According to classic paper, the flexibility characteristic for latrolet (45 degree very thicker than nominal forging lateral), h=1.97T/r2 based on the out of plane bending derived from the fatigue test using 4 inch sch. 40 done by Bonny Forge.
http://crmweb.intergraph.com/smart/ICAS_Caesar2/documents/SIFs_VariousFittings.PDF
While, for fabricated lateral: i = 1.5378(R/T)^2/3 obtained by multiplying the SIF of forged latrolet by (4.4)^2/3, that means h= 0.448T/r2.
Source: PIPING HANDBOOK, CHAPTER B4, STRESS ANALYSIS OF PIPING SYSTEMS
http://www.ewp.rpi.edu/hartford/~ernesto/F2012/EP/MaterialsforStudents/GreyIII/Basavaraju2004.PDF
Comparing with unreinforced fabricated tee, It is 1.7 times larger in SIF.
(1) A Parametric Three-Dimensional Finite Element Study of 45 Degree Lateral Connections, P. P. Raju, WRC Bulletin 301-1985
(2) Stress Indices, Pressure Design, and Stress Intensification Factors for Laterals in Piping, E.C. Rodabaugh, , WRC Bulletin 360-1991
(3) ASME Section VIII Division 2, 5.D.3 Stress Indices for Laterals Di/t<=40, dm/Di<=0.5, di/Sqrt(Dit)<=3.0.
(4) EN 13480-3 : 2002 - Annex O.
(5) Codeti
For lateral io: io'=io/sin(a)^(3/2)
where a is lateral angle, io is 90 degree branch.
CODETI was updated to align with EN-13480 Annex O.
(6) FEM case study such as FE/Pipe, which may show less SIF than URT
See also: