Input variables

Generic variables

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

Gas infrastructure

Location of the facility near which the gas infrastructure is situated.

Underground, except a station
In a tunnel
Station

Maximum Design Factor – f_o

Factor for restricting the allowable stress. The value can be chosen smaller, but not larger.

Design Pressure – P_c

Pressure assumed to be present in the component according to the design terms

Design Temperature – T

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_o: 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 – e_n: Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance.
Corrosion – c₀: Amount of thickness that accounts for the possible effects of corrosions.
Tolerance – c₁: 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 joints.
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 joints in which the bend is divided.

Miter Bend

Multiple Miter Bend Widely Spaced

Multiple Miter Bend Closely Spaced

Single Miter Bend

Calculated Values

Yield strength at operating temperature – R_t: Stress in the component at which the component starts to plastically deform at operating temperature.
Minimum yield strength at 20 °C – R_ta: 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 at 20 °C – S_t: 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 – θ: Cutting angle between the different joints.
Change of direction at miter joint – α = 2θ: The total angle of deflection per miter joint.
Maximum calculation pressure – P_{c max}: Maximum pressure allowed when the stress is time dependent or not.
Minimum miter bend radius – R_min: Minimum required bend radius
Minimum inside length of sleeve segment ends – M: Minimum length of the segment measured at the inside.
Multiple/Single miter bend type: A miter bend is called a multiple miter bend with 3 or more segments, otherwise a single miter bend with 2 segments.
Nominal Required Thickness – e_rn: 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_c/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 pressure is out of scope: minimum operating pressure > 16 bar.: This code determines a minimum pressure.
Design temperature is out of scope: required -40 °C ≤ T ≤ 120 °C.: This code determines a minimum and maximum temperature.
Design factor is too large: required is fo ≤ fo_max (see 7.2).: This code determines a maximum design factor.
Wall thickness is out of scope according paragraph 7.9.2 Table 1.: This code determines for miter bends a minimum thickness.
Number of segments is out of scope: required is NoS ≥ 2: A miterbend has at least 2 segments.
For time dependent design stress: required P_c ≤ 0.4 MPa: This code determines for loads that vary in time a maximum pressure.
For time dependent design stress: required cycles ≤ 100: This code determines for loads that vary in time a maximum number of cycles.
For time independent design stress: required P_c ≤ 2 MPa: This code determines for loads that are constant in time a maximum pressure.
For time independent design stress and change in direction α > 22.5°: required cycles ≤ 7000: This code determines for loads that are constant in time a maximum number of cycles.
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.
For multiple miter bends, the miter cut angle is out of scope: required is θ ≤ 22.5°: This code determines for multiple miter bend a maximum angle.
Miter bend radius is out of scope: required is R ≥ R_min mm.: This code determines 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: Wall thickness is insufficient to bear the applied loads. Increase the wall thickness.

Remarks

For single miter bends, the miter cut angle θ is larger than 22.5°.: The Maximum Allowable Pressure drops rapidly when the angle exceeds this limit.

Calculation errors

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