Specifies the cyclic stress range reduction factor for most piping codes.
-
Some codes use different naming to indicate the cyclic stress range reduction factor.
-
Consult the applicable piping code for methods of combining cycle life data where several thermal states exist and where the number of thermal cycles is high.
-
Unless otherwise specified, the software assumes a value of 1.0 if you do not type a value.
-
For applicable codes, you can also specify the number of cycles, typically in the thousands or greater, instead of the cyclic stress range reduction factor. The software then calculates the cyclic stress range reduction factor as specified in the code.
B31.1
Cyclic stress range factor as defined by equation 1c.
B31.3, B31.3 Chapter IX
Stress range factor as defined by equation 1c and corresponding to Fig 302.3.5. For B31.3, the stress range factor can exceed 1.0 if certain criteria are met.
B31.4, B31.4 Chapter XI
Fatigue factor is obtained from the equation given in Section 403.3.2. The fatigue factor cannot exceed 1.2.
B31.4 Chapter IX
Not used.
B31.8
Stress range reduction factor is obtained from the equation given in Section 833.8(b).
B31.8 CHAPTER VIII
Not used.
B31.9
References B31.1 for detailed stress analysis. For more information, see Paragraph 919.4.1.b.
CODETI
Called U in the code.
NORWEGIAN
Called fr in the code. This value can be as high as 2.34.
DNV
Material ultimate tensile strength at temperature.
CAN Z662
F1 = L - The location factor from Table 4.2
F2 = T - The temperature derating factor from Table 4.4
For F1 = L:
Application |
CLASS 1 |
CLASS 2 |
CLASS 3 |
CLASS 4 |
---|---|---|---|---|
Gas (non-sour) and HVP (non-sour) |
||||
General |
1.000 |
0.900 |
0.700 |
0.550 |
Cased crossings |
1.000 |
0.900 |
0.700 |
0.550 |
Roads |
0.750 |
0.625 |
0.625 |
0.500 |
Railways |
0.625 |
0.625 |
0.625 |
0.500 |
Stations |
0.625 |
0.625 |
0.625 |
0.500 |
Other |
0.750 |
0.750 |
0.625 |
0.500 |
CO2 ( non-sour) |
||||
General |
1.000 |
0.800 |
0.800 |
0.800 |
Cased crossings |
1.000 |
0.800 |
0.800 |
0.800 |
Roads |
0.800 |
0.800 |
0.800 |
0.800 |
Railways |
0.625 |
0.625 |
0.625 |
0.625 |
Stations and terminals |
0.800 |
0.800 |
0.800 |
0.800 |
Other |
0.800 |
0.800 |
0.800 |
0.800 |
LVP multiphase (non-sour), LVP liquid & quasi-liquid hydrocarbon (with low flammability), & LVP oilfield water |
||||
Uncased railway crossings |
0.625 |
0.625 |
0.625 |
0.625 |
All others |
1.000 |
1.000 |
1.000 |
1.000 |
Class 1 - Location areas with no development or containing ten or fewer dwelling units intended for human occupancy
Class 2 - Location areas containing one or more of the following:
-
11 to 45 dwelling units intended for human occupancy.
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Buildings occupied by 20 to 120 persons.
-
Small, well-defined outside areas occupied by 20 to 120 persons.
-
Industrial installations where release of fluid from the pipeline can produce a dangerous or environmentally hazardous condition.
Class 3 - Location areas containing one or more of the following:
-
46 or more dwelling units intended for human occupancy.
-
Facilities from which rapid evacuation can be difficult, such as hospitals, prisons, and day-care facilities.
-
Buildings occupied by more than 120 persons.
-
Small, well-defined outside areas occupied by more than 120 persons.
Class 4 - Location areas where buildings intended for human occupancy have 4 or more stories.
For F2 = T:
Temperature |
Derating Factor T |
---|---|
up to 120 (C) |
1.00 |
150 |
0.97 |
180 |
0.93 |
200 |
0.91 |
230 |
0.87 |
F3 through F9 are not used.
CAN Z662 Chapter 11
F1 - Not used.
F2 = T - Temperature derating factor obtained from Table 4.4
F3 = - FA design factor for Condition A from Table 11.1, column A
F4 = - FB design factor for Condition B from Table 11.1, column B
F5 through F9 are not used.
BS 806
Mean stress to failure in design life at design temperature. F1, F2, ... F9. This value corresponds to the nine possible thermal states.
FDBR
Identical to B31.1 unless you type the thermal expansion coefficients into Temperature so that the software cannot determine EHn. In this case, type a value of 1.0 for Fac and use F1, F2, ... F9 to specify the product of (f * EHn/EC) for each Temperature case, where EHn is the hot elastic modulus at operating conditions and EC is the cold elastic modulus.
SWEDISH METHOD 1
Creep rupture stress at temperature. This value corresponds to the nine possible thermal states.
STOOMWEZEN
Creep related material properties as follows:
-
F1 = Rrg - Average creep stress to produce 1% permanent set after 100,000 hours at temperature (vm).
-
F2 = Rmg - Average creep tensile stress to produce rupture after 100,000 hours at temperature (vm).
-
F3 = Rmmin - Minimum creep tensile stress to produce rupture after 100,000 hours at temperature (vm).
BS 7159
Fatigue factor Kn. This value is used inversely compared to other codes so that its value is greater than 1.0. Kn is calculated as follows:
Kn = 1 + 0.25(As/sn) (log10(n) - 3)
Where:
As = stress range during fatigue cycle
σn = Maximum stress during fatigue cycle
n = number of stress cycles during design life
UKOOA
Ratio r from the material UKOOA idealized allowable stress envelope. This ratio is defined as sa(0:1)/sa(2:1) as shown on the figure below. One value should be given for each of the operating temperature cases.
IGE/TD/12
UTS value.
EN-13480
Stress range reduction factor, U, taken from Table 12.1.3-1 (which matches the B31.1 table above) or computed from equation 12.1.3-4.
GPTC/Z380
Not used.
PD-8010 (Part 1 & Part 2)
Not used.
ISO 14692
F is used in a different way. See the Reference for ISO 14692.
HPGSL
Stress range reduction factor at design temperature.
JPI
Stress range reduction factor at design temperature.