Overview

Polyvinyl Chloride (PVC) is one of the most produced and versatile thermoplastics, formed by polymerizing vinyl chloride monomer (VCM). Adding plasticizers produces flexible PVC; without plasticizers it is rigid PVC (uPVC), the dominant material for drainage pipe, water supply pipe, electrical conduit, window frames, and siding. PVC is inherently flame-resistant (chlorine content), strong, and low-cost.

ρ = 1300-1450 kg/m³ for rigid PVC (uPVC); denser than water (1000 kg/m³); with plasticizers, flexible PVC is ~1150-1350 kg/m³

Mechanical Properties (Rigid PVC, uPVC)

Property	Value
Density	1,380-1,430 kg/m³ (1.4 g/cm³)
Tensile Strength (ultimate)	40-55 MPa (6,000-8,000 psi)
Young's Modulus	2,500-4,000 MPa (2.5-4.0 GPa)
Flexural Strength	70-100 MPa
Compressive Strength	60-80 MPa
Elongation at Break	10-50% (rigid, brittle compared to HDPE)
Hardness (Shore D)	75-85
Impact Strength (notched Izod)	20-60 J/m (lower than HDPE)
Coefficient of Friction	0.3-0.4

PVC is Heavier Than Most Plastics

PVC's 1400 kg/m³ density comes from the heavy chlorine atoms in its molecular structure (-CH₂-CHCl-). This chlorine gives PVC its inherent fire resistance (LOI ~45%, self-extinguishing when flame removed) but also makes PVC products sink in water and generates HCl gas if burned.

Thermal Properties

Property	Value (Rigid PVC)
Glass Transition (T_g)	70-80°C
Heat Deflection Temperature (0.45 MPa)	60-75°C
Continuous Service Temperature	60°C max (for pressure pipe)
Melting/Processing Temp	160-210°C
Thermal Conductivity	0.17 W/m·K (good insulator)
Specific Heat	1000 J/kg·K
Coefficient of Thermal Expansion	50-80 × 10⁻⁶ /°C (~5x steel, less than HDPE)
Flammability	Self-extinguishing (LOI 45%)

Chemical Resistance

Rigid PVC resists a wide range of chemicals:

Excellent: water, dilute acids and alkalis, salt solutions, alcohols, oils, many household chemicals
Good: strong HCl, most dilute inorganic chemicals
Limited: strong oxidizers (concentrated HNO₃, H₂SO₄ above 70%), aromatic and chlorinated hydrocarbons, ketones, esters
Food-safe grades available for potable water and food contact

Pipe Classifications

Schedule 40 / Schedule 80 (US, ASTM D1785)

Most common for plumbing and industrial piping
Schedule 80 has thicker wall for higher pressure
White (Schedule 40) or dark gray (Schedule 80) typically

Pressure Classes (ISO/DIN)

PN6, PN10, PN16 pressure ratings (in bar at 20°C)
Derating required above 25°C

PVC Pipe Types by Application

Use	Specification
Potable water supply	ASTM D1785, NSF-61 certified
Drain, waste, vent (DWV)	ASTM D2665 (non-pressure, thin wall)
Sewer pipe	ASTM D3034 (gravity)
Electrical conduit	Schedule 40/80 gray, UV resistant
Irrigation	Class-rated thin wall
Chemical process (CPVC)	Chlorinated PVC for higher temp (90°C)

Applications

Building & Construction

Water supply: Domestic cold water distribution (NOT hot water — use CPVC or PEX)
Drainage: DWV pipe for sinks, toilets, roof drains
Sewer: Municipal gravity sewers (often large diameter)
Electrical conduit: Protection for electrical wiring
Window profiles: Extruded uPVC window frames (excellent thermal performance, low maintenance)
Siding: Vinyl siding for residential buildings
Gutters and downspouts: Rainwater management

Industrial

Chemical process piping (acids, alkalis, plating solutions)
Ventilation ducting for corrosive fumes
Laboratory drainage
Tanks and tank linings
CPVC (chlorinated PVC) for hot water and corrosive fluids up to 90°C

Consumer Products

Vinyl flooring
Cable insulation (flexible PVC)
Medical tubing (flexible, DEHP-free grades)
Credit cards, packaging films

Temperature Limits

PVC pipe pressure ratings apply at 20-23°C. At 40°C, pressure rating is roughly halved; at 60°C, PVC softens significantly and loses most structural strength. Never use standard PVC for hot water lines (above ~50°C) or compressed air service (catastrophic brittle failure risk).

PVC vs HDPE vs CPVC

Property	Rigid PVC	HDPE	CPVC
Density	1400 kg/m³	960 kg/m³	1550 kg/m³
Pressure temp limit	60°C	60-80°C	90°C
Joint method	Solvent cement	Heat fusion	Solvent cement
Flexibility	Brittle	Very flexible	Moderate
Fire resistance	Self-extinguishing	Flammable	Self-extinguishing
Cost	Lowest	Moderate	Higher
Cold impact	Poor	Excellent	Fair

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Summary

Rigid PVC (uPVC, density ~1400 kg/m³) is the most widely used plastic piping material for drainage, water supply, and electrical conduit. It is strong, chemically resistant, inherently flame retardant (from chlorine), and the lowest-cost piping option. Limitations include temperature (max ~60°C for pressure service), brittleness at low temperatures (impact resistance lower than HDPE), and unsuitability for hot water or compressed air. CPVC extends the temperature range to ~90°C for hot water service.

PVC (Polyvinyl Chloride)