PIPING DRAWINGS C H A P T E R T W E N T Y- O N E

OBJECTIVES 1. Identify cast iron, brass, copper, and thermoplastic pipe and tubing fittings. 2. Draw and label common pipe joints using ANSI/ASME standard designations. 3. Draw a multiview or pictorial piping drawings using standard schematic symbols. 4. Draw the schematic symbols for valves and identify flow direction.

Piping Drawings

UNDERSTANDING PIPING DRAWINGS CAD systems have standard symbols available, and templates for drawing piping symbols are a convenient timesaver when you are sketching piping. Standard Piping Symbols

Single and Double Line PIPING DRAWINGS Piping Symbols Used in a Double-Line Drawing and a Single-Line Drawing (Courtesy of Softdesk, Inc.) Single-Line Drawing Double-Line Drawing

STEEL AND WROUGHT IRON PIPE Steel or wrought iron pipe is used for water, steam, oil, and gas. The American National Standards Institute/American Society of Mechanical Engineers (ANSI/ASME) has developed dimensions for 10 different schedules of pipe

CAST IRON PIPE Cast Iron Pipe, Thicknesses and Weights—American National Standard Cast Iron Pipe Flanges and Fittings

SEAMLESS BRASS AND COPPER PIPE It is used in plumbing for supply, soil, waste drain, and vent lines. It is also particularly suitable for process work where formation of scale or oxidation in steel pipe would be troublesome. Brass pipe and copper pipe are available in straight lengths up to 12'. Brass pipe, generally known as red brass pipe, is an alloy of approximately 85% copper and 15% zinc. Copper pipe is practically pure copper with less than 0.1% of alloying elements. Brass pipe and copper pipe should be joined with fittings of copper-base alloy to avoid galvanic action resulting in corrosion.

COPPER TUBING Fittings Copper tubing is often used in applications for nonferrous construction in sizes below 2". It is suitable for process work, for plumbing, and for heating systems (particularly radiant heating). Fittings Solder joints are also known as capillary joints because the annular space between the tube and the fitting is so small that the molten solder is drawn into the space by capillary action.

PLASTIC AND SPECIALTY PIPES Pipe and tubing of other material, such as aluminum and stainless steel, are also available. A wide variety of plastic pipe, both rigid and flexible, is used in construction. Plastic pipe is lightweight, corrosion proof, resistant to many chemicals, and has a smooth inner surface which offers low flow resistance. PVC (polyvinyl chloride) CPVC (chlorinated polyvinyl chloride) HDPE (high-density polyethylene)

PIPE FITTINGS Pipe fittings are used to join lengths of pipe, to provide changes of direction, to provide branch connections at different angles, or to effect a change in size.

PIPE JOINTS screwed flanged welded Completed Weld soldered

VALVES Valves are used to stop or regulate the flow of fluids in a pipeline. Common types are: Single-Line Valve Drawing Double-Line Valve Drawing Gate valves Globe valves Check valves Pressure-reducing valves Safety valves

Solenoid-Actuated Valves Solenoid valves are electromechanical devices often used to regulate the flow of liquid or gas. Two-Way Two-Position, Normally Closed Solenoid Valve. (Courtesy of Spartan Scientific.)

AMERICAN NATIONAL STANDARD CODE FOR PRESSURE PIPING The American National Standards Institute has adopted an American National Standard Code for Pressure Piping (ANSI/ASME B31.1-1995). This compilation of recommended practices and minimum safety standards covers various types of piping, such as power piping, industrial gas and air piping, oil refinery piping, oil transportation piping, refrigerating piping, chemical industry process piping, and gas transmission and distribution piping. CODE Book