What do you mean by Long Radius and Short Radius elbows?

In a long radius (LR) elbow the radius of curvature is 1.5 times the nominal diameter. In a short radious (SR) elbow the radius of curvature is 1.0 times the nominal diameter of the pipe. LR elbows give less frictional resistance to the fluid compared to the SR

Long radius elbow has 1.5D of pipe ads elbow radius whereas short radius has 1D of pipe

It depends on the length and curvature  of the elbow

ELBOWS(ELL) ARE OF 2 TYPES    1. 90DEGREE  ELL    2. 45DEGREE ELL

 

1. 90 DEGREE ELBOW AGAIN HAVE TWO TYPE

A) 90 DEGREE LONG RADIUS ELBOW(L.R. =1.5 * NPS)

B) 90 DEGREE SHORT RADIUS ELBOW(S.R. =1.0 * NPS)

 

2.  45 DEGREE ELBOW HAVE ONLY LONG RADIUS ELBOW

Long Radius elbow 1.5 x diameter /short radius elbow 1.0 x diameter

Long radius elbow is 1.5Diameter of the pipe while the Short Radius is 1Diameter of the pipe this is for the curvature of the elbow from center of elbow to the edge, we useally use the LR elbow since it gives pressure drop in the flow this from the mechanical point for view and from the stress point of view long radius elbow have less stress intesfication factor which means it is less stiffer than the short radius and this gives felixability in the piping system.

Long radius elbow the curvature of nominal diameter is 1.5 times than the standard. while short radius elbow the curvature has sharp turn.

long radius elbows are used for less frictional loss and in cases of no space consideration, where radius is equal to 1.5 times the nominal size pipe diameter. while in cases of space consideration and no big consideration is given for friction losses (as in short pipe line) the radius is qual to the nominal size pipe diameter. 

Long Radius Elbows are commonly used elbows in all applications. The Radius of the Elbow center is 1.5D and short Radius Elbows used in special cases like jacketed piping. For short radius elbow the radius of center line is 1D.

 

Regards,

Naveen.

Long radius is 1.5 times of pipe NPS while short radius id 1 times

In Long Radius elbow, the radius of curvature is 1.5 times the diameter of the elbow, that is R=1.5D. It gives less frictional resistance to the fluide than short radius elbow. It also create lesser pressure dropes than short radius elbow and it is the most used one.

Both where D is the diameter of the elbow and R is the radius of curvature,

In Short Radious elbow, the radius of curvature is equal to the outer diameter of the tube, that is R=D. The piping is given a sharper turn than a long radius elbow. It is typically used where there is scarcity of space and It is less costly than a long radius elbow.