 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. 
Nominal Thickness – tn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – A 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production. 
Joint Efficiency – E 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 

Calculated Values

Minimum yield strength at 20 °C – Symin 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Allowable Operating Stress – S 
Stress in the component at which it is still allowed (without failure) to use the component. 
Allowable stress test – St 
Stress in the component at which it is still allowed (without failure) to use the component at testing condition. 
Inside Diameter – Di 
Outside Diameter − 2 × Thickness 
Nominal Required Thickness – trn 
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness. 
Maximum Allowable Working Pressure – MAWP 
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure. 
Design margin – P/MAWP 
Ratio of the design pressure to MAWP 
Maximum Allowable Test Pressure – MATP 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 
Head thickness is out of scope: required is t ≤ 0.356 L 
This code determines for heads a maximum thickness. 
Design pressure is out of scope: required is P ≤ 0.665 SE 
This code determines for heads a maximum pressure. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient head thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 

ASME B31.4 Cap Torispherical

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

 

Specific variables

These variables are component specific

 

Calculated Values

 

Scope errors

 

Errors

 

Remarks

 

Calculation errors

ASME B31.4 Miter bend

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

Location – Location 
The physical location of the component 
Test medium – Test medium 
The medium used to test the component 
Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific

Outside Diameter – D 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. 
Nominal Thickness – tn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – A 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production. 
Joint Efficiency – E 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 
Radius miter bend – R 
Radius of the miter bend from the origin of curvature and perpendicular to the neutral axis of the bend. The neutral axis follows the centerlines of the segments. 
Total deflection angle miter bend – Angle 
The angle of the total deflection the miter bend makes, i.e. the angle between the centerlines of the attached pipes. 
Number of Segments – NoS 
The number of segments in which the bend is divided. 

Calculated Values

Minimum yield strength at 20 °C – Symin 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Design factor – F 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Test design factor – Ft 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Allowable Operating Hoop Stress – Sh 
Stress in the component at which it is still allowed (without failure) to use the component. 
Miter bend cut angle – θ 
Cutting angle between the different segments. 
Deflection angle per miter segment – α = 2θ 
The total angle of deflection per miter segment. 
Minimum inside crotch length – Lc min 
The minimum length of a miter bend segment measured at the inside. 
Inside crotch length – Lc 
The length of a miter bend segment at the inside. 
Mean segment radius using nominal wall thickness – r 
(Outside Diameter − 2 × Thickness)/2 
Segment length at centerline – s 
Length of the segment measured at the centerline. 
Segment length limit at centerline – slim 
Limit of segment length at centerline for widely or closely segment spacing. 
Widely/Closely segment spacing 
When the length measured at the centerline is beyond or below the segment length limit, the miter bend does not completely follow the curvature of a circle. When beyond the limit, the miter bend is widely spaced and the segments are longer (extra straight pipe) and the distance from the centerline to the center point of deflection is larger than the bend radius. Below the limit, the miter bend is closely spaced and the segments are shorter (missing straight pipe) and the distance from the centerline to the center point of deflection is smaller than the radius. 
Nominal Required thickness – trn 
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness. 
Maximum Allowable Working Pressure – MAWP 
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure. 
Design margin – P/MAWP 
Ratio of the design pressure to MAWP 
Test pressure factor – FPt 
Factor for maximum test pressure 
Maximum Allowable Test Pressure – MATP 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 
Number of segments is out of scope: required is NoS ≥ 2 
A miterbend has at least 2 segments. 
Inside crotch length is out of scope: required is Lc ≥ pipe O.D. 
This code determines a minimum length. 
No calculation required when deflection angle per miter α ≤ 3° 
This code determines a minimum angle of miter cut θ. Decrease the number of miter segments or increase the total deflection angle of the miterbend. 
Deflection angle per miter α is out of scope: maximum angle = 90° 
This code determines a maximum angle of deflection. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient wall thickness 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 

Remarks

Angle of miter deflection α > 12.5°. 
When a segment of the miterbend has an angle larger than this limit, the maximum allowable pressure shall be limited. 

Calculation errors

Can't calculate maximum hoop stress. Please check miter deflection angle. 
The miter deflection angle determines the maximum allowable hoop stress. 

ASME B31.4 Pipe

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in all reports as input variables

Location – Location
The physical location of the component
Test medium – Test medium
The medium used to test the component
Design Pressure – P
Pressure assumed to be present in the component according to the design terms.
Design Temperature – Td
Temperature assumed to be present in the component according to the design terms.
Material
Name of selected material used for the construction of the component.

Specific variables

These variables are component specific

Outside Diameter – D
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle.
Nominal Thickness – tn
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance.
Corrosion/erosion/threading – A
Amount of thickness that accounts for the possible effects of corrosions.
Tolerance – tol
Tolerance in thickness for production.
Joint Efficiency – E
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties.
Length tangent to tangent – L
Length of the straight part of the pipe (equals the unsupported length of the pipe)

Calculated Values

Minimum yield strength at 20 °C – Symin
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature.
Design factor – F
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections.
Test design factor – Ft
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections.
Allowable Operating Stress – S
Stress in the component at which it is still allowed (without failure) to use the component.
Allowable stress at 20 °C – St
Stress in the component at which it is still allowed (without failure) to use the component at testing condition.
Nominal Required thickness – trn
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness.
Maximum Allowable Working Pressure – MAWP
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure.
Design margin – P/MAWP
Ratio of the design pressure to MAWP
Test pressure factor – FPt
Factor for maximum test pressure
Maximum Allowable Test Pressure – MATP
The maximum pressure at which the component should be tested and survive.
Required Test Pressure – Pt
Required hydrostatic pressure for testing at any point in the piping system

Scope errors

Temperature is out of scope: minimum temperature = -30 °C
This code determines a minimum temperature.
Temperature is out of scope: maximum temperature = 120 °C
This code determines a maximum temperature.

Errors

Can’t find material ‘MaterialName’ in database
Material could not be found in database. Select an existing material name, or select another material via the material selection window.
Insufficient wall thickness
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness.

ASME B31.4 Reducer

Details
Last Updated: 09 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables for reducers (concentric/eccentric).

Location – Location 
The physical location of the component 
Test medium – Test medium 
The medium used to test the component 
Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific.

Large/Small 
Large and Small refer to the large pipe end and the smaller (reduced) pipe end respectively. 
Outside Diameter – D (Large/Small) 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. 
Nominal Thickness – tn (Large/Small) 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – A 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production. 
Joint Efficiency – E 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 
Overall length – L 
Length of the entire reducer. 
Length conical part – Lc 
Length of the part that reduces gradually in diameter and hence, forms a conical shape. 
Angle cone – α 
The angle of the conical section, or the slope with which the diameter reduces. 

Calculated Values

Minimum yield strength at 20 °C – Symin 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Allowable Operating Stress – S 
Stress in the component at which it is still allowed (without failure) to use the component. 
Allowable stress test – St 
Stress in the component at which it is still allowed (without failure) to use the component at testing condition. 
Nominal Required thickness – trn (Large/Small) 
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness. 
Required reinforcement area – Ar (Large/Small) 
The required cross-sectional area that reinforcement or excess thickness should provide. 
Effective reinforcement area – Ae (Large/Small) 
The effective cross-sectional area from reinforcement and excess thickness. The effective area must be at least the required area. 
Maximum Allowable Working Pressure – MAWP (Large/Small) 
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure. 
Design margin – P/MAWP (Large/Small) 
Ratio of the design pressure to MAWP 
Maximum Allowable Test Pressure – MATP (Large/Small) 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 
Reducer angle is out of scope: maximum angle = 30° 
This code determines a maximum reducer angle. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient wall thickness at large end. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient wall thickness at small end. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient reinforcement area at large end junction. 
Reinforcement area is too small. Increase the reinforcement area or thickness. 
Insufficient reinforcement area at small end junction. 
Reinforcement area is too small. Increase the reinforcement area or thickness. 

ASME B31.4 Stubon

Details
Last Updated: 08 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables.

Location – Location 
The physical location of the component 
Test medium – Test medium 
The medium used to test the component 
Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material (header/branch) 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific.

Outside Diameter header and branch – Dh, Db 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. Generally the branch is smaller in diameter than the header. 
Nominal Thickness header, branch and reinforcement – thn, tbn, trn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion header and branch – Ah, Ab 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance header, branch and reinforcement – tolh, tolb, tolr 
Tolerance in thickness for production. 
Joint Efficiency header and branch – Eh, Eb 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 
Angle centerline branch – a 
Angle between the centerline of the branch and the line perpendicular to the header centerline. 
Reinforcement width – wr 
Width of the reinforcement. The width equals the outer radius minus the inner radius. 

Calculated Values

Minimum yield strength at 20 °C header, branch and reinforcement – Syminh, Syminb, Syminr 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Design factor – F 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Test design factor – Ft 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Allowable Operating Stress header, branch and reinforcement – Sh, Sb, Sr 
Stress in the component at which it is still allowed (without failure) to use the component. 
Allowable stress at 20 °C header, branch and reinforcement – Sht, Sbt, Srt 
Stress in the component at which it is still allowed (without failure) to use the component at testing condition. 
Header reinforcement zone length – d 
Length from the branch centerline to the end of the header reinforcement zone. 
Branch reinforcement zone length – L 
Length from the header outside diameter to the end of the branch reinforcement zone. 
Stress ratio branch/header – Sb/Sh, Sbt/Sht. 
Ratio of operating stresses of the branch and the header. This ratio must be ≤ 1. 
Stress ratio reinforcement/header – Sr/Sh, Srt/Sht 
Ratio of operating stresses of the reinforcement and the header. This ratio must be ≤ 1. 
Required thickness header pipe and branch pipe – thr, tbr 
Based on the input, this is the calculated thickness that is required to sustain the loads. The nominal value should be smaller than the nominal design thickness. 
Required reinforcement Area – AR 
The required cross-sectional area that reinforcement or excess thickness should provide for the opening. 
Reinforcement area header – A1 
Cross-sectional area of excess thickness header. 
Reinforcement area branch – A2 
Cross-sectional area of excess thickness branch. 
Reinforcement area of extra added area including weld areas – A3 
Extra reinforcement cross-sectional excess area. 
Total available reinforcement area – A 
The total available cross-sectional area from reinforcement and excess thickness. Sum of areas is corrected for stress ratios. 
Maximum Allowable Working Pressure – MAWP 
The maximum pressure at which the component can be used in operation.This value should be larger than the design pressure. 
Design margin – P/MAWP 
Ratio of the design pressure to MAWP 
Test pressure factor – FPt 
Factor for maximum test pressure based on design pressure. 
Maximum Allowable Test Pressure – MATP 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system.
Tapering header and branch 
The tapering of the header and branch on connecting pipes is checked. 

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 
Angle branch is out of scope: required is 0° < α ≤ 90°. 
This code determines a minimum and maximum branch angle. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient wall thickness for header 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient wall thickness for branch 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient reinforcement area 
Reinforcement area is too small. Increase the reinforcement width or wall thickness of reinforcement, header or branch. 

Warnings

Tapering header in reinforced zone. 
Indicates tapering of header in reinforced zone. 
Tapering branch in reinforced zone. 
Indicates tapering of branch in reinforced zone. 

ASME B31.4 Tee

Details
Last Updated: 09 September 2026

Input variables

Generic variables

These variables can be found in virtually all reports as input variables

Location – Location 
The physical location of the component 
Test medium – Test medium 
The medium used to test the component 
Design Pressure – P 
Pressure assumed to be present in the component according to the design terms. 
Design Temperature – Td 
Temperature assumed to be present in the component according to the design terms. 
Material (header/branch) 
Name of selected material used for the construction of the component. 

Specific variables

These variables are component specific.

Outside Diameter (tapered) header and (tapered) branch – Dh, Dh′, Db, Db′ 
Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle. Generally the branch is smaller in diameter than the header. 
Nominal Thickness (tapered) header and (tapered) branch – thn, th′, tbn, tb′ 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Tapered section 
Section in which the thickness of either the branch or header gradually changes to the thickness of the pipe. 
Corrosion – A 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production. 
Joint Efficiency – E 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties. 
Half width header direction – W0 
Distance from the centerline of the branch part to the end of the header part indicated by the direction. 
Half height branch direction – H0 
Distance from the centerline of the header part to the end of the branch part indicated by the direction. 
Crotch outside radius factor – Rf 
Tee transition outside radius factor. Used value is 0.67 when dimension standards do not provide a value. 
Crotch thickness factor – CF 
Tee crotch thickness factor. Used value is 1.25 when dimension standards do not provide a value.
Tee transition outside radius header to branch – r0 
Tee crotch outside radius. Radius is calculated or user defined. 
Nominal Crotch Thickness – tcn 
Crotch thickness is calculated or user defined. 

Calculated Values

Minimum yield strength at 20 °C – Symin 
Stress in the component at which the component starts to plastically deform at 20 °C ambient temperature. 
Design factor – F 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Test design factor – Ft 
Factor for the allowable stress when considering underthickness tolerance and maximum allowable depth of imperfections. 
Allowable Operating Stress – S 
Stress in the component at which it is still allowed (without failure) to use the component. 
Allowable stress at 20 °C – St 
Stress in the component at which it is still allowed (without failure) to use the component at testing condition. 
Branch/Header diameter ratio – Db/Dh 
Ratio of the outside diameters of the branch and the header. 
Branch inside diameter at header outside diameter – D0 
Inside diameter of the branch where the branch meets the outside diameter of the header. 
Header reinforcement zone length – r1 
Length from the branch centerline to the end of the header reinforcement zone. 
Branch reinforcement zone length – L 
Length from the header outside diameter to the end of the branch reinforcement zone. 
Reinforcement factor – K 
Multiplication factor for the header opening. 
Required reinforcement area – AR 
The required cross-sectional area that reinforcement or excess thickness should provide. 
Total available reinforcement area – A 
The total available cross-sectional area from reinforcement and excess thickness. 
Maximum Allowable Working Pressure – MAWP 
The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure. 
Design margin – P/MAWP 
Ratio of the design pressure to MAWP 
Test pressure factor – FPt 
Factor for maximum test pressure 
Maximum Allowable Test Pressure – MATP 
The maximum pressure at which the component should be tested and survive. 
Required Test Pressure – Pt 
Required hydrostatic pressure for testing at any point in the piping system
Tapering header and branch 
The tapering of the header and branch on connecting pipes is checked. 

Scope errors

Temperature is out of scope: minimum temperature = -30 °C 
This code determines a minimum temperature. 
Temperature is out of scope: maximum temperature = 120 °C 
This code determines a maximum temperature. 
Crotch outside radius is out of scope: required is r0min ≤ r0 ≤ r0max. 
This code determines limits for this radius. 

Errors

Can’t find material ‘MaterialName’ in database 
Material could not be found in database. Select an existing material name, or select another material via the material selection window. 
Insufficient wall thickness for header 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness of the header. 
Insufficient wall thickness for branch 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness of the branch. 
Insufficient reinforcement area or wall thickness. 
Reinforcement area is too small. Increase the reinforcement area or thickness. 

Warnings

Tapering header in reinforced zone. 
Indicates tapering of header in reinforced zone. 
Tapering branch in reinforced zone. 
Indicates tapering of branch in reinforced zone.

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