EN ISO 1127:1996 / ISO 1127:1992 specifies standardized dimensions, tolerances and conventional masses per unit length for stainless steel tubes. The standard adopts outside diameters and wall thicknesses from ISO 4200 and tabulates conventional masses separately for austenitic and for ferritic and martensitic stainless steel tubes. It is intended for welded and seamless stainless steel tubes used in piping, instrumentation and general fabrication.
Key topics and technical requirements
- Dimensions and series: Outside diameters and thickness series are taken from ISO 4200; if thicknesses greater than 14.2 mm are required, ISO 4200 should be consulted.
- Tolerances on outside diameter: Table 1 of the standard defines tolerance classes (percent-based limits with minimum mm values). The specified outside-diameter tolerances include ovality.
- Tolerances on wall thickness: Table 2 lists tolerance classes (percentual tolerances with minimum absolute values). The thickness tolerances include eccentricity.
- Other dimensional tolerances: For tolerances on dimensions other than outside diameter and thickness (for example length, squareness), the standard references ISO 5252.
- Conventional masses per unit length:
- For austenitic stainless steel tubes: masses = ISO 4200 masses × 1.015 (assumes average density 7.97 kg/dm³).
- For ferritic and martensitic stainless steel tubes: masses = ISO 4200 masses × 0.985 (assumes average density 7.73 kg/dm³).
- Informative content: Annex A provides bibliographic and supporting information; the document was prepared by ISO/TC 5 (Ferrous metal pipes) SC1.
Applications and who uses this standard
EN ISO 1127 is used by:
- Tube and pipe manufacturers to produce stainless steel tubes to consistent size/tolerance series.
- Design and mechanical engineers specifying tube sizes for process, chemical, food, pharmaceutical, oil & gas, HVAC and marine systems.
- Procurement and quality-control teams for acceptance criteria, inspection and material traceability.
- Fabricators and welders who require dimensional tolerances (ovality, eccentricity) for fitting and joining.
- Estimators and logistics teams calculating weights and handling requirements using the conventional masses per metre.
Practical uses include specifying tube geometry in drawings and contracts, performing weight and load calculations, establishing inspection criteria, and harmonizing supply across international markets.
Related standards
- ISO 4200 - Plain end steel tubes, welded and seamless (source of dimension series and base masses)
- ISO 5252 - Steel tubes - Tolerance systems (referenced for other dimensional tolerances)
Keywords: stainless steel tubes, ISO 1127, EN ISO 1127, dimensions, tolerances, conventional masses, austenitic, ferritic, martensitic, outside diameter, wall thickness, ISO 4200, ISO 5252.
