In combination with the internal volume (V) and/or the maximum allowable pressure (PS) of the vessel this leads to 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 than 0,5 bar above 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 also liquids whose
vapour pressure at the maximum allowable temp. is greater than 0,5 bar above normal atmospheric pressure (1013 mbar), 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 temp. of not more than 0,5 bar above normal atmospheric pressure (1013 mbar),within the following limits: DN > 25 and PS x DN > 2 000 bar;
d) Fluids in Group 2; Industrial piping for liquids having a vapour pressure at the maximum allowable temp. of not more than 0,5 bar above normal atmospheric pressure (1013 mbar), within the following limits: PS > 10 bar and DN > 200 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) and their nominal diameter and maximum allowable pressure. The classification has been defined in the Figures A.1 to A.4.
EN 13480
The calculation temperature, tc, shall be the maximum temperature likely to be reached at the mid-thickness of the piping, under normal operating conditions, at the calculation pressure pc. The calculation temperature shall be determined as indicated below. Any heat transfer calculation shall be performed on the assumption that there is no
a) For externally uninsulated and internally unlined piping components, the calculation temperature shall be as
1) For fluid temperatures below 40 °C, the calculation temperature for the component shall be taken as the
2) For fluid temperatures of 40 °C and above, unless a lower average wall temperature is determined by test or heat transfer calculation, the calculation temperature for uninsulated components shall be not less than
i) 95 % of the fluid temperature for valves, pipes, ends, welding fittings, and other components having
ii) 90 % of the fluid temperature for flanges (except lap joint flanges) including those on fittings and
= minimum specified value of upper yield strength at calculation temperature " t "
when this temperature is greater than the room temperature
= minimum specified value of 0,2 % proof strength at calculation temperature " t "
when this temperature is greater than the room temperature
= minimum specified value of tensile strength at room temperature
= minimum specified value of 1,0 % proof strength at calculation temperature " t "
when this temperature is greater than the room temperature
= minimum specified value of tensile strength at calculation temperature when this temperature is greater than the room temperature
The design stress in the creep range
f
CR to be used for design under static loading shall be: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 strength
In cases where design lifetimes shorter than 100 000 h are specified, one of the following methods shall be used : a) If a lifetime monitoring system is not provided, the safety factor SFCR shall be equal to 1,5 and shall be applied
b) If a lifetime monitoring system is provided, a safety factor of SFCR = 1,25 may be specified with regard to the
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 calculated
Ec is the value of the modulus of elasticity at the minimum metal temperature (t=c) consistent with the loading
Eh is the value of the modulus of elasticity at the maximum metal temperature (t=h) consistent with the loading
fc is the basic allowable stress at minimum metal temperature consistent with the loading under consideration 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. Therefore, corrosion resistant materials should be considered where a large number of major stress cycle are anticipated.
The sum of primary stresses 1, due to calculation pressure, pc, and the resultant moment, MA, from weight and
For the purpose of classification of pressure equipment in hazard categories, fluids (gas or liquid) are divided into two groups:
1) Group 1 comprises dangerous fluids (under Council Directive 67/548/EEC (27 June 1967), Article 2 (2)), i.e. fluids defined as:
flammable (where the maximum allowable temperature is above flashpoint); very toxic;
In combination with the internal volume (V) and/or the maximum allowable pressure (PS) of the vessel this leads to
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 than 0,5 bar above
b) Fluids in Group 2; Industrial piping, liquefied gases, gases dissolved under pressure, vapours and also liquids whose
vapour pressure at the maximum allowable temp. is greater than 0,5 bar above normal atmospheric pressure (1013 mbar),
c) Fluids in Group 1; Industrial piping for liquids having a vapour pressure at the maximum allowable temp. of not more than 0,5 bar above normal atmospheric pressure (1013 mbar),within the following limits: DN > 25 and PS x DN > 2 000 bar;
d) Fluids in Group 2; Industrial piping for liquids having a vapour pressure at the maximum allowable temp. of not more than 0,5 bar above normal atmospheric pressure (1013 mbar), within the following limits: PS > 10 bar and DN > 200 and
Industrial piping are classified in hazard categories I to Ill according to one of the relevant cases a) to d) and their nominal diameter and maximum allowable pressure. The classification has been defined in the Figures A.1 to A.4.