Pressure & temperature selection
A tube size alone does not define a safe working pressure. Select tubing together with its material, wall thickness, temperature, fittings and the conditions of the complete system.
Read every pressure value with its conditions
A pressure table is tied to its calculation method and assumptions. The supplied Fluidline sheet uses reference calculations based on applicable ASME piping equations, with separate conditions for metric and fractional tubing. It also states that no allowance is made for corrosion or erosion.
The assembled system is limited by its lowest-rated applicable component and connection. A tube table does not establish the rating of a valve, fitting, hose, gauge or complete installation.
What to check before selecting a wall
| Factor | Why it matters |
|---|---|
| OD and minimum wall | Tolerances change the dimensions used in a pressure assessment. |
| Grade and condition | Allowable stress depends on the material and condition. |
| Temperature | Elevated temperatures can require a lower allowable pressure. |
| Fluid and environment | Corrosion, erosion and chemical compatibility can affect suitability. |
| Dynamic loading | Pressure peaks, vibration and fatigue need design assessment. |
| Connection system | Fitting-specific wall ranges, hardness and assembly requirements apply. |
A reference example, not a system rating
The Fluidline seamless-tubing datasheet lists 2,600 psig for ½″ OD × 0.035″ wall stainless steel tubing at its stated reference temperature range of −28 to 37°C. Its worked example applies a 0.76 factor at 537°C for the specified 316 material, giving 1,976 psig. This OD/wall combination is shaded and marked G in the datasheet, so it remains excluded from its gas-service selection guidance.
Download F-Line seamless stainless steel tubing PDFGas service needs its own check
Both supplied tube guides distinguish wall selections for gas service. The shaded regions and accompanying notes are part of the technical information and must not be separated from the table. Check the selected fitting manufacturer’s current tubing recommendations. The F-Line datasheet also flags two conflicting temperature factors for non-stainless alloys for confirmation; do not use those entries until verified.
Use a matched technical reference
The Uni-Lok reference uses its own assumptions and values. Do not combine the highest pressure in one table with the most convenient conditions in another. For ultra-high-pressure applications, review the matched tubing, connection and tool system in the specialist systems section.
Frequently asked questions
What is the pressure rating of 316L stainless steel tubing?
There is no single rating for the grade. It depends on OD, wall thickness, material condition, temperature, tolerances, connection system and the applicable design basis.
Can I apply a room-temperature rating at elevated temperature?
Not without checking the appropriate temperature factors and component limits. The correct factor depends on the material and design basis.