Pipe Branch Reinforcement
per ASME B31.1 -2010 Power Piping Code
Branch (1) Calculations
3/11/2012, ReinfS1.xls
Client:
Description:
Prepared By
Page 1 of 2
Approval
Date
Ben A. Nottingham
Rev.
0
Customer No.:
Item No.:
1
2
Owner No.:
Dwg. No.:
3
4
The user is responsible to verify method and results.
Refer to para. 104.3.1 and Fig. 104.3.1(D) of the Code
-20 to
Design Temperature
400
deg. F (to 204 deg. C)
Dimensional Units
Inch
Rating is based on design
Design Pressure
Design pressure: 350 psig = 24.6 kg/cm^2 = 24.1 bar-G = 2413 kPa
Material Data per ASME B31.1 -2010, Tables A-1 thru A-9
Materials:
Run Pipe:
Appendix H, Example 4, Run & Branch: Carbon Steel, API 5L-A Seamless Pipe
UNS no.: ----
Line Pipe
Branch:
Allowable stress, SEh = 16 ksi = 110 MPa
Coefficient Y = 0.4
Notes: para. H304 in ASME B31.3
Weld: S-1
Weld joint factor, E h = 1.00
Weld strength red. factor, W h = 1.00
Appendix H, Example 4, Run & Branch: Carbon Steel, API 5L-A Seamless Pipe
UNS no.: ----
Line Pipe
Reinf:
Allowable stress, SEb = 16 ksi = 110 MPa
Coefficient Y = 0.4
Notes: para. H304 in ASME B31.3
Weld: S-1
Weld joint efficiency factor, E b = 1.00
Weld strength reduction factor, W b = 1.00
Appendix H, Example 4, Run & Branch: Carbon Steel, API 5L-A Seamless Pipe
UNS no.: ----
Line Pipe
Allowable stress, SEr = 16 ksi = 110 MPa
Weld: S-1
Notes: para. H304 in ASME B31.3
Does Branch-1 intersect a longitudinal weld on the run?
Longitudinal Weld Intersection?
Yes
Allowable stress of run for reinforcement design, SE hr = SE h when branch intersects a weld on the run,
or SE hr = SE h / E h when the branch does not intersect a weld on the run.
16.0
ksi
Dob =
4.5
in.
tnb =
0.237
in.
or h2 =
0.000
in.
Check if diameter and thickness ratios are reasonable using criteria from ASME B31.3, para. 304.3.1(b)(1) & (2).
D ob / D oh =
(D ob / D oh ) must not exceed 1.0
OK … Branch OD is not greater than Run OD.
0.52
D oh / T h =
30.6
D oh / 2 =
4.3
in.
in.
Thickness allowance (corrosion, etc.)
Allowances
Run Dimensions
in.
Sch 40 per ASME B36.10M
Wall thk:
Doh =
Pipe nominal thickness
tnh =
0.322
in.
or h1 =
0.000
in.
Millh = 12.5%
(D oh /T h ) must not exceed 100, unless D ob <(D oh / 2)
Is branch size less than 1/2 of run size?
NPS 4 (DN 100)
Pipe size:
Pipe outside diameter
Thk. tolerance:
0.1882
Branch Dimensions
NPS 8 (DN 200)
Pipe size:
Wall thk:
SE hr =
A=
8.625
in.
Sch 40 per ASME B36.10M
Pipe outside diameter
Pipe nominal thickness:
Thk. tolerance:
Millb =
OK… Run OD/ Run Thk. < 100. See below.
OK… Branch OD may be any size not exceeding Run OD.
0.0%
Required minimum wall thicknesses. Refer to para. 104.1.2 Eq. (3) and Table 104.1.2(A) of B31.1 Code,
t m = [ P D o / (2 (SE + PY )) ] + A
t mh =
0.2817
t mhr =
0.2817
in.
Run actual measured or minimum thickness, T h = t nh (1 - Mill h ) - h 1
Th =
0.282
in.
Run actual corroded thickness (measured or minimum thickness, less corrosion allowance), t ha = T h - A
t ha =
0.094
in.
t mb =
0.2370
in.
Branch actual measured or minimum thickness, T b = t nb (1 - Mill b ) - h 2
Tb =
0.237
in.
Branch actual corroded thickness (measured or minimum thickness, less corrosion allowance), t ba = T b - A
t ba =
0.049
in.
Minimum required run thickness, t mh = [ P D oh / (2 (SE h + PY )) ] + A
Minimum required run thickness for reinforcement design, t mhr = [ P D oh / (2 (SE hr + P Y ) ] + A
OK… Run thickness IS sufficient at design pressure.
Minimum required branch thickness, t mb = [P D ob / (2 (SE b + PY b1 )) ] + A
OK… Branch thickness IS sufficient at design pressure
3/11/2012, ReinfS1.xls
Pipe Branch Reinforcement
per ASME B31.1 -2010 Power Piping Code
Branch (1) Calculations
Nom. thk. of pad:
t nr = 0.322
in. = 8.18 mm
Width of pad from edge of branch:
w r = 0.875
in. = 22.23 mm
Height of saddle above run:
h s = n/a
--
Weld at pad or ring to branch periphery:
W 1s = n/a
--
Weld at ring, pad, or saddle outer edge:
W 2s = n/a
--
Weld at saddle-to-branch periphery:
W 3s = n/a
--
Page 2 of 2
wwr r
wwr r
wr
ααtn
α
tri
thnr
tn
rs
trrnr
Optional Special Weld Dimensions:
α
Angle between run and branch:
= 90
Ring Reinforced (re-pad), 90-degree
Branch
Comments:
-- -- -- -- --- -- -- -- --- --
degrees
Integrally Reinforced B31.1 Branch:
t r i = n/a
--
w r i = n/a
--
Leg of 60 deg. triangle = n/a
Width integral reinf. area = (tr i) tan 30
Other Dimensions
Inside centerline longitudinal dimension of finished branch opening = [ D ob - 2 (T b - A ) ] / sin α
d1 =
4.402
in.
Half width of reinf. zone = d 1 or (T b - A )+(T h -A ) + d 1 / 2, whichever is greater, but not more than D oh
d2 =
4.402
in.
Reinf. zone height outside of run pipe, for ring or saddle = 2.5 (T h - A ) or 2.5 (T b - A ) + t nr , whichever is less
Lr =
0.234
in.
Reinf. zone height outside of run pipe, for integrally reinforced fitting = 2.5 (T h - A )
Li =
0.000
in.
Reinf. zone height outside of run pipe = L r + L i
L4 =
0.234
in.
Outside dimension of reinforcing ring or saddle (along run) = 2 w r + [ (D ob ) ( 2 - sin α ) ]
Dr =
6.250
in.
t min =
0.000
in.
Minimum throat of fillet weld at saddle-to-branch = (smaller of t nb or t nr ) ---[weld reference para. 127.4.8(B)]
Min. throat of weld at branch periphery (except saddle or integrally reinf.) = smaller of 6.0 mm (1/4") or 0.7 t nb
Minimum leg of weld at branch periphery (except saddle or integrally reinf.) = t c / 0.707
Leg height of weld at branch periphery (except saddle or integrally reinf.) = greater of W 1(min) or W 1s
Minimum leg of weld at outer edge of ring, pad, or saddle = 0.5 t nr / 0.707
Leg height of weld at outer edge of ring, pad, or saddle = greater of W 2(min) , or W 2s , but
tc =
0.166
in.
W 1(min) =
0.235
in.
W1 =
0.235
in.
W 2(min) =
0.228
in.
W2 =
0.228
in.
in.
not more than smaller of t nr or L 4 (must fit within the reinf. zone)
W 3(min) =
0.000
Leg height of fillet weld at saddle-to-branch periphery = greater of W 3(min) or W 3s
W3 =
0.000
in.
Maximum width of ring, pad, or saddle which would apply = d 2 - (D ob / 2 ) / sin α
WR max =
2.152
in.
Minimum leg height of fillet weld at saddle-to-branch periphery = 0.7t min /0.707
Rh =
0.234
in.
Rw =
0.875
in.
Factor for complete fillet welds, other than on ring, pad, or saddle edge, which will fit within the reinf. zone height
N wh =
0
Factor for complete fillet welds on ring, pad, or saddle edge which will fit within reinforcement zone width
N ww =
2
Reinforcement height (except weld) = lesser of ( t nr or L 4 ) , or lesser of ( t r i or L 4 ), as applicable
Reinforcement width (except weld) = (lesser of w r or WR max ), or (lesser of w r i or t ri ) tan 30, as applicable
Count of Welds Within Reinforcement Zone
Strength Correction Factors
Factor for strength correction of branch area = 1 if SE b > SE h , or = (SE b / SE h ) if SE b <= SE h
Strength correction factor for reinforcing material = 1 if SE r > SE h , or = (SE r / SE h ) if SE r <= SE h
Strength correction factor for welds, F w = lesser of F b or F r
Areas
Pressure design area expected at end of service life = (t mhr - A ) d 1
Required reinforcement area = A 6 (2 - sin α )
Area of excess thickness in run pipe wall = (2 d 2 - d 1 ) (T h - t mhr )
Area of excess thickness in branch pipe wall = 2 L 4 (T b - t mb ) / sin α
Fb =
1.000
Fr =
1.000
Fw =
1.000
A6 =
0.412
in.^2
A7 =
0.412
in.^2
A1 =
0.000
in.^2
A2 =
0.000
in.^2
Total area of welds within zone = (N wh / 2)(W 1 )+(N wh / 2)(W 3 )+(N ww / 2)(W 2 )
A3 =
0.052
in.^2
Area of added reinforcement metal, except welds, within the reinforcement zone = 2 x R h x R w
A4 =
0.409
in.^2
Area provided in B31.1 integrally reinforced fitting [See Fig. 104.3.1(D), Example B], = R h x R w
A 4i =
0.000
in.^2
Total contributing area (with strength correction for added metal within the reinf. zone)
A c = A 1 + (A 2 )(F b ) + (A 3 )(F w ) + (A 4 + A 4i )(F r )
Ac =
0.461
in.^2
2
Percent of area replaced = A c / A 7 %
2
2
This branch has sufficient reinforcement.
% Area
112%