API Spec 5L specifies requirements since 1928 for manufacture of Line Pipe. The scope of the current issue is defined as: “Requirements for the manufacture of two product specification levels (PSL 1 and PSL 2) of seamless and welded steel pipes for use in pipeline transportation systems in the petroleum and natural gas industries. This standard does not apply to cast pipe.”
EN ISO 3138 specifies requirements (since 2007) for the manufacture of two product specification levels (PSL 1 and PSL 2) of seamless and welded steel pipes for use in pipeline transportation systems in the petroleum and natural gas industries. EN ISO 3138 contains supplements for PSL 2 to the API Spec 5L, means all requirements of API Spec 5L apply, with the exception of those listed in Annex A of ISO 3138.
Pipe manufactured in accordance EN ISO 3138 can be named “ISO 3183 pipe” and may be marked in accordance with EN ISO 3138 no. 4.4.2. If no exceptions to API Spec 5L are taken and the pipe therefore conforms to both standards, the pipe can be named “API 5L pipe” and may be marked in accordance with EN ISO 3138 no..
Supplements to the API Spec 5L in acc. to ISO 3138 Annex A:
ISO 3183 pipes with supplements Annex A of ISO 3138 are PSL2 pipes for Europe natural gas pipelines. The purchaser should request in the purchase order that the pipe manufacturers expressly confirm that the requirements contained in Annex A are met, including the marking requirements of ISO 3138 no. 4.4.
Annex A specifies additional provisions that apply for API 5L PSL 2 pipe for European onshore natural gas transmission pipelines. The chemical elements of the composition could be outside the limits of API Spec 5L and therefore ISO 3183 pipe in accordance with this annex A conforms to ISO 3183 only. The steel grade designation concludes with the letter “E”.
A pipe manufactured with chemistry not in accordance with API Spec 5L (in this case ISO 3138), cannot be certified as conforming with API Spec 5L.
Hydrogen application
PSL 2 incorporates desirable requirements (not included in PSL 1) including minimum notch toughness energy, maximums for tensile strength and carbon equivalent.
These requirements help ensure base metal and weld hardness are maintained at acceptable values and hydrogen embrittlement concern minimised. Therefore, PSL2 material is advantageous for hydrogen piping.
Table: Designation of materials for onshore natural gas transmission pipelines
| API Spec 5L PSL 2 Grade 1 (API 5L pipe) | ISO 3183 Grade 2 (ISO 3183 pipe) | EN Material no. (ISO 3183 pipe) | Remarks |
|---|---|---|---|
| Seamless and welded pipe | |||
| L245NO or BNO | L245NE or BNE | 1.0457 (ISO 8183 pipe) | 3), 4) |
| L290NO or X42NO | L290NE or X42NE | 1.0484 (ISO 8183 pipe) | 3), 4) |
| L320NO or X46NO | – | – | 3), 4) |
| L360NO or X52NO | L360NE or X52NE | 1.0582 (ISO 8183 pipe) | 3), 4) |
| L415NO or X60NO | L415NE or X60NE | 1.8972 (ISO 8183 pipe) | 4) |
| L450NO or X65NO | – | – | 4) |
| Seamless pipe | |||
| L245QO or BQO | – | – | |
| L290QO or X42QO | – | – | |
| L320QO or X46QO | – | – | |
| L360QO or X52QO | L360QE or X52QE | 1.8948 (ISO 8183 pipe) | |
| L415QO or X60QO | L415QE or X60QE | 1.8972 (ISO 8183 pipe) | |
| L450QO or X65QO | L450QE or X65QE | 1.8952 (ISO 8183 pipe) | |
| L485QO or X70QO | L485QE or X70QE | 1.8955 (ISO 8183 pipe) | |
| L555QO or X80QO | L555QE or X80QE | 1.8957 (ISO 8183 pipe) | |
| Welded pipe | |||
| L245MO or BMO | L245ME or BME | 1.0418 (ISO 8183 pipe) | |
| L290MO or X42MO | L290ME or X42ME | 1.0429 (ISO 8183 pipe) | |
| L320MO or X46MO | – | – | |
| L360MO or X52MO | L360ME or X52ME | 1.0578 (ISO 8183 pipe) | |
| L390MO or X56MO | – | – | |
| L415MO or X60MO | L415ME or X60ME | 1.8973 (ISO 8183 pipe) | |
| L450MO or X65MO | L450ME or X65ME | 1.8975 (ISO 8183 pipe) | |
| L485MO or X70MO | L485ME or X70ME | 1.8977 (ISO 8183 pipe) | |
| L555MO or X80MO | L555ME or X80ME | 1.8978 (ISO 8183 pipe) | |
| 1 Explanation of letters: N = normelized M = thermomechnical rolled/formed Q = Quenched and tempered O = Offshore service (without European pipeline)) | 2 Explanation of letters: N = normelized M = thermomechnical rolled/formed Q = Quenched and tempered E = Offshore service (only European pipeline) | – | 3) remommended for hydrogen services, see also note below (see notes); 4) SSC-resistant steel acc. to NACE MR0175/ISO 15156-2 |
Note 1: API 5L Grades X52 and lower (normalised) recommended for hydrogen services at EIGA (European Industrial Gases Assoziation) Doc. EIGA IGC Doc121/14
Note 2: Higher strength material acc. ASME B31.12 Design Code with safety factors based on fracture mechanics
Read More
Qualification of line pipes for pressurised hydrogen applications?
