Pipe Repair Glossary: Terms, Definitions, and Industry Language
Pipe repair involves a specialized vocabulary that spans plumbing trade practice, materials science, building codes, and inspection methodology. This glossary covers the core terms, definitions, and industry language used across residential and commercial pipe repair contexts in the United States. Precise terminology matters because miscommunication between property owners, contractors, inspectors, and insurers can delay repairs, trigger permit rejections, or produce mismatched scopes of work. The definitions below reflect usage found in standards published by organizations including ASTM International, the International Association of Plumbing and Mechanical Officials (IAPMO), and the International Code Council (ICC).
Definition and scope
A pipe repair glossary is a structured reference that defines the technical terms, classification labels, and procedural language used within the pipe repair trade. The scope extends beyond simple dictionary definitions to include regulatory distinctions, material-specific terminology, and method classifications that appear in building permits, inspection reports, contractor proposals, and insurance documentation.
The pipe repair field draws vocabulary from at least 4 overlapping domains:
- Materials science — terms describing pipe composition, corrosion mechanisms, and material ratings
- Repair methodology — terms distinguishing temporary patches from permanent structural repairs
- Regulatory and code language — terms defined by the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC)
- Trade and inspection practice — field terms used in condition assessments, scopes of work, and post-repair verification
Understanding these domains is essential for interpreting proposals, permit applications, and inspection findings correctly. A full overview of how repair methods are classified appears in the Pipe Repair Methods Overview.
How it works
Core terminology: alphabetical reference
ABS (Acrylonitrile Butadiene Styrene): A rigid black thermoplastic used in drain, waste, and vent (DWV) systems. Governed by ASTM D2661 for pipe and fittings.
Annular space: The gap between an existing host pipe and a liner inserted during relining operations. Controlling annular space is critical in cured-in-place pipe lining applications.
Bypass: A temporary pipe assembly routed around a damaged section to maintain service flow during repair work.
CIPP (Cured-In-Place Pipe): A trenchless rehabilitation method in which a resin-saturated felt or fiberglass liner is inserted into a host pipe and cured to form a structural pipe-within-a-pipe. ASTM F1216 governs CIPP installation for pressure pipe applications.
CPVC (Chlorinated Polyvinyl Chloride): A thermoplastic rated for hot and cold water supply, governed by ASTM F441. Requires solvent-cement joints; incompatible with standard PVC solvent.
Dezincification: A corrosion process in which zinc leaches from brass alloys, leaving a porous copper matrix. Common in fittings exposed to aggressive water chemistry.
DWV (Drain, Waste, and Vent): A subsystem classification for non-pressure drainage piping, distinguished from supply-side pressure piping in code requirements.
Electrolytic corrosion (galvanic corrosion): Deterioration caused by electrochemical reactions between dissimilar metals in contact within a common electrolyte (water). Dielectric unions are the standard isolation method. Galvanic corrosion is a primary driver of failures addressed in galvanized pipe repair and copper pipe repair.
Epoxy liner: An internal coating applied to the bore of existing pipes to seal leaks and restore flow capacity without pipe replacement. Distinguished from CIPP by the absence of a structural felt tube; epoxy lining is typically a corrosion barrier rather than a load-bearing repair.
Host pipe: In trenchless repair contexts, the original existing pipe into which a liner or new pipe is inserted or through which pipe bursting occurs.
Hydrostatic test: A pressure test using water (not air) to verify pipe integrity after repair. The IPC specifies test pressures of not less than the working pressure of the system, with a minimum of 15 psi sustained for 15 minutes (IPC Section 312).
Infiltration/inflow (I/I): Groundwater or stormwater entering a sanitary sewer through pipe defects. I/I is a key diagnostic indicator in sewer pipe condition assessments.
Invert: The lowest interior surface of a pipe at any cross-section. Invert elevations are used to establish drainage slope calculations.
Liner: Any material inserted inside an existing pipe to restore structural integrity or hydraulic capacity. Includes CIPP, epoxy, and slip-lining variants. See pipe relining for method comparisons.
Nominal pipe size (NPS): A North American standardized designation for pipe dimensions where the number does not correspond directly to any physical measurement; governed by ASME B36.10M for steel pipe.
No-dig / trenchless: Repair and replacement methods that avoid open excavation. Includes pipe bursting, CIPP, and directional drilling. Covered in depth at trenchless pipe repair.
PEX (Cross-linked Polyethylene): A flexible plastic supply piping rated for potable water, governed by ASTM F876/F877. Three crosslinking methods exist — PEX-A, PEX-B, and PEX-C — with performance differences in burst pressure, flexibility at low temperatures, and fitting compatibility.
Pinhole leak: A small-diameter perforation in copper or other metallic pipe resulting from pitting corrosion, typically 1 mm to 3 mm in diameter. Causes include aggressive water chemistry and microbially influenced corrosion (MIC). Repair strategies are classified at pinhole leak pipe repair.
Pipe bursting: A trenchless method in which a bursting head fractures the host pipe outward while simultaneously pulling a new pipe into position.
Polybutylene (PB): A gray flexible plastic supply pipe manufactured between approximately 1978 and 1995, known for premature failure at fittings. No longer manufactured for plumbing applications in the US.
Potable water: Water meeting the quality standards of the Safe Drinking Water Act (SDWA), enforced by the US Environmental Protection Agency (EPA). Repair materials in contact with potable water must meet NSF/ANSI Standard 61.
Pressure rating (PR): The maximum sustained operating pressure a pipe or fitting is rated to withstand, typically expressed in psi and determined by material, wall thickness, and temperature.
Root intrusion: The penetration of tree or shrub roots into pipe joints or cracks, a common defect found in clay and cast iron sewer lines. Root intrusion is addressed in sewer pipe repair procedures.
Rough-in inspection: A required permit inspection conducted after pipe installation but before walls or slabs are closed. Governed by local adoption of the IPC or UPC. Permitting requirements are detailed at pipe repair permits and codes.
Scale: Mineral deposits (primarily calcium carbonate and magnesium carbonate) accumulating on interior pipe surfaces, reducing flow capacity. Scale severity is measured by the Langelier Saturation Index (LSI).
Slip coupling: A repair coupling with no internal stop, allowing it to slide over a pipe section for connection without cutting back to a fitting hub. Widely used in pipe repair clamps and patch repair contexts.
Solvent cement: A chemical welding agent used to join PVC, CPVC, and ABS fittings by dissolving and fusing the pipe material at the joint. ASTM D2564 governs PVC solvent cement; ASTM F493 governs CPVC.
Spot repair: A localized repair addressing a discrete defect in an otherwise serviceable pipe, as opposed to full-length rehabilitation or replacement. Decision criteria for spot repair versus rehabilitation appear at pipe repair vs pipe replacement.
Tuberculation: A specific form of internal corrosion producing mound-shaped iron oxide deposits inside cast iron and galvanized steel pipes, significantly reducing hydraulic capacity.
Water hammer: A pressure surge or wave caused by abrupt changes in flow velocity, typically when a valve closes rapidly. Water hammer can cause joint failures and is categorized as a vibration-related failure mode under pipe noise and vibration repair.
Common scenarios
Terminology from this glossary appears in 4 common operational situations:
- Contractor proposal review — Terms such as "spot repair," "CIPP," and "pipe bursting" define scope and should match permit application language.
- Permit and inspection documentation — Inspectors reference IPC/UPC-defined terms including "rough-in inspection," "hydrostatic test," and "potable water compliance."
- Insurance claim processing — Adjusters and contractors use terms including "sudden and accidental loss," "infiltration," and "pre-existing deterioration" with specific coverage implications. See pipe repair insurance claims.
- Material selection and compatibility — Terms such as "dielectric union," "NSF/ANSI 61," and "pressure rating" directly govern which repair products are code-compliant and safe.
Decision boundaries
The distinction between temporary repair and permanent structural repair is the most consequential classification in pipe repair practice. Most jurisdictions require that temporary repairs — including mechanical clamps and compression fittings used as