Working pressure calculation for reducers
Type of calculation
Standard
Grade
Temp C°
JointFactor
Product
select
Dimension
select
Pressure req.
Result:
lblResultHeader lblResult lblResultToleranceHeader

Note!
To guarantee the minimum thickness after forming we have to take the tolerance of the pre material in consideration. Here we give you one proposal were we have calculated with the thickness tolerance which are given in EN10253-3 and –4. This tolerance is a little bit greater than for example plate tolerances. In uncertain case don’t hesitate to contact the OSTP unit who produce the fitting to get a correct answer.
CC = Concentric reducers
EC = Exccentric reducers

Note!
To guarantee the maximum pressure after forming we have to take the tolerance of the pre material in consideration. Here we give you one proposal were we have calculated with the thickness tolerance which are given in EN10253-3 and –4. This tolerance is a little bit greater than for example plate tolerances. In uncertain case don’t hesitate to contact the OSTP unit who produce the fitting to get a correct answer.
CC = Concentric reducers
EC = Exccentric reducers
lblResultTolerance lblResultProposalHeader lblResultProposal
1. Standard
Calculation is performed according to regulated formulas and stress values. The Standards defines the grades and their required Design stress.
2. Grade
Different grades have different design stress, selection of grades have impact on the dimensioning of the pipe system. Basis for the selection of grade should be corrosive environment, strength, durability, high temp requirements and cost.
3. Temperature
Select the maximum design temperature for the application.
4. Joint factor
The joint factor (z or Ej) for the longitudinal weld is regulated in the design standards. Z/Ej=1.0 is achieved with 100% Eddy Current or 100% Radiographic testing. This means that the strength of the weld is equal to that of the base material. Welded pipes delivered to EN 10217-7 have a weld factor of 1.0. ASTM-pipes must be 100% X-rayed to get Ej=1.0.
5. OD large end
The outer diameter of the large end of the reducer. Specified in mm.
6. OD small end
The outer diameter of the small end of the reducer. Specified in mm.
7. Length
The length of the reducer in diameter.
8. Pressure requirement
Set the maximum design pressure for your application.
7. Thickness requirement
Set the maximum design thickness for your application.
Calculation basis
The calculation is made using formula 6.4.4-2 in EN 13480-3:2002
For standard EN10253-3 the following applies:
for equipment not subject to non-destructive testing other than visual inspection : 0,7
for equipment subject to random non-destructive testing : 0,85
For standard EN10253-4 the following applies:
Following methods of examination can be used for fittings according to EN10253-4 (Z=1,0)
  • "radiographic examination"
  • "eddy current examination for fittings with wall thickness not greater than 6 mm"
  • "ultrasonic examination"
If you have any questions, please contact soren.nytomt@outokumpu.com
Disclaimers
This calculation tool is intended as a useful guide in calculating the sizes for OSTP welded reducers of certain grades and sizes.
However results obtained should be regarded as rough indications only. Dimensioning of pipe systems is also dependant on external forces, thermal stress, static weight etc.