Oklahoma Process Piping Journeyman

Key Concepts

Pipe Terminology (Pipefitters Dictionary) - Setback: Distance from the beginning of a bend to where the extended centerlines of the two straight legs would intersect. Formula: Setback = Radius × Tangent of ½ the Angle of Bend - Length of Arc: Measured along the centerline of the pipe. Formula: L = Degrees × 0.01745 × Radius - Nominal Pipe Size (NPS): A dimensionless designator — the nominal size does NOT equal the actual OD for most pipe sizes - Schedule: Designates wall thickness, not pipe strength directly

Pipe Material Types and Identification - Steel pipe: Used for high-pressure, high-temperature service; identified by mill markings showing grade, schedule, and heat number - Wrought iron pipe: More corrosion-resistant than steel; rarely used in new construction; identified by threaded ends and lower pressure ratings - Copper tube: Three main types — Type K (thickest wall, underground/high pressure), Type L (medium wall, general plumbing), Type M (thinnest wall, low-pressure domestic); also DWV (drain, waste, vent — thinnest, not pressure-rated) - Plastic pipe: Includes PVC, CPVC, ABS, PE, PB; not suitable for high-temperature service; pressure ratings drop significantly as temperature rises

Key Concepts

Pipe Bend Calculations from Drawings - The length of arc in any bend is measured along the pipe centerline, and the bending radius is also measured to the centerline. - Formula: Length of Arc = Degrees × 0.01745 × Radius - Setback is the distance from the start of a bend to where the extended centerlines of both legs would intersect. Formula: Setback = Radius × Tangent (½ Angle of Bend) - Setback and arc length are always read along the centerline, not the outside wall.

Offset Connections – Travel and Run Relationships - An offset involves three key dimensions: offset (the perpendicular distance to clear), travel (the diagonal pipe length through the bend), and run (the horizontal/parallel distance consumed). - These relationships are governed by the angle of the bend. For a 45° offset: Travel = Offset × 1.414. For a 30° offset: Travel = Offset × 2.000. For a 60° offset: Travel = Offset × 1.155. - Rolling offsets add a third dimension; the true offset is calculated from the combination of the horizontal and vertical components before applying the travel multiplier.

Oklahoma Process Piping Journeyman Exam — 14% of Exam (5 Questions)

Key Concepts

Steel & Wrought Iron Pipe — Schedule and Weight Classifications

• Pipe is classified by nominal pipe size (NPS) and schedule number (or weight designation).
• Common schedules: Sch 40 (Standard), Sch 80 (Extra Strong/XS), Sch 120, Sch 160, and XXS (Double Extra Strong).
• Schedule number relates to wall thickness: higher schedule = thicker wall = higher pressure rating.
• "Standard Weight" = Sch 40 for sizes up to 10"; above 10", Standard Weight wall thickness stays constant while Sch 40 diverges.
• "Extra Strong" = Sch 80 for most sizes. "Double Extra Strong" (XXS) has no schedule number equivalent.

Copper Tube Types

Oklahoma Process Piping Journeyman | 8 Questions | 23% of Exam

Key Concepts

Pipe Bend Geometry - Setback = distance from the start of a bend to where the extended centerlines of both pipe legs intersect. Formula: Setback = Radius × Tangent(½ × Bend Angle) - Arc Length is measured along the pipe centerline. Formula: Arc Length = Degrees × 0.01745 × Radius - Radius is always measured to the pipe centerline, not the pipe wall.

Offset Bends - Common offset angles: 22½°, 30°, 45°, 60°. Each has a specific multiplier to convert offset (rise) to travel and run. - Travel = the actual pipe length through the bend zone. Run = horizontal distance covered. - 45° offset: Travel = Offset × 1.414; Run = Offset × 1.000 - 30° offset: Travel = Offset × 2.000; Run = Offset × 1.732 - 22½° offset: Travel = Offset × 2.613; Run = Offset × 2.414

Key Concepts

Types of Pipe Hangers and Support Hardware - U-bolt: Wraps around pipe, threaded ends bolt through a structural member. Used for rigid support on horizontal runs. - Clevis hanger: Swinging, adjustable hanger; allows vertical adjustment; most common for suspended horizontal pipe. - Saddle: Cradles the pipe from below; used where pipe rests on structural steel or concrete support. - Ring hanger: Split or solid ring; suspends pipe from rods; used for lighter loads and smaller diameters.

Support Requirements Near Fittings and Valves - Heavy inline components (gate valves, globe valves, strainers, large flanges) require supports placed directly adjacent — within one pipe diameter or as close as structurally practical — to prevent bending stress at the joint. - Never allow a valve or large fitting to be the only point of support for a run; the pipe on each side must be independently supported.

Key Concepts

Gate Valves

Gate valves are isolation valves used for fully open or fully closed service — never for throttling. The gate (wedge) moves perpendicular to flow. Key types: - Solid wedge – most common; suitable for most services including steam, water, oil, gas - Flexible wedge – handles thermal expansion better; preferred for high-temperature steam lines - Split wedge (double disc) – self-adjusting to seat; good for non-condensing gases and liquids at normal temperatures - Rising stem (OS&Y) – stem rises with gate; visual indication of open/closed position; required in many process applications - Non-rising stem – stem rotates but does not rise; used where headroom is limited

Components: body, bonnet, stem, packing gland, handwheel, wedge/disc, seats.

Globe Valves

Globe valves provide throttling and flow regulation. Flow makes two direction changes through the body. The disc moves parallel to the stem and seats against a circular seat. - Install with flow entering under the disc (standard practice) to reduce erosion and allow easier operation against pressure - Angle valves are a variation of the globe — inlet and outlet are at 90°, reducing pressure drop and eliminating one pipe elbow; suitable for erosive or flashing…

3 questions | 9% of exam

Key Concepts

Pipe Bending & Fabrication Safety

• Never exceed the minimum bending radius for the pipe material — over-bending causes thinning, cracking, or collapse of the pipe wall, creating a structural hazard.
• Wrinkle bends are only acceptable in low-pressure, non-critical applications; they weaken the pipe and can crack under pressure cycling.
• Always secure the pipe firmly in the bending machine before applying force. Slipping pipe under load causes sudden release of stored energy — a serious crush/strike hazard.
• Wear appropriate PPE (gloves, eye protection) when handling cut or reamed pipe ends — burrs and chips are sharp and can cause severe lacerations.

Pipe Threading Equipment

• Inspect dies, cutters, and reamers before each use. Worn or chipped dies produce poor threads and can grab, causing the machine to jerk.
• Use the correct cutting oil continuously during threading — it lubricates, cools, and improves thread quality. Dry threading damages dies and can cause pipe to seize in the machine.
• Never reach over or across rotating pipe in a threading machine. Keep sleeves, gloves, and loose clothing away from all rotating parts.
• Secure pipe with…