Evenly spaced mitered bends, whether closely or widely spaced, are defined by two parameters:
-
The number of cuts (changes in direction)
-
The equivalent radius or miter spacing
For closely spaced miters, the equivalent radius is equal to the code defined as R1 for B31.3 and R for B31.1. The equation for the equivalent radius to the spacing for evenly spaced miters is:
Req = S / [ 2 tan(q) ]
Where:
|
Req |
= |
equivalent miter bend radius |
|
S |
= |
spacing of the miter cuts along the centerline |
|
q |
= |
code-defined half-angle between adjacent miter cuts: q = a / 2N |
Where:
|
a |
= |
total bend angle |
|
N |
= |
number of cuts |
When using B31.1, an additional parameter, B (length of miter segment at crotch), is examined for closely spaced miters. The following equation is used to compute B for evenly spaced miters:
|
B |
= |
S [ 1 - ro / Req ] |
Where:
|
ro |
= |
outside radius of pipe cross-section |