PVC: The Workhorse
PVC (polyvinyl chloride) is one of the most produced and most chemically resistant plastics at its price point. It resists most acids, alkalis, salts, alcohols, and aqueous solutions. Naturally flame-retardant and self-extinguishing. The default for chemical tanks, duct systems, and wet lab equipment.
The limitation: continuous service temperature of ~140°F (60°C). Above that, PVC loses structural integrity. For ambient-temperature applications, this is irrelevant. For hot process fluids — that's where CPVC enters.
CPVC: When Temperature Matters
CPVC (chlorinated polyvinyl chloride) is standard PVC with additional chlorination (57% to 63-74% chlorine by weight), raising the service temperature to ~200°F (93°C) — a 60-degree improvement.
CPVC retains PVC's broad chemical resistance. It's slightly more brittle at room temperature and marginally less resistant to aromatic hydrocarbons. Slightly more expensive due to the additional processing.
The decision framework is straightforward: if the application involves hot fluids or process temperatures above 140°F, specify CPVC. If it operates at or below that threshold, PVC delivers the same chemical resistance at lower cost.
Head-to-Head Comparison
Temperature: PVC ~140°F. CPVC ~200°F. For hot process fluids, CPVC is required.
Chemical resistance: Both resist acids, alkalis, salts, aqueous solutions. PVC has a slight edge with aromatic hydrocarbons; CPVC is otherwise equivalent or superior.
Mechanical strength: PVC is slightly tougher at ambient temperatures. CPVC maintains better properties at elevated temperatures.
Machinability: Both machine cleanly. PVC and CPVC cements are NOT interchangeable — PVC cement will not reliably bond CPVC.
Cost: CPVC carries a modest premium. Not justified when PVC's thermal rating is sufficient.
Color: PVC is light gray/white. CPVC is off-white/cream — aids visual identification in mixed systems.
Applications
Chemical storage tanks, acid fume ducts, wet scrubbers, electrical enclosures, laboratory furniture, marine hardware, containment trays, splash panels. Ambient-temperature corrosion resistance.
Hot chemical process lines, hot water distribution, industrial plating equipment, high-temperature fluid handling. Semiconductor and pharmaceutical process equipment where metal contamination isn't acceptable.
Frequently Asked Questions
What temperature can PVC handle?
~140°F (60°C) continuous. Above this it softens and loses structural integrity. For hot fluids, specify CPVC at 200°F (93°C).
Can you use PVC cement on CPVC?
No. Different formulations required. PVC cement on CPVC will not achieve a reliable bond and can fail under pressure or thermal stress. Always use CPVC-rated cement.
Is PVC safe for chemical storage?
Yes — widely used for chemical tanks handling acids, alkalis, salts, and aqueous solutions. Always confirm compatibility for specific chemicals and concentrations.
How do PVC and polypropylene compare?
PVC offers better overall chemical resistance at ambient temperatures and is typically less expensive. Polypropylene has better resistance to certain organic solvents, is lighter, and handles higher temperatures. For most ambient-temperature corrosion work, PVC is more economical.
Where can I buy PVC and CPVC?
Plastic-Craft Products stocks both in sheet, rod, and tube at West Nyack, NY. No minimum orders. Call (845) 358-3010 or email [email protected].
Ready to Order PVC or CPVC?
Plastic-Craft stocks both PVC and CPVC — cut to exact dimensions or fabricated to print with no minimum orders. In-house plastic welding and CNC fabrication.
(845) 358-3010