Branch Saddle Design Information
Fully Pressure-Rated Branch-Saddle Fittings
A pipe having a branch outlet connection is weakened by the opening
that must be made in it. Unless the wall thickness of the pipe is
sufficiently in excess of that required to sustain the full pressure,
it is necessary to provide added reinforcement. The amount of added
reinforcement required to sustain the pressure is governed by the
area replacement method. Basically, the volume of the pipe-wall
coupon from the hole for the branch is replaced by added volume
and mass in critical zones around the branch outlet. This methodology
is detailed in ASME Code for Pressure Piping B31.3 "Process
Piping" section #304.3.2 and #304.3.3. Where the 800 psi hoop-stress
of the branch outlet and the 800 psi hoop-stress of the main pipe
meet at the joint intersection, extra material must be added to
reduce the intensified stress in the joint to the allowable 800
psi long term stress.
Branch Connection Nomenclature ASME
B31.3-1996 Edition
Tests conducted on non-reinforced branch connections proves that
the branch outlet in line tees and reducing tees are generally reduced
in strength by about 45% depending on the ratio of the pipe diameters.
Pressure Reduction Ratios in Percent for Unreinforced
Intersections*
*Based on the Code for Pressure Piping, ASA B31.1
for standard weight pipe with 0.1 corrosion allowance: let of Fillet
weld =1/4" for branches 4" or smaller, and 3/8" for
larger branch sizes.
Contact
us today by email or our toll
free number:
sales@oxfordplasticsinc.com
1.800.263.0502
|
