Machinery's Handbook, 31st Edition
Metal Tube
2773
Table 18. Stainless Steel Tube Specifications, Selected Sizes Tube OD (in.) Wall Thickness (in.) Working Pressure (psig) 1 ⁄ 16 0.014 8100 0.020 12000 1 ⁄ 8 0.028 8500 0.035 10900
0.035 0.049 0.065 0.035 0.049 0.065 0.035 0.049 0.065 0.083 0.049 0.065 0.049 0.065 0.083 0.095 0.12 0.12 0.134 0.134
5100 7500 10200 3300 4800 6500 2600 3700
1 ⁄
4
3 ⁄
8
1 ⁄
2
5100 6700 2900 4000 2400 3300 3100 2800 3600 3000 3400 2500
5 ⁄
8
3 ⁄
4
1
1 1 ⁄
4
1 1 ⁄
2
2
0.188 3600 Alternatively, the maximum working pressure of metal tubing can be calculated using the Barlow formula for thin-walled cylinders as given in the following equation. This formula is typically used for steel tubing connected with flare fittings. p max 2 St D = ---- where S is the ultimate tensile strength, t is wall thickness, and D is outer diameter. A fac- tor of safety between 1.5 and 10 should be applied. If the tube is carrying liquid, the pressure rating must be derated to account for the pres sure spikes that occur during valve closures. The amount of reduction of working pressure is called the “water hammer factor” and is typically 20 percent. The types of fittings being used must be carefully considered when working with elevated pressures, and further derating of the system may be required. For pressure ratings of copper tube, consult the “Copper Tube Handbook,” available from the Copper Development Association, Inc. Plastic Tube.— Plastic tube is often selected for its flexibility, clarity, or non-conductiv ity. When selecting from the wide variety of available tubing materials, one must con- sider the operating temperature range in the application, the media being transported, the environment in which the tubing will be located, the pressures involved, whether there will be vacuum, whether there are any standards or certifications needed, whether standard tubing tolerances will be acceptable, and whether the tubing must be transpar- ent. Temperature must be considered not only for extremes, but also for slight variations from 73°F (22°C) because most plastic tubing expands and softens even with slight changes in temperature.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online