European Standard EN 13480-3:2012 Issue 1
Formula
The internal pressures are calculated by using the following formula:
D0/Di ≤ 1.7:
P = (2 · (eord - c1) · f · z) / (Do - (eord - c1))
D0/Di > 1.7:
P = (2 · (eord - c1) · f · z) · (D0 - (eord - c1)) / ((eord - c1)2sup> + (Do - (eord - c1))2sup>)
Symbol (Description)
P = Internal pressure (MPa) (*10 => bar)
eord = Ordered wall thickness (mm)
c1 = Manufacturing tolerance, absolute value (mm)
Do = Nominal outside diameter (mm)
Di = Nominal inside diameter (mm) (Di = Do-2 · eord)
z = Welding factor, 1.0 for seamless tubes
f = Maximal pressure (MPa), see below
At = Min. ductility, transverse (%)
Austenitic steels
At >= 35%
f = Rp1.0t/1.5 (or min. (Rp1.0t/1.2;Rmt/3), id Rmt is available)* (t = here at temp.)
30% <= At < 35%
f = min (Rp1,0 t/1,5 or Rm/2,4)*
* The programme always calculates with Rp 1.0t/1.5 for austenitic grades, but if Rmt or Rm are known for the specific grade and size, and at temperatures for Rmt, this may give a more favourable result in case of At > 35% or > 30% as above.
Austenitic steels with At < 30% and steels other than austenitic (here used for the austenitic-ferritic steels, i. e. duplex stainless steels).
f = min. ((ReHt/1,5 or Rpo.2t/1,5;Rm/2,4)
Attention: Allowed maximum wall thickness
Austenitic corrosion resisting steels 60 mm
Austenitic - ferritic steels 30 mm
Attention: The pressures on these pages are given only as guidance. Dimensioning of piping systems also depends on other factors like external forces, thermal stresses, dead weight etc. Furthermore the design must be made according to regulations from local authorities and approved accordingly.
Proof strength Rp1. (MPa) for austenitic grades (EN 10216-5:2004) | ||||||||||
En No. | 20° | 50° | 100° | 150° | 200° | 250° | 300° | 350° | 400° | At% |
C | C | C | C | C | C | C | C | C | ||
14306 | 215 | 200 | 180 | 160 | 145 | 135 | 127 | 121 | 116 | 35 |
14435 | 225 | 217 | 200 | 180 | 165 | 153 | 145 | 139 | 135 | 30 |
14404 | 225 | 217 | 200 | 180 | 165 | 153 | 145 | 139 | 135 | 30 |
14541 | 235 | 222 | 208 | 195 | 185 | 175 | 167 | 161 | 156 | 30 |
14541 | 215 | 201 | 181 | 162 | 147 | 137 | 127 | 121 | 116 | 30 |
14550 | 240 | 232 | 210 | 195 | 185 | 175 | 167 | 161 | 156 | 30 |
14571 | 245 | 232 | 218 | 206 | 196 | 186 | 175 | 169 | 164 | 30 |
14571 | 225 | 217 | 199 | 181 | 167 | 157 | 145 | 139 | 135 | 30 |
14539 | 250 | 244 | 235 | 220 | 205 | 190 | 175 | 165 | 155 | 30 |
14563 | 245 | 240 | 220 | 205 | 190 | 185 | 180 | 175 | 165 | 35 |
14335 | 210 | 200 | 180 | 170 | 160 | 150 | 140 | 135 | 130 | -40 |
14466 | 295 | 262 | 225 | 205 | 190 | 180 | 170 | 165 | - | 30 |
14547 | 340 | 306 | 270 | 245 | 225 | 212 | 200 | 195 | 190 | 30 |
14558 | 210 | 198 | 185 | 175 | 170 | 165 | 160 | 155 | 150 | 30 |
(1 MPa = 10 bar)
* SS-EN 10216-5:2004/AC:2008 (E)
Proof strength Rp0.2 (MPa) for austenitic - ferritic grades (EN 10216-5:2004) | ||||||||
En No. | 20° | 50° | 100° | 150° | 200° | 250° | At% | RM |
C | C | C | C | C | C | |||
14462 | 450 | 415 | 360 | 335 | 310 | 395 | 22 | 640 |
14362 | 400 | 370 | 330 | 310 | 290 | 280 | 25 | 600 |
14410 | 550 | 530 | 480 | 445 | 420 | 405 | 20 | 800 |
14424 | 4801) | 430 | 370 | 350 | 330 | 325 | 30 | 700 |
(1 MPa = 10 bar)
1) Wall thickness e below 4 mm (e > 4 mm 450 MPa)