Oklahoma Process Piping Journeyman

Key Concepts

Dictionary terminology (Pipefitters Dictionary, Page 5-87) - Bull Head Tee — "a tee the branch of which is larger than the run." - Backing Ring — "a metal strip used to prevent melted metal from the welding process from entering a pipe when making a butt-welded joint." - O.D. Pipe — "Smaller size pipe is usually designated by its inside diameter. Over 14 inches, however, the nominal size is the outside diameter, and such pipe is termed O.D."

Copper tube types (Copper Tube Dimensions sections) - Type K, soft temper — "recommended for underground lines carrying water, oil or gas. Its thick walls are adequate to withstand possible damage from backfilling." - Type M — the lightest wall copper tube, "intended for use with soldered fittings only"; used for vent pipe systems, waste lines, interior drainage, engineered piping systems, and other non-pressure applications. - Nominal 2-inch Type K has an outside diameter of 2.125 in. and an inside diameter of 1.959 in. (Dimensions of Type K Copper Tube table).

Key Concepts

• Setback definition. Setback locates the beginning of a bend. In a piping layout it is the distance from the beginning of the bend to the point where the extended centerlines of the straight pipe on each leg would meet. Setback and length of bend are both measured along the centerline, and the bending radius is also measured to the centerline. (Setback and Length of Bend, p. 1-2; Length of Pipe in Bends, p. 1-1)
• Setback is a function of angle and radius. There is a separate setback value for each angle and radius of bend; cases not in the tables are solved with trigonometry. (p. 1-2)
• Miter cuts are always half the joint angle. A miter cut is always made at one-half the angle of the completed joint — in a 2-piece 90° turn each cut is 45°. The miter cut angle always has its apex at the center from which the radius of the turn is drawn. (Mitering Pipe; The 90° Welded Turn, 3-Piece)
• Piece count vs. joint count in welded turns. A 3-piece 90° turn has 2 mitered joints (each joint 45°, each piece mitered at 22½°). A 4-piece 90° turn…

Key Concepts

Steel and wrought iron pipe by schedule and weight - Dimensions of Standard Weight steel pipe correspond to Schedule 40 sizes only from ⅛ through 10 inches. From 12 through 24 inches, wall thickness is constant at 0.375 inches. (Pipe Fitters Handbook, Dimensions of Schedule 40 Steel and Wrought Iron Pipe notes) - Dimensions of Extra Strong steel pipe correspond to Schedule 80 sizes only from ⅛ through 8 inches. From 10 through 24 inches, wall thickness is constant at 0.500 inches. (Pipe Fitters Handbook, Dimensions of Schedule 80 Steel and Wrought Iron Pipe notes)

Copper tube types and applications - Type DWV copper drainage tube was developed specifically for sanitary drainage service. It is installed by a simple soldering operation in which the solder is drawn into the joint by capillary action. (Dimensions of Type DWV Copper Tube section) - Soft temper Type K is recommended for underground lines carrying water, oil, or gas; its thick walls are adequate to withstand possible damage from backfilling. Typical application: underground water service lines. (Copper Tube selection section — Type K applications)

Key Concepts

Bends and setback - Length of pipe in a bend depends on (1) length of bending radius and (2) number of degrees of bend. Arc length is measured along the centerline of the pipe, and the radius is also measured as extending to the centerline (Page 1-1). - Setback locates the beginning of a bend: it is the distance from the beginning of the bend to the point where extended centerlines of the straight legs would meet, measured along the centerline (Page 1-2). - Setback = Radius × Tangent ½ Angle of Bend (Page 1-2). - A 180° bend is regarded as two 90° bends (Page 1-50). - Wrinkle bends: number of wrinkles = degrees of bend ÷ degrees per wrinkle (e.g., 90 ÷ 9 = 10 wrinkles) (Page 1-105).

Mitering and welded turns - A miter cut is made at one-half the angle of the completed joint; this applies to all mitered welded turns and offset connections (Page 2-1). The miter cut angle always has its apex at the center from which the radius of the turn is drawn (Pages 2-12, 2-15). - 3-piece 90° turn: 2 joints at 45° each; each piece mitered at 22½°…

Hangers and Supports — Pipefitter's Handbook, Part 2 (Pipe Hanger U-Bolts; Spacing of Hangers) and Part 3 (Plastic Pipe support spacing)

Key Concepts

Hanger types and PVC anchoring (Pipe Supporting section) - The clevis or saddle-type hanger is the most favorable type except where thrust along the axis of the pipe must be controlled, as in thermal expansion. - Where firm anchoring is needed (to resist axial thrust), metal compression hangers are satisfactory only when padded with a compressible insert band. The padding requirement is not optional — it is what makes the compression hanger acceptable. - Pipe lines must have additional support beyond the table recommendations at fittings and flanges. - Valves are supported independently and braced to resist twisting during opening and closing.

What the spacing tables do and do not cover - Spacing of Pipe Supports for Lines Carrying Water table notes: the spacing data are based on average conditions and do not include allowance for flanges, fittings, and valves, but do include allowance for insulation. - Spacing of Pipe Supports for Lines Carrying Gas or Steam table footnote (page 2-68): likewise no allowance for flanges, fittings, and valves; insulation is allowed for. **Heavy fittings such…

Key Concepts

Gate valves — components and bonnet construction (Chapter 1, Gate Valves — Description, Page 5-6) - Working parts: a solid or split wedge (gate) fitting between machined seats, a threaded stem or spindle, a handwheel, and packing. - The bonnet may be one-piece screwed directly to the body, a union connection screwed to the body, bolted to the body, or constructed as a yoke, exposing the stem or spindle. - Packing sits in a recess in the top of the bonnet, held by a packing nut screwed to the bonnet or a packing gland bolted to the bonnet. A packing gland bushing, or follower, installed between the gland or nut and the packing, transmits the force exerted by the packing gland or nut to the packing.

Gate valve service characteristics (Chapter 1, Gate Valves — Service Characteristics, Page 5-6) - Flow is straight-way; best where unrestricted flow matters — pump lines, main supply lines, stop-valve service. Suited to infrequent operation, gate wide open or fully closed. Not suitable for throttling (flow regulation). - Split or double disc type: install with stem vertical, handwheel up, as a precaution against possible jamming of the disc spreader mechanism. Good for…

Key Concepts

Torch bending practice. If heating by torch, start the first heat of the bend at the setback point with the torch moving forward, then heat the pipe evenly with repeated passes toward the end of the bend length. As each heat is applied, form the bend with a bending machine or template. Bending should be done so a minimum of flattening takes place at the outside of the bend, and where possible short sections of the bend should be formed continuously from one end of the arc to the other, rather than applying all bending pressure to the center of the arc. (Full Text, Fabrication of Bends section, Page 196 (1-96))

Pre-bend allowances. Before actually bending, allowance must be made for straight ends (tangents), threaded ends, flanges, welding joints and other clearances before cutting the pipe off at the overall length. (Full Text, Fabrication of Bends section)