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316/316L stainless steel instrumentation tubing (exact OD)
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Important: Before using these data in engineering, design or installation decisions on systems exposed to mechanical, pressure, rupture, fatigue, impact or water-hammer risk, it is essential to read the technical notice and limitation of liability at the end of this sheet.
SKU VT-tubing-inoxidable · seamless 316/316L stainless steel tubing, 1/8 in to 1 in OD · 6 m lengths · price from $110,849 COP + VAT per length, made to order (Jul 2026, confirmed on quotation)
1. TECHNICAL SPECIFICATIONS
Stainless steel tubing is precision tube designated by exact outside diameter (OD) in inches and wall thickness in thousandths — not by NPS nominal size with schedule — and is connected with twin-ferrule compression fittings. It is supplied to ASTM A269/A269M-25 in grades 316/316L and 304, seamless, annealed, in 6 m lengths, 1/8 in to 1 in OD, for instrumentation, pneumatics, hydraulics and sampling lines.
General product data
| Product standard | ASTM A269/A269M-25 (seamless and welded austenitic stainless steel tubing for general service) |
| Grades | TP316 / TP316L (dual certification is standard practice); TP304 depending on lot |
| Supply condition | Seamless, solution annealed (joint factor E = 1.00) |
| Maximum hardness | 90 HRB (192 HBW / 200 HV) per ASTM A269/A269M-25, Table 2 — suitable for twin-ferrule fittings |
| Diameter range | 1/8 in (3.18 mm) to 1 in (25.40 mm) OD, fractional |
| Wall thicknesses | 0.028 in (0.71 mm) to 0.120 in (3.05 mm) |
| Presentation | 6 m lengths, made to order |
| Connection | Twin-ferrule compression fitting matching the tube OD |
Dimensional tolerances (ASTM A269/A269M-25, Table 4)
| OD range | OD tolerance | Wall tolerance |
|---|---|---|
| 1/8 in to under 1/2 in | ±0.005 in (±0.13 mm) | ±15 % |
| 1/2 in to 1 in | ±0.005 in (±0.13 mm) | ±10 % |
Reference mechanical properties of the grade (annealed)
ASTM A269 controls hardness and forming tests (flaring for seamless tube, flanging for welded); it does not publish a minimum tensile table. Reference tensile values for annealed TP316 come from ASTM A213/A213M-24.
| Property | TP316 / TP304 (A213/A213M-24) |
|---|---|
| Tensile strength, min. | 515 MPa (75 ksi) |
| Yield strength, min. | 205 MPa (30 ksi) |
| Elongation, min. | 35 % |
| Hardness, max. | 90 HRB (192 HBW / 200 HV) |
Chemical composition (ASTM A269/A269M-25, Table 1), mass %
| Element | TP316 (UNS S31600) | TP316L (UNS S31603) |
|---|---|---|
| Carbon | ≤0.08 | ≤0.035 |
| Manganese | ≤2.00 | ≤2.00 |
| Phosphorus | ≤0.045 | ≤0.045 |
| Sulfur | ≤0.030 | ≤0.030 |
| Silicon | ≤1.00 | ≤1.00 |
| Chromium | 16.0–18.0 | 16.0–18.0 |
| Nickel | 10.0–14.0 | 10.0–15.0 |
| Molybdenum | 2.00–3.00 | 2.00–3.00 |
Dual-certified 316/316L material simultaneously meets the lower maximum carbon of the L grade and the mechanical properties of the non-L grade.
⚠ Important: this technical data sheet is a reference guide to the product's properties; it is not a quality certificate for the product you are buying. Heats vary from one another and may differ from the values stated here, or even depart from the standards. If your application requires compliance with a standard, always check the quality certificate (mill certificate) of the lot you are buying. If in doubt, ask one of our technical advisors →
2. ENGINEERING CALCULATIONS
The allowable working pressure of each OD × wall combination is calculated with equation (3a) of paragraph 304.1.2 of ASME B31.3-2024 — the code form of the Barlow formula with the Y stress-redistribution correction:
P = 2 · S · E · t / (D − 2 · Y · t)
Calculation values
| Variable | Value | Source |
|---|---|---|
| S — allowable stress, ASTM A269 TP316 at ≤38 °C (100 °F) | 137.9 MPa (20,000 psi) | ASME B31.3-2024, Table A-1 |
| E — joint quality factor (seamless) | 1.00 | ASME B31.3-2024 |
| Y — wall thickness coefficient (austenitic, ≤482 °C) | 0.4 | ASME B31.3-2024, para. 304.1.2 |
| D — maximum outside diameter | nominal OD + 0.005 in | ASTM A269/A269M-25 tolerance, Table 4 |
| t — minimum wall | nominal − 15 % (OD < 1/2 in) or − 10 % (OD ≥ 1/2 in) | ASTM A269/A269M-25 tolerance, Table 4 |
The calculation uses the maximum OD and minimum wall the standard allows: the least favorable tube a compliant manufacturer may deliver. It is the same method used by industry reference MS-01-107 for A269 tubing. With S = 137.9 MPa against the grade's minimum ultimate tensile strength (515 MPa), the resulting design factor against rupture is 515 / 137.9 ≈ 3.7 (≈4:1); heavy-wall combinations not covered by code equation (3a) are validated in industry by repeated pressure testing with a 4:1 design factor.
Worked example: 1/2 in OD × 0.049 in wall
- D = 12.70 + 0.13 = 12.83 mm (0.505 in) — maximum OD with tolerance.
- t = 1.24 × 0.90 = 1.12 mm (0.0441 in) — minimum wall with −10 % tolerance.
- P = 2 × 137.9 × 1.00 × 1.12 / (12.83 − 2 × 0.4 × 1.12) = 308.9 / 11.93 = 25.9 MPa.
- 25.9 MPa = 259 bar = 3,755 psi.
- Conservative round-down to the nearest 100 psi: 3,700 psi (255 bar).
Heavy wall (t ≥ D/6)
For small ODs with heavy wall (for example 1/8 × 0.035 in or 1/4 × 0.065 in) the wall exceeds D/6 and equation (3a) no longer applies per paragraph 304.1.2 itself; for those cells the matrix uses the thick-wall (Lamé) formulation:
P = S · E · (D² − d²) / (D² + d²)
where d is the inside diameter at minimum wall. All results are rounded down to the nearest 100 psi.
3. WORKING PRESSURE MATRIX OD × WALL
Allowable working pressure at ≤38 °C (100 °F) for seamless ASTM A269 TP316/316L tubing (also valid for TP304: same S = 137.9 MPa in ASME B31.3-2024, Table A-1). Each cell: psi · bar. Empty cells: non-standard combination for twin-ferrule fittings.
| OD, in (mm) | Wall 0.028 in (0.71 mm) | 0.035 in (0.89 mm) | 0.049 in (1.24 mm) | 0.065 in (1.65 mm) | 0.083 in (2.11 mm) | 0.095 in (2.41 mm) | 0.109 in (2.77 mm) | 0.120 in (3.05 mm) |
|---|---|---|---|---|---|---|---|---|
| 1/8 (3.18) | 8,500 · 586 | 10,900 · 751 | — | — | — | — | — | — |
| 3/16 (4.76) | 5,400 · 372 | 7,000 · 482 | 10,200 · 703 | — | — | — | — | — |
| 1/4 (6.35) | 4,000 · 275 | 5,100 · 351 | 7,500 · 517 | 10,200 · 703 | — | — | — | — |
| 5/16 (7.94) | — | 4,000 · 275 | 5,800 · 399 | 8,000 · 551 | — | — | — | — |
| 3/8 (9.53) | — | 3,300 · 227 | 4,800 · 330 | 6,500 · 448 | 7,500 · 517 ¹ | — | — | — |
| 1/2 (12.70) | — | 2,600 · 179 | 3,700 · 255 | 5,100 · 351 | 6,700 · 461 | — | — | — |
| 5/8 (15.88) | — | — | 2,900 · 199 | 4,000 · 275 | 5,200 · 358 | 6,000 · 413 | — | — |
| 3/4 (19.05) | — | — | 2,400 · 165 | 3,300 · 227 | 4,200 · 289 | 4,900 · 337 | 5,800 · 399 | — |
| 7/8 (22.23) | — | — | 2,000 · 137 | 2,800 · 193 | 3,600 · 248 | 4,200 · 289 | 4,800 · 330 | — |
| 1 (25.40) | — | — | — | 2,400 · 165 | 3,100 · 213 | 3,600 · 248 | 4,200 · 289 | 4,700 · 324 |
¹ Value limited to 7,500 psi by repeated pressure testing of the fitting with a 4:1 design factor (industry reference MS-01-107); the thick-wall calculation for the tube alone gives 8,600 psi.
Gas service (air, nitrogen, hydrogen, helium): select the heavier walls of each OD. A heavy wall resists ferrule action better and coins out minor surface defects that on a thin wall would leave gas micro-leak paths.
Temperature derating — grades 316/316L
Multiply the matrix pressure by the table factor. Factors from industry reference MS-01-107 (Table 26), derived from the ASME B31.3 S values at temperature.
| Temperature | 316/316L factor | Example: 1/2 in × 0.049 in |
|---|---|---|
| ≤38 °C (100 °F) | 1.00 | 3,700 psi (255 bar) |
| 93 °C (200 °F) | 1.00 | 3,700 psi (255 bar) |
| 204 °C (400 °F) | 0.96 | 3,552 psi (244 bar) |
| 315 °C (600 °F) | 0.85 | 3,145 psi (216 bar) |
| 426 °C (800 °F) | 0.80 | 2,960 psi (204 bar) |
| 537 °C (1000 °F) | 0.76 | 2,812 psi (193 bar) |
Weld factor
The matrix applies to seamless tube (E = 1.00). If the lot is welded and drawn, multiply by 0.85 (double-welded) or 0.80 (single-welded), in line with the ASME B31.3 joint quality factors. Example: 1/2 in × 0.049 in single-welded = 3,700 × 0.80 = 2,960 psi (204 bar).
4. TUBING VS PIPE AND A269 VS A213
Is 1/2 inch tubing the same as 1/2 inch pipe?
No: 1/2 in tubing measures exactly 12.70 mm outside diameter, while NPS 1/2 pipe measures 21.34 mm outside diameter per ASME B36.10M-2022 — 68 % larger. In tubing, the size IS the actual outside diameter; in pipe, NPS is a nominal name whose actual OD comes from a table. That is why a 1/2 in compression fitting never fits 1/2 in pipe, and vice versa.
| Concept | Tubing (this data sheet) | Pipe (NPS) |
|---|---|---|
| Designation | exact outside diameter in inches | nominal NPS + schedule |
| What “1/2 inch” means | OD = exactly 12.70 mm | OD = 21.34 mm (ASME B36.10M-2022) |
| What “1/4 inch” means | OD = exactly 6.35 mm | OD = 13.72 mm (ASME B36.10M-2022) |
| Wall | in thousandths of an inch: 0.028 to 0.120 in | by schedule: SCH 10 / 40 / 80… |
| Typical connection | twin-ferrule compression fitting | NPT thread, welding or flange |
| Typical standards | ASTM A269 / A213 | ASTM A312 / A53 / A106 |
Which standard applies: ASTM A269 or ASTM A213?
ASTM A269/A269M-25 is the general-service tubing standard — corrosion and temperature resistance in instrumentation and process lines — and is the one covering this product. ASTM A213/A213M-24 governs seamless tubes for boilers, superheaters and heat exchangers, with minimum tensile requirements and service-specific tests. The same tube may carry dual A269 + A213 certification; the lot certification is confirmed on quotation.
What pressure does stainless steel tubing withstand?
It depends on the OD × wall combination: from 2,000 psi (137 bar) at 7/8 in × 0.049 in up to 10,900 psi (751 bar) at 1/8 in × 0.035 in at ≤38 °C, per this data sheet's matrix calculated with ASME B31.3-2024. Larger OD at the same wall means lower pressure; heavier wall at the same OD means higher pressure.
5. FITTINGS, BENDING AND CLEANLINESS
Twin-ferrule compression fitting: how it works
As the nut is tightened, the back ferrule bites into the tube surface (mechanical grip against pressure and vibration) and drives the front ferrule against the tapered seat of the body (primary seal). The system requires the tube to be softer than the fitting: that is why the tubing must arrive annealed at ≤90 HRB (200 HV) hardness — exactly the maximum ASTM A269/A269M-25 already guarantees for TP304/TP316.
Tightening sequence (no torque wrench)
- Cut the tube square and deburr inside and outside.
- Insert the tube until it bottoms firmly against the shoulder of the fitting body.
- Tighten the nut finger-tight and mark its position.
- With a wrench, tighten 1 1/4 turns from finger-tight for 1/4 in to 1 in OD; for 1/16, 1/8 and 3/16 in OD tighten 3/4 turn.
Installation is controlled by turns, not by torque: this is the instruction published by twin-ferrule fitting manufacturers. The fitting allows repeated disassembly and reassembly following the manufacturer's reassembly instruction.
Bend radii with a hand tube bender
R is the bend radius to the tube centerline; L is the minimum straight length between the end of the bend and the fitting so the tube can bottom fully. Data from industry reference MS-13-43 (hand tube bender, 1/8 to 1/2 in OD); 5/8 to 1 in ODs require a bench-top bender.
| Tube OD | Bend radius R | Minimum straight length L |
|---|---|---|
| 1/8 in (3.18 mm) | 9/16 in (14.3 mm) | 23/32 in (18.3 mm) |
| 1/4 in (6.35 mm) | 9/16 in (14.3 mm) or 3/4 in (19.1 mm) | 13/16 in (20.6 mm) |
| 5/16 in (7.94 mm) | 15/16 in (23.8 mm) | 7/8 in (22.2 mm) |
| 3/8 in (9.53 mm) | 15/16 in (23.8 mm) | 15/16 in (23.8 mm) |
| 1/2 in (12.70 mm) | 1 1/2 in (38.1 mm) | 1 3/16 in (30.2 mm) |
Cleanliness and handling
- Cleaning, descaling and passivation per ASTM A380/A380M-25 where the service demands it (analysis gases, oxygen, high purity).
- Do not drag lengths across rough surfaces or out of the rack: scratches in the sealing zone cause leaks in gas service.
- Use a sharp tube cutter with light passes; always deburr before inserting into the fitting.
- Cap the ends of stored lengths to prevent internal contamination.
6. Application notes
Feasibility
Made-to-order product in 6 m lengths. Available ODs, walls and grades (304 / 316 / 316L) are confirmed on quotation; the manufacturer's test certificate (MTC) per ASTM A269/A269M-25 is supplied on request. For gas service, quote the heaviest available wall for the required OD.
Installation
Square cut, inside and outside deburr, full insertion to the fitting shoulder, and 1 1/4 turns from finger-tight (3/4 turn for ≤3/16 in OD). Respect the minimum straight length L after every bend and support the line with clamps to limit vibration — unsupported vibration is the typical cause of fatigue in instrumentation lines.
Design
The matrix applies to seamless tube at ≤38 °C: apply the temperature factor (0.96 at 204 °C; 0.85 at 315 °C) and, for welded lots, the joint factor (0.85 or 0.80). System pressure may be limited by the fitting, valve or instrument — not only by the tube. Do not mix fractional (in) and metric (mm) tubing: 1/4 in = 6.35 mm is not interchangeable with 6 mm tube.
7. Technical notice and limitation of liability
The pressures, dimensions, weights and other characteristics in this sheet are theoretical calculation values obtained from nominal properties published in the standards cited (ASME B36.10-2022, ASME B31.3-2024, ASTM A106/A106M-19a, ASTM A53/A53M-24, API Spec 5L 46th ed.). They guide selection; they are not a certificate of conformity for any given lot.
The actual behavior of each lot varies with manufacturing — wall tolerance (up to −12.5%), out-of-roundness, residual stresses — and with the raw material — chemical composition within the ranges the standard allows, heat-to-heat differences. To certify a lot, the tests defined by its product standard are required: tensile test, flattening test and hydrostatic test, documented in the manufacturer's mill test certificate (MTC), which TECTUL supplies upon request; testing of the lot in an independent laboratory can also be arranged.
These values must not be used as the sole criterion in critical or safety applications, or wherever failure of the line may compromise people, property or the environment: in such cases the design belongs to the project's responsible engineer under the applicable code (ASME B31.3, B31.1 or the one governing the installation), with the design temperature, corrosion allowance and load cases of the actual service. Before deciding with these data, consult our technical team.
Sources
- ASTM A269/A269M-25 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service (composición, dureza máx. 90 HRB, tolerancias Tabla 4)
- ASTM A213/A213M-24 — Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes (propiedades mecánicas de referencia TP316)
- ASME B31.3-2024 — Process Piping (párr. 304.1.2 ecuación 3a, Tabla A-1: S = 137,9 MPa para A269 TP316 a ≤38 °C, factores de calidad de junta)
- ASME B36.10M-2022 — Welded and Seamless Wrought Steel Pipe (OD reales de pipe NPS para la comparativa tubing vs pipe)
- ASTM A380/A380M-25 — Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems
- Swagelok MS-01-107 RevW (octubre 2023) — Tubing Data: referencia de industria del método de cálculo, matriz de presiones A269 y factores de temperatura (Tabla 26)
- Swagelok MS-13-43 — Hand Tube Bender Manual: referencia de industria de radios de curvado y longitudes rectas mínimas
- Swagelok MS-13-58 — An Installer's Pocket Guide for Tube Fittings: secuencia de apriete 1 1/4 vueltas / 3/4 de vuelta