West Virginia Plumbing Contractor

Key Concepts

Scope and applicability (IPC Chapter 1) - The code applies to erection, installation, alteration, repair, relocation, replacement, addition, use or maintenance of plumbing systems, and regulates nonflammable medical gas, inhalation anesthetic, vacuum piping, nonmedical oxygen systems, and sanitary and condensate vacuum collection systems. Fuel gas distribution piping and equipment, fuel-gas-fired water heaters and water heater venting systems are regulated by the International Fuel Gas Code (101.2). - Where a general and a specific requirement conflict, the specific governs; where sections specify different materials or methods, the most restrictive governs (102.1). Where the code and manufacturer's instructions conflict, the more restrictive provisions apply (301.7). - A reference to a chapter or section number not identified by name refers to that chapter/section of this code (102.11).…

Key Concepts

Fixture counts and facility location - Fractional fixture numbers from Table 403.1 ratios are rounded up to the next whole number; for multiple occupancies the fractions for each occupancy are first summed, then rounded up (IPC 2018, 403.1.1). Occupant load of each sex is found by dividing the total occupant load in half. - Separate facilities for each sex are required, except: dwelling/sleeping units; structures or tenant spaces with total occupant load (employees + customers) of 15 or fewer; mercantile occupancies with maximum occupant load of 100 or fewer; business occupancies with maximum occupant load of 25 or fewer (403.2, Exceptions 1–4). - Occupancies other than malls: required public and employee toilet facilities not more than one story above or below the space served,…

Key Concepts

• Prohibited drainage. Storm water shall not be drained into sewers intended for sewage only (IPC 2018, Section 1101.3). Where the storm drain connects to a combined sewer line, a trap is required (Plumbing Basics for Contractors, Ch. 15, p. 651).
• Disposal. Rainwater from roofs and storm water from paved areas, yards, courts and courtyards shall drain to an approved place of disposal. For one- and two-family dwellings, and where approved, storm water may discharge onto flat areas such as streets or lawns provided it flows away from the building (Section 1101.2).
• General requirements. Conductors and the building storm drain are tested per Section 312 (1101.4); pipe size shall not be reduced in the direction of flow (1101.5); fittings per Table 706.3…

Key Concepts

Administration - Construction documents for buildings more than two stories in height must indicate where penetrations will be made and the materials/methods for maintaining structural safety, fire-resistance rating and fireblocking (IFGC 106.3.1, p. 4). - Commencing work before obtaining the necessary permits subjects the person to 100 percent of the usual permit fee in addition to the required permit fees (IFGC 106.6.1, p. 5).

Structural safety (Section 302) - Joists: bored holes not within 2 inches of top and bottom; diameter shall not exceed one-third the depth. End notching ≤ one-fourth the depth; top/bottom notches ≤ one-sixth the depth (302.3.2, p. 20). - Wood studs: bored holes shall not exceed 40 percent of stud depth; 60 percent permitted in nonbearing partitions or where each…

Key Concepts

Accident costs (1.2.0 Costs and Impacts of Accidents). The accident-cost "iceberg" splits costs into direct (insured) — medical bills, compensation, insurance premiums — and the larger, unseen indirect (uninsured) costs: property and equipment damage, production delays, supervisory time, retraining, and damage to image/morale.

Gloves (2.1.3, steps from 29 CFR 1910.137). Air test rubber gloves: hold the glove by its cuff, flip it several times to make a seal, and roll the glove toward its fingers so an air pocket forms; hold the rolled portion tightly and inspect the inflated exterior for cracks or degradation; hold the glove close to your ear — if air escapes or the glove will not hold pressure, it is damaged and must be removed from service. Inspect gloves daily;…

Key Concepts

Pictorial drawings. Pictorial drawings present a three-dimensional view of an object, much like a photograph. Plumbers use two types: the isometric drawing and the oblique drawing (Ch. 4, Section 2.1.0, p. 200).

• Isometric: all vertical lines are shown vertically; all horizontal lines are projected at a 30-degree angle and appear to go back into the horizon. On a box sketch, lines horizontal in the front view and lines horizontal in the right-side view are both drawn 30 degrees from horizontal; dashed lines indicate hidden back and bottom edges (Section 2.1.1, Figure 12, p. 201). Converting a floor plan: any horizontal line on the floor plan becomes a 30-degree angled line.
• Oblique: a pictorial drawing that creates the illusion of depth using lines…

Key Concepts

Sizing and pressure (IPC 2018, Chapter 6) - Water service pipe shall be sized for the required quantities and pressures and shall be not less than 3/4 inch (19.1 mm) in diameter — §603.1. - Water service pipe or tubing installed underground and outside the structure: working pressure rating not less than 160 psi at 73.4°F; where water pressure exceeds 160 psi, the material must be rated not less than the highest available pressure — §605.3. - Hot water distribution pipe and tubing: pressure rating not less than 100 psi at 180°F — §605.4. - Fixture supply pipe shall extend to the floor or wall adjacent to the fixture and terminate not more than 30 inches from the point of connection — §604.5. -…

Key Concepts

Relief valves and discharge piping (IPC 2018, Chapter 5) - Temperature and pressure relief valves shall bear the label of an approved agency and have a temperature setting of not more than 210°F (99°C) and a pressure setting not exceeding the tank or water heater manufacturer's rated working pressure or 150 psi (1035 kPa), whichever is less. Relieving capacity shall equal or exceed the heat input (Section 504.5). - Relief valves shall conform to ANSI Z21.22 and shall not be used as a means of controlling thermal expansion (504.4). Temperature relief valves shall be located to be actuated by water in the top 6 inches of the tank; no check valve or shutoff valve between the relief valve and the heater or tank (504.4.1).…

Key Concepts

Slope and fitting rules. Horizontal drainage piping is installed at uniform slope per Table 704.1, except piping upstream of a grease interceptor shall be not less than 1/4 inch per foot (2-percent slope) (704.1). Horizontal branches connect to bases of stacks and to horizontal stack offsets not less than 10 times the diameter of the drainage stack downstream (704.3). Double sanitary tee patterns shall not receive back-to-back water closets, except where the horizontal developed length between the water closet outlet and the double sanitary tee is 18 inches or greater (706.3). A horizontal branch connecting within 2 feet above or below a vertical stack offset located more than four branch intervals below the top of the stack requires the offset to be vented per…

Key Concepts

• Fitting allowance is the distance from the end of the pipe that goes into the fitting (face) to the center of the fitting. For threaded pipe, fitting allowance = center-to-face measure − thread-in measure (Ch. 3, Sec. 2.3.0 / 2.4.0).
• Thread makeup (also called thread-in or thread engagement) is the distance the pipe screws into the fitting; it can be found by measuring the depth of the fitting's socket or thread (Ch. 3, Sec. 2.2.0).
• Not every joint has a fitting allowance. Plastic glued and threaded joints have fitting allowances; cast-iron no-hub and face-to-face flanged joints do not. Cast-iron hub-and-spigot fittings do have published allowances (Ch. 3, Sec. 2.3.0).
• General principles of measurement (Ch. 3, Sec. 2.5.4): for a center…

Key Concepts

Measuring and layout - Retractable steel tape measures are available in lengths up to 30 feet; for longer pipe runs, 25-, 50-, or 100-foot steel tapes wound by a hand crank are used (Sec. 1.2.3). - The framing square is L-shaped with a 24-inch-long, 2-inch-wide blade perpendicular to a 16-inch-long, 1-1/2-inch-wide tongue. The combination square has a 12-inch blade (Sec. 1.2.4).

Leveling - The 24-inch spirit level is standard; spirit levels also come in 28-inch, 48-inch, 72-inch, and 78-inch lengths. A level is accurate only up to its own length (Sec. 1.3.1). - Heat, cold, and moisture affect laser performance; performance of all lasers begins to deteriorate rapidly at 110°F or higher (Sec. 1.3.6).