ASME B31.3 Minimum Allowable Wall Thickness Calculation (Design Conditions)
Plant ID
Plant
Equipment Number: 1234
Equipment Name:
Name
Name
Equipment Type:
Pipe
Date:
10th August 2014
Piping Classification
Piping Spec & Grade: D1, SA-106 grade B
Pipe Schedule:
Sch 120
Nominal Thickness: 0.562 in
Design Conditions: 1480 psig, -20⁰ to 100⁰ F
Design Code:
ASME B.31.3
P&ID Dwg:
5-007.032.PI.10-0012
Pressure design thickness (t)
Reference: ASME B31.3, 304.1.2 (a)
t=
PD
2(SEW + PY)
where
t = pressure design wall thickness, inches
P = internal design gage pressure, psig
D = outside diameter of pipe, inches
S = stress value for material from Table A-1, ASME B.31.3
E = quality factor from table A-1A or A-1B, ASME B.31.3
W = weld joint strength reduction factor
Y = coefficient from Table 304.1.1, valid for t < D/6, ASME B.31.3
P=
D=
S=
E=
W=
Y=
1480 psi
6.625 in
20000 psi
1
1 in
0.4
t=
0.238 in
Minimum allowable wall thickness (tm)
tm = t + c
where
tm = pressure design wall thickness + ca, inches
c = corrosion allowance
t=
ca =
0.238 in
tm =
0.288 in
0.05 in
ckness Calculation (Design Conditions)
ASME B31.3 Minimum Allowable Wall Thickness Calculation (Operating Conditions)
Plant ID
Plant
Equipment Number: 1234
Equipment Name:
Name
Name
Equipment Type:
Pipe
Date:
10th August 2014
Piping Classification
Piping Spec & Grade: D1, SA-106 grade B
Pipe Schedule:
Sch 120
Nominal Thickness: 0.562 in
Operating Conditions:1480 psig, -20⁰ to 100⁰ F
Design Code:
ASME B.31.3
P&ID Dwg:
5-007.032.PI.10-0012
Pressure design thickness (t) for MAOP
Reference: ASME B31.3, 304.1.2 (a)
t=
PoD
2(SEW + PY)
where
t = pressure design wall thickness, inches
Po = maximum allowable operating pressure (MAOP), psig
D = outside diameter of pipe, inches
S = stress value for material from Table A-1, ASME B.31.3
E = quality factor from table A-1A or A-1B, ASME B.31.3
W = weld joint strength reduction factor
Y = coefficient from Table 304.1.1, valid for t < D/6, ASME B.31.3
P=
D=
S=
E=
W=
Y=
300 psi
6.625 in
20000 psi
1
1 in
0.4
t=
0.049 in
Minimum allowable wall thickness ™ for MAOP
Composite Clock Spring Requirment
tm = t + c
Min 20% of nominal wall thickness remaining
where
tm = pressure design wall thickness + ca, inches
At least 0.12 inches wall thickness remaining
Remaining wall thickness above tn for MAOP
c = corrosion allowance
t=
ca =
0.049 in
tm =
0.099 in
0.05 in
Percentage wall thickness re
T-nominal
T-actual:
% T-Remaining:
ckness Calculation (Operating Conditions)
Composite Clock Spring Requirments:
Min 20% of nominal wall thickness remaining
At least 0.12 inches wall thickness remaining
Remaining wall thickness above tn for MAOP
Percentage wall thickness remaining
0.562 in
in
0%
ASME B31.3-2010, Table A-1A Basic Casting Quality Factors, E c
These quality factors are determined in accordance with para. 302.3.3(b). See also
para. 302.3.3(c) and Table 302.3.3C for increased quality factors applicable in special
cases. Specifications are ASTM.
Spec. No.
Description
Ec [Note (2)]
Notes
Iron
A 47
A 48
A 126
A 197
A 278
A 395
A 571
Malleable iron castings
Gray iron castings
Gray iron castings
Cupola malleable iron castings
Gray iron castings
Ductile and ferritic ductile iron
castings
Austenitic ductile iron castings
1.00
1.00
1.00
1.00
1.00
0.80
0.80
(9)
(9)
(9)
(9)
(9)
(9), (40)
(9), (40)
Carbon Steel
A 216
A 352
Carbon steel castings
Ferritic steel castings
0.80
0.80
(9), (40)
(9), (40)
Low and Intermediate Alloy Steel
A217
Martensitic stainless and alloy
castings
A 352
Ferritic steel castings
A 426
Centrifugally cast pipe
0.80
0.80
1.00
(9), (40)
(9), (40)
(10)
Stainless Steel
A 351
A 451
A 487
0.80
0.90
0.80
(9), (40)
(10), (40)
(9), (40)
Copper and Copper
Alloy
B 61
Steam bronze castings
B 62
Composition bronze castings
B 148
Al–bronze and Si–Al–bronze castings
B 584
Copper alloy castings
0.80
0.80
0.80
0.80
(9),
(9),
(9),
(9),
Nickel and Nickel Alloy
A 494
Nickel and nickel alloy castings
0.80
(9), (40)
Aluminum Alloy
B 26, Temper F
Aluminum alloy castings
B 26, Temper T6, T71 Aluminum alloy castings
1.00
0.80
(9), (10)
(9), (40)
Austenitic steel castings
Centrifugally cast pipe
Steel castings
(40)
(40)
(40)
(40)
Table 304.1.1 Values of Coefficient Y for t < D/6
Temperature, °C (°F)
Materials
Ferritic steels
Austenitic steels
Other ductile metals
Cast iron
≤ 482
(900 &
lower) 510 (950) 538 (1000) 566 (1050) 593 (1100)
0.4
0.4
0.4
0…
0.5
0.4
0.4
0.7
0.4
0.4
…
0.7
0.4
0.4
…
0.7
0.5
0.4
…
≥ 621
(1150 &
Up)
0.7
0.7
0.4
…