-PIPING

1                 Line velocities and pressure drops, with line diameter D in inches: liquid pump discharge, (5 + D /3) ft/sec, 2.0 psi/100 ft; liquid pump suction, (1.3 + D /6) ft/sec, 0.4 psi/100 ft; steam or gas, 20D ft/sec, 0.5 psi/100 ft.

2                 Control valves require at least 10 psi drop for good control.

3                 Globe valves are used for gases, for control and wherever tight shutoff is required. Gate valves are for most other services.

4                 Screwed fittings are used only on sizes 1.5 in. and smaller, flanges or welding otherwise.

5                 Flanges and fittings are rated for 150, 300, 600, 900, 1500, or 2500 psig.

6                 Pipe schedule number = 1000P/S, approximately, where P is the internal pressure psig and S is the allowable working stress (about 10,000 psi for A120 carbon steel at 500°F). Schedule 40 is most common.