How to Reduce the Nozzle Loads in START-PROF

Read about START-PROF pipe stress analysis software

If the equipment load is greater than the allowable values as specified above, first try to understand the reason of the increased load. The increased load may be caused by:

If high loads are caused by force-controlled loads then:

If high loads are caused by thermal expansions then try to apply any of the following methods to reduce the nozzle loads:

Let's show it on the simple example of the straight pipe between two anchors.

Without considering the anchor flexibility the axial force must be calculated by the equation:

If we consider right nozzle flexibility λ, then the equation is

For example, pipe 219x6 mm, l= 6m, dT=100 degrees, α=0.000012, E=2000000 kg/cm2, A=40.1 cm2 we have


if we consider the nozzle flexibility λ=0.14 mm/tf (very stiff nozzle) then the nozzle load reduces for 3 times!


Here are the complete equations to determine support loads, internal forces, stresses for restrained, unrestrained, and restrained pipe with flexibility

Using of the unbalanced expansion joints should be careful. The thrust force may transfer the huge axial load on the equipment

Here are the possible correct and wrong variants of pump piping with unbalanced expansion joint


Even after all trial and error if it is not possible to reduce the loads within allowable limits then forward the actual load values (increased by at least 20% if all piping data is not final) to vendor for FEA analysis and their acceptance.