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  5. PCC RToD

RToD Bend (D210)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 Extrados – d1n 
Extrados is the outer radius of the bend. Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Nominal Thickness neutral line – d2n 
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 – d3n 
Intrados is the inner radius of the bend. Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production. 
Strength reduction coefficient – z 
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 on the intersection of the lines perpendicular to neutral axis, through the points where the bend ends turn straight 

Calculated Values

Allowable Stress at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress at 20 °C – ft 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Extrados factor – C1 
Bend correction factor at the outer radius of the bend (bend radius + half the outside diameter) 
Neutral line factor – C2 (equals 1) 
Bend correction factor, considered unity at the neutral axis 
Intrados factor – C3 
Bend correction factor at the inner radius of the bend (bend radius − half the outside diameter) 
Nominal Required Thickness extrados, neutral line, intrados – d1rn, d2rn, d3rn 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Wall thickness neutral line is out of scope: required d ≤ 0.19 De 
This code determines for bends a maximum thickness. 
Bend radius is out of scope: required r ≥ 0.5 De 
This code determines for bends a minimum 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 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. 
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.

 

RToD Cap Hemispherical (D201)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 – dn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Strength reduction coefficient – z 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties 

Calculated Values

Allowable Stress at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress at 20 °C – ft 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Nominal Required Thickness – drn 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Dish thickness is out of scope: required dd ≤ dmax. 
This code determines for heads a maximum 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 dish thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness.

 

RToD Cap Elliptical and Torispherical (D203)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 knuckle, dish – dkn, ddn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Nominal Inside Knuckle Radius – ri1n 
Nominal inside radius of the knuckle (small radius). Custom defined size for torispherical and estimated size for elliptical. 
Nominal Inside Dish Radius – ri2n 
Nominal inside radius of the dish (large radius). Custom defined size for torispherical and estimated size for elliptical. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Strength reduction coefficient – z 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties 

Calculated Values

Allowable Stress at temperature knuckle, dish – f, f2 
Stress in the component at which it is still allowed (without failure) to use the component 
Corrected allowable Stress at temperature knuckle – fe 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress at 20 °C knuckle, dish – ft, f2t 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Corrected allowable stress at 20 °C knuckle – fet 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Outside height – he 
Outside height from tangent line to top of dish. 
Nominal Required Thickness knuckle, dish – dkrn, ddrn 
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. 
Diameter dished zone – D1 
Diameter at the inside defining the boundary of the dished zone and the knuckle zone. 
Minimum distance isolated openings – l3 
Minimum required distance between the edges of multiple openings. 
Stability pressure knuckle – Pk 
Critical pressure to maintain stability in the knuckle. 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Dish thickness is out of scope: required dd ≤ dmax. 
This code determines for heads a maximum thickness. 
Knuckle thickness is out of scope: required dk ≤ dmax. 
This code determines for heads a maximum thickness. 
Inside knuckle radius is out of scope: required ri1 ≥ ri1min. 
This code determines for heads a minimum radius. 
Inside knuckle radius is out of scope: required ri1 ≤ ri1max. 
This code determines for heads a maximum radius. 
Head height is out of scope: required 0.14 De + 0.72 dd ≤ he ≤ 0.3 De + 0.4 dd 
This code determines for heads a minimum and maximum height. 

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 dish thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient knuckle thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 

 

RToD Knuckled Flathead (D203)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 knuckle, dish – dkn, ddn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Nominal Inside Knuckle Radius – ri1n 
Nominal inside radius of the knuckle 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Strength reduction coefficient – z 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties 

Calculated Values

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 – Pd / 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. 
Scope errors
Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Dish thickness is out of scope: required dd ≤ dmax. 
This code determines for flat covers a maximum thickness. 
Knuckle thickness is out of scope: required dk ≤ dmax. 
This code determines for flat covers a maximum 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 dish thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient knuckle thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness.

 

RToD Miter bend (D211)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 – dn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Strength reduction coefficient – z 
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

Allowable Stress at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress at 20 °C – ft 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Miter bend cut angle – φ 
Cutting angle between the different segments. 
Segment length at centerline – Ls 
Length of the segment measured at the centerline. 
Minimum segment length at centerline – Ls min 
Minimum required segment length measured at the centerline. 
Nominal Required Thickness – drn 
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. 
Ratio outside diameter to thickness – De / d 
Ratio for the relationship with Pd / f and φ in figure 2. 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Number of segments is out of scope: required is NoS ≥ 2 
A miterbend has at least 2 segments. 
Angle of miter cut is out of scope: required is φ ≤ 22.5° 
This code determines a maximum angle. 
Segment length is out of scope: required is Ls ≥ Lsmin 
This code determines a minimum length. 
Miter bend is not allowed in creep range. 
This code determines that miter bends are not applicable in the creep range. 
Ratio of diameter to thickness is out of scope: required 20 ≤ De/d ≤ 200 (fig. 2). 
Fig.2 shows a relationship between d /De versus Pd /f 

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. 

Calculation errors

Can't calculate required thickness. Please check input data. 
An error occured in the calculation for the required thickness.

 

RToD Pipe (D201)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 – dn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Strength reduction coefficient – z 
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

Allowable Stress at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress at 20 °C – ft 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Nominal Required Thickness – drn 
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. 
Minimum strength reduction coefficient isolated openings – zmin 
Minimum required effectiveness of the strength in the opening. 
Minimum distance isolated openings – l3 
Minimum required distance between openings to consider them isolated. See D0501. 
Maximum unreinforced opening diameter – Max(Di2, D'i2) 
Maximum allowed diameter for an opening without reinforcement. See D0501. 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Wall thickness is out of scope: required d ≤ 0.3 Di 
This code determines for pipes a maximum thickness. 
Wall thickness cone is out of scope: required d ≤ 0.3 Di / Cos(α) 
This code determines for cones a maximum thickness. 
Cone angle is out of scope: required α ≤ 70° 
This code determines a maximum cone 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 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 

 

RToD Pipe (ext.) (D301)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 – De 
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 – dn 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Strength reduction coefficient – z 
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties 
Infinite length – L′ 
The unsupported lenght of the shell is infitely long, meaning the external pressure can not collapse the shell. 
Maximum unsupported length – L 
Maximum length of the straight part of the pipe that is unsupported. 
Out of roundness – u 
relative out of roundness regarding the shape of the shell. 
Margin – γ 

Calculated Values

Allowable Stress at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Modulus of elasticity – E 
Tendency to deform (tensile strain) along an axis when opposing forces (tensile stress) are applied along that axis. 
Poisson's ratio – ν 
(Negative) ratio of transverse to axial strain. An extension (or contraction) in the direction of a load corresponds in a contraction (or extension) in a direction perpendicular to the applied load. The ratio between these two quantities is the Poisson's ratio. 
Unsupported length – L 
Actual length of the straight part of the pipe that is unsupported. 
Number of lobs – n 
Positive integer ≥ 2, to be determined such that the required thickness becomes maximum. 
Nominal Required Thickness – drn 
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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Wall thickness is out of scope: required d ≤ 0.2 De 
This code determines for pipes a maximum 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 wall thickness 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 

Remarks

Restricted unsupported length: L = x mm 
The unsupported length is restricted to a maximum: L ≤ L′ 

Calculation errors

Can't calculate maximum unsupported length for external pressure. 
The shell has insufficient strength to determine the unsupported length.

 

RToD Reducer (D201)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 cylindrical end 
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 cylindrical end – De (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 cylindrical end – dn (Large/Small) 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol (Large/Small) 
Tolerance in thickness for production 
Strength reduction coefficient – z 
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 – Lk 
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

Allowable Stress cylindrical end at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress cylindrical end at 20 °C – ft 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Nominal Required Thickness cylindrical end – drn (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. 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Cone angle is out of scope: required α ≤ 70° (paragraph 1). 
This code determines a maximum cone 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 thickness cone at large end. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient thickness cone at small end. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 

 

RToD Reducer (D203)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 cone, knuckle 
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 – De (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 cone, knuckle – dn (Large/Small) 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Nominal inside or outside knuckle radius – ri1n (Large/Small) 
Nominal inside radius (at large end) or outside radius (at small end) of the knuckle. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol (Large/Small) 
Tolerance in thickness for production 
Strength reduction coefficient – z 
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 – Lk 
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

Allowable Stress knuckle at Temperature – f 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress knuckle at 20 °C – ft 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Allowable Stress cone at Temperature – f2 
Stress in the component at which it is still allowed (without failure) to use the component 
Allowable stress cone at 20 °C – f2t 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Corrected allowable Stress at temperature knuckle – fe 
Stress in the component at which it is still allowed (without failure) to use the component 
Corrected allowable stress at 20 °C knuckle – fet 
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature 
Knuckle radius – ri1
The inside radius of the knuckle
Maximum thickness for cone and knuckle – dmax 
This code determines for cone and knuckle a maximum thickness. 
Nominal Required Thickness cone, knuckle – drn, drn (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. 
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 – Pd / 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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Cone thickness at large end is out of scope: required d ≤ 0.3 Di / Cos(α) 
This code determines for cones a maximum thickness. 
Knuckle radius at large end is out of scope, required ri1 ≥ (De-2d)/(2 + 38 Cos(α) 
This code determines a minimum radius. 
Knuckle radius at large end is out of scope, required ri1 ≤ (De-2d)/(2 + 4.67 Cos(α) 
This code determines a maximum 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 knuckle thickness. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient cone thickness at large junction. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness. 
Insufficient cone thickness at small junction. 
Wall thickness is insufficient to bear the applied loads. Increase the wall thickness.

 

RToD Reducer (D207)

Details
Last Updated: 10 September 2026

Input variables

Generic variables

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

Design Pressure – Pd 
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 cylinder, cone 
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 cylinder, cone – De 
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 cylinder, cone – dcn, dkn (Large/Small) 
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance. 
Corrosion – Ca 
Amount of thickness that accounts for the possible effects of corrosions. 
Tolerance – tol 
Tolerance in thickness for production 
Length conical part – Lk 
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

Yield strength at operating temperature – Re (Large/Small) 
Stress in the component at which the component starts to plastically deform at operating temperature. 
Modulus of elasticity – E (Large/Small) 
Tendency to deform (tensile strain) along an axis when opposing forces (tensile stress) are applied along that axis. 
Poisson's ratio ν 
(Negative) ratio of transverse to axial strain. An extension (or contraction) in the direction of a load corresponds in a contraction (or extension) in a direction perpendicular to the applied load. The ratio between these two quantities is the Poisson's ratio. 
Axial stresses cylinder – Sax:c (Large/Small) 
Stress that tends to stretch the component along the axial direction. 
Axial stresses cone – Sax:k (Large/Small) 
Stress that tends to stretch the component along the axial direction. 
Tangential stresses cylinder – Stg:c (Large/Small) 
Stress that tends to stretch the component along the tangential (circumferential) direction. Also called hoop stress. 
Tangential stresses cone – Stg:k (Large/Small) 
Stress that tends to stretch the component along the tangential (circumferential) direction. Also called hoop stress. 
Combined stresses cylinder – Sv:c (Large/Small) 
Stress that results from several stresses acting in several directions. 
Combined stresses cone – Sv:k (Large/Small) 
Stress that results from several stresses acting in several directions. 
Required effective junction length cylinder, cone – lc, lk (Large/Small) 
Minimum axial length along the cylinder or cone in the junction to sustain the loads. 
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 – Pd / MAWP 
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. 

Scope errors

Design temperature material is out of scope. 
The material properties are not available at the design temperature. 
Cone angle is out of scope: required α ≤ 70° (paragraph 1). 
This code determines a maximum cone 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. 
Combined stress at large end concentric or eccentric cylinder junction Sv:c is too large (paragraph 3). 
The combined stress exceeds the allowable stress. 
Combined stress at large end concentric or eccentric cylinder junction Sv:c:i is too large (paragraph 3). 
The combined stress at the inside exceeds the allowable stress. 
Combined stress at large end concentric or eccentric cylinder junction Sv:c:e is too large (paragraph 3). 
The combined stress at the outside exceeds the allowable stress. 
Combined stress at large end concentric or eccentric cone junction Sv:k is too large (paragraph 3). 
The combined stress exceeds the allowable stress. 
Combined stress at large end concentric or eccentric cone junction Sv:k:i is too large (paragraph 3). 
The combined stress at the inside exceeds the allowable stress. 
Combined stress at large end concentric or eccentric cone junction Sv:k:e is too large (paragraph 3). 
The combined stress at the outside exceeds the allowable stress. 
Combined stress at small end concentric or eccentric cylinder junction Sv:c is too large (paragraph 3). 
The combined stress exceeds the allowable stress. 
Combined stress at small end concentric or eccentric cylinder junction Sv:c:i is too large (paragraph 3). 
The combined stress at the inside exceeds the allowable stress. 
Combined stress at small end concentric or eccentric cylinder junction Sv:c:e is too large (paragraph 3). 
The combined stress at the outside exceeds the allowable stress. 
Combined stress at small end concentric or eccentric cone junction Sv:k is too large (paragraph 3). 
The combined stress exceeds the allowable stress. 
Combined stress at small end concentric or eccentric cone junction Sv:k:i is too large (paragraph 3). 
The combined stress at the inside exceeds the allowable stress. 
Combined stress at small end concentric or eccentric cone junction Sv:k:e is too large (paragraph 3). 
The combined stress at the outside exceeds the allowable stress. 

 

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