2.1 Approved Materials, Certification, and General Installation Rules

What Chapter 3 is for

IPC Chapter 3 holds the rules that do not belong to any single system. It is the home for materials approval, pipe protection, trenching, support, testing, penetrations and engineered design. On the Colorado Journeyworker exam, General Regulations is worth 5 scored items, but the chapter's reach is much larger than that number suggests: a sizeable share of the drainage, vent and water-supply items ultimately trace back to a Chapter 3 rule about support spacing, shield plates or test pressure.

IPC 301.1 frames it exactly that way — Chapter 3 governs "the general regulations regarding the installation of plumbing not specific to other chapters."

Direct connection, and the two exceptions

IPC 301.3 is the baseline of sanitary design: fixtures, drains, appurtenances and appliances that receive or discharge liquid waste or sewage must be directly connected to the sanitary drainage system. Two carve-outs:

• The section does not override the indirect waste systems required by Chapter 8 (covered in Chapter 15 of this guide).
• Exception: bathtubs, showers, lavatories, clothes washers and laundry trays need not discharge to the sanitary drainage system where they discharge to an approved graywater system under IPC Chapters 13 and 14.

IPC 301.4 is the mirror image on the supply side: every fixture, device or appliance that requires water to operate must be directly or indirectly connected to the water supply system.

Materials: identified, certified, installed to standard

Four short sections do the work, and exam items usually hinge on which one applies.

Note the direction of 303.2. It is a one-way ratchet: a standard or a manufacturer instruction can be more demanding than the code and you must follow it, but it can never be less demanding than the code.

IPC 301.7 states the companion rule explicitly for conflicts: "the more restrictive provisions shall apply." When an exam item pits a manufacturer instruction against a code minimum, the answer is always whichever is tighter.

Sizes are nominal

IPC 301.5: unless otherwise indicated, pipe, tube and fitting sizes in the code are nominal or standard sizes as designated in the referenced material standards. A "2-inch" trap is a nominal 2-inch trap; you are not being asked for an actual measured inside diameter.

Prohibited locations

IPC 301.6 prohibits plumbing systems in an elevator shaft or elevator equipment room. The only exception is floor drains, sumps and sump pumps at the base of the shaft, provided they are indirectly connected to the plumbing system and comply with IPC 1003.4 (oil separators). That last cross-reference is the tell: elevator pit water routinely carries hydraulic oil.

Exclusion of materials detrimental to the sewer

IPC 302.1 bars from the building drainage or sewer system:

• ashes, cinders or rags;
• flammable, poisonous or explosive liquids or gases;
• oil, grease or any other insoluble material capable of obstructing, damaging or overloading the drainage or sewer system, or of interfering with sewage treatment processes.

IPC 302.2 requires the code official or other authority having jurisdiction to determine that industrial waste products will not damage the public sewer or interfere with the treatment plant before they are introduced. In Colorado this routinely means the local wastewater or sanitation district gets the final word, and Board Rule 1.2(E)(1)(vv) formally lets those district regulations supersede the IPC's interceptor requirements.

Rodentproofing

A small section that appears on exams precisely because candidates skip it. IPC 304 requires:

• 304.2 Strainer plates — openings on drain inlets not greater than 1/2 inch in least dimension.
• 304.3 Meter boxes — constructed so rodents cannot enter the structure by way of the water service pipes connecting the meter box and the structure.
• 304.4 Openings for pipes — the annular space between a pipe and the sides of a wall, floor or ceiling opening must be sealed with compatible caulking or closed with a gasketing system.

IPC 315.1 repeats and extends the annular-space rule for penetrations generally: the space between a pipe and a sleeve, or between a pipe and a building-envelope opening, must be sealed with caulking, foam sealant or a gasketing system designed for the conditions and compatible with the pipe, sleeve and building materials. Where the pipe penetrates a fire-resistance-rated assembly or its membrane, sealing follows Section 714 of the International Building Code, not this section.

Flood hazard areas

IPC 309 points at Section 1612 of the IBC for structures in flood hazard areas and lists what must be located and installed accordingly: water service pipes, pump seals below the design flood elevation, potable well covers (sealed unless the casing or sleeve is elevated not less than 1 foot above the design flood elevation), sanitary drainage piping, storm drainage piping, manhole covers, fixtures and fittings, water heaters, and vents. The exception permits components below that elevation if they are designed to keep water out and to resist hydrostatic and hydrodynamic loads including buoyancy. In coastal high-hazard areas and coastal A zones, plumbing must additionally not be mounted on or penetrate through breakaway walls.

Toilet facilities for workers, washrooms and structural care

• IPC 311.1 requires toilet facilities for construction workers, maintained in a sanitary condition; non-sewer types must conform to PSAI Z4.3.
• IPC 310 sends washroom and toilet room lighting, ventilation and interior finish to the IBC and IMC, and fixture location and compartments to IPC 405.3.
• IPC 301.2 sets the overall standard of care: plumbing must be installed "with due regard to preservation of the strength of structural members and prevention of damage to walls and other surfaces through fixture usage."

Alternative engineered design

IPC 316.1 provides the path for a system the prescriptive code does not cover. A registered design professional must indicate on the permit application that the system is an alternative engineered design, submit sufficient technical data to substantiate it, and submit two complete sets of signed and sealed construction documents including floor plans and a riser diagram, showing direction of flow, pipe sizes, grade of horizontal piping, and loading and location of fixtures and appliances. The design must provide an equivalent level of quality, strength, effectiveness, fire resistance, durability and safety. Approval is recorded on the permit and permanent permit records; denial must be in writing with reasons. Testing and inspection follow the ordinary rules.

Controlled-flow roof drain systems (IPC 1110) are the storm-drainage application of this section, so remember the cross-reference when you reach Chapter 16.

Colorado in practice

Colorado amends IPC 303 very little, but it does amend 305.1 (see the next section) and it adds the hanger rod sizing table 308.5.1. Remember the exam rule from Chapter 1: answer from the model IPC. The Colorado amendments below are flagged so you can keep the field version and the exam version separate.