EN 1594 calculation is according EN13480
Input variables
Generic variables
These variables can be found in virtually 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 – fo ≤ fomax (see 7.2).
Factor for restricting the allowable stress. The value can be chosen smaller, but not larger.
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 (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 – De, De2
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 – dn, d2n, d3n
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance.
Corrosion header and branch – Ca, Ca2
Amount of thickness that accounts for the possible effects of corrosions.
Tolerance header, branch and reinforcement – tol, tol2, tol3
Tolerance in thickness for production
Strength reduction coefficient header and branch – zh, zb
Effectiveness of the strength, depending on whether joints are seamless, welded, or expected to perform worse than the base material properties
Angle centerline branch – y
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
Allowable Operating Stress header, branch and reinforcement – f, f1, f2
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 – ft, f1t, f2t
Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature
Stress ratio branch/header – f1/f, f1t/ft
Ratio of operating stresses of the branch and the header. This ratio must be ≤ 1.
Stress ratio reinforcement/header – f2/f, f2t/ft
Ratio of operating stresses of the reinforcement and the header. This ratio must be ≤ 1.
Required thickness header pipe and branch pipe – dr, d2r
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.
Reinforcement limit header direction – Wmax
Length from the branch outside diameter to the end of the header reinforcement zone.
Reinforcement limit branch direction – Hmax
Length from the header outside diameter to the end of the branch reinforcement zone.
Material area header – A0
Cross-sectional area of header material between reinforcement limits.
Material area branch – A1
Cross-sectional area of branch material between reinforcement limits.
Material area of extra added reinforcement including welds – A2
Cross-sectional area of reinforcement material between reinforcement limits.
Total available material area – A
Total cross-sectional area of material between reinforcement limits. Sum of areas is corrected for stress ratios.
Total pressure area – Ap
Total cross-sectional area with pressure in header and branch between reinforcement limits.
Strength reduction coefficient at opening – z3
Effectiveness of the strength in the opening.
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 – DP/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.
Tapering header and branch
The tapering of the header and branch on connecting pipes is checked.
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 ≤ fomax (see 7.2).
This code determines a maximum design factor.
Wall thickness header is out of scope according paragraph 7.9.2 Table 1.
This code determines for headers a minimum thickness.
Wall thickness branch is out of scope according paragraph 7.9.2 Table 1.
This code determines for branches a minimum thickness.
Angle branch is out of scope (center line branch to header wall): required is 45° ≤ α ≤ 135°.
This code determines a minimum and maximum branch angle.
Angle branch is out of scope (center line branch to header wall): required is 45° ≤ γ ≤ 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: required is z3 ≥ zmin.
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.