Oklahoma Residential Journeyman Plumbing and Natural Gas

Study Brief: General Plumbing Knowledge and Regulations

Key Concepts

Permits & Inspections (IRC Chapter 1 / IPC Chapter 1) - Permits are required before starting plumbing work. The authority having jurisdiction (AHJ) issues permits and conducts inspections. - Existing plumbing legally in place before code adoption may continue without change, unless deemed unsafe by the building official (IRC R102.7). - Additions/alterations must conform to current code requirements without requiring the entire existing system to be brought up to code (IRC R102.7.1). - Where conflicts exist between a general requirement and a specific requirement, the specific requirement governs (IRC R102.1).

Key Concepts

Pipe Material Identification & Approved Uses

• Copper tubing: Type L or heavier required for oil supply piping (M2203.2). Type K, L, and M used in water supply — know which grades are approved for buried, interior, and hot water applications.
• CPVC: Approved for hot and cold water distribution; requires solvent cement joints. Not interchangeable fittings with PVC.
• PEX: Approved for water supply and distribution. Cannot be used exposed to UV or in certain high-temp applications. Requires listed fittings (insert or expansion type).
• PVC: DWV and cold water supply only — not rated for hot water. Schedule 40 most common for drain/waste/vent.
• Cast iron: Used for DWV systems. Joints made with hub-and-spigot (lead and oakum) or no-hub (mechanical coupling) connections. Cast iron fittings are prohibited for oil piping (M2202.2).
• Steel pipe:…

Key Concepts

Fixture Installation & Standards Fixtures must conform to ANSI/ASME standards and be installed per manufacturer instructions. All fixtures must have approved materials and be free from defects. Slip-joint connections are permitted on the drain side only; tailpieces must be a minimum of 1-1/4" diameter for lavatories and 1-1/2" diameter for kitchen sinks and tubs.

Fixture Traps - Each fixture must have an individual trap unless specifically exempt. - Trap seal depth: minimum 2 inches, maximum 4 inches. - Trap arm length (distance from trap weir to vent): cannot exceed the distance allowed by the drain pipe diameter (e.g., 1-1/4" pipe = 30" max; 1-1/2" = 42" max; 2" = 60" max; 3" = 72" max). - Crown-vented traps and S-traps are prohibited.

Key Concepts

Water Service and Distribution Materials Approved materials for water service include copper (Types K, L), CPVC, PEX, PEX-AL-PEX, PE, and galvanized steel. Water distribution inside the dwelling uses Types L and M copper, CPVC, and PEX. All materials must be listed and comply with applicable ASTM/ASSE/NSF standards. Per IRC Section P2904, PEX and CPVC are acceptable for fire sprinkler integration in one- and two-family dwellings.

Lead Content Requirements Per the Reduction of Lead in Drinking Water Act and IRC Section P2903.9, all pipe, fittings, fixtures, and fittings in contact with potable water must be lead-free — defined as ≤0.25% weighted average lead content. Solder and flux must contain no more than 0.2% lead.

Key Concepts

Drain and Sewer Pipe Materials & Joints Approved materials include ABS, PVC, cast iron, and copper. Joints must match the pipe material — use only approved transition fittings when changing materials. Prohibited connections include improper material mixing without listed adapters and any joint that reduces flow or creates a ledge inside the pipe.

Horizontal Drainage Slope Requirements - Pipe 2½" and smaller: minimum ¼" per foot (2% slope) - Pipe 3" and larger: minimum ⅛" per foot (1% slope) - Maximum slope where velocity exceeds self-cleaning velocity must still be evaluated

Drainage Fittings for Direction Changes Use only sanitary tees, wyes, long-sweep bends, and 45° fittings in the direction of flow. Sanitary tees are permitted only for vertical-to-horizontal or horizontal-to-vertical connections (not horizontal-to-horizontal). Short-pattern fittings and double sanitary tees on horizontal runs are generally prohibited in drain…

Key Concepts

Trap Seal Protection (P3101.2) The vent system must prevent any fixture trap seal from being subjected to a pressure differential exceeding 1 inch of water column (249 Pa). Every trap and trapped fixture must be vented.

Vent Terminal Heights (P3103.1) - Standard roof extension: ≥ 6 inches above roof or above anticipated snow accumulation, whichever is greater - Roof used for assembly/recreation: ≥ 7 feet above roof - Covered by solar panel or architectural feature: ≥ 2 inches above roof surface - Sidewall terminal: ≥ 10 feet from lot line and ≥ 10 feet above grade within 10 feet horizontally

Oklahoma Residential Journeyman Plumbing & Natural Gas Exam Study Brief

Key Concepts

Trap Seal Requirements Every trap must maintain a liquid seal of not less than 2 inches and not more than 4 inches (P3201.2). This is non-negotiable — too shallow allows sewer gas breakthrough; too deep allows solids to accumulate.

Trap Design & Material Standards Traps must be self-cleaning, have smooth and uniform interior waterways, and be constructed of approved materials. No interior partitions are permitted except in integral fixture traps (e.g., water closets). Traps must be accessible.

Prohibited Trap Types (P3201.2) The following trap designs are prohibited: - Bell traps - Crown-vented traps - Drum traps (except for special use with approval) - Full S-traps - Running traps (except where approved) - Trap designs that depend on moving parts to maintain the seal

Key Concepts

Isometric Drawings represent a 3D piping system in 2D, showing pipe runs, fittings, direction changes, grades, and vent connections. You must read pipe sizes, flow directions, and fitting types directly from the isometric.

Fitting Allowances (Center-to-End): Each fitting has a "take-out" value — the distance from the fitting center to the end of the socket/hub. The actual pipe cut length = measured face-to-face distance minus fitting allowances. Allowances vary by material (threaded, copper sweat, plastic, cast iron hub, no-hub).

• Cast Iron Hub pipe: Allowance is the depth of the hub (socket depth). No-hub pipe uses a coupling band — minimal allowance.
• Copper fittings: Allowance = socket depth (shorter than threaded).
• Threaded fittings: Allowance = thread engagement depth.

Key Concepts

Gas Piping Materials & Joining - Approved materials: black steel (Schedule 40), galvanized steel, CSST, copper (for LP only where approved), and polyethylene (underground only). - Threaded steel pipe requires tapered NPT threads; joint compound (pipe dope) must be approved for gas and applied to male threads only. - CSST must be installed per its listing and manufacturer's instructions and requires arc-fault bonding.

Electrical Bonding - CSST must be bonded to the electrical grounding system. Bond clamps must be installed within 6 feet of the gas meter or point of entry. Standard metallic pipe also requires bonding but CSST has stricter requirements due to lightning-induced arc damage risk.

29 CFR 1926 | 10 questions, 12% of exam

Key Concepts

Employer Accident Prevention Responsibilities (§1926.20) - Employers must initiate and maintain safety programs with frequent and regular inspections by competent persons. - Unsafe equipment must be tagged, locked out (controls rendered inoperable), or physically removed — not just set aside. - Only qualified (trained or experienced) employees may operate machinery and equipment. - Each failure to provide PPE or training to an individual employee is a separate violation.

Safety Training & Education (§1926.21) - Employers must instruct every employee in recognition and avoidance of unsafe conditions. - Employees handling flammable liquids, gases, or toxic materials require specific instruction referencing Subparts D and F. - Employees exposed to poisons or caustics must be trained in safe handling, personal hygiene, and PPE use.