Refrigeration, LPG and LNG – pipes and fittings for low temperature
In short: systems operating at low temperature need steel that stays tough in the cold. Typical choices:
- fine-grain pipe: EN 10216-3 (P355NL1) and EN 10216-4 (P215NL, P265NL, 12Ni14);
- ASTM: A333 Gr. 6 pipe, A420 WPL6 fittings and A350 LF2 / LF3 flanges;
- cryogenic systems: nickel steel (X8Ni9) or austenitic stainless steel.
This guide is for buyers and designers in refrigeration, gas and chemical plants.
Why is low temperature special?
- Brittle fracture. Ordinary carbon steel can become brittle in the cold and crack under impact or stress. For low-temperature steels the standard specifies impact energy at low temperature.
- Sudden cooling. Gas expansion or a leak can chill the line rapidly.
- The whole joint matters. Fittings, flanges and bolting must withstand the cold too.
Material overview
| Temperature range (qualitative) | Pipe | Fitting | Flange |
|---|---|---|---|
| Moderately cold | P355NL1, P265NL, A333 Gr. 6 | P355NL1, WPL6 | P355NL1, LF2 |
| Colder range | 12Ni14, A333 Gr. 3 | – | LF3 |
| Cryogenic (e.g. LNG) | X8Ni9 or austenitic stainless | austenitic stainless | X8Ni9, stainless |
The design sets the minimum design temperature and the required impact test. We choose the grade to match.
The complete package
- Pipes: EN 10216-3 / -4, ASTM A333.
- Fittings: EN 10253-2 (P355NL1), ASTM A420 WPL6.
- Flanges: P355NL1, ASTM A350 LF2 / LF3, X8Ni9.
- Bolting in material suited to low temperature.
- Gaskets for the medium and temperature.
- Valves: with LCB or stainless bodies.
Buyer checklist
- Minimum design temperature.
- Impact test: temperature and required value.
- Grade and standard for every component.
- Size and rating.
- Certificate: 3.1 or 3.2.
- Valves: body material and seals for low temperature.
Common mistakes
- Ordinary carbon-steel flange or fitting with low-temperature pipe.
- Impact-test temperature not stated, so it is unclear what must be proven.
- Unsuitable bolting in the cold flanged joint.
Frequently asked questions
What does "NL" mean in P355NL1?
It denotes a normalised fine-grain steel for low-temperature service, with a specified impact energy.
What is LF2?
LF2 is a forged carbon-steel flange material to ASTM A350, intended for low temperature.
Request a quote
Send your material list, minimum design temperature and impact-test requirement. We quote the complete line in one offer.
Related: Fine-grain & low-temperature pipes · Flanges · P355NL1 · 12Ni14
Send us your material list – one quote for the complete package (pipe, fittings, flanges, gaskets, bolting), sourced direct from manufacturers, no minimum order.
Request a quote