ASME B31.3
Sr. No. 1
This Process Piping Code is a Section of the American Society of Mechanical Engineers Code for Pressure Piping, ASME B31, an American National Standard. (i) For metallic piping not designated by the owner as Category M, High Pressure, or High Purity Fluid Service (see para. 300.2 and Appendix M), Code requirements are found in Chapters I through VI (the base Code) and fluid service requirements are found in (a) Chapter III for materials (b) Chapter II, Part 3, for components (c) Chapter II, Part 4, for joints (ii) For nonmetallic piping and piping lined with nonmetals, all requirements are found in Chapter VII. (iii) For piping in a fluid service designated as Category M, all requirements are found in Chapter VIII. (iv) For piping in a fluid service designated as Category D, piping elements restricted to Category D Fluid Service in Chapters I through VII, as well as elements suitable for other fluid services, may be used. (v) For piping designated as High Pressure Fluid Service, all requirements are found in Chapter IX. These rules apply only when specified by the owner. (vi) For piping designated as High Purity Fluid Service, all requirements are found in Chapter X. (vii) Requirements for Normal Fluid Service in Chapters I through VI are applicable under severe cyclic conditions unless alternative requirements for severe cyclic conditions are stated. (viii) Requirements for Normal Fluid Service in Chapters I through VI are applicable for Elevated Temperature Fluid Service unless alternative requirements for Elevated Temperature Fluid Service are invoked.
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EXCLUSIONS This Code excludes the following: (a) piping systems designed for internal gage pressures at or above zero but less than 105 kPa (15 psi), provided the fluid handled is nonflammable, nontoxic, and not damaging to human tissues as defined in 300.2, and its design temperature is from −29°C (−20°F)
through 186°C (366°F) (b) power boilers in accordance with BPV Code2 Section I and boiler external piping which is required to conform to B31.1 (c) tubes, tube headers, crossovers, and manifolds of fired heaters, which are internal to the heater enclosure (d) pressure vessels, heat exchangers, pumps, compressors, and other fluid handling or processing equipment, including internal piping and connections for external piping 3
Design Temperature The design temperature of each component in a piping system is the temperature at which, under the coincident pressure, the greatest thickness or highest component rating is required 301.3.2 Uninsulated Components (a) For fluid temperatures below 65°C (150°F), the component temperature shall be taken as the fluid temperature unless solar radiation or other effects result in a higher temperature. (b) For fluid temperatures 65°C (150°F) and above, unless a lower average wall temperature is determined by test or heat transfer calculation, the temperature for uninsulated components shall be no less than the following values: (1) valves, pipe, lapped ends, welding fittings, and other components having wall thickness comparable to that of the pipe: 95% of the fluid temperature (2) flanges (except lap joint) including those on fittings and valves: 90% of the fluid temperature (3) lap joint flanges: 85% of the fluid temperature (4) bolting: 80% of the fluid temperature
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Bases for Design Stresses Other Materials. Basic allowable stress values at temperature for materials other than bolting materials, cast iron, and malleable iron shall not exceed the lowest of the following: (1) the lower of one-third of ST and one-third of tensile strength at temperature (2) except as provided in (3) below, the lower of two-thirds of SY and two-thirds of yield strength at
temperature (3) for austenitic stainless steels and nickel alloys having similar stress–strain behavior, the lower of twothirds of SY and 90% of yield strength at temperature [see (e) below]
(4) 100% of the average stress for a creep rate of 0.01% per 1 000 h (5) 67% of the average stress for rupture at the end of 100 000 h (6) 80% of the minimum stress for rupture at the end of 100 000 h
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Thickness calculation for Straight pipe: The required thickness of straight sections of pipe shall be determined Straight Pipe Under Internal Pressure (a) For t < D/6, the internal pressure design thickness for straight pipe shall be not less than that calculated in accordance with either eq. (3a) or eq. (3b):
(b) For t ≥ D/6 or for P/SE > 0.385, calculation of pressure design thickness for straight pipe requires special consideration of factors such as theory of failure, effects of fatigue, and thermal stress.
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Allowable Displacement Stress Range, SA
When Sh is greater than SL, the difference between them may be added to the term 0.25Sh in eq. (1a). In that case, the allowable stress range is calculated by eq. (1b):
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Stress due to Sustained Load The equation for the stress due to sustained loads, such as pressure and weight, SL, is provided in eq. (23a). The equation for the stress due to sustained bending moments, Sb, is provided in eq. (23b).
The equation for the stress due to sustained torsional moment, St, is
The equation for the stress due to sustained longitudinal force, Sa, is
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FLUID SERVICE:fluid service: a general term concerning the application of a piping system, considering the combination of fluid properties, operating conditions, and other factors that establish the basis for design of the piping system. See Appendix M. (a) Category D Fluid Service: a fluid service in which all of the following apply: (1) the fluid handled is nonflammable, nontoxic, and not damaging to human tissues as defined in para. 300.2 (2) the design gage pressure does not exceed 1 035 kPa (150 psi) (3) the design temperature is not greater than 186°C (366°F) (4) the fluid temperature caused by anything other than atmospheric conditions is not less than −29°C (−20°F)
(b) Category M Fluid Service: a fluid service in which the potential for personnel exposure is judged to be significant and in which a single exposure to a very small quantity of a toxic fluid, caused by leakage, can produce serious irreversible harm to persons on breathing or bodily contact, even when prompt restorative measures are taken. (c) Elevated Temperature Fluid Service: a fluid service in which the piping metal temperature is sustained equal to or greater than Tcr as defined in Table 302.3.5, General Note (b). (d) High Pressure Fluid Service: a fluid service for which the owner specifies the use of Chapter IX for piping design and construction; see also para. K300. (e) High Purity Fluid Service: a fluid service that requires alternative methods of fabrication, inspection, examination, and testing not covered elsewhere in the Code, with the intent to produce a controlled level of cleanness. The term thus applies to piping systems defined for other purposes as high purity, ultra high purity, hygienic, or aseptic. (f) Normal Fluid Service: a fluid service pertaining to most piping covered by this Code, i.e., not subject to the rules for Category D, Category M, Elevated Temperature, High Pressure, or High Purity Fluid Service.
gh Pressure, requirements equirements
are applicable
are applicable
EN 13480 This European Standard EN 13480 for Metallic industrial piping consists of seven interdependant and non dissociable Parts which are: - Part 1: General; - Part 2: Materials; - Part 3: Design and calculation; - Part 4: Fabrication and installation; - Part 5: Inspection and testing; - Part 6: Additional requirements for buriedd piping; CEN/TR 13480-7, Guidance on the use of confirmity assessment procedures This European Standard specifies the requirements for industrial piping systems and support, including safety systems, made of metallic materials (but initially restricted to steel) with a view to ensure safe operation. This European Standard is applicable to metallic piping above ground, ducted or buried, irrespective of pressure.
temperature
Calculation temperature The calculation temperature, tc, shall be the maximum temperature likely to be reached at the mid-thickne piping, under normal operating conditions, at the calculation pressure pc. The calculation temperature sha determined as indicated below. Any heat transfer calculation shall be performed on the assumption that th heat loss due to wind.
a) For externally uninsulated and internally unlined piping components, the calculation temperature s follows : 1) For fluid temperatures below 40 °C, the calculation temperature for the component shall be taken as the fluid temperature; 2) For fluid temperatures of 40 °C and above, unless a lower average wall temperature is determined by te or heat transfer calculation, the calculation temperature for uninsulated components shall be not less than the following values, but not less than 40°C: i) 95 % of the fluid temperature for valves, pipes, ends, welding fittings, and other components having wall thickness comparable to that of the pipe; ii) 90 % of the fluid temperature for flanges (except lap joint flanges) including those on fittings and valves; iii) 85 % of the fluid temperature for lap joint flanges; iv) 80 % of the fluid temperature for bolting.
Steels other than austenitic steels 5.2.1.1 Design conditions The design stress shall be in accordance with the following:
where,
ReHt
= minimum specified value of upper yield strength at calculation temperature "
f
when this temperature is greater than the room temperature = design stress
Rp0,2t Rm
= minimum specified value of 0,2 % proof strength at calculation temperature when this temperature is greater than the room temperature = minimum specified value of tensile strength at room temperature
Austenitic steels 5.2.2.1 Design conditions The design stress shall be in accordance with the following: for A > 35 %
where, A
= elongation at rupture
Rp1,0t
= minimum specified value of 1,0 % proof strength at calculation temperature when this temperature is greater than the room temperature
Rm t
= minimum specified value of tensile strength at calculation temperature when this temperature is greater than the room temperature
Time-dependent nominal design stress Steels 5.3.2.1 Design conditions The design stress in the creep range f CR to be used for design under static loading shall be:
where SFCR is a safety factor which depends on the time and shall be in accordance with Table 5.3.2-1.
If the design lifetime is not specified, the mean creep rupture strength at 200 000 h shall be used. In cases where the 200 000 h values are not specified in the material standards, the mean creep rupture s at 150 000 h or 100 000 h shall be used. In cases where design lifetimes shorter than 100 000 h are specified, one of the following methods shall be a) If a lifetime monitoring system is not provided, the safety factor SFCR shall be equal to 1,5 and shall be a
to the mean creep rupture strength at the relevant lifetime of at least 10 000 h; b) If a lifetime monitoring system is provided, a safety factor of SFCR = 1,25 may be specified with regard t
mean creep rupture strength at the relevant lifetime of at least 10 000 h. In no case, shall the 1 % creep strain limit (mean value) at 100 000 h be exceeded.
The minimum required wall thickness for a straight pipe without allowances and tolerances, e, shall be calc as follows:
The allowable stress range
fa
shall be given by:
where,
Ec is the value of the modulus of elasticity at the minimum metal temperature (t=c) consisten under consideration; Eh is the value of the modulus of elasticity at the maximum metal temperature (t=h) consiste
under consideration; fc is the basic allowable stress at minimum metal temperature consistent with the loading un U is the stress range reduction factor (see NOTE 1) taken from Table 12.1.3-1
NOTE 1 - U applies essentially to non-corroded piping. Corrosion can sharply decrease cyclic lifetime. The resistant materials should be considered where a large number of major stress cycle are anticipated.
Stress due to sustained loads The sum of primary stresses 1, due to calculation pressure, pc, and the resultant moment, MA, from wei other sustained mechanical loads shall satisfy the following equation:
For the purpose of classification of pressure equipment in hazard categories, fluids (gas or liquid) are divid
1) Group 1 comprises dangerous fluids (under Council Directive 67/548/EEC (27 June 1967), Article 2 (2) explosive ; extremely flammable; highly flammable; flammable (where the maximum allowable temperature is above flashpoint); very toxic; toxic; oxidizing. 2) Group 2 comprises all other fluids not referred to in Group 1.
In combination with the internal volume (V) and/or the maximum allowable pressure (PS) of the vessel this 4 specific cases: a) Fluids in Group 1; Industrial piping for gases, liquefied gases, gases dissolved under pressure, vapours and also liquids whose vapour pressure at the maximum allowable temperature is greater th normal atmospheric pressure (1013 mbar),within the following limits: DN > 25;
b) Fluids in Group 2; Industrial piping, liquefied gases, gases dissolved under pressure, vapours and als
vapour pressure at the maximum allowable temp. is greater than 0,5 bar above normal atmospheric p within the following limits: DN > 32 and PS x DN > 1000 bar;
c) Fluids in Group 1; Industrial piping for liquids having a vapour pressure at the maximum allowable tem 0,5 bar above normal atmospheric pressure (1013 mbar),within the following limits: DN > 25 and PS x
d) Fluids in Group 2; Industrial piping for liquids having a vapour pressure at the maximum allowable tem 0,5 bar above normal atmospheric pressure (1013 mbar), within the following limits: PS > 10 bar and PS x DN > 5 000 bar.
Industrial piping are classified in hazard categories I to Ill according to one of the relevant cases a) to d) an diameter and maximum allowable pressure. The classification has been defined in the Figures A.1 to A.4.
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o be reached at the mid-thickness of the The calculation temperature shall be ormed on the assumption that there is no
ts, the calculation temperature shall be as
component shall be taken as the
temperature is determined by test mponents shall be not less than
d other components having
ding those on fittings and
ngth at calculation temperature " t "
om temperature
ength at calculation temperature " t " om temperature at room temperature
ength at calculation temperature " t "
om temperature
at calculation temperature
om temperature
ic loading shall be:
nce with Table 5.3.2-1.
00 000 h shall be used. dards, the mean creep rupture strength
of the following methods shall be used : all be equal to 1,5 and shall be applied
5 may be specified with regard to the
be exceeded.
s and tolerances, e, shall be calculated
metal temperature (t=c) consistent with the loading
metal temperature (t=h) consistent with the loading
re consistent with the loading under consideration
om Table 12.1.3-1
rply decrease cyclic lifetime. Therefore, corrosion tress cycle are anticipated.
resultant moment, MA, from weight and
es, fluids (gas or liquid) are divided into two groups:
EC (27 June 1967), Article 2 (2)), i.e. fluids defined as:
bove flashpoint); very toxic;
pressure (PS) of the vessel this leads to
dissolved under pressure, owable temperature is greater than 0,5 bar above
under pressure, vapours and also liquids whose
bar above normal atmospheric pressure (1013 mbar),
re at the maximum allowable temp. of not more than ollowing limits: DN > 25 and PS x DN > 2 000 bar;
re at the maximum allowable temp. of not more than ollowing limits: PS > 10 bar and DN > 200 and
of the relevant cases a) to d) and their nominal efined in the Figures A.1 to A.4.
