Line Volume per Length: Solvent Holdup in Stainless Tubing
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How much liquid a run of tube holds, from its inside diameter, in gallons, liters and pounds of solvent.
DocumentREF-LV-01
SeriesEngineering Reference
Revision2026.1
Issued24 September 2026
Use this sheet to account for solvent sitting in transfer lines, to size a system charge, and to estimate how much solvent is trapped between two valves.
Internal volume by tube size
| Tube OD | Wall (in) | ID (in) | in³ per ft | gal per 10 ft | L per m | Butane lb / 10 ft | Propane lb / 10 ft | 75/25 lb / 10 ft | 50/50 lb / 10 ft |
|---|---|---|---|---|---|---|---|---|---|
| 1/4" | 0.035 | 0.180 | 0.31 | 0.013 | 0.016 | 0.06 | 0.06 | 0.06 | 0.06 |
| 3/8" | 0.035 | 0.305 | 0.88 | 0.038 | 0.047 | 0.18 | 0.16 | 0.18 | 0.17 |
| 1/2" | 0.065 | 0.370 | 1.29 | 0.056 | 0.069 | 0.27 | 0.24 | 0.26 | 0.25 |
| 3/4" | 0.065 | 0.620 | 3.62 | 0.157 | 0.195 | 0.76 | 0.66 | 0.74 | 0.71 |
| 1" | 0.065 | 0.870 | 7.13 | 0.309 | 0.384 | 1.50 | 1.30 | 1.45 | 1.40 |
| 1-1/2" | 0.065 | 1.370 | 17.7 | 0.766 | 0.951 | 3.73 | 3.23 | 3.60 | 3.48 |
| 2" | 0.065 | 1.870 | 33.0 | 1.43 | 1.77 | 6.95 | 6.02 | 6.72 | 6.48 |
| 2-1/2" | 0.065 | 2.370 | 52.9 | 2.29 | 2.85 | 11.2 | 9.67 | 10.8 | 10.4 |
| 3" | 0.065 | 2.870 | 77.6 | 3.36 | 4.17 | 16.4 | 14.2 | 15.8 | 15.3 |
| 4" | 0.083 | 3.834 | 138.5 | 6.00 | 7.45 | 29.2 | 25.3 | 28.2 | 27.3 |
| 6" | 0.109 | 5.782 | 315.1 | 13.64 | 16.94 | 66.4 | 57.6 | 64.2 | 62.0 |
| 8" | 0.109 | 7.782 | 570.8 | 24.71 | 30.69 | 120.3 | 104.3 | 116.3 | 112.3 |
Walls are the standard sanitary and instrument walls used on N.B. Oler systems. Solvent weights are liquid full values at 60°F (16°C): butane 4.87 lb/gal, propane 4.22 lb/gal; blends by liquid volume. Colder liquid is denser, see REF-SC-01.
Formulas
- Inside diameter: ID = OD - 2 x wall.
- Volume per foot: in³/ft = (π / 4) x ID² x 12. Gallons = in³ / 231. Liters = in³ x 0.016387.
- Solvent holdup: lb = gallons x liquid density. For a section trapped between two closed valves, use the length between the valve seats and add the valve body volume.
- Hose and fittings. Hose ID often differs from tube ID of the same nominal size. Use the hose maker's ID, and add tee, cross and valve volumes when a line has many fittings.
Trapped liquid is a hazard. Liquid locked between two closed valves builds pressure quickly as it warms. A 10 ft liquid full section of 1 inch line holds about 1.5 lb (0.7 kg) of butane. Never close both ends of a liquid full line without a relief path.
Sources. Tube dimensions per ASTM A269/A270 standard walls. Densities from NIST Chemistry WebBook saturated liquid data at 60°F (16°C), as used in REF-SC-01.
Questions about your system? Call the shop at 541-330-6409, Monday to Thursday, 8 to 4 Pacific, or email info@nboler.com.