Ovalization Factor

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According to and RD 10-249-98 section 5.1 and 5.2, the greater factor of initial elliptical cross-section is set

In the absence of data for actual initial ellipticity of bent pipe cross-sections based on observation (for example, during projection stage), two analyses must be run: one with a=0% and another with the greater value of  a, based on manufacturing specifications or according to the manufacturer (see section 5.2.6.8).
Factor is used for:

Keep in mind that according to RD 10-249-98 section 5.2.6.8, initial ellipticity a should be increased 1.8 times for low-temperature pipelines. This is automatically taken into account when analyzing using  RD 10-249-98 section 5.2.
In addition, according to section 5.2.6.8, if initial ellipticity is less than 3%, ellipticity is not considered in stress analysis. This is not automatically considered in START-PROF.