Mississippi Residential Plumbing

Key Concepts

Permit Requirements (IPC Chapter 1, Section 105) All plumbing work requires a permit before work begins. Applications must include a description of the work, location, and be submitted to the code official. Work without a permit is a violation subject to stop-work orders and penalties.

Permit Exemptions Minor repairs and maintenance that do not alter the plumbing system or create unsafe conditions may be exempt. However, any new installation, replacement of major components, or work that changes the system's design requires a permit.

Key Concepts

Water Service Pipe (IPC Section 603) - Minimum water service pipe diameter: ¾ inch - Water service and building sewer in the same trench: sewer must be constructed of materials listed in Table 702.2, OR pipes must be horizontally separated by ≥5 feet of undisturbed/compacted earth - At crossings, water service must be sleeved 5 feet horizontally from sewer centerline on both sides, or the bottom of water service must be ≥12 inches above the top of the sewer

Approved Pipe Materials - Water service and distribution pipe materials are listed in IPC Tables 605.3 and 605.4 - Common approved materials: copper (Types K, L, M), CPVC, PEX, PEX-AL-PEX, PE, galvanized steel - Pipe must be listed…

Key Concepts

Fixture Material Standards (Section 402) Plumbing fixtures must have smooth, impervious surfaces free from defects. Porcelain enamel must be acid resistant. Sheet copper for general applications must conform to ASTM B152 and weigh at least 12 oz/sq ft. Sheet lead for pans must weigh at least 4 lbs/sq ft and be coated with asphalt paint or approved coating.

Prohibited Fixtures (Section 401.2) - Water closets with concealed trap seals or unventilated spaces are prohibited - Water closets that allow siphonage of bowl contents back into the tank are prohibited - Trough urinals are prohibited

Key Concepts

General Scope (IPC Section 601): Chapter 6 governs all materials, design, and installation of hot and cold water supply systems for human occupancy, including individual water supply systems (wells, springs, cisterns).

Minimum Water Service Size (Section 603.1): Water service pipe shall be not less than ¾ inch in diameter, sized to deliver required flow and pressure.

Sewer/Water Service Separation (Section 603.2): When water service and building sewer share a trench, sewer must be an approved material (Table 702.2). If not approved material, minimum 5-foot horizontal separation is required. At crossings, sleeving extends 5 feet each direction from sewer centerline, and the water service bottom must be ≥12 inches above the top of the sewer when within 5…

(17 questions, 21% of exam — IPC 2021, Chapter 7)

Key Concepts

Drainage Fixture Unit (DFU) Values DFUs quantify the probable discharge load of each fixture. Common values to memorize: - Water closet: 4 DFU (tank-type) - Bathtub/shower: 2 DFU - Lavatory: 1 DFU - Kitchen sink: 2 DFU - Clothes washer: 2 DFU - Floor drain: 2 DFU

Slope Requirements (IPC Section 704.1) - Pipe < 3 inches: minimum slope ¼ inch per foot (2%) - Pipe ≥ 3 inches: minimum slope ⅛ inch per foot (1%) - Maximum slope: ½ inch per foot for pipes 2½ inches and smaller (steeper creates self-siphonage risk)

Key Concepts

Isometric/Riser Diagrams are 3D schematic representations of DWV systems showing pipe runs, fixture connections, direction changes, and vent locations without true scale. You must read flow direction (gravity, top-to-bottom), identify fixture connections, and trace DFU accumulation from remote fixtures toward the building drain.

Drainage Fixture Units (DFUs) are the core design currency of DWV sizing. IPC Table 709.1 assigns DFU values to each fixture type. Key residential values to memorize: - Bathtub/shower: 2 DFU - Lavatory: 1 DFU - Water closet (flush tank): 3 DFU - Kitchen sink: 2 DFU - Clothes washer: 2 DFU - Floor drain: 2 DFU - Bathroom group (water closet + lavatory + bathtub/shower): 5 DFU

29 CFR 1926 (OSHA Construction Standards)

Key Concepts

Personal Protective Equipment (PPE)

• Under § 1926.20(f)(1), the employer must provide PPE to each individual employee — failure to provide PPE to even one employee is a separate violation.
• Employers are required to pay for PPE; employees cannot be required to supply their own as a condition of employment.
• Training on PPE use is also a per-employee obligation under § 1926.20(f)(2).

Fire Protection & Portable Extinguishers

• § 1926.24 requires the employer to develop and maintain an effective fire protection and prevention program throughout all phases of construction, repair, alteration, or demolition.
• Portable fire extinguishers must be inspected monthly and maintained annually. One 2A-rated…

(6 questions, 8% of exam)

Key Concepts

Indirect Waste & Air Gaps vs. Air Breaks (IPC Ch. 8)

• Air gap = physical open space between discharge pipe and flood level rim — required for food handling, potable clear-water waste (sterilizers, relief valves), and swimming pools (§802.1.1, 802.1.3, 802.1.4)
• Air break = discharge pipe terminates above trap seal, but may touch receptor — acceptable for nonpotable clear-water waste (boilers, process tanks, filters) and commercial dishwashers (§802.1.5, 802.1.6)
• Air gap minimum size: not less than twice the effective opening of the indirect waste pipe (§802.3.1)
• Indirect waste piping exceeding 30 inches horizontal OR 54 inches total developed length must be trapped (§802.3)
• Standpipes extend…

Key Concepts

Gas Piping Materials (IFGC Chapter 4) - Steel pipe: Black steel (ASTM A53) with threaded joints is the standard for interior gas piping. Galvanized steel is prohibited underground and in some wet locations. - Copper: Permitted for natural gas only if the gas is not corrosive; prohibited for LP-gas in some jurisdictions. Must use ACR-grade or Type K/L copper tubing with flare or brazed fittings — not soldered. - CSST (Corrugated Stainless Steel Tubing): Must be installed per the manufacturer's listing and requires bonding/grounding (see electrical bonding below). Not permitted to be used as a connector to an appliance. - Polyethylene (PE): Approved for underground use only, outside buildings; must be yellow-colored and marked for gas service.…

Key Concepts

Pipe Sizing (IFGC Section 402) - Size LP gas piping using IFGC Tables 402.4(1)–402.4(37) for undiluted propane, based on pipe length, pressure drop, and material type - Three variables drive table selection: (1) inlet pressure, (2) allowable pressure drop, and (3) pipe/tubing material - For propane, common low-pressure sizing uses 11 in. w.c. inlet / 0.5 in. w.c. drop tables; use the correct propane-specific table (not natural gas) - Total pipe length = developed length + equivalent lengths for fittings

Two-Stage Regulator Systems - First-stage regulator: reduces LP tank pressure (up to 200+ psig) to an intermediate pressure (typically 10 psig) - Second-stage regulator: reduces intermediate pressure to **low delivery pressure (11 in. w.c. / 0.5…

Key Concepts

Tank Materials, Standards & Listing (UL 58 / UL 80)

• UL 58 covers underground steel fuel oil tanks
• UL 80 covers steel indoor/above-ground fuel oil tanks (typically smaller, residential)
• Tanks must be listed and labeled per the applicable UL standard based on installation type

Above-Ground & Indoor Tank Capacity Limits

• Indoor above-ground tanks are generally limited to 660 gallons aggregate capacity per building
• Single above-ground tanks are typically limited to 330 gallons
• Tanks must be placed on non-combustible supports and protected from physical damage
• Minimum clearance from heat-producing appliances and ignition sources must be maintained

Key Concepts

Water Supply & Distribution Piping Materials (IPC Chapter 6, Table 605.3)

Approved materials for water distribution piping include: - Copper (Types K, L, M) – ASTM B88; most versatile, above and below grade - CPVC – ASTM D2846 or ASTM F441; approved for hot and cold distribution - PEX – ASTM F876/F877; flexible, widely used in residential; not for outdoor UV exposure - PE-RT – ASTM F2769; similar flexibility to PEX - PVC – ASTM D1785 or D2241; cold water only - Galvanized steel – ASTM A53; threaded joints; limited modern use